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+{"book_title": "1001 Inventions That Changed the World", "author": "Various", "genres": ["history", "nonfiction"], "tags": ["science", "pedia"], "chapter_title": "Chapter 1", "text": "To invent is to create something new\u2014something that did not exist before. An invention can be an idea, a principle (such as democracy), a poem, a dance, or a piece of music, but in this book we have restricted ourselves to technological inventions. Technology is the practical application of our understanding of the world to achieve the things we need or want to do. Technology goes beyond \"things\"such as computers or bicycles: it includes techniques and processes, such as the alphabet, numerical systems, and the extraction of metals from their ores."}
+{"book_title": "1001 Inventions That Changed the World", "author": "Various", "genres": ["history", "nonfiction"], "tags": ["science", "pedia"], "chapter_title": "The Ancient World", "text": "The invention of the first stone tools more than 2 million years ago was the moment when humankind started to distinguish itself from all other species on the planet. It took our forebears another 1.2 million years before they found other ingenious ways to use their natural resources\u2014by learning to control fire, build shelter, and make items of clothing. But having gained momentum, the ideas kept coming, and the inventions that followed resulted in full-blown civilizations.\n\n----\n\nStone Tools\n\nInvented: c. 2,600,000 B.C.E.\n\nSummary: Early humankind ushers in the age of inventions.\n\n\u2002\"The best moteriols... include obsidian (a form of natural glass), chert, flint, and chalcedony.\" \u2014Floyd Largent, writer\n\nThe very first human invention consisted of sharp flints, found and used in their natural state by primitive peoples, who then went on to purposely sharpen stones. The practice reaches back to the very dawn of humankind; stone tools found in 1969 in Kenya are estimated to be 2,600,000 years old.\n\nThe principal types of tools, which appeared in the Paleolithic period, and varied in size and appearance, are known as core, flake, and blade tools. The core tools are the largest and most primitive, and were made by working on a fist-sized piece of rock or stone (core) with a similar rock (hammerstone) and knocking large flakes off one side to produce a sharp crest. This was a general-purpose implement used for hacking, pounding, or cutting. Eventually, thinner and sharper core tools were developed, which were more useful. Much later, especially during the last 10,000 years of the Stone Age, other techniques of producing stone artifacts\u2014including pecking, grinding, sawing, and boring\u2014came into play.\n\nThe evolution of tool making enabled early humankind to complete many tasks previously impossible or accomplished only very crudely. Animals could be skinned, defleshed, and the meat divided up with stone cutters, cleavers, and choppers. Clothing was made from animal hides cleaned with rough stone scrapers and later punctured with awls. Hunting became more efficient with spearheads fashioned from stone flakes. And with the aid of stone adzes (axes), early humankind could create shelter and begin to shape the physical world to its liking.\n\nNotes:\n\n- Stone Age humans became adept at chipping flakes of hard, volcanic rocks to make tools and weapons.\n\n----\n\nControlled Fire\n\nInvented: c. 1,420,000 B.C.E.\n\nSummary: Homo erectus harnesses lightning.\n\n\u2002\"Seek wood already touched by fire. It Is not then so very hard to set alight.\" \u2014African proverb\n\nFire is an essentia! tool, control of which helped to start the human race on its path to civilization. The original source of fire was probably lightning, and for generation' blazes ignited in this manner remained the only source of fire.\n\nInitially Peking Man, who lived around 500,000 B.C.E., was believed to be the earliest user of fire, but evidence uncovered in Kenya in 1981, and in South Africa in 1988, suggests that the earliest controlled use of fire by hominids dates from about 1,420,000 years ago. Fires were kept alive permanently because of the difficulty of reigniting them, being allowed to burn by day and damped down at night. Flint struck against pyrites or friction methods were the most widespread methods of producing fire among primitive people.\n\nThe first human beings to control fire used it to keep warm, cook their food, and ward off predators. It also enabled them to survive in regions previously too cold for human habitation. They also used it in \"fire drives\" to force animals or enemies out of hiding. Controlled fire was important in clearing forest for roadways, grasslands for grazing, and agricultural lands\u2014uncontrolled, the fire destroyed the potential of the soil. Mastering fire also opened up the possibilities of smelting metals, enabling humankind to escape the limitations of the Stone Age.\n\n----\n\nBuilt Shelter\n\nInvented: c. 400,000 B.C.E.\n\nSummary: Homo heidelbergensis builds the first hut.\n\n\u2002\"...next to agriculture, shelter is the most necessary to man. One must eat, one must have shelter.\" \u2014Philip Johnson, architect\n\nThe earliest evidence for built shelter appears to have been constructed by Homo heidelbergensis, who lived in Europe between around 800,000 B.C.E. and 200,000 B.C.E. Anthropologists are uncertain whether these were ancestors of Homo sapiens (humans) or Homo neanderthalensis (Neanderthals) or both.\n\nAt the French site of Terra Amata, which dates back around 400,000 years, archeologists have found what they believe to be the foundations of large oval huts. One of these shows evidence of fire in a hearth, although other archeologists postulate that natural processes could be responsible. Archeology on sites from hundreds of thousands of years ago is complicated. Claims of the discovery of built shelters in Japan from more than 500,000 years ago were discredited in 2000. In fact, all evidence for humans in Japan before 35,000 years ago is currently questionable.\n\nWe do know that our ancestors spent time in caves for hundreds of thousands of years. But caves are only found in certain areas. Whether they started building 100,000 or 400,000 years ago, their ability to create shelters close to food, water, and other resources provided our ancestors with protection against the elements and dangerous animals. Living close to work also gave them more time to experiment with different ways of doing things; in other words, time to invent.\n\n----\n\nClothing\n\nInvented: c. 400,000 B.C.E.\n\nSummary: Early humans covertheir nakedness.\n\n\u2002\"Clothes make the man. Naked people have little or no Influence in society.\" \u2014Mark Twain, More Maxims of Mark (1927)\n\nAround 400,000 years ago, Homo sapiens devised a solution to protect the vulnerable naked human body from the environment\u2014clothes. Anthropologists believe the earliest clothing was made from the fur of hunted animals or leaves creatively wrapped around the body to keep out the cold, wind, and rain.\n\nDetermining the date of this invention is difficult, although sewing needles made from animal bone dating from about 30,000 B.C.E. have been found by archeologists. However, genetic analysis of human body lice reveals that they evolved at the same time as clothing. Scientists originally thought the lice evolved 107,000 years ago, but further investigations placed their evolution a few hundred thousand years earlier.\n\nClothing has changed dramatically over the centuries, although its ancient role as an outward indication of the status, wealth, and beliefs of the wearer is as important as ever. During the Industrial Revolution the textile industry was the first to be mechanized, enabling increasingly elaborate designs to be made at a faster rate. In the twenty-first century, mechanization has allowed sophisticated practical clothing to be devised to protect us from dangers such as extreme weather, chemicals, insects, and outer space. Without clothes we would not have been able to explore and exploit our world and the surrounding universe to the extent that we have.\n\n----\n\nSpear\n\nInvented: c. 400,000 B.C.E.\n\nSummary: Humans learn to kill with sharpened poles.\n\nThe earliest example of a sharpened wooden pole, or spear, comes from Schoningen in Germany. There, eight spears were dated to 400,000 B.C.E. The ancient hominid hunters who sharpened each pole used a flint shaver to cut away the tip to form a point and then singed the tip in the fire to harden the wood, making it a more effective weapon. A similar technique was used by hunters in Lehringen near Bremen in Germany, where a complete spear was found embedded inside a mammoth skeleton, suggesting such spears were used mainly for hunting rather than warfare or self-defense. The need for food was so great that a mammoth would be attacked with only a flimsy spear, although its use would have been more to scare the mammoth in the direction of a trap or pit dug previously than to attack it directly.\n\nAround 60,000 B.C.E., Neanderthals living in rock shelters and temporary hunting camps in France sharpened small pieces of flint and slotted them into the tips of their spears. Hunters in the Sahara used sharpened stones in the same way, while Central Americans used obsidian, a natural volcanic glass. Around the world, Stone Age people gradually learned how to work small stones or flints into tiny, sharpened blades known as microliths for use as spear points. The greatest advance, however, came with the development of metalworking, notably copper, in southeast Europe after 5000 B.C.E., followed by bronze, an alloy of copper and tin, around 2300 B.C.E., and then iron a millennium later. These new technologies allowed hunters and warriors to make hard, sharp, effective spear points.\n\n----\n\nFishhook\n\nInvented: c. 35,000 B.C.E.\n\nSummary: Early humans discover how to retain their caught fish.\n\n\u2002\"Opportunities are... everywhere and so you must always let your hook be hanging.\" \u2014Augustine \"Og\" Mandino, writer\n\nThe major problem with dating inventions earlier than the written word is that there are no first-hand accounts documenting their conception or use. Paleoarcheologists have the difficult task of piecing together the prehistory of man based on scraps of physical evidence left behind by our ancient ancestors. The fishhook is one such ingenious conception of early man and is probably more important to the success of humans than most of us would suspect.\n\nThe earliest examples of fishhooks so far found by archeologists date from around 35,000 B.C.E. Appearing well before the advent of metalworking, early fishhooks were fashioned from durable materials of organic origin such as bone, shells, animal horn, and wood. With the addition of a variety of baits on the hook, prehistoric man gained access, previously largely denied, to an easy source of energy loaded with protein and fat. Adding fish to his diet also ensured a healthy intake of essential fatty acids.\n\nOver thousands of years the technology of fishhooks has evolved to optimize prey attraction, retention, and retrieval. The very earliest fishhooks of all are thought to have been made from wood, although, being more perishable than those of bone or shell, very few examples of these primitive hooks have survived. Wood might seem much too buoyant a material to be ideal for catching fish, but actually wooden hooks were used until the 1960s for catching species such as burbot.\n\nGaining easy access to adequate food supplies is thought to have been an essential factor in the success of early man. To fish in fecund waters requires very little energy and time, and this enabled our ancestors to pursue other activities, meaning that they were able, not just to survive, but to prosper.\n\nNotes:\n\n- Prehistoric ivory barbed harpoon hooks show evidence of meticulous carving.\n\n----\n\nTally Stick\n\nInvented: c. 35,000 B.C.E.\n\nSummary: Counting makes its debut in Swaziland.\n\n\u2002\"...with worn-out, worm-eaten rotten bits of wood... a savage mode of keeping accounts.\" \u2014Charles Dickens, novelist\n\nTally sticks, or tallies, are batons of bone, ivory, wood, or stone into which notches are made as a means of recording numbers or even messages. The archeological and historical records are rich in tallies, with the Lebombo bone as the earliest example. Found in a cave in the Lebombo Mountains in Swaziland and made from a baboon's fibula, it dates back to 35,000 B.C.E. Its markings suggest that it is a lunar phase counter, indicating an appreciation of math far beyond simple counting.\n\nTally sticks became the primary accounting tool of medieval Europe, which was largely illiterate. During the 1100s King Henry I of England established the Exchequer to be responsible for the collection and management of revenues. To keep track of taxes owed and paid, split tally sticks were employed. Usually made of squared hazel wood, notches were made the thickness of the palm of the hand to represent \u00a31000, the thickness of a thumb for \u00a3100, a little finger for \u00a310, a swollen barley grain for \u00a31, and a thin score mark for a shilling. The notches would span the stick's width, which subsequently would be split so that both halves had the same markings, to avoid forgeries. The halves differed in length; the longer half, or stock, was for the person making the payment, hence \"stockholder,\" and the shorter half, or foif for the recipient of the money orgoods.\n\n----\n\nDrill\n\nInvented: c. 35,000 B.C.E.\n\nSummary: Early humans learn howto bore small holes.\n\nIt is thought that early man used a primitive drill\u2014 perhaps a modified spear\u2014to pierce wood and animal skins. Much later, the woodworkers of ancient Egypt refined this technique by making any necessary holes with a bow drill. Adapted from the fire-stick, it had a cord wrapped round it and was held taut with a bow. Holding the drill vertically, the operator moved the bow backward and forward, pressing downward on alternate turns, with an idle return stroke. (There is also evidence of dental drilling from as long ago as 9000 B.C.E., accomplished by the same means.) The Romans replaced the bow drill with the auger, but the bit froze between turns. It was not until the Middle Ages that use of the carpenter's brace made continuous rotation of the drill possible.\n\nThe term \"drill\" may either refer to the machine supplying the rotational energy needed for penetration, or to the \"drill bit,\" which is the part that rotates and actually cuts into the material. Various kinds of drills have evolved to meet specific needs.\n\nAny drill has the capacity to make small holes in wood or brick, but more powerful machines are required to create pipe-sized holes in masonry or metal. Modern drills include a chuck to grip the drill bits or simple attachments. Some drills have chucks that can be unscrewed in order to receive larger attachments, such as sanding tools, wire brushes, grinding stones, and circular saws.\n\nThe tip of a drill bit is conical in shape with cutting edges. The fluted part, or body, of a drill is now usually made of hardened, high-carbon steel. The angle formed by the tapering sides of the point determines how large a chip is taken off with each rotation. The bit also has helical flutes, which affect the drill's cutting and chip-removal properties.\n\n----\n\nSharp Stone Blade\n\nInvented: c. 30,000 B.C.E.\n\nSummary: Stone Age humans progress to sharpening their tools and weapons.\n\n\u2002\"Regardless of our ancestral heritage, we're all descended from fllntknappers.\" \u2014Bert Mathews, sharp stone maker\n\nThe use of stone instruments more than two million years ago heralded what we call the Stone Age and the very origins of humankind. While it is impossible to date when distinctly worked (rather than simply found) stone blades first appeared in the world, it seems to have occurred circa 30,000 B.C.E.\n\nThe technique that evolved to create sharp stones is now called lithic reduction. This involves the use of an implement (made of stone itself or of wood or bone) to strike a stone block in order to break off flakes. Such flakes will be naturally sharp and can be turned into a range of useful tools and weapons such as scrapers, scythes, knives, arrow heads, or spear points. Some early toolmakers may also have used what was left of the stone block to make axe heads.\n\nVarious kinds of stone were used to make blades, although one of the most popular was flint\u2014leading to the term \"flintknapper\" to describe anyone making stone blades by lithic reduction. As the techniques of flintknapping developed, particularly the use of repetitive blows at particular angles, the craftsmen were able to gain much greater control over the size, sharpness, and type of blade.\n\nThe period after the end of the last Ice Age, 10,000 years ago, was characterized by increasingly sophisticated stone tools with multiple uses. Other tools were produced using blades made by knapped flint or obsidian, a type of naturally occurring glass. Small, sharp blades, known as microliths, became part of wooden cutting implements for use in farming, as well as barbs on arrows and spears, making them particularly effective as hunting weapons.\n\n----\n\nSewing\n\nInvented: c. 25,000 B.C.E.\n\nSummary: Clothing is fitted using needle and thread.\n\nThe history of sewing is closely allied to the history of tools. The earliest needles ever discovered date from the Paleolithic era (the early Stone Age), around 25,000 B.C.E. Key finds from that period include needles in southwest France and near Moscow in Russia. These were made of ivory or bone, with an eyelet gouged out. Some have been found alongside the remains of foxes and hares that were used for their fur.\n\nSewing gave our early ancestors the opportunity to make clothing more closely tailored to the human body, improving its insulation and comfort, as well as inviting decoration. Early scraps of cloth found in France and Switzerland have included decorative seeds or animal teeth sewn on by thread, applied perhaps with the aid of fishbones or thorns. Native Americans sewed with the tips of agave leaves.\n\nMetal needles were developed in the Bronze Age (2000-800 B.C.E.) and initially were made of several strands of wire melted together. Needles from this era have been found in North Africa and China, where steel was introduced. The first known stitched buttonhole dates from 4200 B.C.E.\n\nEmbroidery\u2014complex, decorative needlework\u2014 appeared in Bronze Age Egypt and India. In China silk was being sewn and embroidered in the same era. Protective thimbles have been used since Roman times. The famous Bayeux Tapestry, depicting the Norman invasion of England, is an example of crewelwork, a form of embroidery with loosely twisted yarn. At least four types of stitch have been identified in the tapestry. Later, the mechanization of textile production began in the sixteenth century with the stocking frame, which led to automated looms. Elandstitching was transformed from the 1830s onward by the arrival of the sewing machine.\n\n----\n\nAtlatl\n\nInvented: c. 23,000 B.C.E.\n\nSummary: Early humans extend spear-throwing range.\n\n\u2002\"The atlatl is the tool ancient peoples used to 'bring home the bacon.'\" \u2014Robert \"Atlatl Bob\" Perkins, primitive technologist\n\nWhen Spaniards first met the Aztecs in around 1500, the explorers were horrified when their armor was easily penetrated by the Aztec throwing darts. The Aztecs achieved this feat with the atlatl, a simple device used by many ancient peoples for long-range hunting. It probably dates from around 23,000 B.C.E.\n\nThe atlatl consists of a throwing board and a dart about 6 feet (180 cm) long. The board, typically about 2 feet (60 cm) long, has a spur at its end. The dart's rear is cut down the middle so that it fits onto the spur like two fingers around a card.\n\nGripping a handle at the front end of the throwing board, the atlatl thrower can hurl the dart with considerably more force than he could by hand.\n\nDuring the thrower's tennis swing-like motion, the flexible dart flexes and energy builds up. The dart is weighted with a stone tip and often another counterweightto maximize the buildup of energy.\n\nWhen the atlatl dart is released, the spring energy in the flexible dart is added to the forward force, accelerating the dart to speeds that can exceed 100 miles per hour (160 km/h). The atlatl was so effective at bringing down prey that some scholars speculate it may have played a significant role in the extinction of the North American woolly mammoth. Now, at least 25,000 years after its invention, the atlatl is still used by enthusiastic hobbyists.\n\n----\n\nBow and Arrow\n\nInvented: c. 20,000 B.C.E.\n\nSummary: Distant targets come within deadly reach for the first time.\n\n\u2002Whose arrows are sharp, and all their bows bent, their horses' hoofs shall be counted like flint.. \u2014Isaiah 5:28\n\nEvidence of the early use of bows and arrows has been found in cave paintings in Western Europe and North Africa. Its development probably arose in the Upper Paleolithic (Old Stone Age) around 20,000 B.C.E., when people realized that the weapon would enable hunters to kill outside theirthrowing range.\n\nBows and arrows were portable, easy to make, and the materials to make them were relatively easy to obtain. The bow consisted of a thin flexible shaft of wood; this was bent, and a length of sinew, deer gut, plant fiber, or rawhide was strung tightly between its ends. Sometimes the bowstring was twisted to make it stronger. Ash, mahogany, and yew were all used for bows. Sometimes the wood was backed with sinew to make the bow stronger and stop it breaking.\n\nThe arrow was a thin shaft of wood, sharpened at one end, with feathers attached to the other to give it aerodynamic stability. Arrowheads were made from flint or other rocks, antler, or bone.\n\nThe bow was the first machine that stored energy. Energy from the archer's muscles gradually transferred to the bow as it was drawn back; when the bow was released, it gave the projected arrow a far greater velocity than that produced by a spear-thrower. In about 1500 B.C.E. a shorter and lighter bow Was developed, the composite bow. Short and curved, it was built up from layers of materials that reacted differently under tension or compression. It was an accurate weapon to use from horseback.\n\nModern bows are made from fiberglass, carbon, and aluminum as well as wood, while the arrows are usually made of composite materials.\n\n----\n\nBoomerang\n\nInvented: c. 18,000 B.C.E.\n\nSummary: The advent of an easily retrievable weapon.\n\nThe oldest boomerang so far found was discovered in a cave in the Carpathian Mountains in southern Poland and is believed to be date from 18,000 B.C.E. The practice of throwing wood has also been illustrated in North African rock paintings that date from the Neolithic Age (approximately 6000 B.C.E.). The wood thrown consists variously of a \"throwing club,\" where the effect is concentrated at one end, or a \"throwing stick,\" a sharpened, straight rod of hard wood that rotates, or a boomerang, which developed from these into a specialized form and has a return throw.\n\nAncient tribes in Europe are said to have used a throwing axe; in Egypt a special type of curved stick was used by the Pharaohs for hunting birds. The use of throwing woods is thought to have spread throughout North Africa from Egypt to the Atlantic.\n\nBoomerangs are most commonly associated with Australian Aborigines. They have been made in various shapes and sizes depending on their geographic origins and intended function. In the past they have been used as hunting weapons, musical instruments, battle clubs, and recreational toys. The most recognizable type is the returning boomerang. Some have \"turbulators\" (bumps or pits on the top surface) to make the flight more predictable. A returning boomerang is an airfoil and its rapid spin makes it fly in a curve rather than a straight line.\n\nOther types of boomerang are of the nonreturning sort, and some were not thrown at all but were used in hand-to-hand combat by Aboriginal people. The throwing wood, however, was mainly used for hunting ratherthan as a battle weapon.\n\n----\n\nBraided Rope\n\nInvented: c. 17,000 B.C.E.\n\nSummary: Fibers are twisted into a valuable tool.\n\n\u2002\"There are nearly as many types of rope as there are fibrous materials on Earth.\" \u2014Brendan McGuigan, writer\n\nOne of the oldest artifacts in the world, rope is still extensively used in many environments. It seems unlikely that it will be replaced for many years. Traditionally made from natural fibers such as hemp, jute, or coir, rope is now also made from synthetic materials such as nylon and even steel.\n\nRope is braided fiber, twisted to form a supple, strong medium. Its strength is tensile, so its main use is to link objects, one of which acts as a stable anchor for the others to hang from or pull against. The oldest evidence of man-made rope was found in the caves of Lascaux, southwest France, and date from 17,000 B.C.E. Rope has always been used to tie and carry prey, making it an essential hunting tool.\n\nBefore machinery made it possible to create long lengths of rope, essential in sailing ships, weaving fibers was done by hand\u2014an arduous process. The ancient Egyptians developed the first tools for weaving rope, which they used to move huge stones. Machines for spinning long lengths of rope were later housed in buildings called cake-walks, or roperies, which could be up to 300 yards (275 m) long. A prime example of such a ropery exists in the former naval dockyard in Chatham, England, where rope is still produced on the premises after nearly 300 years. This ropery, 440 yards (400 m) long, was built in 1720 and at that time was the longest building in England.\n\n----\n\nLunar Calendar\n\nInvented: c. 15,000 B.C.E.\n\nSummary: Early humans record the passing of time.\n\n\u2002\"Day is pushed out by day and each new moon hastens to its death..\" \u2014Horace, Odes, Book II\n\nThe earliest known lunar calendar is in the caves at Lascaux, southwest France, and dates from around 15,000 B.C.E. Various series of spots represent half of the moon's near-monthly cycle, followed by a large empty square, which perhaps indicates a clear sky.\n\nA lunar calendar counts months (a period of 29.530588 days) and is based on the phases of the moon. Months have twenty-nine and thirty days alternately, and additional days are added every now and then to keep step with the actual moon phase.\n\nThe lunar calendar was widely used in parts of the ancient world for religious observation. Agriculturally the lunar calendar is confusing as it takes no account of annual seasonal variations in temperature, daylight length, plant growth, animal migration, and mating. The lunar month divides into the solar year twelve times but with 10.88 days remaining.\n\nMeton of Athens (circa 440 B.C.E.) noticed that nineteen solar years were equal to 234.997 lunar months. This led to the nineteen-year Metonic cycle where years three, five, eight, eleven, thirteen, sixteen, and nineteen had thirteen lunar months each, and all the otheryears had twelve months.\n\n----\n\nAlcoholic Drink\n\nInvented: c. 10,000 B.C.E.\n\nSummary: A pleasurable beverage appears.\n\nThe accidental fermentation of a mixture of water and fruit in sunlight is thought to have led to the first discovery of an alcoholic drink by a prehistoric people. Evidence of intentionally fermented beverages exists in the form of Stone Age beer jugs dated as early as the Neolithic period (10,000 B.C.E.). Other jugs have been excavated in Southwest Asia and North Africa.\n\nAlcoholic beverages have been an integral part of many cultures, used as a source of nutrition, in meals, for celebrations, and also in religious ceremonies. Alcohol can give a sense of wellbeing, but also acts as a depressant, lowering behavioral inhibitions.\n\nAlcohol consumption became a status symbol for the wealthy. During the Middle Ages, concoctions were distilled to produce spirits. Alcohol has also served as a thirst quencher when water was polluted. In the 1700s, home-brewing processes were replaced by commercially made beer and wine, which became important for the economies of Europe.\n\nBeer was the first known alcoholic beverage, but many others have been produced since then. The Chinese are thought to have produced yellow wine 4,000 years ago. In Europe the monasteries owned the best vineyards: French monks produced a sparkling wine, which was named after the Champagne region of France. Brandy is supposed to have been accidentally discovered when a Dutch trader tried boiling wine \"to remove the water and save cargo space.\" (Brandewijn means \"burnt wine\" in Dutch.)\n\nAttitudes to alcohol consumption have varied over time and different countries have limited the hours when drinking establishments are open, or even banned the sale of alcohol altogether, as Americans did in the Prohibition, between 1920 and 1933.\n\n----\n\nPottery\n\nInvented: c. 10,000 B.C.E.\n\nSummary: Japanese hunter-gatherers create the first fired clay pots.\n\n\u2002\"Vases and shards... the true alphabet of archeologists in every country.\" \u2014Sir William Flinders Petrie, archeologist\n\nAs applies to all early inventions, we do not know the name of the man or woman who invented pottery. No first potter carved his or her name or initials in the base of a pot to claim first prize. However, it has long been assumed that whoever the creative person was, he or she would have lived somewhere in the Near East of Asia. It was therefore something of an archeological shock when, in the 1960s, pots dating to around 10,000 B.C.E. were discovered on the Far Eastern side of Asia, thousands of miles away at Nasunahara on the island of Kyusu in Japan. These pots, found in caves, were made by nomadic hunter-gatherers, rather than settled farmers or urban dwellers. Just as important, the pots were made by firing or heating the. clay to harden it, suggesting that these people had knowledge of advanced technologies.\n\nThe significance of the first Japanese pots is that they predate the first pots made in the Near East by around 1,000 years. Those pots, found in Iran, were made by drying the clay in the sun in order to harden it, a far more primitive technology than firing the clay.\n\nThe Japanese pots have a round base and widen gently to a ridged top and a rounded, incised rim. They are known as Incipient Jomon, because they are the forerunners of the jomon or \"cord-marked\" vessels developed in Japan around 9000 B.C.E. These later pots had pointed bases and were made by building up coils of clay into the desired shape. The patterns of the cord-marked pots were often quite complex, suggesting that they were intended for ritual or funerary use rather than for such everyday uses as cooking and storage.\n\n----\n\nOil Lamp\n\nInvented: c. 10,000 B.C.E.\n\nSummary: Night is banished forever by a burning lump of fat.\n\n\u2002\"I gave illuminating oil for lighting the lamps of your temple.\" \u2014Inscription of Nesuhor (589-570 B.C.E.)\n\nThe humble oil lamp may only be needed to provide light during the occasional power cut today, but for thousands of years versions of it allowed man to see by night, as well as provide decoration and symbolic power in ceremonies and festivals. Only with the invention of the Argand Lamp in 1780, and eventually electric lighting, were oil lamps all but extinguished.\n\nEstimates suggest that crude lamps were first used around 80,000 B.C.E. A lamp is a vessel containing flammable oil with a slow-burning wick designed to draw up the fuel from the reserve. Early man made lamps from stone or seashell crucibles filled with animal fat, with a piece of vegetation as the wick.\n\nThe first real oil lamp appeared alongside settled agriculture around 10,000 B.C.E. (the Upper Paleolithic period\u2014otherwise known as the Stone Age). With the planting of the first crops came the potential for plant oils, such as olive oil, to be used in these lamps. As well as a source of light, they were important symbols in rituals and ceremonies\u2014the Bible and Koran both contain many references.\n\nThe Romans mass-produced clay lamps (a newly made batch was discovered buried in Pompeii by the great eruption of 79 C.E.). In the Middle Ages candles became popular, but these never produced a flame as bright as an oil lamp. Elowever, in the eighteenth century the Industrial Revolution provided the pressure necessary for innovation. In 1780 the scientist Aime Argand developed a brighter lamp with a metal casing that burned oil with a steady, smokeless flame, but with the advent of electric lighting a civilization-old technology was finally laid to rest.\n\n----\n\nSling\n\nInvented: c. 10,000 B.C.E.\n\nSummary: Stones are put to a lethal purpose.\n\n\u2002\"David defeated Goliath with a sling and a rock. He killed him without even using a sword.\" \u2014Samuel 17:50\n\nThe sling is a prehistoric weapon probably dating back more than 10,000 years. The oldest known surviving slings were found in Tutankhamen's tomb, dating from 1325 B.C.E. And of course slings feature in the Bible, most famously in the story of David and Goliath.\n\nA sling is used to throw a missile many times farther than is possible with the human arm alone. It consists of a cradle, or pouch, in between two lengths of cord. A stone is placed in the pouch. Both cords are held in the hand, and the thrower draws back his arm and swings the sling up and forward. One of the two cords is released and the stone is projected away.\n\nAs a weapon, the sling was a great success, being cheap to make, light to carry, easy to use, and relying on ammunition that was readily available. Not surprisingly, it became common all over the ancient world, except Australia where spears seem to have been preferred. A slingstone can be thrown by an expert up to 650 yards (600 m), farther than most bows could achieve, though with less accuracy. The Greeks and Romans introduced lead shot as an option for ammunition, although stones remained most popular. By the Middle Ages the sling had largely given way to more sophisticated weaponry.\n\n----\n\nGranary\n\nInvented: c. 9500 B.C.E.\n\nSummary: Early farmers build thefirst grain storage.\n\nThe world's first purpose-built granary was unearthed by Ian Kuijt, Associate Professor of Anthropology at the University of Notre Dame, Indiana, at Dhra' on a parched plateau next to the Dead Sea in the Jordan Valley. The structure, roughly 9 feet (2.9 m) square, was found about 2 feet (0.6 m) underground.\n\nThe granary is smallerthan other nearby structures that appear to have been houses, an indication of its different use. Interestingly, the structure has two levels, an architectural feature never seen before in buildings of this age. Its significance as the world's first granary is that it belongs to one of the world's first settled farming communities, built just as people began to live in one place all year round rather than wandering from place to place in search of their food. In other words, it marks the time when early people were making the historic transition from huntergatherers to settled farmers.\n\nThe granary enabled people to store wheat and barley grains, nuts, and other produce harvested in the summer to see them through the winter months, or indeed through an unproductive summer. With food in storage, and thus constant supply, the population could rise, in turn spurring technological advances in agriculture and other occupations.\n\nThere were, of course, downsides to this development, as the first farmers concentrated on a reduced variety of crops, unbalancing their diets in comparison to the wide range of food foraged by their ancestors. The first farmers of Dhra' probably did little more than weed and water the crops that were already there, but they were helped by the fact that, at that time, the plateau they farmed was far wetter than it is now, giving them a wider variety of crops to tend than can grow in the region today.\n\n----\n\nMetalworking\n\nInvented: c. 8700 B.C.E.\n\nSummary: Mesopotamiansfashion objects from metals.\n\n\u2002\"Iron weapons revolutionized warfare and iron implements did the same for farming.\" \u2014Alan W. Cramb, Professor of Engineering\n\nThe use of metals to make tools, weapons, or jewelry has been one of humanity's pivotal achievements. Manipulated metals are everywhere, from kitchen utensils to high-tech weapons and tools. Even items that contain no metal are likely to owe some debt to a metal tool that was used in their construction.\n\nAs near as archeologists can tell, the love affair between humans and metals probably began around 8700 B.C.E., evidenced by a copper pendant found in northern Iraq. Smelting, the extraction of metal from a metal-containing rock, began around 5000 B.C.E. when copper ores were melted to get at the metal. By 4000 B.C.E. people were using gold and adding arsenic to copper to create arsenical bronze, probably the first man-made alloy, or metal mixture. Although harder than copper, arsenical bronze took a heavy toll. Metalworking gods of several cultures are described as lame, probably the result of their long exposure to the valued but unfortunately poisonous metal.\n\nAround 3500 B.C.E., tin and copper were combined to make bronze. Trade spread the hot new trend and people made bronze weapons, armor, decorations, and tools. The Bronze Age gradually came to an end as trade dwindled and tin became hard to come by. Iron and the Iron Age were the replacement. Centuries later, people mixed small amounts of carbon with their iron to make steel.\n\n----\n\nDugout Canoe\n\nInvented: c. 7500 B.C.E.\n\nSummary: Hollowed-out logs become the first boats.\n\n\u2002\"The ancient Greeks used dugouts and called them monooxylon, which means 'single tree.'\" \u2014John Crandall, Dugout Canoes\n\nSometimes there is no real need to be clever, or complex, or even particularly sophisticated when it comes to inventions. Sometimes simple wins.\n\nThis is definitely the case with the dugout canoe. The people of 7500 B.C.E. needed a way to travel on water, but many of the materials used in the very earliest boatbuilding still lay a long way ahead in the future. So they came up with a simple answer using the technology that was accessible to them.\n\nThe dugout canoe is, in its most basic terms, a hollowed-out log, nothing more than a tree trunk laid down on its side and its interior removed. All that was required was that the hollowed log had to be big enough for at least one person to sit inside, and the wood had to be sound, not rotten. If a log fulfilled these two criteria, it was a potential canoe.\n\nAs these vessels were made before the invention of metal tools, the logs were hollowed out using a controlled fire and a sharpened rock implement (known as an adze) to scrape away the burned wood. Then, to reduce drag in the water, the front and the back of the log were fashioned into a point.\n\nDugout canoes have been excavated in various locations in northern Europe and are the oldest form of boat ever discovered. Before their arrival there were no other forms of water travel in existence\u2014only swimming and clinging to driftwood.\n\n----\n\nChisel\n\nInvented: c. 7500 B.C.E.\n\nSummary: The chisel becomes a standard building tool.\n\n\u2002\"Ancient masons... could carve marble at more than double the speed of today's craftsmen.\" \u2014Evan Hadingon, Smithsonian magazine\n\nChisel-like tools have been dated to the Paleolithic era, which stretches across a vast expanse of evolutionary time, from before the first Homo sapiens to roughly 10,000 B.C.E. During this time humans were making and refining stone tools, which became gradually more specialized over time. Other materials were also used, and bone chisels from around 30,000 B.C.E. have been uncovered in Southern France, near the village of Aurignac. Although very difficult to date exactly, it is thought that by about 7500 B.C.E., what we would recognize today as a chisel was in fairly common use.\n\nBy the time of the Bronze Age, chisels had become quite varied and included gouges\u2014chisels with curved blades\u2014and tanged chisels, where the blade is connected to the handle by a collar. The Greek architect Manolis Korres believes the chisels used by the ancient Greeks were actually sharper and sturdier than today's versions. While working on restoring the Parthenon, Korres made reconstructions of various ancient tools by looking at tool marks in marble. Of course, the ancient Greeks needed specialized tools to craft their iconic temple in Acropolis..\n\nDuring the medieval period, carpenters employed tools known as \"former\" chisels. These had a broad, flared blade, which was used to carve rough wood. A mallet could be used with stouter tools, called \"firmer\" chisels, to shape and finish wood. There were also other chisels for detailed and speciality work.\n\nThe chisel has changed little since medieval times, although you will probably find a less impressive selection of tools in a modern DIY store than you would have in a medieval carpenter's workshop.\n\n----\n\nDried Brick\n\nInvented: c. 7500 B.C.E.\n\nSummary: Humankind builds with portable mud blocks.\n\nBuildings erected using preformed, shaped bricks of dried mud date back to around 7500 B.C.E. Examples have been found by archeologists in Cayonu in the upper Tigris Valley and close to Diyarbakir in southeast Anatolia, both in modern-day Turkey.\n\nMore recent bricks, dating from between 7000 and 6400 B.C.E., have been found in Jericho in the Jordan Valley and in C^atalhoyuk, again in Turkey. These early bricks were made of mud molded by hand and then left out to dry and harden in the sun. The bricks were then laid into walls using a simple mud mortar. Mud is an exceptionally good material for building in dry climates: it is readily available wherever agriculture is practiced, it may be dug from riverbeds, and it has good structural and thermal qualities.\n\nSome years later, mud bricks were shaped in wooden molds, enabling a form of organized mass production to take place. This became important, as bricks were increasingly used to build not only small-scale houses, farms, granaries, and other farm structures, but whole villages and later towns and cities, including their large palaces, temples, and other state and public buildings.\n\nWherever stone was unavailable, or in short supply, the humble mud brick took its place. Mud bricks were used throughout the Near East, as well as by the civilizations of Egypt and the Indus Valley, where the bricks were standardized in size, in the ratio of four units long to two units wide and one unit deep. This simple but effective building material was paramount until the first kiln-fired bricks were developed in Mesopotamia during the third millennium B.C.E.\n\n----\n\nSledge\n\nInvented: c. 7000 B.C.E.\n\nSummary: Arctic peoples invent the ice-traveling vehicle.\n\nLong before the snowmobile, our ancestors found an environmentally friendly way to get around in the snow\u2014the sledge. In fact, the sledge (and variations on its theme) was key in many areas of ancient life.\n\nA sled is a vehicle that moves by sliding across the ground. Sleighs are horse-drawn vehicles, with passenger seating. Sledges tend to be large vehicles consisting of a wooden base mounted on smooth runners, useful for transporting large objects. Evidence of wooden sledge usage reaches back to 7000 B.C.E., to peoples living in the Arctic regions of northern Europe. Initially sledges may have been pulled by humans, but with time dogs and oxen were commandeered to take the strain. Inuits have used dog-sleds since pre-Columbian times. Sledge use has extended to hotter climates, too, including the dry, dusty lands of Mesopotamia.\n\nExactly where and when the sledge was developed is unknown, but it is likely that it was developed independently by different communities in the world Human-pulled sledges were key in man's early expeditions to the Arctic and Antarctic. In the twentieth century, dog teams of Huskies were used to tow sleds on expeditions. More recently, kites have been used to tow sleds. They use wind power, so fewer resources need be carried on the sledges.\n\nIn today's world the sledge is used in sport and leisure. A small sled with rounded edges at the front can provide hours of fun in the form of a toboggan. Bobsledding is a sport featuring in the Winter Olympics, where teams of competitors race down tracks in a specially streamlined vehicle.\n\n----\n\nFort\n\nInvented: c. 7000 B.C.E.\n\nSummary: The debut of strong, communal defenses.\n\nDefenses have been constructed for thousands of years. Bronze and Iron Age hillforts took advantage of natural hills for defense purposes, and the Romans built the Saxon Shore Forts along the southeast coast of Britain to deter invasion.\n\nThe word fort is derived from the Latin forth meaning \"strong\" and many military installations are known as forts. The term fortification also refers to improving other defenses such as city walls. Permanent fortifications were built of enduring materials, but field fortifications needed little preparation, using earth, timber, or sandbags.\n\nThe arrival of cannons in the fourteenth century made medieval fortifications obsolete. Later constructions included ditches and earth ramparts to absorb the energy of cannon fire. Explosive shells in the nineteenth century led to a further evolution; the profile of the fort became lower, surrounded by an open sloping area that eliminated cover for the enemy. The fort's entry point was a gatehouse in the inner face of the ditch, with access via a bridge that could be withdrawn. Most of the fort was built underground, with passages connecting blockhouses and firing points. Guns mounted in open emplacements were protected by heavy parapets. Offensive and defensive tactics became focused on mobility. In the twentieth century defending tanks were concentrated in mobile units behind the line. If an offensive was launched, reinforcements could be sent to that area.\n\nReinforced concrete fortifications were common during the nineteenth and early twentieth centuries, but modern warfare has made large-scale fortifications obsolete; now, only deep underground bunkers provide sufficient protection. Today, forts mostly survive as populartourist destinations.\n\n----\n\nTravois\n\nInvented: c. 7000 B.C.E.\n\nSummary: Native Americans invent a carrying device.\n\n\u2002\"What is life? It is a flash of a firefly in the night. It is the breath of a buffalo in the wintertime..!' \u2014Crowfoot, chief of the Blackfoot First Nation\n\nNative Americans on the Great Plains led nomadic lives. They used buffalo for almost everything, eating their meat and making clothes and tent coverings from their skins. Living on herds of animals that were always on the move, they were constantly on the move too, which meant living in tents and owning only what could be carried to the next camp.\n\nIdeally, however, people like to carry more than can fit into one bag. On roadways and hard ground, carts are the best solution, and in the far north snow and ice lie on the ground and dragging a sled is easy because the ground is slippery. Traveling across soft soil, however, neither of these options work. The response of the Native Americans was to invent the travois.\n\nThe travois was a tall wooden \"A,\" 6.5 feet (2 m) high, where the things to be carried sit on the crossbar and the whole thing is dragged along on the splayed poles. The dragging ends move along quietly and with little friction. Before the Spanish arrived and introduced horses into the New World, dogs were used; harnessed to the travois, they could drag up to 66 pounds (30 kg). For the horse, the travois was scaled up and carried bigger loads. Occasionally Native Americans used the travois to carry their sick or elderly, either pulled by a horse or by multiple dogs. Boy Scouts continue to be taught to use the travois for dragging wounded comrades to this day.\n\n----\n\nShoe\n\nInvented: c. 7000 B.C.E.\n\nSummary: Native Americans insulate human feetfrom the round.\n\n\u2002\"It is the same to him who wears a shoe, as if the whole Earth were covered with leather.\" \u2014Persian proverb\n\nFrom their earliest use, simply as a protective covering for the feet, to the vast fashion industry producing them today, shoes have been essential items for humans. As with any invention from antiquity, it is uncertain - when shoes were first worn, and archeological evidence has continued to complicate the issue. The oldest shoes in existence are from around 7000 B.C.E. and were discovered in America.\n\nThe earliest shoes appear to have been constructed variously from rope, leaves, and animal skins. As these are all highly perishable materials, archeological examples are rare, but some argue that there is other evidence pointing to shoe use from up to 40,000 years ago. Archeologists examining ancient bones have noticed a reduction in the size and strength of toe bones during this period, which they attribute to the feet being covered. However, this conclusion isfarfrom proved.\n\nThe original design for most shoes is similar to that of the modern sandal, and consisted of a protective sole held onto the foot by bands or straps. While our need for shoes may seem obvious, their invention was a major development in the ability of humans to travel, work, and endure harsh conditions.\n\nAn etiquette regarding shoes has developed in many parts of the world. In large parts of Asia it is customary for people to remove their shoes when entering a home; this practice has spread to North America and Europe in many homes. In Asia, indoor shoes are often provided by hosts, but this is less common elsewhere. Muslims invariably remove their shoes before entering a mosque.\n\n----\n\nWoven Cloth\n\nInvented: c. 6500 B.C.E.\n\nSummary: Clothes making is revolutionized by the world's first weavers.\n\nThe first handmade material that humans created to make into clothing was felt, which was made by intermeshing animal fibers under heat and pressure. Felt lacked the necessary durability, however, and the real textile breakthrough came later with weaving.\n\nWeaving is accomplished with a loom, a frame that holds vertical threads taut while the weaver interlaces a horizontal thread. The thread itself is obtained through spinning, in which animal or plant fibers are twisted together by hand or machine.\n\nThe earliest evidence of weaving was discovered in 1962, in the town of (^atalhoyuk, Turkey. A piece of carbonized cloth, it was found to date from 6500 B.C.E. It is unclear whether the cloth was made from flax (a wild Mediterranean plant) or from sheep's wool. A more recent piece of linen, dating from 5000 B.C.E. and woven from flax, was discovered in Egypt prior to this find, and it seemed likely that the Turkish cloth was made from the same material. Flax experts disagreed, however, stating that the plant was not found in this region of Turkey at that time. Wool experts concurred after discovering that the cloth is scaly; flax cloth is smooth, so they concluded that the Turkish cloth must have been made of wool. The issue was finally resolved after the cloth was dipped in an alkali solution. This would have destroyed wool, but instead it removed the cloth's black coloring to reveal a network of cross-striations consistent with flax.\n\nIt was shortly after weaving with flax that textiles made from wool and silk became available. The breakthrough led to a variety of textile products, including warmerand more durable clothing.\n\n----\n\nMap\n\nInvented: c. 6500 B.C.E.\n\nSummary: Charting of the world begins with the Babylonians.\n\nSome of the earliest known examples of maps\u2014in the form of Babylonian tablets\u2014are Egyptian land drawings and paintings discovered in early tombs. However, in 1961 a town plan of Catalhoyuk in Turkey was unearthed, painted on a wall. Featuring houses and the peak of a volcano, it is around 8,500 years old.\n\nThe sixth-century tablet known as Imago Mundi shows Babylon on the Euphrates, with cities on a circular land mass, surrounded by a river. Some maps are known as T and 0 maps. In one, illustrating the inhabited world in Roman times, T represents the Mediterranean, dividing the continents, Asia, Europe, and Africa, and 0 is the surrounding Ocean. The T and 0 Hereford Mappa Mundi of 1300, drawn on a single sheet of vellum, includes writing in black ink and water painted green, with the Red Sea colored red.\n\nGreek scholars developed a spherical Earth theory using astronomical observations, and in 350 B.C.E. Aristotle produced arguments to justify this practice.\n\nIn the first century C.E., Ptolemy, an astronomer and mathematician, developed a reference-line principle. His Guide to Geography lists 8,000 locations with their approximate latitudes and longitudes. However, Ptolemy underestimated the size of the Earth. His suggestion that India could be reached by traveling westward resulted in Columbus underestimating the distance centuries later. Cartography greatly benefited from a wealth of corrective information brought to Europe by Marco Polo in the thirteenth century.\n\nThe 1891 International Geographical Congress established specifications for a scale map of the world, and World Wars I and II brought more progress.\n\n----\n\nWattle and Daub\n\nInvented: c. 6000 B.C.E.\n\nSummary: Building begins with wood and mud.\n\n\u2002\"...developed when on enterprising human first daubed mud upon a branch shelter...\" \u2014Joseph F. Kennedy, The Art of Natural Building\n\nThe technique of wattle and daub was first pioneered by human civilizations as early as 6000 B.C.E. as a way of weatherproofing their shelters. In its essence, wattle and daub is a way of filling in the gaps between the structural elements of wooden houses.\n\nIn a typical Tudor example, oak staves were placed vertically between structural beams and then thin twigs of a flexible hardwood, such as willow or hazel, were woven horizontally between the staves, creating a robust mesh, or \"wattle.\" The wattle was then coated with daub\u2014a mixture of clay or mud and animal dung, strengthened with straw or horsehair. This mixture was pressed onto the wattle by hand. The mud and dung helped the daub adhere to the wattle, and the fiber content prevented cracks from forming. The finished wall was sometimes burned to make it hard, like pottery, or coated with lime to make it more weatherproof. This resulted in a strong wall that kept out the wind and rain, the cold in the winter, and the heat in the summer.\n\nWattle and daub walls did have their disadvantages, however. If they became damp, they had a tendency to rot or become beetle-infested. And the term \"breaking and entering\" is thought to have originated from the ease with which criminals could enter such a building, simply by breaking through the wall.\n\n----\n\nIrrigation\n\nInvented: c. 6000 B.C.E.\n\nSummary: Sumerians pioneer watering channels.\n\nIt is unknown who first irrigated his crops with water brought specially from a nearby river, but archeological evidence suggests that, wherever farming began to take place, irrigation soon followed. There is evidence of irrigation from around 6000 B.C.E. in Sumer in Mesopotamia, and also on ancient Egyptian farms near the Nile. Some 2,000 years later, irrigation occurred in Geokysur in South Russia, and in the Zana Valley in the Andes Mountains of Peru. By 3000 B.C.E. the the same techniques were used by the Indus Valley Civilization in what is now Pakistan.\n\nWhen, at around 6000 B.C.E., the first farmers in Mesopotamia planted their crops of barley, wheat, and other plants near the Tigris or Euphrates rivers, they relied on rain, the occasional flood, and the ability of the soil to hold water to ensure that their crops grew from seed to harvest. Water could be carried in buckets from the river, but if the rain stopped and there was a lengthy drought, the crops would die.\n\nThe problem of over-reliance on natural water supplies was solved by creating artificial means of bringing the water to the fields. The water was either diverted from a major river through canals and drainage ditches that flowed alongside the fields, or it was stored in reservoirs and ponds that were refilled in times of flood, and distributed from these. The effect of this irrigation was to extend the area of fertile land from just a narrow strip on either side of a river to a wide band that could be several miles across. Having more irrigated land resulted in more crops, and thus theabilitytosupporta rising population.\n\n----\n\nAxe\n\nInvented: c. 6000 B.C.E.\n\nSummary: Early humans develop the first axe to clear areas of rain forest.\n\nMore than a million years ago, members of the species Homo erectus were making stone tools designed for chopping that can be described as early hand axes. They were teardrop-shaped and roughly made, flaked on either side to form a sharp cutting edge. However, not until the rise of farming during the late Stone Age did such tools come to resemble what we would now recognize as the axe. There was widespread trade in these tools around this time and stone axes have been uncovered at many Neolithic meeting places.\n\nAxes clearly designed to be mounted (hafted) on handles have been found at a site near Mount Hagen in New Guinea. By analyzing samples of pollen from around the same era\u2014thought be around 8,000 years ago\u2014archeologists have concluded that they were probably employed in the opening up of the rain forest, during agricultural development, to allow light to reach crops.\n\nBy the Bronze Age in Britain, woodworkers had developed a range of axes for different cutting purposes. Archeologists have been able to suggest what these might have looked like by experimenting with their own reconstructed tools, to produce different cut marks.\n\nAlthough primarily a functional tool, the axe is also a symbol of power. It is possible to identify the remains of highly ranked members of a society by looking at their grave goods, which sometimes include axes. For example, an excavation of a Bulgarian cemetery dating back to 4000 B.C.E. uncovered a number of gold-covered axes. Their inclusion in the grave has been interpreted as signifying high levels of authority.\n\n----\n\nScratch Plow\n\nInvented: c. 5500 B.C.E.\n\nSummary: Mesopotamians invent a literally groundbreaking tool.\n\nAround 9500 B.C.E., in a number of populations distant from one another, people began to select and cultivate plants for food and other purposes. These people were the first farmers. In what is now known as the Fertile Crescent in Southwest Asia, small populations engaged in small-scale farming and began to grow the eight founder crops of agriculture\u2014emmerand einkorn wheat, hulled barley, bitter vetch, peas, chickpeas, lentils, and flax. Flowever, it took thousands of years before the farmers developed the practices and technologies necessary to enable cultivation of the land on a larger scale.\n\nIn 5500 B.C.E. the first plow, a tool used to prepare the soil for planting, was developed in Mesopotamia by the Indus Valley Civilization. It was known as the scratch plow and represented one of the greatest advances in agriculture. It consisted simply of a wooden stick attached to a wooden frame, but was able to aerate the soil and scratch a furrow to allow the planting of seeds. The plow was pulled by domesticated oxen and left strips of undisturbed earth between each plowed row. To increase the productivity of their fields, farmers often cross-plowed them at right angles. The squarish fields that resulted are known to archeologists as \"Celtic fields.\"\n\nMany different types of plow have superseded this simple device, but it is still used in many parts of the world. In certain areas, including northern Europe, the scratch plow was ineffective in dealing with sticky clay soils. However, in India farmers continue to use the primitive plow to introduce organic materials into soils that have been cultivated for up to 2,000 years.\n\n----\n\nPlaster\n\nInvented: c. 5500 B.C.E.\n\nSummary: Egyptians make a versatile new material.\n\n\u2002\"It Is... poured around the stone or anything else of this kind that one wishes to fasten.\" \u2014Theophrastus, philosopher and scientist\n\nPlaster goes by various names\u2014plaster of Paris, partly dehydrated gypsum, or calcium sulfate hemihydrate. Gypsum is a common mineral found in a variety of crystalline forms, from the fine grain of alabaster to the large, flat blades of selenite.\n\nPlaster was first used as a building material and for decoration in the Middle East at least 7,000 years ago. In Egypt, gypsum was burned in open fires, crushed into powder, and mixed with water to create plaster, used as a mortar between the blocks of pyramids and to provide a smooth facing for palaces. In Jericho, a cult arose where human skulls were decorated with plaster and painted to appear lifelike. The Romans brought plasterwork techniques to Europe.\n\nGypsum is found worldwide, as far east as Thailand and as far west as New Mexico, where a huge sandy deposit is used by the construction industry. The name \"plaster of Paris\" comes from a large deposit mined in Montmartre from the sixteenth century. The French king ordered that the wooden houses of Paris be covered in plaster as a protection against fire.\n\nPlaster has played a key role in the fine arts as well as the building trade. The art of fresco consists of painting on a thin surface of damp plaster; and stucco is a plaster-based ornamental rendering material. In medicine, plaster was first used to support broken bones in Europe in the early nineteenth century.\n\n----\n\nToothpaste\n\nInvented: c. 5000 B.C.E.\n\nSummary: Dental care is boosted by Egyptian mixtures.\n\nThe development of pastes designed to clean teeth and freshen the breath began in Egypt as early as 5000 B.C.E. Myrrh, volcanic pumice, and the burned ashes of ox hooves were mixed with crushed eggshells, oyster shells, and other fine abrasives, then applied with a finger to scour teeth and help remove food and bacterial deposits.\n\nIn China around 300 B.C.E. a nobleman named Huang-Ti claimed that toothaches could be cured by inserting pins into certain areas of a patient's gums. Eiuang-Ti's theories grew to become the world's first recorded and systematic approach to oral hygiene.\n\nGenerally, however, the composition of what people used as toothpaste remained an intriguing mix of practicality, myth, and superstition until well into the seventeenth century. In the first century C.E., for example, it was thought that toothaches could be avoided by removing animal bones from wolves' excrement and wearing them in a band around one's neck. At the same time the Greeks and Romans were using wires to bind teeth together and began producing rudimentary instruments for tooth maintenance and extraction.\n\nTooth powders first became available in Europe in the late eighteenth century, although ill-conceived mixtures continued to be made available. Their highly abrasive ingredients, such as brick dust and pulverized earthenware, scoured away the protective enamel of the teeth and did more harm than good, despite the addition of glycerine to make the paste more palatable. In the 1850s chalk was added to act as a whitening agent and a new product called Creme Dentifrice saw toothpaste sold in jars for the first time. In 1873 the Colgate company began the mass production of aromatic toothpaste in jars.\n\n----\n\nCarpentry\n\nInvented: c. 5000 B.C.E.\n\nSummary: Woodworking supplements long-established ways of working with stone.\n\n\u2002\"Many remains of... stone architecture exhibit forms that imitate constructions in wood.\" \u2014John Capotosto, writer\n\nBefore the discovery of metallurgy, long before plastics, the materials that Stone Age man used were those that he found around him in nature: stone, mud, bone, and of course wood.\n\nWood is'an extremely important material, having numerous useful properties; it floats, it burns, and it can be shaped relatively easily into a variety of different objects. The craft of shaping and using wood\u2014carpentry\u2014has its roots in prehistoric times.\n\nEarly woodwork consisted of the use of wood for basic tools, but there is also-archeological evidence that Neanderthals were shaping wood into new forms as long ago as the middle Paleolithic (Old Stone Age, 300,000 to 30,000 years ago), using tools made from flint and stone. In this way many useful things were created from wood, including fire-hardened spears and logs hollowed out to create simple boats.\n\nBy the Neolithic (New Stone Age), basic woodworking had evolved into a more complex craft\u2014carpentry. The largely nomadic cultures of the Paleolithic era were settling down into more agrarian societies, resulting in an increase in permanent dwellings, and these were often constructed of timber. Researched settlements in Japan and elsewhere include wooden houses of circa 5000 B.C.E.\n\nThe word carpentry actually derives from the Latin word carpentrius, which means maker of a carriage or wagon. Even in ancient Rome, however, carpenters were producing not only wagons but a whole array of different wooden products, from weapons (bows, spears, and large rock-throwing machines) to beautifully crafted furniture.\n\n----\n\nRowboat\n\nInvented: c. 4500 B.C.E.\n\nSummary: Propelling a boat with paddles begins in Mesopotamia.\n\n\u2002\"Rowing is only a magical ceremony by means of which one compels a demon to move the ship.\" \u2014Friedrich Nietzsche, philosopher\n\nAlthough it is common knowledge that rowboats were used as far back as 3000 B.C.E. in Egypt as a means of traveling and trading along the Nile River, evidence has been uncovered recently to suggest that they were in existence much earlier. In a grave uncovered in the Mesopotamian city of Eridu, archeologists found a clay model of a boat, and the grave is thought to have been dug before 4000 B.C.E. Mesopotamia\u2014widely cited as as \"the cradle of civilization\"\u2014was the name given in the Hellenistic Period to a broad geographical area that took in what we now know as Iraq and a part ofwestern Iran.\n\nThe model they found was of a wide boat with a shallow bottom, rather like a barge, which was designed to float on the shallow rivers of Mesopotamia. Both the Euphrates and the Tigris rivers were part of the region and, flowing from the north of the area to the south, they quickly became an integral part of the transport system set up by the emerging non-nomadic civilizations.\n\nSince wood was in scarce supply, most of the boats in Mesopotamia were fashioned from the hollow and buoyant reeds that grew abundantly in the marshes at the mouths of the two rivers. The reeds were molded into a boat shape and held tightly in place with ropes. Bitumen was used to cover the reeds, calk the boat, and make it watertight.\n\nFloating downstream on the current was simple enough, but going upstream was problematic. It was common practice to use animals walking alongside the water to drag the boat back but, as was discovered, often it was easier and quicker to row.\n\n----\n\nCanal\n\nInvented: c. 4000 B.C.E.\n\nSummary: Artificial waterways debut in the Middle East.\n\nChina's Grand Canal, completed in the thirteenth century and stretching almost 1,200 miles (1,930 km) from northern Beijing to Hangzhou in the south, is the oldest still in use today. Although the most ancient part of this waterway dates as far back as 486 B.C.E., canals had been in use for irrigation and transportation for centuries prior to this. The earliest evidence suggests that artificial waterways were excavated and in use across Iraq and Syria by 4000 B.C.E.\n\nThe first British canal, the Fossdyke, was built by the Romans, but it was not until the birth of the Industrial Revolution in the mid-eighteenth century that the construction of a canal network began in earnest, eventually totalling almost 4,000 miles (6,440 km). Canal systems also proliferated throughout Europe and the United States, with horse-drawn barges providing the principal means of cheap transportation for coal, cotton, and other commodities.\n\nThe advent of railroads in the mid-nineteenth century spelled the beginning of a decline for British canals, many of which fell into disuse for more than a hundred years until their rediscovery for boating vacations. In mainland Europe and North America, however, the distances to be traveled were much greater. Despite the arrival of the railroads, investment was warranted in wide and deep canals to admit seagoing ships into the heart of those continents; industry has reaped the benefits of canal-borne bulk transportation to this day.\n\nPerhaps the most famous canals are those that have drastically shortened circuitous and treacherous sea voyages, including the Suez Canal of 1869, linking Europe and the East, and the Panama Canal of 1914, between the Pacific and the Atlantic, both remarkable testaments to engineering vision.\n\n----\n\nGlue\n\nInvented: c. 4000 B.C.E.\n\nSummary: Beeswax and saps serve as adhesives.\n\n\u2002\"Ancient Egyptians made glue by boiling animal hides and used it as a binder... for woodworking.\" \u2014Joe Hurst-Wajszczuk, writer\n\nWe may not make direct use of adhesives every day, but glue is an important component of many common manufactured items: Books, envelopes, supermarket packaging, and even cheap sneakers benefit from this invention. Although in recent decades chemists have provided us with super glues\u2014substances so phenomenally strong that the user is warned to take extreme- care\u2014naturally occurring alternatives such as beeswax and tree sap have been in use for much longer.\n\nIn the burial sites of ancient tribes, archeologists have discovered pottery vessels whose cracks had been mended with plant saps. This tar-like glue was also applied to Babylonian statues that had eyeballs glued into their corresponding sockets. Egyptian carvings from more than 3,000 years ago portray the adhesion of veneer to sycamore, while in northern Europe 6,000-year-old clay pots have been discovered with repairs made with a glue deriving from birch bark tar.\n\nThe ancient Egyptians also developed adhesives made from animals, a technique the Romans and Greeks refined in the first five centuries B.C.E. The Romans subsequently made various types of glue using other natural ingredients\u2014such as vegetables, milk, cheese, and blood\u2014and were the first to use tar and beeswax to fill the seams of their ships.\n\n----\n\nLog-laid Road\n\nInvented: c. 4000 B.C.E.\n\nSummary: Logs open up roads in impassable terrain.\n\n\u2003\"Look well to your seat, 'tis like taking an airlng\n\n\u2003On a corduroy road, and that out of repairing.\" \u2014James Russell Lowell, \"A Fable for Critics\"\n\nNicknamed corduroy roads, log-laid roads consist of whole logs, or logs split down the middle, that are laid across the roadway, one tightly against the next, to create a resistant road surface over swampy or muddy land. Sand is used to cover the surface and reduce the discomfort of traveling over the corduroy-like surface.\n\nDespite enabling easier travel through once inaccessible places, corduroy roads could be dangerous for the user. In the best of conditions the ride was already bumpy and uncomfortable, but if rain washed away the sandy cover or logs became loose or wet, the surface became highly hazardous to horses and any vehicles that were attached to them.\n\nThe first known log-laid road was constructed in 4000 B.C.E. Evidence of corduroy roads, made from oak planks covering marshy areas, has been found in Glastonbury, England, dating backto 3800 B.C.E.\n\nOver the centuries log-laid roads have mainly been replaced by plank roads, using flat boards instead of logs to give a smoother journey. However, both the Nazi and Soviet forces created them on the Eastern Front in World War II. More recently, corduroy roads have lost their original function and become the foundations for other surfaces after decaying very slowly in anaerobic soils. In the United States, roads such as the Alaska Highway that were built in the early twentieth century retain their log-laid foundations.\n\n----\n\nRivet\n\nInvented: c. 4000 B.C.E.\n\nSummary: Early Egyptians start a construction trend.\n\nThe humble rivet may be small, but is has a lot to answer for\u2014including, quite possibly, the sinking of the Titanic. Rivets have been in widespread use for thousands of years but, because engineers now depend on them to secure boats, bridges, aircraft, and other more complex constructions, their reliability has become paramount.\n\nRivet holes have been found in Egyptian spearheads dating back to the Naqada culture of between 4400 and 3000 B.C.E. Archeologists have also uncovered many Bronze Age swords and daggers with rivet holes where the handles would have been. The rivets themselves were essentially short rods of metal, which metalworkers hammered into a pre-drilled hole on one side and deformed on the other to hold them in place. Today, a wide variety of rivets exist, as do specialized tools for installing them.\n\nThe extensive use of rivets in modern engineering and architecture has, inevitably, increased the likelihood of the odd one or two coming unstuck. Materials scientists have blamed rivets for RMS Titanic's infamous descent in 1912, killing over 1,500 people.\n\nJennifer McCarty and Timothy foecke carried out an in-depth study of the sunken wreck and concluded that shoddy workmanship had sent her to the ocean floor. More specifically, a large proportion of the three million rivets driven into the ship were made with substandard iron when, McCarty and Toecke claim, they should have been made from steel. The weaker iron rivets used at the front of the Titanic, where it struck the iceberg, were unable to withstand the stress of an impact, as the steel rivets used in the body might have done.\n\n----\n\nWheel and Axle\n\nInvented: c. 3500 B.C.E.\n\nSummary: The Mesopotamian potter's wheel points the way to wheeled transport.\n\n\u2002\"Using wheels to reduce friction while moving objects was one of the most important inventions...\" \u2014Odis Hayden Griffin, engineer\n\nMost inventions do not appear out of thin air or from the ingenious brain of a brilliant scientist, but evolve from something already in existence. This is certainly true of the wheel and its attached axle, which developed from two different sources. The first was the revolving potter's wheel, invented in Mesopotamia in around 3500 B.C.E. Although not a tool essential to the potter's craft, the wheel did help in the faster production of better-quality pots. The second source was the sledge, a primitive but effective means of hauling large loads on parallel sleds or bars of wood. The sledge was ideal in icy and snowy conditions, and on hot sand, but not on hard, dry terrain, where great effort was required to pull it along.\n\nEvidence that the use of the potter's wheel and the sledge came together in the invention of the wheel is found in some of the world's earliest picture-writing. Examples in Uruk, in Sumer, southern Mesopotamia, dating to around 3200 B.C.E., show various sledges, some with sleds, others with wheels. These first wheels were crude but effective: solid wooden discs made of two or three planks pegged together and then cut to form a wheel. When a pair of wheels was mounted on a fixed axle that enabled them to rotate together simultaneously, it was then but a short leap of the imagination to use the wheel-and-axle combination to carry a physical or human load in a cart, wagon, or chariot., Mesopbtamia should not, however, claim sole deeds to this invention. Wheels were found in graves in the northern Caucasus, and wheels also appear on a clay pot from Poland; this earlier evidence dates to around 3500 B.C.E.\n\n----\n\nPlywood\n\nInvented: c. 3500 B.C.E.\n\nSummary: Egyptians learn to layer sheets of wood.\n\nIn gilding, a thin layer of gold covers an object of base material to give the appearance of a solid gold object. Plywood originated in much the same way. With fine woods in short supply in Egypt around 3500 B.C.E., it became necessary to find alternative solutions to the demands of high-quality furniture making. One such solution involved taking thin sheets of decorative woods and glueing them to thicker pieces of low-quality wood. This is believed to have been done purely for cosmetic and economic reasons, but the process also brings about improvements to the physical properties of the resulting hybrid wood.\n\nSince the days of Egyptian plywood, the material has maintained its place in popular design, as illustrated by its use in the stylish furniture of Gerrit Rietveld, Marcel Breuer, and Alvar Aalto. Unlike the designers of 5,000 years ago, however, these men were aware that the plywood items they were producing would offer greater resistance to unwanted flexing. The composite wood is rigid because the grain of each successive layer is set at an angle of ninety degrees to the layerto which itisglued.\n\nStumbling across furniture in the middle of the night with the lights turned out can be a painful experience. Fortunately for the Egyptian carpenters, their stumbling in the dark was metaphorical and it involved stumbling across the superior strengths of plywood furniture rather than the furniture itself. In fact, the applications of plywood are by no means limited to furniture; it finds its way into building construction, the hulls of boats, shelves, and automobiles. However, it was only with the advancements in adhesives during the twentieth century that all of these uses have been practical.\n\n----\n\nLubricating Grease\n\nInvented: c. 3500 B.C.E.\n\nSummary: Oils and fats speed the first wheeled vehicles.\n\n\u2002\"Men of former times used to employ lard... for greasing their axles.\" \u2014Pliny, historian\n\nAs long as there have been wheels, there has been the need for lubrication. Any tribologist (an expert in the science of lubrication) will tell you that it serves to reduce friction. It conserves epergy, reduces wear and tear, prevents overheating, and reduces noise.\n\nThe ancient civilization of Mesopotamia, and later those of Greece and Rome, used wheels in pottery for channeling water and for transportation. Olive oil was used as an axle lubricant, and an Egyptian chariot dated to 1400 B.C.E. was found with animal fat on the axles. Fats add a crucial viscosity that water lacks.\n\nFor Roman chariot racers, wheel lubrication would have been life-saving, and a mosaic has been found in Spain showing a man holding an amphora of oil beside the racetrack, much like the pit-stop mechanics of today. A first century B.C.E. bronze wheel found in Jutland had special grooves for making the axle easier to grease. More than 1,500 years later, Leonardo da Vinci invented a self-oiling axle-end, using olive oil.\n\nOlive oil and animal fat remained the primary forms of grease even as late as the nineteenth century. Sperm oil from whales and neatsfoot oil from animal hooves were used in the British Industrial Revolution to lubricate steam engines and locomotives. In the 1850s, mineral oils, particularly petroleum oil, were developed and revolutionized industry.\n\n----\n\nCart\n\nInvented: c. 3500 B.C.E.\n\nSummary: Mesopotamians raise transport onto wheels.\n\n\u2002\"The customers hod a tendency to stop shopping when the baskets became too full or too heavy.\" \u2014Sylvan N. Goldman, businessman\n\nThe origins of the cart are inextricably linked to the invention of the wheel. In fact, one theory of how the wheel was invented suggests that the cart and the wheel were- developed simultaneously, inspired by earlier bladed sledges that were dragged across logs.\n\nThe earliest sources of evidence for wheeled vehicles are Mesopotamian tablets. Although the dating methods used for these artifacts are not exact, the tablets are known to be from the middle of the fourth millennium B.C.E. Around the same time there is also evidence for wheeled vehicles in Europe, including wheel tracks at a long barrow near Kiel, Germany, and wagon pictographs found on a beaker at Bronocice, Poland. This has led archeologists to debate whether wheeled vehicles were developed in multiple places simultaneously or whether the technology quickly diffused out of Mesopotamia.\n\nCarts have been in continuous use since their inception, evolving over time to incorporate wheels with spokes and suspension springs for added comfort. However, the invention of the automobile, and to some extent the railroad, has undoubtedly led to the cart's decline as a mode of transport.\n\nToday carts take all sorts or shapes and functions, from traditional horse-drawn carts, through rickshaws and tuktuks to the electric-powered golf cart. And we must not forget the ubiquitous shopping cart (or trolley), invented in 1937 in Oklahoma, United States, by Sylvan Goldman, who wanted to make it easier for his customers to buy more groceries from his chain of Piggly-Wigglysupermarkets.\n\n----\n\nSail\n\nInvented: c. 3500 B.C.E.\n\nSummary: Egyptians harness wind power on water.\n\n\u2002\"Pacific island societies used an upside-down triangular sail attached to a single vertical pole.\" \u2014Thomson Gale, The World of Invention (2006)\n\nFor thousands of years sails have been used to harness the wind. By 3500 B.C.E., ancient Egyptian vessels were being blown up the Nile by the prevailing wind before returning under oars, and the Phoenicians pioneered the development of hardier vessels for sea voyages.\n\nFlowever, these vessels used square-rigged sails to catch the wind and carry them along with it. In order to progress into the wind the sail must instead be used as an aerofoil to produce a lifting force perpendicular to the wind passing over it. The sail can be angled toward the wind and a component of the lift force generated gives forward thrust to the vessel, thus allowing modem craft to sail within a few degrees of the very direction from which the wind is blowing.\n\nSails were employed in this way in the Arabian Sea in 300 C.E., but further developments were minor until the fifteenth century and the advent of the European full-rigged vessel. This bore multiple masts hung with both triangular and square sails, providing maneuverability as well as stability and power.\n\nCommercial sailing peaked in the nineteenth century with the emergence of the Americas as competition in trade. Speed and size were paramount, characterized by clippers traveling at up to 20 knots (37 km/h) from China, North America, and Australia, and by vast full-riggers powered around Cape Horn by more than an acre (0.4 ha) of sail area.\n\n----\n\nOven\n\nInvented: c. 3000 B.C.E.\n\nSummary: Egyptians transform bread baking.\n\n\u2002\"Heavy pottery bread molds were set In rows on a bed of embers to bake the dough... within them.\" \u2014Jane Howard, Bread in Ancient Egypt\n\nJust as the Egyptians brought the prehistoric era to an end in about 3000 B.C.E., they appearto have produced the first closed oven. It was invented as a way to satisfy the demand for better bread. Flatbread had been around for approximately 5,000 years, but Egyptian ovens enabled the bakers to produce bread with yeast; bread was no longer flat, it was rising.\n\nA traditional oven is one of the simplest inventions; it traps heat within its walls in order to cook the food placed within. However, when considering the timing of the invention of the oven it is necessary to consider the agricultural advances that resulted in the need for it. After the last ice age, around 10,000 years ago, the land began to warm up from its frostbitten slumber and gradually provide its inhabitants with grain and other foods from plant species that had been hibernating beneath the ice. Our predecessors may have been a little slow in responding to these new sources of nutrition but, as demonstrated by the Egyptian bakers, they eventually got there.\n\nOpen tandoor (cylindrical'clay brick) ovens have been found in Mohenjo-daro, the Indus Valley city settlement also dating from 3000 B.C.E. However, it was the ancient Greeks who developed front-loaded and portable ovens, and used them to turn breadmaking into a profitable venture.\n\n----\n\nFlail\n\nInvented: c. 3000 B.C.E.\n\nSummary: Egyptians separate wheatfrom chaff with a new invention.\n\n\u2002\"The straw was removed' and the grain along with the chaff was swept up, and placed in a basket.\" \u2014John Carter, How to Use a Flail\n\nThe flail is one of the oldest agricultural tools known to man, having been in use for more than 5,000 years. It has served as a symbol of power and even as a weapon. Despite the introduction of motor-driven harvesting machines in the nineteenth century, it is still used to this day in some parts of the world. Its primary function is for threshing\u2014the forced separation of grain from the parent plant.\n\nIt is not clear where the flail originated, but it was certainly used in ancient Egypt. The flail is essentially a handle\u2014called the staff\u2014coupled at one end by a length of leather to the end of a second shorter rod. The staff is held at the free end and the rod is swung downward and from side to side. As it strikes a pile, usually spread on the ground, of harvested wheat or other grain crop, it knocks out the husks, after which the grain can be sifted out for use.\n\nIn Egypt, the flail was used as a symbol for the royal dynasties, and therefore became a mark of power. Often seen alongside a shepherd's crook, the two implements together symbolized the pharaoh's ability to provide food and look after his people, in the way that a shepherd would care for his flock. The crook and flail were also the sign of the god Osiris, lord of the Underworld, and on the coffinette of Tutankhamun, which originally contained the viscera of the dead pharaoh, he holds them crossed over his chest.\n\nThe use of flails for threshtng is highly labor intensive. Today the tool has been all but replaced by modern machinery. The combine harvester can\u2014as the name suggests\u2014both harvest the crop and separate out the grain in a single process.\n\n----\n\nBell\n\nInvented: c. 3000 B.C.E.\n\nSummary: The bell tolls for the ancient Chinese.\n\nThe ancient Chinese were technologically and culturally advanced. Between 3950 and 1700 B.C.E., the people of the Yang-shao culture farmed pigs, grew wheat and millet, made highly specialized tools, and produced painted pottery. They also produced pottery instruments called lings, which became the first tuned bells. One of the earliest examples of these clay bells is a small red ling uncovered at an excavation site in the Henan Province of central China.\n\nLater, during the Shang and Zhou Dynasties, the Chinese made bells from metal and decorated them with intricate designs. Bells came to play an important part in culture by the fifth century B.C.E., when sets of bronze bells were used in ritual ceremonies for musical accompaniment. Large, clapperless bells known as zhong were sometimes struck with mallets. It is said that these represented the sound of the Autumn Equinox, when all the crops had been harvested\u2014in Chinese, the word zhong means \"bell,\" but also \"cultivated\" when pronounced slightly differently.\n\nDuring the Qin Dynasty, in the second century B.C.E., the bell became a symbol of power and authority following the installation of six large bells at the imperial court. In modern China, the bell has a different meaning: education and worship.\n\nToday in the western world, the bell is used both functionally and symbolically. Bell chimes tell us of the time of day, but are also associated with the church and traditional celebrations such as Christmas and weddings. Hand bells are still played by members of the church community and in schools as part of music education. There are even examples of bells being used in music therapy in retirement homes and hospitals.\n\n----\n\nCandle\n\nInvented: c. 3000 B.C.E.\n\nSummary: Fats, waxes, and wicks light the world.\n\n\u2002\"Native Americans burned oily fish (candlefish) wedged into a forked stick.\" \u2014Bob Sherman, Candle Making History\n\nIt is difficult to attribute the invention of the candle to one society or country. The first \"candles\" may have been nothing more than melting lumps of animal fat set on fire. Later, these evolved into reeds dipped into animal fat, longer burning than their predecessors but still without a wick (a central slow-burning core to the candle, usually made from fiber or cord).\n\nArcheological evidence indicates that both the Egyptians and the Greeks were using candles with wicks (not dissimilar to those we know today) as long ago as 3000 B.C.E. Many ancient cultures appear to have developed some variation of the candle, using materials such as beeswax or tallow or even the product of berries to make the wax. This surrounded a wick madefrom fibers of plant material, rolled papyrus, or rolled rice paper.\n\nBurning with a regular flame and at a constant speed, the candle remained the preferred way of producing controlled artificial light for millennia. Candles remained a cheap, efficient way of creating light throughout the Middle Ages and right up until the mid-nineteenth century) when paraffin first became commercially available and the paraffin lamp entered most homes. Since the advent of gas and then electricity, the role of candles has largely been to create a peaceful, reflective, and nostalgic atmosphere, either in a religious setting or in the home.\n\n----\n\nPliers\n\nInvented: c. 3000 B.C.E.\n\nSummary: A tool for gripping evolves from simple tongs.\n\nPliers are hand tools used for gripping objects by using the principle of the lever. They utilize the hand's powerful closing grip of the fingers into the palm to apply force precisely to a small area. There have been many designs with different jaw configurations to grip, turn, pull, adjust, or cut a variety of items.\n\nPliers are an ancient invention and probably developed from tools used for handling hot coals when fires were used for cooking. Sticks and wooden tongs were used at first. These were replaced by metal tongs, which were effectively early pliers, around 3000 B.C.E. when iron was being forged. A Greek Macedonian gold wreath from the fourth century B.C.E., also shows evidence of the use of pliers.\n\nModern pliers consist of three elements: a pair of PVC-sheathed handles, the pivot, and the head section with its gripping jaws orcutting edges. The pliers'jaws always meet each other at one point. Adjustable slipjoint pliers have grooved jaws, and the pivot hole (holding the rivet connecting the two halves) is elongated so that the halves can pivot in either of two positions to accommodate objects of different sizes.\n\nPliers may be used to grip a plumbing pipe and loosen it, repairtaps, bend (round-nose pliers), and cut wire (pliers with jaws). Diagonal cutting pliers are used for cutting wire and small pins in areas that cannot be reached by larger tools. There are also smaller versions such as the mini \"side-cutting\" pliers used for jewelry and those in Swiss Army knives.\n\nThe basic design of pliers has changed little over the years, and they are still used in many occupations that require dexterity and precision.\n\n\u2002\"A pair of needle nose pliers used on the Apollo 16 lunar module sold for more than $33,000.\" \u2014Heritage Auction Galleries, Dallas, March 2008\n\n----\n\nInvestment Casting\n\nInvented: c. 3000 B.C.E.\n\nSummary: Humankind learns to shape metal in molds.\n\n\u2002\"For much of history, investment casting was confined to sculpture and works of art.\" \u2014European Investment Casters' Federation\n\nInvestment casting is one of the oldest metalworking practices, occurring as long ago as 3000 B.C.E., and remains vital in producing very specific, one-piece metal designs. Today, the process is used to produce complex parts for nuclear power plants, but thousands of years ago essentially the same method was used to produce small metal ornaments and statues.\n\nCivilizations such as the Egyptians and the Mesopotamians used the investment casting\u2014or \"lost wax\"\u2014process to create small idols or jewelry with intricate patterns. The intended shape and design of each object was first sculpted from natural beeswax, and then coated with several layers of thick and heat-resistant plaster. This mold was then heated, the wax inside melted and drained out, and molten metal was poured into the resulting hollow space. After cooling, the plaster was removed, to reveal metal in the exact shape of the wax template.\n\nDuring World War II the process was adopted extensively to produce precise components for military machinery, a trend that continued after the end of the war and expanded into other commercial industries. With the expansion came more refined ways of implementation, such as more advanced waxes, but the basic ingredients of the process have remained unchanged in millennia.\n\n----\n\nButton\n\nInvented: c. 3000 B.C.E.\n\nSummary: Early humankind creates a sartorial accessory.\n\nButtons have been attached to clothing for around 5,000 years, but our Bronze Age ancestors used them more for ornamentation than for their potential as a fastener. In their early incarnations, buttons were simply added to clothes for decoration, while the clothes were fastened by pins and belts. The buttons were usually hand-carved from bone, wood, or horn.\n\nIt was the Greeks who first came up with the idea of using buttons to fasten clothes. The first \"buttonhole\" was simply a loop of thread, through which a button could be passed to create a fastening.\n\nHowever, buttons were not adopted in Europe until the return of the Crusaders in the thirteenth century. The introduction of this new fastening coincided with a new trend for \"form-fitted\" clothing and its popularity soared. By 1250, the French had established the Button Makers' Guild. In fact, the word \"button\" probably derives from the French bouton meaning \"bud,\" or bouter meaning \"to push.\"\n\nButtons became a status symbol, and the wealthy would wear clothing adorned with hundreds of them. By the sixteenth century the finest buttons were encrusted with precious gems and diamonds, and by the eighteenth century they were being crafted from porcelain, ivory, and glass.\n\nThe advent of London's Pearly Kings and Queens, whose costumes are covered by mother-of-pearl buttons, coincided with a huge cargo of the buttons thatarrived by ship from Japan in the 1860s.\n\nWith the dawn of mass-produced buttons, their power as a status symbol diminished and so did their popularity. Most modern buttons are made of plastic, but even today highly priced clothing is often distinguished by unusual ornamental buttons.\n\n----\n\nHelmet\n\nInvented: c. 3000 B.C.E.\n\nSummary: Head protection debuts in Mesopotamia and Egypt.\n\n\u2002\"And he had a helmet of brass upon his head, and he was clad with a coat of mail.\" \u2014Samuel 17:5, on Goliath\n\nIn English, \"helmet\" is the generic term given to any device that protects the head, usually from impact-related damage. Today helmets can be found in a wide array of activities from sports to space exploration and are made from advanced composite materials, including plastics and Kevlar, combining maximum protection with minimum weight.\n\nArcheological evidence suggests that helmets have been around since the third millennium B.C.E., being used by the ancient Mesopotamian civilizations. At this time, and for many centuries afterward, the helmet was used exclusively for the purposes of war. The ancient Egyptians were also making helmets at around the same time, taking advantage of the toughness of crocodile skin as their material.\n\nEarly arms and warfare reached a peak around the fifth century B.C.E. with the ancient Greeks. In addition to bronze body-fitting armor and broad shields, the Greek hoplites (foot soldiers) also sported a bronze helmet, most often in the Corinthian style\u2014solid metal protecting the head and neck, with a narrow aperture for the eyes, nose, and mouth. This style of helmet not only protected the head but was also fearsome for enemies to behold.\n\nThe helmet has seen many revisions over the centuries since. The Romans added hinged cheek flaps, and in medieval times visors were added, affording additional facial protection. In peacetime, protective helmets have since become highly specialized, so that, for example, a cycling helmet facilitates the passage of air to cool the head.\n\n----\n\nSki\n\nInvented: c. 3000 B.C.E.\n\nSummary: Lapps use wooden skis to move on snow.\n\nThe invention of the ski has contributed greatly to society for the past 5,000 years. Unlike today, early skis were not used for fun and leisure but for work and transportation, playing a key role in both hunting and warfare. They were made of wood and were not designed for speed: They simply served the purpose of keeping the traveler on top of the snow, with walking sticks employed to keep balance.\n\nHunters have been using skis to chase animals in ice-covered terrain since around 3000 B.C.E., when the Lapps from Sapmi (a territory incorporating parts of present-day Norway, Sweden, Finland, and Russia) began to use skis extensively. However, it is not clear who invented skiing. The world's oldest surviving ski dates back to around 3000 B.C.E. and was discovered at Kalvtr\u00e4sk, northern Sweden, in 1924. It is 80 inches (204 cm) long and 6 inches (15.5 cm) wide, that is, slightly longer and twice as wide as modern skis. The earliest indirect evidence for the use of skis in ancient civilizations may date back even further, with rock carvings near the White Sea and Lake Onega in Russia thought to be more than 5,000 years old. However, the most famous ancient rock carvings depicting skiers\u2014 wearing animal masks and mounted on very long skis\u2014are located in Rodoy, Norway.\n\nWell preserved skis have also been found under the surface of bogs in Finland and Sweden. However, predating these is the earliest ski\u2014a Norwegian word deriving from an Old Norse term meaning \"stick of wood\"\u2014which looked very different from its modern relative. It was made from the bones of big animals, and leather strips were used to attach it to the boot.\n\nNotes:\n\n- The world's oldest ski was made from pine wood.\n\n----\n\nIce Skate\n\nInvented: c. 3000 B.C.E.\n\nSummary: Finns traverse the icy terrain on bone skates.\n\nThe ice skate is believed to have been invented circa 3000 B.C.E. in Finland. For many years scientists were not sure where exactly the skate originated, ancient models having been found throughout Scandinavia as well as Russia. However, in 2008 news emerged that people living in what is now southern Finland would have benefited the most from skating on the crude blades. This country's nickname, \"the land of the thousand lakes,\" is an understatement as it boasts no fewer than 187,888 of them. Finland is also a cold land and therefore each winter its thousands of frozen lakes have presented serious transportation problems for the population. With neighboring villages often separated by lakes, and rowboats locked up until spring, the options were to try to navigate around the frozen water or find a way to negotiate the slippery surfaces.\n\nThe first skates consisted of the leg bones of large animals. Holes were drilled at the ends of the bones and strips of leather threaded through to tie the skates to the feet. As in skiing, skaters used tnin poles to propel themselves along, and it was only with the arrival of iron runners in fourteenth-century Holland that the poles were dispensed with.\n\nIn an inadvertent homage to the skate's origins on their country's lakes, students in the Finnish city of Jyv\u00e4skyl\u00e4 still commute to their classes by donning skates to traverse the lake that divides the city. The evolution of the skate has seen metal attached to wood and metal attached to metal, but the fundamental fact that keeping your balance enables you to glide almost effortlessly across slippery ice has ensured the skate's continued popularity.\n\n----\n\nCuneiform\n\nInvented: c. 3000 B.C.E.\n\nSummary: Sumerians originate wedge-shaped writing.\n\n\u2002\"Our earth is degenerate in these latter days.... The end of the world is evidently approaching.\" \u2014Inscription on an Assyrian tablet, circa 3000 B.C.E.\n\nAbout 5,000 years ago, the Sumerians of ancient Mesopotamia invented humankind's first writing system. Having already established the world's first true civilization by introducing agriculture and domesticating cattle, they decided that it was more efficient to record their economic transactions in writing rather than use tokens to represent the number of beasts and the amount of harvest they traded. Their initial use of simple pictograms (drawings representing actual things) quickly developed into a complex system of symbols where items were illustrated by one sign and their volume by another.\n\nThe Sumerians' innovation was not only used for commercial purposes, but also extended to phonetic\u2014rather than wholly pictographic\u2014ideograms that expressed concepts such as deity and royalty as well as thoughts.\n\nAs the symbols evolved, the notes that were recorded on clay tablets became more cuneiform (wedge-shaped), owing to the wedge-tipped reed the Sumerians used as a writing utensil. They were initially drawn in vertical columns, but the writing direction soon changed to left to right in horizontal rows. Rediscovered in the nineteenth century, the cuneiform script (whose last known inscription is an astronomical text from 75 C.E.) carries major significance as the first means of chronicling events in writing.\n\n----\n\nDam\n\nInvented: c. 2800 B.C.E.\n\nSummary: Egyptians block a river for the first time.\n\nDams are built for a number of purposes: to generate hydroelectric power; control flooding; safeguard water supplies for irrigation!, domestic, or industrial use; provide for recreation; or ease navigation.\n\nThe earliest known dam was built by the Egyptians across the Garawi Valley in 2800 B.C.E. and measured 370 feet (113 m) along its crest. The masonry shell was filled with earth and rubble, but as it was not sealed against water, the center of the dam was soon washed away. This failure discouraged the Egyptians from further forays into dam construction.\n\nThe Romans, armed with their knowledge of concrete, were more successful. Their constructions initially relied on sheer weight of material to resist the water, but in the first century they built the first archtype dam at Glanum in France. The apex of the arch pointed upstream, transferring the force along the dam and into the solid bedrockofthevalley sides. This design was also favored by the Mongols in fourteenthcentury Iran, but it was otherwise little used until the nineteenth century, when French engineer Francois Zola designed his eponymous arch dam, using rational stress analysis for the first time.\n\nIn the latter half of the nineteenth century, concrete was used as the primary construction material for the first time in a gravity dam in New York and an arch dam in Queensland, Australia. More complex structures were now within reach, and multiple arch, cupola, and buttress dams sprang up around the United States.\n\nChina is home to the world's largest dam project, the Three Gorges Dam, which is expected to be fully operational in 2009. It spans the Yangtze River and has been constructed to ease flooding on the Yangtze and provide hydroelectric power for millions.\n\n----\n\nChair\n\nInvented: c. 2800 B.C.E.\n\nSummary: Egyptians give a supporting back to a stool.\n\n\u2002\"A chair is a very difficult object. A skyscraper is almost easier. That is why Chippendale is famous.\" \u2014Ludwig Mies van der Rohe, architect\n\nChairs have been invented that swing, swivel, rock, roll, recline, fold, massage, and even electrocute, Before all of those, however, came the invention of the chair in its simplest form, about 4,800 years ago. More than a thousand years before that, man had invented a way of resting in a sitting position off the floor, on the simple backless seats known as stools.\n\nStools were raised to an art form by the ancient rgyotians. Beside creating beautiful and ornate stools, the Egyptian craftsmen also focused on function by fabricating stools that folded. Some examples have floor rails and crossing spindles with carved goose neads inlaid with ivory to resemble feathers and eyes. In the Third Dynasty (2650-2575 B.C.E.), Egyptians were also to give stools their greatest adornment, a back to support the seated person in an upright position. By steadily increasing the height of the back from a simple lumbar support, Egyptians soon arrived at high-back chairs.\n\nAs they had with stools, the Egyptians turned chairs into art without sacrificing function for appearance. Chairs in the Middle Kingdom (20401640 B.C.E.) were padded for comfort with a cushion, or they had backs of full height. These chairs were curved and fashioned from timber slats and were supported on narrow legs. Sometimes, chairs were painted to give the appearance of animal skin. In the era of the New Kingdom (1540-1070 B.C.E.) a new feature was added to the chair: arms. Thousands of years later, with humankind becoming more sedentary than ever, retractable leg rests are a common option in the guest for the most comfortable chair ever invented.\n\n----\n\nSoap\n\nInvented: c. 2800 B.C.E.\n\nSummary: Babylonians improve human hygiene.\n\n\u2002\"Soap is... the first manufactured substance with which we come into contact in our lives.. \u2014John A. Hunt, A Short History of Soap\n\nSoap, in the form we know it today, was first produced by the Babylonians in around 2800 B.C.E. Clay cylinders containing a soaplike material were found during excavations of Babylon. Engraved in the side of a cylinder was a recipe for boiling fats with ashes.\n\nSoap works by acting as an emulsifying agent. Each soap molecule consists of a long, fatty tail and an electrically charged \"head.\" In water the soap molecules form small spheres, called micelles, where the charged heads are on the outside and the waterrepelling fatty chains are in the middle. As dirt and grease are not soluble in water, they are contained within the micelles. The micelles can then be washed away, leaving behind a clean surface.\n\nTrue soap was made by boiling oil and fat with alkaline salts to form glycerin and the salts of fatty acids. The salts are solid and are like the soap we use today. Sodium salts make hard soaps, while potassium salts produce a softer product. Calcium and magnesium salts form an insoluble residue, the scum that soap produces in hard water.\n\nThe first hard white soap was produced in Spain from olive oil and the ashes of the salsola plant. However, it was only in the late nineteenth century, after processes for producing alkalis had been discovered, that there was a rapid expansion in the commercial production of soap.\n\n----\n\nArched Bridge\n\nInvented: c. 2500 B.C.E.\n\nSummary: An innovation transforms architecture.\n\nThe exact date and location of the initial historic transition from simpler bridges to arch-supported types is now lost to us. The development and use of the arched bridge has been attributed variously to the Indus Valley Civilization of around 2500 B.C.E.; the Mesopotamians, Egyptians, Sumerians, and Chinese; and the Etruscans and Romans, who built most of the surviving early arch-based architecture in Europe.\n\nEarly arches were corbeled, not really an arch as we understand the term today. A corbel is a projecting, stone supporting piece. It is a simple example of a cantilever. Such an arch is constructed by progressively corbeling from the two sides with horizontal joints until they meet at a midpoint. At the top, where the two sides meet, a capstone is placed.\n\nThe Romans, aided by their invention of a cement material to bind stone together, refined the techniques of arch construction. Arch-based Roman bridges and aqueducts may be seen today throughout many cities in Europe and the Middle East.\n\nThe basic arch design proper can be likened to a beam curved to form a semicircle and prevented from straightening and spreading by strong abutments at either end. Traditionally, the shape of a stone arch is made from wedge-shaped blocks, carefully cut to fit perfectly together.\n\nKnown as \"voussoirs,\" these blocks gradually take the curve of the arch from a central, vertical keystone down to the outermost, horizontal footers. The weight of the bridge users pushes downward onto the keystone, and its wedge shape transfers that energy outward onto the voussoirs, thereby spreading the forces sideways and around the arch instead of straight downward. The development of the arch enabled longerand stronger bridges to be made.\n\n----\n\nBrazing and Soldering\n\nInvented: c. 2500 B.C.E.\n\nSummary: Metal items are joined together by another metal with a lower melting point.\n\n\u2002\"Zillah bore Tubal-Cain; he was the forger of all instruments of bronze and iron.\" \u2014Genesis 4:22\n\nMetallurgy is one of the most ancient fields of technology and also one of the most important. The use of metals has been so essential to humankind that long periods of history\u2014the Bronze Age and the Iron Age\u2014have been named after the metals that were used most predominantly in those times.\n\nBeing able to join pieces of metal together has always been essential in making metal artifacts. The joining can be done in a number of different ways, including welding, brazing, and soldering. Metal items to be joined by welding must themse'ves be partly melted before the joining can take place.\n\nBrazing or soldering\u2014which are sometimes called \"hard\" and \"soft\" soldering respectively, with brazing carried out at a higher temperature\u2014are processes whereby pieces of metal are joined together by the introduction of a metal melted into liquid form. This \"filler\" metal acts like glue in joining the pieces of metal together. The temperature required to melt the filler metal is lower than that required to melt the metals to be joined. This factor allows metal items to be joined together without themselves ever having to undergo whole or partial melting.\n\nBrazing was discovered before either welding or soldering. It may have occurred as ^arly as 4000 B.C.E., and samples of work where brazing was used to integrate pieces of metal have been dated to 2500 B.C.E. The techniques of brazing and soldering have been refined over thousands of years. They continue to be important today, having applications in a variety of metallurgical fields, most notably engineering and electronics.\n\n----\n\nGlass\n\nInvented: c. 2500 B.C.E.\n\nSummary: Egyptians develop a transparent material.\n\nArcheological findings suggest that glass was first created during the Bronze Age in the Middle East. To the southwest, in Egypt, glass beads have been found dating back to about 2500 B.C.E.\n\nGlass is made from a mixture of silica sand, calcium oxide, soda, and magnesium, which is melted in a furnace at 2,730\u00b0F (1500\u00b0C). Most early furnaces produced insufficient heat to melt the glass properly, so glass was a luxury item that few people could afford. This situation changed in the first century B.C.E. when the blowpipe was discovered.\n\nGlass manufacturing spread throughout the Roman Empire in such quantities that glass was no longer a luxury. It flourished in Venice in the fifteenth century, where soda lime glass, known as cristallo, was developed. Venetian glass objects were said to be the most delicate and graceful in the world.\n\nGlass is normally a clear or translucent brittle material, but it may be colored, depending on the way it has been made. The three classes of ingredients used for making glass are: alkalies, earths, and metallic oxides. Crown-glass, used for windows, uses no lead but includes black manganese oxide. Cheap bottle glass uses iron oxide, alumina, and silica.\n\nIn the 1950s Sir Alastair Pilkington introduced \"float glass production,\" a revolutionary method still used to make glass. In this process a film of glass, which is highly viscous, is floated onto molten tin, which is fluid, and, as the two do not mix, the contact surface between them is perfectly flat.\n\nOther developments have included safety glass, heat-resistant glass, and fiberoptics, where light pulses are sent along thin fibers of glass. Fiberoptic devices are used in telecommunications and in medicine for viewing inaccessible parts of the human body.\n\n----\n\nWelding\n\nInvented: c. 2500 B.C.E.\n\nSummary: Anatolians join iron pieces by hammering.\n\n\u2002\"...embracing the fracture with a pair of hot tongs and closing so tight till the weld leans out...\" \u2014Vannoccio Biringuccio, sixteenth-century writer\n\nWelding is the process of joining pieces of metal with heat, pressure, or a combination of both, so that they completely fuse together.\n\nThe first instance of welding is thought to have been in the smelting of iron ore to create wrought iron, some of the earliest evidence of which was discovered in a Hattic tomb in northern Anatolia, dated to around 2500 B.C.E. Lumps of the iron ore were heated in furnaces until the impurities melted into a slag, trapped in pores in the still solid iron. The hot piece was then hammered to expel the liquid slag and weld together the particles of surrounding iron.\n\nSimilar methods of heating and hammering were used to join separate pieces of iron, and examples of this were discovered in Tutankhamun's tomb of 1350 B.C.E. This type of forge welding remained the only known technique for centuries. One of the most renowned ancient examples is the Delhi Iron Pillar from the fourth or fifth century, which is a testament to the skill of the Indian metalworkers of the day.\n\nElectricity paved the way for the development of arc welding and resistance welding, as well as the oxyacetylene torch. Welding flourished during the two world wars, and is still being developed to this day with the use of more challenging materials such as aluminum, and new technologies such as laser and electron beam welding.\n\n----\n\nBellows\n\nInvented: c. 2500 B.C.E.\n\nSummary: A new invention transforms Mesopotamian metal smelting.\n\n\u2002\"He gave me a skin-bag flayed from an ox... and therein he bound... the blustering wind.\" \u2014Homer, The Odyssey\n\nThe ability to extract metals from their ores is one of the most significant discoveries in antiquity Until the invention of bellows, furnace fires were stoked by breath alone. Teams of men, using biowpipes, would blow on the charcoal to supply the oxygen required to increase its temperature. The teams could achieve temperatures high enough to smelt copper and tin and melt metals such as bronze, silver, and gold.\n\nBellows improved this process not least because arm and leg power is considerably less exhaustible than lung power. They also enabled much larger furnaces to be used; one man with bellows could generate heat around seventy times faster than one with a blowpipe. A pan found in Talla, Mesopotamia, dated around 2500 B.C.E., is believed to be the earliest evidence of bellows, although they likely predate this. The pan, which held a fire, has a projection with two holes in it, thought to be where bellows were attached. Two bellows were used alternately to generate a continuous a stream of air and maintain the constant temperatures required for smelting.\n\nAnother advantage of bellows is that they use ambient air, which is higher in oxygen and lower in carbon dioxide and water vapor than exhaled breath. This enabled even higher temperatures, hot enough to smelt iron, to be achieved for the first time but, a'though required for ancient iron production, the presence of bellows alone does not indicate that iron was in use. It would be another millennium before bellows reached Egypt and later Europe. One thing is clear\u2014a world of possibilities opened up once societies could extract iron from its ore.\n\n----\n\nFlush Toilet\n\nInvented: c. 2500 B.C.E.\n\nSummary: Sanitation arrives in the Indus Valley.\n\nThe Internet? Television? The internal combustion engine? All of these things are important, but they pale in significance next to arguably the most important invention of all time\u2014the toilet.\n\nArcheological research indicates that toilets flushed by water have existed since about 2500 B.C.E. Inhabitants of the Indus Valley developed a sophisticated system of toilets and accompanying plumbing; each house had a toilet with a seat, the waste being borne away by water in a sewer system covered with dry-clay bricks. This system was used in India for most of the existence of the Indus Valley Civilization, which ran from about 3000 to 1700 B.C.E.\n\nAncient Egypt also developed a similar system that removed waste through the use of running water. The ancient Romans were so fastidious that they constructed a toilet for use when they were traveling. Their sewerage systems were sophisticated, and public toilets were common.\n\nAfter some lamentably unsanitary times from 500 to 1500 C.E., the toilet saw some major innovations during the second half of the last millennium. John Harrington, godson of England's Queen Elizabeth I, had invented the water closet in 1596, but his invention was not widely adopted. The late 1700s saw development in toilet technology, with several inventors taking up Harrington's ideas and producing further refinements. One of these, developed in 1778 by Joseph Bramah, was installed in many ships.\n\nThe first all-ceramic toilet appeared in 1885, designed by china manufacturer Thomas Twyford. It incorporated in one piece the earlier innovation of the water trap, consisting of water held within a U-shaped bend in the outflow pipe that insulated the user from malodorous air in the sewage system beiow.\n\n----\n\nSewage System\n\nInvented: c. 2500 B.C.E.\n\nSummary: Indus Valley toilets are connected to sewers.\n\n\u2002\"When the plumbers and sanitary engineers had done their work... diseases began to vanish.\" \u2014Lewis Thomas, medical researcher and essayist\n\nIt was probably more the need to get rid of foul smells than an understanding of the health hazards of human waste that led to the first proper sewage systems. While most early settlements grew up next to natural waterways\u2014into which waste from latrines was readily channeled\u2014the emergence of major cities exposed the inadequacy of this approach.\n\nEarly civilizations, like that of the Babylonians, dug cesspits below floor level in their houses and created crude drainage systems for removing storm water. But it was not until around 2500 B.C.E. in the Indus Valley that networks of precisely made brick-lined sewage drains were constructed along the streets to convey waste from homes. Toilets in homes on the street side were connected directly to these street sewers and were flushed manually with clean water.\n\nCenturies, later, major cities such as Rome and Constantinople built increasingly complex networked sewer systems, some of which are still in use. These days the waste is transported to industrial sewage works rather than to the sea or rivers.\n\nAfter its installation, the early sewage technology of many cities in Western Europe remained in place without improvement. As recently as the late, nineteenth century it was often so inadequate that fatal contagious diseases caused by foul water, such as cholera and typhoid, were still common.\n\n----\n\nPesticide\n\nInvented: c. 2500 B.C.E.\n\nSummary: Sumerians use sulfurto protect their crops from rodents and insects.\n\n\u2002\"Odysseus fumigated the hall, house and court with burning sulfur to control pests.\" \u2014Homer, The Odyssey\n\nCivilization was founded on agriculture. The earliest cities grew up around 9,000 years ago when nomadic hunter-gatherers settled in Mesopotamia, herding animals and growing crops for the first time. But relying on the success of an annual crop was risky. Poor weather, an infestation of insects, or crop dCeases couid ruin the harvest and starve a population. Humans are still unable to control the climate, but solutions to the other problems were proposed in the most ancient of times.\n\nEarly attempts to limit damage by pests were mostly physical interventions, such as crop rotation and the manual removal of grubs. The first evidence fora chemical agent comes from Sumeria in 2500 B.C.E., where elemental sulfur was used to ward off insects. The Sumerians had developed a sophisticated agriculture, employing irrigation and mass labor to farm barley, wheat, chickpeas, and vegetables. Sprinkling sulfur on these plantations could ward off fungi, rodents, and insects such as locusts.\n\nNatural methods of eliminating pests dominated until World War II, when the chemical DDT (dichloro-diphenyl-trichloroethane) was first used to kill mosquitoes in a bid to reduce the diseases they spread, such as malaria and typhus. DDT was succeeded five years later by organophosphates when insects first showed immunity to DDT. Today, around 2.5 million tons of chemical pesticides are used around the world annually. However, alternative technologies, fears about toxic effects on humans, and a renewed interest in organic farming and natural pesticides are reducing our reliance on chemical pesticides.\n\n----\n\nStandard Measures\n\nInvented: c. 2500 B.C.E.\n\nSummary: The Indus Valley facilitates fair trading.\n\n\u2002\"We are concerned here with methodical digging for systematic information.\" \u2014Sir Mortimer Wheeler, at Mohenjo-daro\n\nTrade between people depends on a uniform set of weights and measures that can be used by both sides of the transaction to ensure that the amount obtained or handed over is correct. The first such standard weights were developed in the Indus Valley Civilization of southern Asia. This civilization was among the most advanced of its time\u2014equal to any in the Near East or Egypt\u2014and boasted large cities, such as Mohenjo-daro and Harappa. The system its merchants or accountants devised consisted of cubes of chert, a crystalline form of silica. These cubes were organized in series, doubling in weight from one unit to two units to four to eight and on to sixty-four units. The next block weighed 160 units, the next 320, and then proceeded in multiples of 160. The smallest units were used by jewelers to weigh tiny amounts of gold and other precious metals and gems. The largest units were so large they were lifted with the help of a rope, and were used to weigh grain and timber.\n\nIn Mesopotamia at much the same time, natural produce such as grain was used as a comparison, but grain can vary in size and weight, making it an unreliable measure. A uniform system was thus invented, using local stones carved into the shape of a sleeping goose. The multiples of sleeping geese were surprisingly effective in regulating quantity.\n\n----\n\nWrought Iron\n\nInvented: c. 2500 B.C.E.\n\nSummary: The metal that gave its name to the Iron Age.\n\n\u2002\"Good iron is not hammered into nails, and good men should not be made into soldiers.\" \u2014Chinese proverb\n\nWhen people talk about iron, they generally mean wrought iron. This is one of three major materials whose base is iron ore\u2014a common element that has the ability to combine with other elements and therefore occurs in many forms. In order to produce its wrought, or worked, variety, charcoal and ore are heated sufficiently to reduce iron oxide to iron without melting it. The final product contains slag and other impurities that keep it from corroding.\n\nFirst produced in around 2500 B.C.E, wrought iron is theoldestform of Ton and gave the iron Age its name. Its availability increased when blast furnaces proliferated throughout Western Europe in the fifteenth century, before its slightly younger relative, cast iron (the malleable form of which is nowadays used in pipes as well as machine and car parts), became more popular.\n\nToday, wrought iron is most commonly used in the restoration of historic ironwork and the construction of high-quality commissions. Steel, the third type of iron, has a higher carbon content and greater hardness. The mild steel developed by Henry Bessemer in the nineteenth century was not only stronger but cheaper to make. The introduction of-steel initiated the gradual demise of what was once an indispensable material.\n\n----\n\nInk\n\nInvented: c. 2500 B.C.E.\n\nSummary: The Chinese introduce permanent dyes to highlight carved lettering.\n\n\u2002\"The palest ink will always be much better than even the sharpest memory.\" \u2014Chinese proverb\n\nAn ink consists of a liquid base and a pigment, or dye. The pigment provides a colored residue that sticks to a surface when the liquid dries. The first inks were invented by the Chinese some 4,500 years ago, made from a mixture of soot, lamp oil, gelatin (from animal skins), and musk (to counteract the smell of the oil). The ink was used to blacken the raised surfaces of stone carvings to emphasize shapes and letters. Later, in China and elsewhere, more reliable inks were developed using powdered minerals, plant extracts, and berryjuices as pigments.\n\nWith the advent of writing, and of papyrus and then paper, new types and colors of ink were required for use with writing implements designed for detailed and permanent texts. Some 2,500 years ago, the Chinese developed a solid ink to be stored as a stick; such inks are still in use today. When required, ink is simply scraped off the stickand mixed with water.\n\nOther early ink recipes included metal dyes, seed husks, and the inkof cuttlefish (yielding a deep brown ink known as sepia). One enduring recipe, invented some 1,600 years ago, consists of iron salts, tannin (from tree galls), and thickener. This ink is a blue-black color when first used but fades to brown overtime.\n\nWith the arrival of the printing press in the fifteenth century a d'fferent sort of ink was required to stick to printing blocks. A thick, oily ink made from soot, turpentine, and walnut oil was developed specifically for printing. Modern inks are complex fluids, consisting of varying amounts of solvents, pigments, dyes, resins, lubricants, and other materials.\n\n----\n\nEnclosed Harbor\n\nInvented: c. 2500 B.C.E.\n\nSummary: The first man-made dock is built on the Indian coast.\n\nThe world's first enclosed harbor, or tidal dock, is believed to have been constructed thousands of years ago during the Harappan or Indus Valley Civilization. It is located at Lothal, in the present-day Mangroul harbor, on India's Gujarat coast, bordering the Indian Ocean.\n\nThe dock was discovered in 1955 and is believed to have been constructed around 2500 B.C.E. It was trapezoid in shape and its walls were constructed from burned brick. It measured 40 yards (37 m) from east to west and 24 yards (22 m) from north to south. Inlet channels allowed excess water to escape and prevented erosion of the banks. On its northern side the structure was connected with the estuary of the Sabarmati River, and lock gates on that side ensured that ships remained afloat in the dockyard.\n\nThe entrance to the dock was able to accommodate two ships at a time, and the dock had facilities for loading and unloading cargo from the merchants' boats that constantly plied the harbor.\n\nShips coming to and from the dock at Lothal probably traveled north as far as the Tigris and Euphrates river deltas. Sumerian goods transported to Lothal included cotton fabrics, beaded jewelry, and foodstuffs.\n\nA major flood occurred in 2200 B.C.E., and by 1900 B.C.E. the dock at Lothal was buried in sand and silt. These natural events initiated a period of decline in the area that lasted hundreds of years. Excavations that began in the 1950s have provided archeologists with evidence of the activities of this porttown. While some researchers question the structure's intended use, the experts are agreed that it is an excellent example of ancient maritime architecture.\n\n----\n\nTunnel\n\nInvented: c. 2180 B.C.E.\n\nSummary: Babylonians excavate the first enclosed roadway.\n\nThe Babylonians are said to have built a tunnel under the Euphrates River in circa 2180 B.C.E. using what is now known as the cut-and-cover method. The river was diverted, a wide trench was dug across the riverbed, and a brick tube was constructed in the trench. The riverbed was filled in over the tube and the river allowed to resume its'normal course. However, there is no firm proof of this tunnel's existence, so we need to look to the more recent past. Many tombs of the Egyptian New Kingdom pharaohs buried between 1481 and 1069 B.C.E. in the Valley of the Kings were approached bytunnelsdug in the solid rock, butthese are as much entrances as tunnels.\n\nThe first real tunnel\u2014that is, one that was dug through solid rock from both ends, to meet in the middle\u2014was Hezekiah's Tunnel (the Siloam Tunnel) in Jerusalem. This tunnel was dug through solid rock to act as an aqueduct and bring water into the city during an imminent siege by the Assyrians. The two opposing teams of excavators made several directional errors during construction, resulting in a 1,757-foot (535 m) curving tunnel that gently slopes from the Gihon Spring down to the Pool of Siloam by the city walls; as a straight distance, it covers only 1,104 feet (309 m). More famously, and more accurately, the Greek engineer Eupalinos dug a straight tunnel through Mount Kastro on Samos to supply its capital with water. The 3,399-foot (1,036 m) tunnel, dug sometime between 550 and 530 B.C.E., was perfectly constructed: the two teams of excavators met in the middle with a vertical difference between the two tunnels ofonly 1.5 inches (3 cm).\n\nNotes:\n\n- Hezekiah's Tunnel is an underground water channel that may have incorporated an existing cave.\n\n----\n\nWater Filter\n\nInvented: c. 2000 B.C.E.\n\nSummary: The Indus Valley purifies drinking water.\n\nThe human quest for clean, drinkable water has been going on for thousands of years, and methods of purifying water have undergone countless incarnations over this time. According to the evidence of Sanskrit writings dating to approximately 2000 B.C.E., water filtration appears to have been developed in the Indus Valley, located in current day Pakistan and western India. The Sus'ruta Samhita, ancient Sanskrit medical writings, include instructions on purifying water: \"Impure water should be purified by being boiled over a fire, or being heated in the sun, or by dipping a heated iron into it, or it may be purified by filtration through sand and coarse gravel and then allowed to cool.\" Early purification methods were focused on the aesthetic qualities of water, such as taste and appearance, ratherthan hygiene.\n\nThe ancient Egyptians were also concerned with the appearance of their drinking water. As early as 1500 B.C.E. they were using alum to settle out particles clouding their drinking water. Hundreds of years later, Hippocrates invented what is known as the \"Hippocrates sleeve,\" a cloth sack for filtering water after it had been boiled.\n\nIn the eighteenth century modern sand filtration methods were introduced, which led to water filtration in large cities. But it was not until the nineteenth century that the linkbetween health and waterquality was established. Until this point all purifying methods were still based on the notion that pure water was simply water that looked clear and tasted good. When a cholera outbreak in London in 1855 was traced to a contaminated water source, the public finally came to realize that invisible contaminants in water could cause major health problems.\n\n----\n\nMechanical Lock\n\nInvented: c. 2000 B.C.E.\n\nSummary: Egyptian locksmiths learn to deter thieves.\n\n\u2002\"Later locks were so beautifully fashioned that the artist obscured the mechanical intention.\" \u2014F. J. Butter, Locks and Builders' Hardware\n\nThe Egyptians, and possibly other ancient peoples around the same time, invented the first mechanical locks some 4,000 years ago. The locks were a development of the simple wooden crossbeam that slides horizontally across the back of a door to bar entry. To hold the beam, or bolt, in place, a set of movable pins were located on the back of the door which dropped by gravity into recipient holes on the bolt as it moved into place. To unlock the door from the outside, a wooden key with matching pegs or prongs was inserted through a hole; the key raised the pins above the bolt, allowing it to be pulled back by a handle. Such keys could be up to 2 feet (0.6 m) long.\n\nThe introduction of metal locks around a thousand years ago provided smaller, stronger, and more precise locking mechanisms. \"Wards,\" solid obstructions within the lock to counteract tampering, were introduced by the Romans. Portable \"travel\" locks, or padlocks, were particularly useful to merchants on the trade routes of Europe and Asia.\t.\n\nIn Renaissance Europe the locksmith became a master craftsman. Bespoke ornamental locks were commissioned by the rich as a symbol of taste as well as prudence. Since that time, the age-old and' continuous battle between locksmith and lock picker has led to many ingenious variations.\n\n----\n\nAnesthesia\n\nInvented: c. 2000 B.C.E.\n\nSummary: Egyptians find ways to limit pain under surgery.\n\n\u2002\"...and Adam slept: and God took one of his ribs, and closed up the flesh instead thereof.\" \u2014Genesis 2:21\n\nMany breakthroughs made in modern medicine, such as open heart surgery or joint replacements, would never have been possible in a world without pain control But how did anesthesia develop?\n\nAs it turns out, early physicians never, to the best of our knowledge, resorted to knocking people out prior to performing surgery. Ancient Egyptian and Assyrian physicians compressed both carotid arteries at the same time, limiting blood flow to the brain and so inducing loss of consciousness in patients for the purpose of conducting a procedure. In addition, the Egyptians discovered that opium could help to ease pain, and the Assyrians used their own painkilling mixtures of belladonna, cannabis, and mandrake root. The Greeks and Romans copied and developed these techniques, and medieval Arabs even developed a form of inhalational anesthesia.\n\nThe advent of modern anesthesia can be traced to the latter half of the eighteenth century, when Joseph Priestley isolated nitrous oxide. Sir Humphrey Davy realized that it had anesthetic and soporific qualities, but it was considered more of an amusing way to pass the afternoon than a medical breakthrough. All that changed when a U.S. dentist started using it to perform dental extractions painlessly. A few years later, diethyl ether became the anesthetic drug of choice, first for dental procedures, and subsequently for other operations. Chloroform, which had the benefit of being less flammable, but the caveat of being much more likely to cause complications, was used in lieu of ether in some areas.\n\n----\n\nSpoked-wheel Chariot\n\nInvented: c. 2000 B.C.E.\n\nSummary: Egyptians develop a fast fighting platform.\n\n\"The Good God, Golden Horus, Shining in the chariot, like the rising of the Sun...\" \u2014Tablet of victory of Amenhotep III (1391-1353 B.C.E.)\n\nThe development of the spoked-wheel chariot circa 2000 B.C.E. revolutionized warfare. Bronze tools allowed carpenters to discard the solid, heavy, planked wheel in favor of a lighter, spoked wheel. This was made by placing a set of same-length spokes around a central hub and then fixing them within a wooden, circular rim, itself held together by an outer bronze band.\n\nSpoked wheels were larger and lighter than their predecessors and ran better over uneven ground. Used on a two-wheeled chariot that was pulled by a single horse and driven by a charioteer, with room for a warrior alongside, the charioteer could now easily outpace the foot soldier while the warrior\u2014with the advantage of speed and maneuverability- -attacked him with spear, lance, or bow. The use of such chariots soon spread throughout the Near East. The Hyksos people introduced them to Egypt in 1600 B.C.E. and by 1000 B.C.E. they were in use across Europe. Independently, the Chinese began to use these new chariots around 1300 B.C.E. The subsequent use of iron rather than bronze made them even more effective, increasing both the speed and strength of these fearsome war machines.\n\n----\n\nFired Brick\n\nInvented: c. 2000 B.C.E.\n\nSummary: Fired bricks are developed in the Middle East.\n\n\u2002\"And they said to one another, 'Come, let us make bricks, and burn them thoroughly.'\" \u2014Genesis 11:3\n\nIn ancient times, brick houses were made first by compacting together wet mud and clay into slabs and leaving them to dry in the sun. Once solid, the bricks were piled up to fashion a basic building. However, the major problem with sun-dried bricks is that rainy weather can revert them to wet mud. It took brick makers a long time to arrive at a solution\u2014buildings were constructed from dried mud blocks for more than 5,000 years before the fired brick appeared.\n\nUsing a combination of clay, sand, and water, brick makers in the Middle East formed a pliable mass of matter called a clot. The clot was shaped in a wooden mold to create what is known as a \"green\" (that is, unfired) brick. This was placed in a kiln and baked at nearly 3,600\u00b0F (2,000\u00b0C), before being allowed to cool down into a permanently hard, more durable brick.\n\nThe fired brick enabled the construction of the first truly permanent structures\u2014buildings much more resilient than those of mud bricks to harsh climates, changes in temperature, and weathering.\n\nFired bricks have been refined since they were first invented, the chemical ingredients of the clot mixture having been altered and optimized. Advances in technology have also made mass production possible. However, the premise behind the brick-making process remains exactly the same.\n\n----\n\nSaw\n\nInvented: c. 2000 B.C.E.\n\nSummary: Egyptians introduce the metal-toothed saw.\n\nThe saw evolved from Neolithic tools. Archeologists have found metal-toothed Egyptian saws dating back to OO B.C.E., but China claims that the saw was invented by Lu Ban in the fifth century B.C.E. Early blades were of copper; the Romans then used iron and reinforced the blade at the top, holding it in a wooden frame. In the nineteenth century in Europe a rigid blade of steel with a pistol-grip handle was introduced to produce a more accurate cut.\n\nThe cutting edge of a saw blade may be either serrated or abrasive. A handsaw with a stiff serrated blade can cut on both the push and pull strokes, but flexible blades allow cutting on the pull stroke only. Each tooth is bent to a precise angle, called the \"set,\" which is determined by the saw's intended use. Some teeth are usually splayed to each side, so that the blade does not stick, or \"bind,\" in the cut. An abrasive saw uses an abrasive disc or band for cutting.\n\nA number of different categories of hand-powered saws exist, designed either to be pushed forward or pulled backward, or both, and used by one or two people. These were followed by mechanically powered saws, using steam, water, petrol, or electricity, but they all had the same purpose of cutting large pieces of material into smaller ones. Later designs of saw include the circular saw (a rotating metal disc with saw teeth around its edge) and the chain saw (the blade is a chain carrying small cutting teeth).\n\nSamuel Miller's invention of the circular saw in 1777 only came into use when mills became steam-powered. In 1813, Tabitha Babbitt, a Massachusetts Shaker spinner, invented a circular saw as an improvement for lumber production. An early chain saw was developed in 1830 by the German orthopedist Bernard Heine for cutting bone.\n\n----\n\nAlphabet\n\nInvented: c. 2000 B.C.E.\n\nSummary: First phonetic alphabet originated in Egypt.\n\n\u2002\"All the teamin' my father paid for was a bit o' birch at one end and an alphabet at the other.\" \u2014George Eliot, author\n\nIn 1999, Yale Egyptologist John Darnell revealed to the world that the 4,000-year-old graffiti he had discovered at Wadi el Hol in Egypt's western desert represented humankind's oldest phonetic alphabet. Incorporating elements of earlier hieroglyphs and later Semitic letters, Darnell's discovery contradicted the long-held belief that alphabetic writing originated in the area of Canaan (modern-day Israel and the West Bank) midway through the second millennium B.C.E.\n\nNevertheless, the writings\u2014carved into soft limestone cliff\u2014are thought to be the work of Canaanites, or rather Semitic-speaking mercenaries serving in the Egyptian army during the early Middle Kingdom (c. 2050 B.C.E.-c. 1780 B.C.E.). Presumably developed as a simplified version of Egyptian hieroglyphs, the alphabet enabled those soldiers\u2014as well as ordinary people in general\u2014to record their thoughts and to read those of others. Many of the words are thought to be the names of people\u2014the desire to record them stemming from the belief that your afterlife would improve if people read out your name afteryourdeath.\n\nToday, the impact of the first phonetic writing system is still felt all over the world, since all subsequent alphabets (with the exception of the' Korean Hangul) have either directly, or indirectly, descended from it.\n\n----\n\nUmbrella\n\nInvented: c. 2000 B.C.E.\n\nSummary: The Chinese invent a collapsible shade.\n\n\u2002\"The American people never carry an umbrella. They prepare to walk in eternal sunshine.\" \u2014Alfred E. Smith, U.S. politician\n\nit was either the Chinese or the ancient Egyptians who first invented the umbrella. Early records from both cultures indicate that umbrellas were used to screen monarchs and people of high standing from the sun. The job of hoisting an umbrella above the emperor was often reserved for the servant of highest rank. The Chinese developed the technology furthest, waxing their paper parasols to provide protection from rain. Around 4,000 years ago, the Chinese also made their umbrellas collapsible, and since then the overall design has changed very little.\n\nMaking its way to Rome and Greece, the umbrella was used to shade women and even effeminate men from the sun while attending the open-air theater. These umbrellas were made from leather or skins. The umbrella reached England during the reign of Queen Anne, at the start of the eighteenth century, and were used only by women for protection from the rain. These umbrellas were made from waxed or oiled silk, which became difficult to open or close when wet. But umbrella use was discouraged by the religious, who saw it as interfering with God's intention to wet the faithful, and later on by carriage drivers, who lost business from people who could walk comfortably in inclement weather.\n\nThe umbrella's association with femininity was finally shaken off in the mid-eighteenth century when a writer and hospital founder named Jonas Hanway began to carry one. He was a man of poor health, who for thirty years carried an umbrella to ward off heat and cold. Gradually the umbrella came to be accepted by both sexes equally.\n\n----\n\nQuernstone\n\nInvented: c. 2000 B.C.E.\n\nSummary: Stones developed for the grinding of grain.\n\n\u2003\"Be he 'live, or be he dead\n\n\u2003I'll grind his bones to make my bread.\" \u2014Jack and the Beanstalk, English Fairy Tales (1890)\n\nAs humankind ceased to live as nomadic huntergatherers and began to settle down and raise crops, a different style of tool became necessary. People were now able to grow grain. However, grain had to be ground into flour in order to make bread. To accomplish this task an early form of mill, called a quernstone, eventually emerged.\n\nApproximately 4,000 years ago, humans worked out that they could place one rough stone on top of another and use the two of them to grind grain into small particles. Early versions consisted of a rough rock base, or quern, and a smaller rock that could be ground over the top of it, often referred to as a rubbing stone.\n\nA major advance occurred when the top stone was made to turn on the stationary bottom stone rather than move parallel to the long axis of the stone. These so-called \"rotary querns\" eventually evolved to feature a central hole in the upper stone that would allow grain to be poured in from the top and flour to work its way out from between the two stones. Later societies experimented with using different types of stone\u2014the Romans favoring types of lava for their rough and sharp surfaces.\n\nThe quernstone evolved into larger water- and wind-powered mills, but is still in use in societies where grain is ground by hand.\n\n----\n\nAqueduct\n\nInvented: c. 2000 B.C.E.\n\nSummary: Water conduits invented by the Minoans.\n\n\u2002\"It is a wretched business to be digging a well just as thirst is mastering you.\" \u2014Titus Maccius Plautus, playwright\n\nAn aqueduct is any artificial conduit for the delivery of water, though the term is often misunderstood to refer only to the arches sometimes used to enable these channels to span low ground.\n\nAncient civilizations on the Tigris, Euphrates, and Nile diverted water from these great rivers for irrigation, but the paucity of supply in Minoan Crete encouraged the development of complex storage and distribution systems for the first time in the second millennium B.C.E.\n\nIt is the Romans who are best known for their innovative water supply systems. Between 312 B.C.E. and 226 C.E. the Romans constructed eleven major aqueducts to provide Rome with water.\n\nAqueducts did not become commonplace again until the late nineteenth century, when rising populations in the United Kingdom outgrew local water sources, and engineers developed systems of aqueducts to provide a clean and reliable supply.\n\nThe United States followed suit in the twentieth century with the construction of vast aqueducts to supply its cities, and these, including the 444-mile-long (715 kilometer) California Aqueduct remain among the largest and longest in the world.\n\n----\n\nRubber Ball\n\nInvented: c. 1600 B.C.E.\n\nSummary: Ancient Mesoamericans were the first people to invent rubber balls.\n\nWhile other ancient civilizations were playing with balls made of stitched-up cloth or cow bladders, the people of Mesoamerica (present-day Mexico and Central America) were playing a game of life and death using balls made from a processed rubber. By adding the juice of the morning glory vine to latex (raw liquid rubber) harvested from the native rubber tree (Castilla elastica), they created balls that had great bounce.\n\nAs early as 10 B.C.E., the Mesoamericans used this method to make resilient rubber balls that defied the natural brittleness of solid latex. Their amalgamation could be shaped into any conceivable form, but would harden within minutes, making it impossible to reshape the object afterward. They used this process for a variety of artifacts and produced balls of different sizes, the biggest being larger than a volleyball and weighing upto eight pounds (3.6 kg).These were then used in ritual ball games that had great political and religious significance.\n\nWhile modern followers of sports refer to matches as \"a matter of life and death,\" this was actually the case for the contestants on Central America's fields and ball courts. For the Mesoamericans, the games epitomized their worldview of life as a struggle between good and evil. Winners were showered with riches, whereas the leader of the \"evil\" losers was sacrificed in the belief that this was the only way to keep the sun shining and the crops growing.\n\nThe Mesoamericans' rubber ball was therefore, a potentially life-changing device long before Charles Goodyear's heat- and sulfur-treated gum of 1839 added a new facet to leisure activities.\n\n----\n\nShadow Clock\n\nInvented: c. 1500 B.C.E.\n\nSummary: Egyptians harness the light of the sun to tell the time.\n\nThe sun travels across the sky at the rate of 15 degrees per hour (reappearing ata given pointafter one day) and the shadow that it casts moves at a similar rate. In sunny climes the shadow has been used as a clock. The most ancient clock was the vertical obelisk. This tapering column, rather like Cleopatra's Needle in London, cast a shadow that varied in its length and orientation as the day progressed.\n\nThe Egyptians had a small, portable shadow clock. It consisted of a T-shaped bar that lay on the ground, except that close to the shorter crossbar was a 90-degree bend that lifted the crossbar above the long horizontal stem so that its shadow would fall on the stem. The long stem was pointed directly toward the west point on the horizon in the morning. At noon, it was pointed in the reverse direction, toward the east. There were five variably spaced markers on the bar, the one directly under the \"T\" indicating where the shadow would be at noon and the subsequent ones for the five hours between noon and sunset (or sunrise and noon if it was being used in the morning). The Egyptians divided the period when the sun was above the horizon into ten \"hours.\" There were two more \"hours\" for the twilight dawn and dusk periods, and the night was divided into twelve \"hours,\" making the twenty-four-hour day.\n\nThe use of this shadow clock required the Egyptians to have an accurate knowledge of the direction of their cardinal points. North, south, east, and west were very important to them, as is demonstrated by the sides of their pyramids, which are aligned very accurately in these directions.\n\n----\n\nScissors\n\nInvented: c. 1500 B.C.E.\n\nSummary: Egyptians create the first fabric cutters.\n\n\u2002\"Scissors... evolved, step by step, with many other tools destined to cut, separate, and pierce.\" \u2014Massimiliano Mandel, Scissors\n\nSpring-type scissors probably date from the Bronze Age. Consisting of blades connected by a C-shaped spring at the handle end, they were used in Egypt from 1500 B.C.E. to cut silhouettes for artwork.\n\nPivoted scissors used in ancient Rome and parts of Asia were made of bronze and iron, as were sixteenthcentury European ones. Scissors and other implements became more widely used as their quality improved with better methods of metal forging, but cast steel was not used until 1761, when Robert Hinchliffe manufactured scissors in Sheffield. Many were hand-forged with elaborate handles, but the styles were simplified in the nineteenth century to facilitate large-scale mechanical production.\n\nThe steel used in scissors contains varying amounts of carbon, depending on the quality of scissors. Drop hammers form the rough shape of the blade from blanks made from red-hot steel bars. The blades are then trimmed and hardened. The steel may contain from 0.55 to 1.03 percent carbon, with the higher carbon percentages providing a harder cutting edge for certain applications.\n\nSurgical and other specialized scissors are made of stainless steel; cheaper scissors are made with softer steel that is cold pressed. Shears used for sheet-metal work, called tin snips, have high-leverage handles but are constructed in the same way as scissors.\n\n----\n\nWater Clock\n\nInvented: c. 1500 B.C.E.\n\nSummary: Egyptians free timekeeping from the sun.\n\nFor millennia, humankind has kept track of the progress of time by observing natural bodies, most notably the sun and the st^rs. In cloudy periods, however, these cannot be seen. The water clock, or clepsydra in Greek, is a timekeeper that works by measuring a regulated, uniform flow of water out of, or into, a vessel. With sufficient water, and a large enough vessel, this timekeeper can \"run\" for a day or two without needing to be refilled, or emptied.\n\nImagine a cylindrical water container with a hole in the bottom. The rate at which water drips out of the container is a function of the pressure exerted by the water that it contains; so the more water in the vessel (that is, the greater the \"head\" of water) the faster is the flow rate. When the container is full, the water level goes down quickly, but the flow is slower when it is nearly empty. Around 1500 B.C.E. the Egyptians realized that if the sides of the bucket tapered parabolically, the water level would go down at a uniform rate, and this would make a reasonable basis for a clock. Others introduced multiple cistern systems that ensured that the head of water remained constant. The dripping of the clepsydra in ancient times has found an echo in the ticking of a modern clock.\n\nLater on, the Romans and Chinese constructed complicated float systems that followed the changing water level and moved an hour hand on a circular dial, or rang bells at specific times.\n\nSimple forms of the clepsydra were also used to measure specific time intervals, for the regulation of religious services or political debates, in the way that sand glasses are now used as egg timers.\n\n----\n\nSteel\n\nInvented: c. 1500 B.C.E.\n\nSummary: East Africans harden iron with carbon.\n\n\u2002\"The Iron Age itself came very early to Africa, probably around the sixth century B.C.E....\" \u2014Richard Hooker, historian\n\nSteel was first produced in carbon furnaces in subSaharan East Africa, around 1500 B.C.E. Steel is an alloy of iron and 0.2-2.4 percent carbon. It can also contain trace elements such as vanadium, manganese, or tungsten. The carbon acts as a hardening agent and prevents the lattices of iron crystals from sliding past each other. The more carbon present in steel, the harder it is, but this is at the expense of increased brittleness. By controlling the exact ratio of iron to carbon and other elements, the properties of the steel can be tuned to those needed fora specific function.\n\nDamascan steel (also known as Wootz steel) was famed for its strength and ability to keep an edge. It actually originated from India around 300 B.C.E. before being widely exported; it was identified by its banded appearance. Recent studies of blades made with Wootz steel have found that they contain carbon nanotubes that contributed to their legendary properties. Unfortunately, the process for making the steel died out in the eighteenth century after the necessary ores were depleted.\n\nModern steel making took off in Europe in the late 1850s with the invention of the Bessemer process. The key element of this process was the removal of impurities via oxidation, achieved by blowing air through the molten iron. For the first time this allowed cheap production of steel onan industrial scale.\n\n----\n\nSword\n\nInvented: c. 1500 B.C.E.\n\nSummary: Iron smelting brings sword-length weapons.\n\nA sword consists of a blade and a handle, which is itself made up of a hilt, or grip, and a pommel, or counterweight. A sword blade has one or two edges for striking and cutting, and a point for thrusting. The word \"sword\" comes from the Old English sweord, meaning to wound or hurt.\n\nHumans developed weapons from sharpened flint tools, and in the Bronze Age short-bladed weapons such as daggers were used. It was then impractical to make bronze swords more than 3 feet (90 cm) long, but with the development of smelting technology and stronger alloys, longer iron swords became possible from about 1500 B.C.E.\n\nThe Chinese single-edged steel sword appeared in the third century B.C.E. By Roman times the hilt was distinct from the short, flat blade, and by the European Middle Ages the sword had acquired its main basic shape and a variety of designs were devised to fulfill different functions. Medieval swords had a doubleedged blade, a large hilt, and protective guard and were designed to be gripped in both hands. A curved blade for cutting, used in Asia, was introduced into Europe by the Turks in the sixteenth century, and in the West was modified into the cavalry saber.\n\nHunting swords and the naval cutlass developed from the sixteenth-century \"hanger,\" with its convex cutting edge, as did the bayonet, developed in the seventeenth century for use with firearms. During the seventeenth and eighteenth centuries, the shorter \"smallsword\" became a fashion accessory. The smallsword and the rapier remained popular dueling swords well into the eighteenth century.\n\n----\n\nRudder\n\nInvented: c. 1420 B.C.E.\n\nSummary: Egyptians learn to direct their watercraft from the stern.\n\nEgyptian tomb paintings from around 1420 B.C.E. depict a ship fitted with steering oars on either side of the stern and are thought to be the earliest evidence of the use of the rudder principle, by which water flowing past the boat's hull is redirected. The same technique was long used on Mediterranean cargo ships, but the Vikings preferred a single oar, mounted to the starboard side of the stern of their longboats. The oar could be easily lifted in shallow water but was not always effective in heavy seas, when it could be raised out of the water by the waves.\n\nA rudder is most efficient when mounted along the vessel's centerline, and in accordance with this Chinese vessels have been designed with hinged rudders on the stern since the first century B.C.E. There is no evidence of such a practice in Europe until some eleven centuries later, and centerline rudders did not become widespread until the thirteenth century C.E. It is not certain whether this change came about through independent development in northern Europe or by a transfer of knowledge from China. Either way, the rudder was a key enabler for the subsequent rise of Western fleets to naval superpowers.\n\nIn the early 1900s the Wright brothers used vertical rudders behind the tailfins of their pioneering gliders to steer their first powered aircraft during its first flight of 1903. Modern aircraft use similar rudder systems to control side-to-side yawing motion. The rudder, albeit with a host of variations and. specializations, is still the means by which we steer not only our ships but a multitude of other craft both in the water and the sky.\n\n----\n\nAbacus\n\nInvented: c. 1000 B.C.E.\n\nSummary: Mesopotamians usher in the age of computing with the first calculator.\n\nThe early calculating instrument we know as the abacus\u2014consisting of a wooden frame supporting wires or rods on which wooden beads slide from side to side\u2014was developed in Mesopotamia from a flat, sand-covered, stone counting board on which pebbles were moved. This aid to calculation was in use long before the adoption of the Hindu-Arabic numeral system and can be adapted to any numeral base. The abacus has a huge advantage over counting on the fingers of the hand, simply because it can be used to record very large numbers accurately.\n\nThe easiest type of abacus to understand is the modern Western version that uses a base of ten. Here each wire carries ten beads and represents a decadal unit, that is one, ten, 100, 1,000 and so on. A number, say 617,483, can be represented by positioning the respective numberof beads, on each wire, against one side of the abacus. It is then a relatively easy task to add or subtract another number from the first one.\n\nAfter a calculation, the whole abacus can also be reset for further computing by a simple shake.\n\nAbaci were widely used throughout the ancient world and are still important as a teaching aid in preschool. The movement of the beads helps children to understand the groupings of ten that are the foundation of our present number system.\n\nOther abaci were produced with an interior d'viding bar. The Chinese suan-pad, introduced about 1200 C.E., had five beads on one side of the bar and two above. The Japanese soroban originally had afive-to-one bead distribution. The Russian schety followed the European pattern with ten beads and no bar.\n\n----\n\nPontoon Bridge\n\nInvented: c. 1000 B.C.E.\n\nSummary: Chinese make a temporary water crossing.\n\nIn 1000 B.C.E. it was recorded that King Wen of the Zhou Dynasty, ancient China, designed the first pontoon bridge. The invention was to be incorporated into his elaborate wedding ceremony, allowing the wedding procession to cross the Weihe River.\n\nKing Wen's design was of a floating bamboo deck structure supported by boatlike pontoons to allow a water crossing. Since their invention, the floating bridges have become much more than just a decorative water crossing\u2014they have become a military weapon. One of the earliest recorded pontoon bridges to be used in combat was built in 974 C.E. by the Song Army of ancient China, who constructed it in fewer than three days. However, such bridges take a lot less time to destroy or dismantle--a necessary practice to prevent the enemy from following.\n\nKing Wen's design is still being used by the military to this day. In 2003 the U.S. Army's \"Assault Float Ribbon Bridge\" was used to cross the Euphrates River near Al Musayib during \"Operation Iraqi Freedom.\"\n\nNot all pontoon bridges are temporary structures. Some are established across rivers where it is uneconomical to build a suspension bridge. These bridges include an elevated section to allow boats to pass. One of the longest of these bridges spans Lake Washington in Washington State; the Lacey V. Murrow Memorial Bridge, 6,620 feet (2,019 m) in length, was completed in 1940 and cost $10 million less than an orthodox bridge to build.\n\nCheap though they are, pontoon bridges are not particularly safe. They are especially vulnerable to bad weather and have been known to be destroyed by strong winds. In fact, part of the Lacey V. Murrow Memorial Bridge sank in 1990 after a heavy storm and was subsequently rebuilt.\n\n----\n\nBattering Ram\n\nInvented: c. woo B.C.E.\n\nSummary: Assyrians build a newsiegeweapon.\n\n\u2002\"Forty-six of Hezekiah's... towns and innumerable smaller villages I besieged and conquered.\" \u2014King Sennacherib of Assyria\n\nThe battering ram has none of the subtleties of the Trojan horse, but the results are the same; an uninvited entry. Principally weapons of war, early battering rams were heavy wooden beams, sometimes with a metal-covered end that was on occasion shaped as a ram's head (hence the name), whose sole purpose was to breach the fortifications of towns and castles.\n\nIn its simplest mode of operation, the battering ram was carried by several people who would run with the ram and thrust it at the target with as much force as they could muster. The key to success was speed, however, and later rams were wheeled.\n\nBattering rams became increasingly sophisticated. One important example was the siege engine of the Assyrians of circa 1000 B.C.E. Their ram was suspended from a covered wooden frame so that it could be continuously swung at the target, while the frame provided protection for the soldiers within. Wet hides or earth were used to defend against flaming arrows. Mounted on wheels, this ram was easily maneuvered.\n\nDespite changes in warfare, battering rams still have their place today, attached to military vehicles. One person-operated metal rams are also used by today's law enforcement agencies.\n\n----\n\nSandwich\n\nInvented: c. 1000 B.C.E.\n\nSummary: Hittites serve meat between slices of bread.\n\nThe invention of the sandwich is popularly credited to John Montague, Fourth Earl of Sandwich. Its origins go much further back than this, however. Another common belief comes from the Jewish tradition\u2014 that the sandwich was invented by Hillel the Elder in The first century B.C.E. During Passover, Hillel the Elder's invention is commemorated in the text: \"This is what Hillel did when theTemple existed: he used to enwrap the Paschal lamb, the matzo, and the bitter herbs and eat them as one.\" At this point of the remembrance service, the participants do likewise.\n\nEvidence suggests that the sandwich may go back even further than this, to the days of the Hittite Empire, hundreds of years before. There are records of soldiers of the empire being issued with meat between slices of bread as their rations.\n\nToday's sandwich comes in a multitude of varieties from international cuisines. Although there has been some controversy over what constitutes a sandwich (resulting in one court ruling in the United States), it is generally understood to be a meal made from two slices of bread and a filling.\n\nThe Earl of Sandwich's part in the story, apart from giving the meal its name, lay in popularizing the sandwich in England in the eighteenth century. It is believed that Montague liked the sandwich because he could eat it without getting grease on his fingers from meat, making it a suitable snack to eat while playing cards. Whether or not this is true is debatable, but certainly after this time the sandwich became the dominant lunchtime meal in England. Being easy to prepare, portable, and adaptableto limitlessvariations, the sandwich has never lost its popularity and can now be bought from thousands of dedicated outlets and chains across the world.\n\n----\n\nInoculation\n\nInvented: c. 1000 B.C.E.\n\nSummary: Chinese monk pioneers smallpox protection.\n\n\u2002\"The English are fools... they give their children the smallpox to prevent their catching it.\" \u2014Voltaire, Letters on the English (c. 1778)\n\nSmallpox is believed to have first appeared around 10,000 B.C.E. Ramses V died suddenly in 1157 B.C.E.; his mummy bears scars that have a striking resemblance to those left by that scourge. Smallpox killed about a third of its victims and left many survivors scarred. But it was noted that survivors never got smallpox again.\n\nAfter the eldest son of China's Prime Minister Wang Dan died around 1000 B.C.E. of smallpox, Wang Dan sought a cure for it. A Daoist monk introduced the technique of variolation, a type of inoculation. Scab-coated pustules taken from survivors were ground up and blown into the nose like snuff.\n\nReports of inoculation reached Europe in the 1700s. In London, in 1721, Lady Wortley Montague and the Princess of Wales urged that four condemned prisoners be inoculated. Several months later the men were exposed to smallpox and all survived. Now that variolation was deemed safe, the royal family underwent it and the procedure became fashionable.\n\nExposing a person to smallpox to prevent smallpox seems madness, but as the scabs were taken from survivors, the virus had been weakened. Mortality from variolation was about 1 percent; mortality from smallpox was 20 to 40 percent. In 1774 Benjamin Jesty inoculated his wife with the cowpox virus. In 1796 Edward Jenner did the same with young James Phipps and the process of vaccination was started.\n\n----\n\nKite\n\nInvented: c. 1000 B.C.E.\n\nSummary: Unknown Chinese establish a long and colorful tradition.\n\n\u2002\"Tie the handkerchief corners to the extremities of the cross, so you have the body of a kite.. \u2014Benjamin Franklin, to Peter Collinson, 1752\n\nThe kite was first invented in China about 3,000 years ago. The first recorded construction of a kite was by the Chinese philosopher Mo Zi (c. 470\u2014391 B.C.E.) who spent three years bui'ding it from wood. Materials ideal for kite building, such as silk for the sail material and bamboo for a strong, light frame, were plentiful in China, and kites were soon used for many purposes. Stories and records from ancient China mention kites that were used to measure distances, to test the wind, and to communicate during military maneuvers. The earliest Chinese kites were often fitted with musical instruments to create sounds as they were flown; they were decorated with mythical symbols.\n\nThe first kites were flat and rectangular in shape, but kites are now designed in a variety of forms, including boxes and other three-dimensional assemblies. Kites flown as a hobby are particularly popular in Asia, where kite flying is a ritual incorporated into the national festivals of many countries. The Chinese people believe that kites are lucky and they fly them to ward off evil spirits.\n\nThe kite has been used in important scientific research, including Benjamin Franklin's famous experiment to prove that lightening is electricity. The Wright brothers constructed a 5-foot (1.5 m) box kite in the shape of a biplane when they were experimenting with the principles of controlling an airplane in flight. This research helped the brothers achieve their dream of making the world's first controlled, heavier-than-air, human flight in 1903. Modern kites have been used to pull sledges over snow-covered terrain in the Antarctic.\n\nNotes:\n\n- Kites constructed in butterfly designs have long been prominent in the Chinese kite-flying tradition.\n\n----\n\nPulley\n\nInvented: c. 750 B.C.E.\n\nSummary: Assyrians revolutionize the lifting of weights.\n\nA pulley is one of the simplest machines, essentially a circular lever in the form of a wheel or fixed curved block, with a groove around it to accommodate a rope or belt. The earliest evidence for the existence of the pulley comes from Assyria in the eighth century B.C.E.; a painting of a battle scene shows a warrior using a simple pulley to lift a bucket over a wall.\n\nPulleys are mainly used to move or lift a load. A single fixed pulley can be used to change the direction in which a force is applied, as it may be easier to pull on a rope than to drag or push the load. When the rope is fixed at one end and another pulley is added, the system effectively halves the required force, as each part of the rope carries an equal share of the load. This does not reduce the mechanical work required: work is the multiple of force and distance and the rope\u2014now doubled in length\u2014will need to be pulled twice as far. More pulleys can be added to make a \"compound pulley\" system, further multiplying the effectiveness of the force applied.\n\nPulleys have been in use throughout the world for many centuries. Although the earliest hard evidence of their use dates from the eighth century B.C.E., it is highly likely that the principle was in use long before that. Early humans most likely created pulleys by throwing a rope or a fibrous vine over the branch of a tree to hoist up a heavyweight.\n\nIt is highly probable that pulleys were used by the builders of early massive constructions, such as the ziggurats of Mesopotamia (built as early as the fourth millennium B.C.E.), Stonehenge (built in 2200 B.C.E.), and the pyramids of Egypt (third millennium B.C.E.).\n\nNotes:\n\n- A remnant of a simple bronze pulley without wheel was found at Gezer, in Israel.\n\n----\n\nBuckle\n\nInvented: c. 700 B.C.E.\n\nSummary: The ancient Greeks introduce the buckle fastener.\n\nThe buckle originated in circa 700 B.C.E. Many examples survive from ancient Greece and Rome, and indeed from all over Europe into the Middle Ages. The word buckle comes from the Latin word bucca meaning \"cheek.\" Due to its ease of use and manufacture, the buckle continues as a solution to the many fastening problems posed by clothing and equipment.\n\nEarly buckles were manufactured from bone, ivory, and metal and were used on military gear, harnesses, and armor, being favored mainly because of their durability. The use of the buckle was not restricted to these areas though; they were commonly used as fasteners on boots and shoes and, prior to the invention ofthezip, on clothing.\n\nThe addition of decorative ornamentation lifted the buckle out of its utilitarian realm. Buckles made of silver and bronze and inlaid with precious stones have been found in graves and tombs such as that of Childeric I, king of the Franks, who died in 481 C.E.\n\nJeweled shoe buckles were in vogue during the reign of Louis XIV. During the nineteenth century, the British Navy was at the height of its power, but it had one intractable problem; the sailors' clothes were fastened with laces and eyelets. In cold, wet conditions the fastenings became fiddly to use, and waterlogged clothes were poorly supported by the laces. One clever seaman allegedly had the idea of fastening a buckle to a leather strap and using this to hold up his trousers; it worked and was easy to use, even with freezing fingers.\n\nToday, buckles remain a fashion accessory though lack the status of jewelry.\n\n----\n\nMetal Anchor\n\nInvented: c. 650 B.C.E.\n\nSummary: Greeks use metal to weigh down anchors.\n\nThe need to moor ships and boats is as old as the vessels themselves. The ancient world\u2014Mesopotamia, Egypt, Greece, and Rome\u2014used whatever came to hand for the task, from a basketful of stones to a sackful of sand, lowered by rope. Single large stones with a rope-hole became common.\n\nUse of metal crept in gradually during classical times, as ships increased in size and varied anchor designs were developed for different situations and vessel types. In 500 B.C.E., bronze anchors were cast in Malta. Some crude wooden anchors had pieces of lead or other heavy metals added for weight, while a popular wooden hook design gradually became fashioned entirely in iron instead. Iron anchors have been recovered from Roman merchant vessels. Soon the classic form developed. This featured flukes (the pointed ends of arms at the anchor base) and a stock (a horizontal bar that upends the anchor to ensure that one fluke becomes well embedded).\n\nThe invention of the anchor has been credited to the legendary King Midas (700 B.C.E.), but other tales relate how, around 650 B.C.E., Greek sailors first added hooks to a stone anchor and established the basic future design. Anchor design changed little over the centuries. By 1700, the prevalent anchor design was the kedge type made from iron, which featured a long shank. By 1901, a stockless anchor made from cast steel had been patented. In 2003, the world's oldest wooden anchor, with a metal crown, was found at the former ancient Greek colony of Klazomenai in modern Turkey. Dating back to 600 B.C.E., this may have been close to the birth of the fully metal anchor.\n\n----\n\nCrossbow\n\nInvented: c. 550 B.C.E.\n\nSummary: Chinese pioneer the longbow's smaller rival.\n\nThe crossbow originated in ancient China circa 550 B.C.E. and is thought to have been developed from the horizontal bow trap, which was used to kill game. For use as a weapon, the Chinese developed many different designs of crossbows and drawstrings. Some had stirrups attached to them to hold the bow down when the bowmen were rearming. Later crossbowcannons had winches to pull back the strings, because people would not have been strong enough to do this unaided. The Chinese also invented grid sights in 100 C.E. and a machine-gun type of crossbow, which had a magazine of bolts fitted above the arrow groove; as one bolt was fired another dropped into its place. Poisoned crossbow bolts were also used.\n\nKnowledge of the crossbow was probably transmitted from China to Europe via the Greeks and Romans. The weapon could be used by an untrained soldier to injure or kill a knight in armor. The crossbow was adopted in Europe in the tenth century C.E. and used throughout the Middle Ages. William the Conqueror brought the medieval crossbow to England in 1066, but the Welsh longbow supplanted the crossbow during the reign of Edward I (1272-1307). Many viewed it as an inhuman weapon, requiring no skill and having no honor, and in 1139 the Pope, through the Second Lateran Council, condemned the use of crossbows against anyone except infidels.\n\nToday, crossbows are mostly used for target shooting in modern archery. In some countries crossbow hunting is still allowed, such as a few states in the United States, Asia, Australia, and Africa.\n\n----\n\nCrane\n\nInvented: c. 550 B.C.E.\n\nSummary: Greeks use cranes for heavy construction.\n\n\u2002\"Archimedes had stated that given the force, any given weight might be moved...\" \u2014Plutarch, Life of Marcellus\n\nThe extent to which human beings extend their natural capabilities through the use of machines is something that distinguishes us from other members of the animal kingdom. Ctanes are an especially relevant example of this; the ability to raise and maneuver weights vastly greater than those that people could lift and move unaided has played a defining role in the development of human society.\n\nThe crane is a system of pulleys and cords or wires attached to a framework that enables the movement of heavy weights both vertically and horizontally through the use of mechanical advantage. The earliest cranes have been dated to approximately 550 B.C.E., although there are Greek architectural constructions still in existence that predate this by several hundred years, and that undoubtedly would have required some sort of supporting pulley mechanism. Cranes were used in ancient Greece for a variety of purposes. They were integral to Greek construction and were also used for pulling heavy loads. The Claw of Archimedes was a wall-based crane used to hoist invading ships to a great height, only to drop them to their destruction.\n\nCranes continued to be used extensively in ancient Rome, where a \"treadmill crane\" was used to help in building projects. In reconstructions, single blocks of stone weighing as much as 100 tons have - been lifted considerable heights above the ground using this technology. Cranes fell out of use for a while, only to reappear in the late Middle Ages. They have continued to see heavy usage through to the present day.\n\n----\n\nArtificial Limb\n\nInvented: c. 550 B.C.E.\n\nSummary: A Persian reportedly creates the first replacement body part.\n\n\u2002\"Demeter, goddess of agriculture, ate Pelops' shoulder, but made him a prosthetic ivory shoulder\" \u2014Ampulove, History of Prosthetics\n\nThe earliest written reference to an artificial limb occurs in an epic Indian poem, the \"Rig-Veda,\" which was compiled between 3500 and 1800 B.C.E. Written in Sanskrit, the poem includes a description of the amputation of the warrior Queen Vishpla's leg during battle. Later fitted with an iron prosthesis by the Ashvins (celestial physicians), she returned to combat.\n\nMost authorities doubt the story of Queen Vishpla, and turn to the Histories of Herodotus for the first plausible reference to a prosthetic limb. Herodotus describes how, in the mid sixth century B.C.E., Hegesistratus of Elis, a Persian soldier and seer imprisoned by the Spartans, was sentenced to death, and cut off part of his foot to escape from the stocks. Hegesistratus fashioned a wooden prosthesis to help walk the 30 miles (48 km) to Tregea, but unfortunately was captured by Zaccynthius and beheaded.\n\nIn the first century B.C.E., Pliny the Elder wrote in his Natural History of Marcus Sergius, a Roman general who led his legion against Carthage in the Second Punic War (218 to 210 B.C.E.). The general sustained twenty-three injuries, necessitating the amputation of his right arm. An iron hand was fashioned to hold his shield, and he returned to battle. He fought four more battles, and had two horses killed from beneath him.\n\nThe oldest known prosthesis was discovered in a tomb in Capua, Italy, in 1858. Made of copper and wood, it dates to 300 B.C.E., during the period of the Samnite Wars. Regrettably, the Capua leg did not survive another war\u2014it was destroyed in 1941 when the Museum of the Royal College of Surgeons was seriously damaged in an air raid.\n\n----\n\nWinch\n\nInvented: c. 500 B.C.E.\n\nSummary: Persians use the winch in bridge building.\n\n\u2002\"They stretched the cables by twisting them taut with wooden windlasses.\" \u2014Herodotus of Halicarnassus, historian\n\nThe first known reference to a winch is made in the writings of Herodotus of Halicarnassus on the Persian Wars in 480 B.C.E., in which wooden winches were used to tighten cables used in a bridge that crossed the Hellespont. The idea caught on quickly and within a hundred or so years the winch had reached Greek construction sites, though evidence suggests that it was invented by the Assyrians in the fifth century B.C.E.\n\nA simple winch is used to wind rope or cable, but the tool has many more applications when fitted with a cleat to maintain tension and prevent the rope or cable from unwinding. Cleated winches have long served on boats and harborsides to keep ships and boats closely moored to docksides. They are important for lifting work on construction sites, enabling workers to complete tall projects in a fraction of the time otherwise required.\n\nIn medieval times a cleated winch was an important component of the rack, a bedlike torture device designed to stretch a person by infinitely painful degrees. Cleated winches are used to raise flags on flagpoles and keep them aloft, and mini winches also feature on the reels of fishing rods, allowing anglers to maintain or release line tension when playing a fish. Winches are used by tow-trucks, and they play a vital role in helicopter rescues, safely extracting people from dangerous situations.\n\n----\n\nHammock\n\nInvented: c. 425 B.C.E.\n\nSummary: Alcibiades creates a new type of bed.\n\nThe precise year of the hammock's invention is impossible to tell, but estimates of 1000 B.C.E. are considered reasonable, with the Mayan Indians most often credited with the invention. However, there is no evidence for this, and the hammock's creation is often attributed to a later inventor. In Greece, Alcibiades (c. 450-404 B.C.E.) was a student of Socrates, and some sources attribute its invention to him.\n\nWestern European society was first introduced to the hammock in 1492 when Christopher Columbus returned from the Bahamas where he had found the native people resting and sleeping in them. He took some hammocks back to Europe and within a century or so they were standard issue for European sailors. In the cramped ships of the time their value was obvious, as they could be stowed away or hooked up for use almost instantly. More than any other form of bed, they allowed sailors to sleep in paradoxical harmony with the rocking movement of their ship, hanging downward under the pull of gravity while the ship rolled, pitched, and yawed around them.\n\nArriving in the wake of Columbus in 1500, the Portuguese explorer Pero Vaz de Caminha saw a Caribbean native asleep in a suspended fishing net. He called this innovation a rede de dormir, or \"net for sleeping,\" and rede remains the Portuguese name for a hammock. At much the same time the Spanish conquistadors were also encountering hammocks used by Caribbean Indians. The term they used was homoca, itself derived from hamaca, the Indian name for the hamak, or hammok, tree whose bark supplied the fibers from which the hammocks were woven.\n\nAside from twenty-first-century materials being adopted, the hammock's design has remained largely unchanged over the centuries.\n\n----\n\nChain Mail\n\nInvented: c. 400 B.C.E.\n\nSummary: Romanians make the first known protective metal shirt.\n\n\u2002\"...Chain mail makers, slowly going mad while they clipped together chain mail rings..\" \u2014Ursula K. Le Guin, Tehanu (1990)\n\nChain mail was originally called just mail or chain in England and maille in France (the French word maille means \"meshy\" or \"netted\"). It was not until the 1700s that chain mail became its common English name.\n\nMail is constructed from a series of links made from wire. These are bent into circles around a forming cylinder, and the finished links are welded or riveted into the form of a shirt. The result is a sturdy piece of armor that affords very effective protection from most cutting blows while at the same time being relatively lightweight and flexible.\n\nChain mail alone could not protect against crushing injuries, however, and warriors therefore combined it with a gambeson, which was worn underneath the mail. This was a padded jacket made from layers of wool and other materials that provided effective resistance to impact injuries.\n\nThe first mail shirt on record is from a Romanian Celtic chieftain's burial chamber and dates back to the fourth century B.C.E. Chain mail saw extensive use throughout the first half of the last millennium, being employed throughout Europe and Asia, but it was not until the thirteenth century C.E.. that mail armor really came into its own. Extending over the whole of a knight's body, the basic mail shirt (or hauberk} was joined by individual mail pieces for the legs, arms, and head, providing more complete protection.\n\nKnights did not wear this type of full armor for long, however. Items of plate armor were increasingly added to the mail, and these grew increasingly more sophisticated. Foot soldiers continued to wear chain mail until late medieval times.\n\n----\n\nDistillation\n\nInvented: c. 400 B.C.E.\n\nSummary: Alcohol distillation precedes that of water.\n\n\u2002\"Reserve your right to think, for even to think wrongly is better than not to think at all.\" \u2014Hypatia of Alexandria, distillery inventor\n\nDistillation is not a process confined to spirit production; it is a method of separating chemical substances by their volatility. Chemicals are separated from solutions by heating them until they boil and turn into gas. The gas is then collected and cooled, when it condenses into a liquid. As different chemicals boil at different temperatures, it is possible to separate them by controlling the heating temperatures.\n\nThere is evidence of the distillation of alcohol dating back to the second millennium B.C.E. although recent evidence from Pakistan demonstrates that it was not until 400 B.C.E. that the process was well understood. The idea of boiling water and collecting it as steam, which separates out dirt, salts, and bacteria, seems to have come 800 years later, when Hypatia of Alexandria (c. 350-415 C.E.) invented the first apparatus for distilling water. However, it was not until the eighth century C.E. that pure chemical substances were obtained by distillation. The alembic still was invented by Persian chemist Jabir Ibn Hayyan. Later, in the ninth century, petroleum was distilled to produce kerosene by another Muslim chemist, al-Razi, and the extraction of essential oils by steam distillation was invented by Avicenna in the eleventh century.\n\n----\n\nPike\n\nInvented: c. 400 B.C.E.\n\nSummary: Macedonians deploy the pike in the phalanx.\n\nA major weapon advancement in the complicated history of ancient warfare, the invention of the pike in 400 B.C.E. is credited for the Macedonian takeover of Greece, Egypt, and parts of Asia.\n\nPhilip II of Macedonia (382-336 B.C.E.), father of the famous Alexander the Great, is credited with adopting the pike (also called the sarissa), as well as the Macedonian phalanx, a type of infantry formation of soldiers. The pike was around 20 feet (6 m) long, and this great length enabled soldiers to strike while they were themselves out of range of shorter weapons. The phalanx consisted of a tight formation of soldiers and pikes. The men in the front of the phalanx would hold their pikes straight out, creating an equivalent depth of about five rows of men.\n\nBefore Philip's invention, the Macedonian army was considered ill-equipped and ill-trained. The combination of the pike and the phalanx formation ensured that the soldiers were well defended\u2014the phalanx arrangement only failed if the formation was broken or outflanked, which happened rarely. The pike was an effective weapon only when used in the phalanx, and was essentially useless outside of it. Away from the phalanx formation, Philip's men used javelins. They were adept in the use of both types of weapons, an impressive military feat since the skills required to use each of them are quite different.\n\nAlexander the Great inherited Philip's military tactics with the pike and phalanx and used them to conquer Egypt, Persia, and what is now northern India. Versions of the pike were still being used in military operations up until the eighteenth century. While the phalanx may seem an unwieldy fighting unit today, it was able to act like a modern-day tank, breaking away to crash into enemy ranks with impunity.\n\n----\n\nMagnetic Compass\n\nInvented: c. 400 B.C.E.\n\nSummary: An invention fails to find its ideal application.\n\n\u2002\"Magnus magnes ipse est globus terrestris. (The whole Earth is a magnet.)\" \u2014William Gilbert, physician and natural philosopher\n\nThe Chinese discovered the orientating effect of magnetite, a magnetic ore known as lodestone (or leading stone), as early as the fourth century B.C.E. and the earliest compasses were used for quasi-magical purposes. They consisted of a piece of lodestone floating on a stick in a bowl of water, which swung around so that it always pointed in a consistent direction. It was another thousand years before they were used for navigation. Previously navigators in the northern hemisphere had used the North Star to indicate direction, and followed earlier maps, but the compass, which aligned with the North Star, was more useful because it could be used in all conditions.\n\nMagnetic compasses work in this way because molten iron in the center of the Earth acts as a magnetic core, as if it were a giant bar magnet, and causes the needle to set parallel to the north-south axis of the globe. It was only realized later that the directions of the magnetic north and geographical north (Earth's axis) were not parallel to each other and varied by about 12 degrees.\n\nIt was later discovered that iron or steel needles stroked by a lodestone became magnetized and also lined up in a north-south direction. In 1745 Gowin Knight, an English inventor, developed a method of magnetizing steel permanently.\n\n----\n\nBlast Furnace\n\nInvented: c. 400 B.C.E.\n\nSummary: Chinese smelting begins with bronze.\n\nThe oldest known blast furnaces were built during the Han Dynasty of China in the fourth century B.C.E. Early blast furnace production of-cast iron evolved from furnaces used to melt bronze. Iron was essential to military success by the time the State of Qin had unified China (221 B.C.E.). By the eleventh century C.E., the Song Dynasty Chinese iron industry switched from using charcoal to coal for casting iron and steel, saving thousands of acres of woodland.\n\nIn a blast furnace, fuel and ore are supplied through the top of the furnace, while air is blown into the bottom of the chamber. The chemical reaction takes place as the material moves downward, producing molten metal and slag at the bottom, with flue gases exiting from the top of the furnace.\n\nThe oldest known blast furnaces in the West were built in Durstel in Switzerland, the M\u00e4rkische Sauerland in Germany, and Lapphyttan in Sweden, where they were active between 1150 and 1350 C.E. There have also been traces of blast furnaces dated as early as 1100 found in Noraskog, also in Sweden. These furnaces were very inefficient compared to those used today.\n\nFrench Cistercian monks, who are known to have been skilled metallurgists, passed on their knowledge of technological advances regarding blast furnaces between the thirteenth and the seventeenth centuries. Iron ore deposits were often donated to them and the monasteries sold their surplus iron as well as the phosphate-rich slag from their furnaces, which was used as an agricultural fertilizer.\n\nIn 1709 Abraham Darby, a Quaker iron founder in Shropshire, England, used coke instead of charcoal to. smelt iron ore in his improved blast furnace. He also processed cast iron into wrought iron and steel.\n\n----\n\nCatapult\n\nInvented: c. 400 B.C.E.\n\nSummary: Sicilians introduce one of the first great war machines.\n\n\u2002\"The first stone... fell with such weight and force upon a building that a great part... was destroyed.\" \u2014Marco Polo, The Travels of Marco Polo (c. 1298)\n\nThe word catapult came from two Greek words: kata, meaning \"downward,\" and pultos, which refers to a small circular shield. Katapultos was taken to mean \"shield piercer\" The weapon was said to have been invented in 399 B.C.E. in the Sicilian city of Syracuse and, according to Archimedes, was derived from a composite bow, which was similar to the crossbow.\n\nEarly catapults had a central lever with a counterweight at the opposite end to the projectile basket. Torsion-powered catapults entered into common use in Greece and Macedon around 330 B.C.E. Alexander the Great used them to provide cover on the battlefield as well as during sieges.\n\nThe Chinese, Greeks, and Romans used various types of catapults. The ballista, built for Philip of Macedon, was similar to a giant crossbow and, using tension provided by twisted skeins of rope, it could aim heavy bolts, darts, or spears. The trebuchet consisted of a lever and a sling and could be used to hurl large stones. The mangonel, credited to the Romans, fired heavy objects from a bowl-shaped bucket at the end of its single giant arm.\n\nCatapults used as siege weapons were usually constructed on the spot because they were too cumbersome to move around. Sometimes beehives or carcasses of dead animals were catapulted over castle walls to infect those inside. The weapon reached Europe during medieval times and the French used them during their siege of Dover Castle in 1216 C.E. Cannons replaced catapults as the standard European siege weapon in the fourteenth century C.E.\n\n----\n\nStirrup\n\nInvented: c. 300 B.C.E.\n\nSummary: The Chinese gain an important advantage in mounted warfare.\n\n\u2002\"The stirrup... enabled the horseman to become a better archer and swordsman.\" \u2014Professor Albert Dien, historian\n\nThe oldest recorded account of a single metal mounting stirrup is a depiction found on a pottery shard uncovered from a tdmb in western China belonging to the Jin Dynasty and dating to around 300 B.C.E. The stirrup was at first used primarily as a tool to assist the rider in mounting his horse.\n\nChina at that time was constantly plagued by threats of mounted warfare from its northern nomadic neighbors. Considering that the Chinese developed the harness and horse collar a thousand years before theirarrival in Europe, and that they had an established expertise in metal casting, it is not surprising that stirrups appeared among China's elite mounted cavalry. Their use of a single stirrup for mounting soon evolved toward using stirrups in pairs to provide a stable foundation for riding and fighting in war.\n\nWith the arrival of stirrups, the cavalry became a dominant military instrument; they fundamentally altered the approach to mounted warfare. A pottery horse dating to 322 B.C.E. excavated from a tomb near the town of Nanjing in China's eastern Jiangsu Province is the earliest known evidence of stirrups deliberately forged and used as a pair.\n\nConsidering man's long dependence on the horse for transportation and communication, and its strategic importance in warfare, the invention of the stirrup came relatively late in history, although circumstantial evidence points to its appearance in the Middle East as early as 850 B.C.E. Its invention preceded a huge leap forward in the communication between and migration of cultures.\n\n----\n\nSaddle\n\nInvented: c. 300 B.C.E.\n\nSummary: Horsemen end the age of bareback riding.\n\n\u2002\"Every occasion will catch the senses of the vain man and with that... saddle you may ride him.\" \u2014Sir Philip Sidney, politician\n\nIt is unclear when humans first began to domesticate and ride horses\u2014evidence from cave paintings in France suggests that horses might have been bridled as long ago as 15,000 B.C.E. But while early riders had the use of bits, bridles, and harnesses to control their mounts, they sat uncomfortably on little more than folded blankets or cloth, or rode bareback. Asian horsemen created a felt and wood saddle around 300 B.C.E., but it was not until around 100 C.E. that riders gained a saddle that offered genuine comfort.\n\nThe first padded, framed saddles were developed in Han Chin sometime between 25 and 220 C.E. They consisted of a wooden frame covered in a stiff material such as leather, padded with cloth and shaped for comfort. To ensure a good ride, the pommel, or front, and the cantie, or rear, of the saddle were raised above the seat. What began as a simple but effective means of sitting on a horse soon became a status symbol, as riders decorated the leather of their saddles with inscribed designs and personal emblems and fashioned them with intricate ivory and other inlays.\n\nAlthough the saddle had a great effect on horsemanship, its full effect was not at first realized, for the rider still remained insecure perched on his seat. It was not until the invention of the stirrup shortly afterward that the saddle truly came into its own.\n\n----\n\nMoldboard Plow\n\nInvented: c. 300 B.C.E.\n\nSummary: The Chinese transform a farm implement.\n\n\u2002\"The moldboard plow... buries almost all the old crop stubble, straw, and residue...\" \u2014Rick Kubik, farm safety expert\n\nThe simple moldboard plow was one of the most significant developments in history, but the name of its inventor is lost in time.\n\nWhen humans first began tilling their fields, they would simply drag a stick or a hoe through the soil. The resulting furrows were perfect for planting seeds for cultivation. Once humans had domesticated the ox, around 7000 B.C.E., they were able to harness its pulling power to increase plowing efficiency. The oxen pulled a hoe contained by a wooden frame.\n\nBut the real breakthrough occurred in the third century B.C.E. when the Chinese designed the kuan, or mold board plow. This consisted of a hitch, to attach it to an animal, and an asymmetric moldboard blade, which cut through the earth horizontally, with the added benefit of slicing through the roots of weeds. Once the earth had been cut horizontally, the forward motion of the curved plowshare pushed the soil against the blade, which turned the soil upside down before depositing it back on the ground, to the side of the new furrow. This aerated the soil, but it was the inverting of the earth that brought new advantages. Any surviving weeds were buried by the inverted earth and, especially in dry soil, nutrients and moisture were brought back to the surface. Now much larger areas could be farmed more efficiently.\n\n----\n\nLever\n\nInvented: c. 260 B.C.E.\n\nSummary: Archimedes explains how leverage works.\n\n\u2002\"Give me a lever long enough and a fulcrum on which to place if and I shall move the world.\" \u2014Archimedes, mathematician and physician\n\nThe lever was first described in 260 B.C.E. by Archimedes (c. 287-212 B.C.E.), but probably came into play in prehistoric times. A lever can be used to raise a weight or overcome resistance. It consists of a bar, pivoted at a fixed point known as the fulcrum. Extra power can be gained for the same effort if the position ofthefulcrum is changed.\n\nLevers may be divided into classes. First-class levers have the fulcrum in between the applied force and load, which are at opposite ends, such as with the seesaw. Second-class levers have the fulcrum at one end, and the applied force at the other, such as with a bottle opener. Finally, third-class levers have the effort in between the fulcrum and the load; for example, tweezers have two class three levers that are pressed together to do the work for which they are designed.\n\nThe Egyptians used a lever in 5000 B.C.E. for weighing, pivoting a bar at its center to balance weights and the objects to be weighed. Ramps and levers were also used to move stones higher up a structure, adapting the principle of the shaduf, which was developed in Egypt in 1500 B.C.E. This machine had a lever pivoted near one end with a water container hanging from the short arm and counterweights attached to the long arm. Several times a person's weight could be lifted by pulling down the long arm.\n\n----\n\nNail\n\nInvented: c. 250 B.C.E.\n\nSummary: Handmade nails are individually forged.\n\n\u2002\"It is a great advantage that every honest employment is deemed honorable, l am... a nail maker.\" \u2014Thomas Jefferson, U.S. president, in a letter\n\nNails were among the first metal objects made by hand. In Roman times, any sizable fortress would have a workshop where workmen fashioned the metal items required by the army? Here, workmen called \"slitters\" cut up iron bars for the attention of \"nailers,\" who gave them a head and a point.\n\nEarly nails were usually square in section, and the head of each was formed simply by turning over one end to make an L-shape. Such nails were expensive to produce, and they were so valued that people sometimes burned their houses when moving in order to retrieve nails from the ashes for reuse.\n\nIn 1590 water-powered slitting mills were introduced into England. After rolling the hot iron into sheets, each sheet was slit into long, narrow, square-sectioned bars by rollers that cut like shears. The flat, headless, machined bars continued to be finished off as nails and spikes by hand, often by blacksmiths producing them to order. This was the procedure until the advent of the nail-making machine at the end of the eighteenth century; by the end of the nineteenth century, the handmade nail industry was extinct.\n\nNails are made in a variety of forms. Most common, dating from the late nineteenth century, is the \"wire nail,\" as distinct from \"stamped nails,\" \"pins,\" \"tacks,\" or \"brads.\" Nails are now available in many different sizes and shapes, with a variety of heads.\n\n----\n\nArchimedes Screw\n\nInvented: c. 250 B.C.E.\n\nSummary: Archimedes raises water for irrigation by an ingenious means.\n\n\u2002\"An enormous amount of water is thrown out... by means of a trifling amount of labor.\" \u2014Diodorus Siculus, historian\n\nThe Archimedes screw was first mentioned in the writings of Athenaeus of Naucratis in 200 B.C.E. He described the use of a screw mechanism to extract bilgewaterfrom a ship named Syracusia, and attributed its invention to Archimedes.\n\nArchimedes (c. 287-212 B.C.E.) himself lived in Syracuse, Sicily, and was devoted to the exploration of mathematics and science. The polymath is thought to have spent time studying in Egypt, and the screw named for him is used in the Nile delta to this day, more than 2,000 years later, as a means to raise water from rivers for irrigation purposes.\n\nThe Archimedes screw consists of a helix within a hollow tube, the lower end of which is placed in a fluid. The screw is then rotated and the fluid is lifted up through the spiral chamber to the top of the tube. In ancient times this tool was applied throughout the Mediterranean for irrigation, it was especially used by the Romans in their water supply systems, and as a means of extracting waterfrom their mines in Spain.\n\nTechnology took a backward step in the Dark Ages, but the Archimedes screw reappeared in the fourteenth century as a means of supplying public fountains with water. It was then largely superseded by reciprocating pumps, but came into its own in the 1600s for the reclamation of land from the sea, particularly in the Netherlands. Powered by windmills, they raised waterfrom low-lying land up into canals.\n\nThe Archimedes screw is still used for drainage and flood control today, but also has many modern applications in oil pumping, sewage treatment, agriculture, and even cardiac medicine.\n\n----\n\nCompound Pulley\n\nInvented: c. 250 B.C.E.\n\nSummary: Archimedes introduces the block and tackle.\n\nThe simple pulley enables the user to lift a load more easily by changing the direction from which the force is applied. When the rope is fixed at one end and another pulley is added, the system provides a mechanical advantage by multiplying the applied force, making it possible to lift heavy loads. More pulleys can be added to the system, now known as a \"compound pulley\" system, further multiplying the effectiveness of the force applied.\n\nAs an indication of the benefit of the system, the addition of a second pulley to a one-pulley lifting mechanism halves the amount of force required to make the lift. A third pulley, properly rigged, reduces the amount of force required to a quarter.\n\nIn 250 B.C.E., the Greek scientist and inventor Archimedes (c. 287-212 B.C.E.) adopted this principle by mounting several pulleys on the same axle to create a \"block\" that was much more convenient to use than a series of separate pulleys. A single rope\u2014called the \"tackle\"\u2014fixed at one end, can be threaded between a fixed block and around each of the pulleys (\"sheaves\") in a movable block so that the load on the system is shared between the ropes under tension.\n\nAccording to Plutarch, whose account provides us with the earliest record of the block and tackle, Archimedes used his new invention single-handedly to move a whole warship. Whether this is true we cannot know, but the block and tackle has certainly been an essential tool for lifting and moving heavy loads ever since. It can be found today in the cranes and lifting gear used in construction, engineering, freight loading, and warehousing as well as on almost every yacht and sailing boat, including small dinghies with the simplest of rigging.\n\n----\n\nPipe Organ\n\nInvented: c. 240 B.C.E.\n\nSummary: Ktesibios reinvents a primitive instrument.\n\n\u2002\"All one has to do is hit the right keys at the right time and the instrument plays itself.\" \u2014J. S. Bach, composer and organist (attributed)\n\nLong before the development of the pipe organ, its essential musical element\u2014a set of pipes of different sizes that resonate at different pitches when air is passed through them\u2014existed in the form of the syrinx. This simple instrument was used widely throughout the eastern Mediterranean region.\n\nHowever, in 240 B.C.E., Ktesibios (c. 285-222 B.C.E.), a Greek engineer, developed a way of supplying a steady flow of air to the pipes. He attached them to a closed box into which air was pumped using pressurized water, creating and maintaining steady air pressure in the box. The pipes were opened or closed to the air source by a simple switch system operated from a keyboard. This device was originally called hydraulis, later organum, and produced loud sounds, clearly audible outdoors and ideal for use at games and processions. The instrument appears in paintings, mosaics, and writings throughout Byzantium.\n\nThe pipe organ is the oldest musical instrument still used in classical music. It was developed in the Byzantine Empire, and was adopted by the Christian church in the first century C.E. The hydraulic system was replaced by bellows in the following century.\n\n----\n\nDry Dock\n\nInvented: c. 200 B.C.E.\n\nSummary: A Phoenician finds a new way to launch ships.\n\nThe dry dock was invented in Egypt by a Phoenician, some years after the death of Ptolemy IV Philopator, who reigned from 221 to 204 B.C.E. His method of launching a ship consisted of digging a trench under it close to the harbor, then making a channel from the sea to fill the excavated space with water.\n\nDry docks continued to be used throughout antiquity. In Europe the first dry dock was commissioned in 1495 by King Henry VIII at Portsmouth, England. Dry docks are mainly used for the maintenance and repair of ships, and more rarely for their construction because the time required to build a ship is so long. While early dry docks were often used for launching ships, slipways are more frequently used in modern times.\n\nThere are two types of dry docks: graving docks, where \"graving\" is the term for scouring a ship's bottom, and floating dry docks. The graving dry dock consists of a water-filled narrow basin, usually made of concrete, with gates that can be opened and closed, into which a vessel may be floated. The water is then pumped out, leaving the vessel supported on blocks, so that the ship can be serviced. When the work is finished, water is let back into the dock and the ship refloated. Earlier dry docks were built in the same shape as the ships that were to be docked there, but more recently, graving docks have been built in a boxshape, to conform to boxier ship designs.\n\nA floating dry dock is usually built of hollow steel. The dock is first submerged, the ship is brought into its channel, and the dock is then floated by removing ballast from the hollow floor and walls. The fully drained dock supports the craft on blocks attached to the dockfloor. Floating dry docks are usually operated in sheltered harbors to avoid wave damage.\n\n----\n\nWindmill\n\nInvented: c. 200 B.C.E.\n\nSummary: China and Persia harness wind power.\n\n\u2002\"There are, indeed, few merrier spectacles than that of many windmills bickering together.. \u2014Robert Louis Stevenson, writer\n\nThe early history of the windmill is much contested, and it is not known for sure when or where it first appeared. Some date it as far back as Babylonia in the seventeenth century B.C.E., while others claim it was not until 200 B.C.E. that wind power was used to pump water in China and mill cereal in Persia. It is, however, reliably documented that windmills were widespread in Persia by the seventh century C.E. They ground grain between millstones rotated by wind blowing on woven reed sails mounted around a vertical axis.\n\nThe earliest European windmills were built in France and England in the twelfth century and are thought by some to have been the result of a transfer of knowledge from the returning Crusaders. However, the horizontal-axis mills of northern Europe bore scant resemblance to their Persian counterparts and were probably an entirely separate development.\n\nWindmills became increasingly practical with the advent of fantails to turn them automatically into the wind, and improved sails for efficiency and control. Until the dawn of the Industrial Revolution, windmills sprang up in their thousands throughout Europe and North America for grinding foods, sawing wood, and pumping water for drainage, irrigation, or desalination. Since the late twentieth century, wind-driven technology has gained economic importance in the form of wind turbines for electricity generation.\n\n----\n\nAstrolabe\n\nInvented: c. 150 B.C.E.\n\nSummary: Hipparchus develops a calculator of astronomical positions.\n\n\u2002\"...when I seek out the massed wheeling circles of the stars, my feet no longer touch the Earth...\" \u2014Claudius Ptolemy, mathematician and astronomer\n\nAn astrolabe is a device with which astronomers solved probiems relating to time and the position of the sun and stars in the sky. Its main element is a twodimensional circular stereographic projection of the hemispherical sky. The projection was most probably formalized by the Greek astronomer Hipparchus (190-120 B.C.E.), who worked on the island of Rhodes.\n\nThe astrolabe was suspended vertically and a cross-arm was used to measure the altitude above the horizon of the sun (in the day) and bright stars (at night). The rim of the astrolabe is marked off in months, days, and hours, and most astrolabes have a series of longitude-specific circular main plates each marked off with lines of constant altitudes, azimuths, declinations, and right ascensions. Fitting over the plate is a cutaway fretwork (a \"rete\") that delineates that portion of the celestial sphere that can be seen above the horizon at any specific time at a specific 'atitude. The rete contains pointers that mark the positions of about twelve of the brightest stars.\n\nBy noting the elevation of the sun, or these bright stars, the traveler can tell the time of day or night. By noting how well the observed star positions correspond to a specific plate, the travelers can estimate their latitude. The stellar positions a'so enable the accurate establishment of north on the horizon.\n\nClaudius Ptolemy (c. 85-165 C.E.) wrote about the stereographic projection and probably owned an astrolabe. The astrolabe was popular in the Islamic world because it enabled Muslims to ascertain prayer times and the direction of Mecca. The oldest existing instruments date from the tenth century C.E.\n\n----\n\nAntikythera Mechanism\n\nInvented: c. 150 B.C.E.\n\nSummary: A controversial astronomical calculator is attributed to the Greeks.\n\n\u2002\"This device is... the only thing of its kind. The design is beautiful, the astronomy is exactly right.\" \u2014Professor Michael Edmunds, Cardiff University\n\nOne of the most remarkable inventions of the ancient world came to light in 1900 when a Greek sponge diver discovered the wreck of an ancient Greek or Roman cargo shipthat had sunk off the Greek island of Antikythera around 80 B.C.E. Among the objects recovered from the wreck was a geared mechanism that, from the shape of its inscribed Greek letters, dated to between 150 and 100 B.C.E.\n\nThe mechanism has more than thirty gearwheels and three main dials. When reassembled, it formed a scientific instrument that could be used to calculate the astronomical positions of the sun, moon, and the five planets then known. When a date was entered via a crank, now lost, the mechanism calculated the position of the sun, moon, or planet. The Antikythera mechanism, as it is known, is the first known geared device and thus the first known clockwork mechanism, and the oldest known scientific instrument.\n\nThe concept of differential gearing was not rediscovered until the sixteenth century, while the complexity and miniaturization of its parts are comparable to the finest eighteenth-century clocks. Crucially, while the mechanism is based on theories of astronomy and mathematics developed by Greek scientists of the day, it has a heliocentric rather than the then current geocentric view of the solar system and presumes a theory of planetary motion and a knowledge of the laws of the gravity that were not known at the time. Recent research has revealed it also organized the calendar in the four-year cycle of ancient Greek games. Whoever built this mechanism would have been astonishingly ahead of his time.\n\n----\n\nParchment\n\nInvented: c. 150 B.C.E.\n\nSummary: Animal skin becomes a writing material.\n\n\u2002\"... when... Ptolemy suppressed the export of paper, parchment was invented at Pergamum...\" \u2014Pliny the Elder, Natural History, Book 13\n\nAccording to Pliny the Elder, parchment was developed in the city of Pergamum (now Bergama, Turkey) because a king of Egypt, fearing that Pergamum's great library might overshadow that of Alexandria, stopped exporting papyrus to the city.\n\nIt seems more likely that parchment already existed and was refined at Pergamum. Also, this was not the first time animal skin had been written on. Leather had been used occasionally, possibly dating back to circa 2000 B.C.E. However, previous attempts involved tanning the leather and produced documents that were slightly hairy, stiff, and one-sided. Parchment, on the other hand, was made from the skins of sheep, calves, and goats that were cleaned and, crucially, scraped thoroughly. Both sides of the smooth, flexible surface were ideal for writing and ultimately allowed sheets to be sewn together into \"books\" that were far easier to read than papyrus scrolls. Although papyrus was cheaper than parchment, it was Europe's favored surface up until the fourteenth century's advances in paper making, especially for medieval illuminated manuscripts, such as the stunning Tres Riches Heures of the Ducde Berry of the early 1400s.\n\nThe finest parchments, especially those made from the skins of very young, or even unborn, animals, were called vellum. The term is often used today for any kind of high-quality special paper.\n\n----\n\nBelt Drive\n\nInvented: c. 100 B.C.E.\n\nSummary: Romans connect a belt drive to a treadmill.\n\nThe belt drive is a vital component of most modern machines. In it, a ring of a flexible material is wound around two or more shafts. As one shaft rotates, the belt moves, causing other shafts to rotate as well. This simple pulley device has long been a versatile and reliable means of transferring power.\n\nIn 100 B.C.E., while constructing Haterii's Tomb in Rome, workers used a treadmill-powered crane to lift heavy material. This was a historic moment for mechanics. In 1203, French innovators replaced the human workers who had been powering belt-driven technology with a team of donkeys.\n\nIntroducing animal power was far from the final stop for the belt drive. Water-powered mills used belt drives to harness water power, and Industrial Revolution-era factories employed belt drives, called line shafts, to transfer power throughout the factory.\n\nBelt drives are also commonly used in engine designs. Belt drives can be found in most mechanical movers, from motorcycles to helicopters. Automobile engines usually contain belt-drive systems called V-belts and serpentine belts. These systems redirect and disperse engine powerto accessories.\n\nV-belts, named for their triangular \"V\" profile, are generally used to power the vehicle's air-conditioning compressor, alternator, power-steering pump, and water pump. They are frequently called fan belts.\n\nA serpentine belt, an alternative to using a combination of several V-belts, has a longer life than the combined V-belts. A serpentine belt system uses a single, long belt to power the same number of accessories as numerous V-belts. Its name comes from its comp'ex, snakelike path around multiple shafts. A spring-loaded pulley is used to keep the serpentine belt under optimum tension.\n\n----\n\nWatermill\n\nInvented: c. 100 B.C.E.\n\nSummary: Greeks use the energy of running water to grind grain.\n\n\u2002\"Restyour mill-turning hand... the nymphs now carry out the chores your hands performed.\" \u2014Antipater of Thessalonica, epigrammatist\n\nThe earliest reference to watermills is found in the writings of Antipater of Thessalonica, describing their use for the grinding of grain in the first century B.C.E. These ancient Greek devices consisted of a millstone mounted on a vertical axis and rotated against a stationary stone bed by a horizontal paddle wheel spinning in a fast-flowing stream. This type of watermill has also been discovered throughout Ireland, Scandinavia, and China.\n\nThe Romans were the first to devise a more efficient and versatile machine with a horizontal axis, which may have been inspired by ancient Eastern waterwheels, originally used for lifting water. The medieval Islamic nations embraced the watermill from the seventh century, building mills in bridges and on the sides of moored ships, or channeling water from dams to supply them. They were used to make pulp for paper, saw wood, grind cereal, and crush sugar cane and mineral ores.\n\nThe nineteenth century brought a surge in the need for industrial power in northern Europe and North America, and new cast-iron waterwheels fed the demand. These were eventually replaced by steam engines, fueled by coal brought on the canals.\n\nIn northern England, 1880, water was used for the first time to generate electricity through a new type of turbine initially conceived in 1826 by Benoit Fourneyron. More plants followed, and in the 1920s 40 percent of electricity in the United States came from hydropower. Other countries, including Norway and Brazil, now meet almost all their electricity needs by harnessing the energy of flowing water.\n\n----\n\nBlown Glass\n\nInvented: c. 100 B.C.E.\n\nSummary: Syrians first shape glass with the aid of a blowtube.\n\n\u2002\"Blowing allowed for previously unparalleled versatility and speed of manufacture.\" \u2014Rosemarie Trentinella, Metropolitan Museum of Art\n\nIt was the Syrians who first learned to blow molten glass through a hollow metal tube and shape it into intricate forms. Although the technique for producing glass had existed for about two and a half millennia, it was only in approximately 100 B.C.E. that the hazardous art of glassblowing\u2014using glass melting at a few thousand degrees Fahrenheit\u2014was mastered.\n\nGlassblowing is the process for forming glass into a desirable shape, and this ability to form iconic, practical, and elegant shapes out of glass has been of incalculable value and practical benefit to society. Glassblowing machines have now largely replaced the Syrian specialists, but the science behind the technique remains the same. Molten glass is first introduced to the end of a hollow tube. A bubble of air is then blown through the tube, and as the bubble passes out of the tube a covering of molten glass forms around the sphere of air. This glass-covered bubble, still attached to the tube, is either placed within a mold of the required form and enlarged through further blowing, or sculpted with tools into the desired shape. The glass is then allowed to cool slowly to complete the process. It is the fact that glass has no set melting or freezing points that makes glassblowing possible; as the temperature rises or falls, the state of the glass gradually changes.\n\nThe rise of the Roman Empire at around the same time as the beginnings of glassblowing greatly facilitated the proliferation of the art. By adding manganese oxide to the mix, the Romans also discovered clear glass in around 100 C.E., which was used for architectural purposes.\n\n----\n\nOdometer\n\nInvented: c. 27 B.C.E.\n\nSummary: Vitruvius makes measuring distances simpler.\n\nMeasuring the distance between two places is a basic task in cartography. The earliest method was to walk and count the number of times a specific foot hit the ground\u2014a thousand right steps, for example, made a mile (from the Latin \"mille,\" meaning one thousand).\n\nThe Roman architect and engineer, Vitruvius (c. 75 B.C.E.-c. 15 B.C.E.), mechanized the process. Around 27 B.C.E. he devised a wheelbarrow-type device that dropped a pebble into a container every time its large wheel of known circumference rotated once. At first this was pushed along by hand, but it was soon incorporated into a chariot, the standard chariot wheel being 4 feet (1.2 m) in diameter. This wheel turned 400 times in a Roman mile. Needless to say, the smoothness of the road was important. The device was described by Hero of Alexander in chapter thirty-four of his book Dioptra.\n\nAround 300 C.E. the Chinese\u2014some sources suggest Chang Heng\u2014devised a similar, but more musical, instrument. Every time the road wheel of a special coach rotated once, a pin moved a tooth on an internal cog wheel. Every complete rotation of the cog wheel activated a stick that banged a drum. Every tenth drum beat was replaced by a sounding gong. Distances between towns could be easily measured in this way to an accuracy of a tenth of a mile.\n\nEarly motor cars had odometers (or mileometers) fitted to one of the road wheels, these having separate gears that registered distances of 1,10,100,1000 miles, and so on. Measured distances were a function of the tire pressure. Since 1980, cars have had odometers that indicate the number of miles traveled up to 999,999.\n\nSimple hand-pushed odometers are still used today by city surveyors, and these are sometimes called waywisers or perambulators.\n\n----\n\nBall Bearing\n\nInvented: c. 40\n\nSummary: The Romans reduce rotational friction.\n\n\u2002\"... the balls... will touch in one point only between the load and its resistance... \u2014Leonardo da Vinci, The Madrid Codices (c. 1490)\n\nBall bearings are a low-cost method of allowing different parts of a mechanism to rotate past each other without much energy Joss from friction. They have many uses, including in bicycles, gyroscopes, electric motors, and turbines. They did not come into general use until the Industrial Revolution, but the concept has been around for more than 2,000 years.\n\nRoman Emperor Caligula (12-41 C.E.) had two large ships built at Lake Nemi. When the remains of these ships were recovered in the early 1930s, marine archeologists found the earliest known ball bearings. There were two types found\u2014bronze spheres and wooden balls. The wooden ball bearings supported a rotating table, similar to a lazy Susan or dumbwaiter.\n\nPrior to this discovery, historians had believed that Leonardo da Vinci invented ball bearings.\n\nBall bearings became so widely used in factories, vehicles, and other machinery, that during World War II, the Allies made a concerted effort to bomb German ball bearing plants in order to disrupt the German war effort. The Germans had astutely stockpiled millions of bearings and were able to continue supplying factories despite ball bearing production being halved.\n\nThese days, for applications with high load, speed, and/or precision requirements, ball bearings are increasingly being replaced by fluid bearings, which usea layer of gas or liquid to support the load.\n\n----\n\nClaw Hammer\n\nInvented: c. 79\n\nSummary: The Romans devise a tool used to pound in, and remove, nails.\n\n\u2002\"A worker may be the hammer's master, but the hammer still prevails...\" \u2014Milan Kundera, writer\n\nHammers\u2014tools for striking or pounding\u2014have been around for millions of years in the form of specially shaped stones used to break or shape other stones, bones, or wood. They are most commonly associated with woodworking. But after the invention of the nail, someone realized it would be very useful to be able to insert and remove nails with the same tool. Nails were valuable, and a carpenter who hammered one at the wrong angle would have rescued and reused it. Thus, the claw hammerwas born.\n\nA claw hammer has a two-sided head attached to a handle and can be said to be roughly T-shaped. One side of the head is the striking surface and is usually flat. The other side is a rounded or angled wedge and is used for removing nails. Archeologists found an iron claw hammer at Pompeii that was buried in the eruption of Mount Vesuvius in 79 C.E. First-century Romans were skilled at making nails; archeologists found almost 900,000 at the Roman fortress of Inchtuthil in Scotland that the garrison had abandoned in the late 80s C.E.\n\nVarious types of claw hammers were patented between 1867 and 1941. For many years, the hammer was the principal tool for carpenters and builders. However, since the invention of the nail gun in the 1950s, builders have increasingly been relying on them instead of hammers for their nai'ing needs because they are easier, faster, and more fun to use. The fact that they provide inexperienced home contractors with the capability to leave a plethora of nails in our wails is, of course, merely a side effect of the new technology.\n\n----\n\nHorseshoe\n\nInvented: c. 100\n\nSummary: The Romans invent the \"hipposandaL\"\n\n\u2002\"Horseshoing, very likely was invented by different nations at about the same period....\" \u2014Scientific American (1891)\n\nHorses have played central roles in the histories of various powerful empires, and their employment was boosted by the invention of the horseshoe. Protecting horses' hooves from wear and tear on hard or rough surfaces allowed for longer journeys when the horse was the common mode of transport and a domestic working animal. It also made them more effective when used in the cavalry as part of a military campaign.\n\nThe precise date of its invention is unknown, but the Roman poet Catullus mentions a mule losing its shoe in the first century B.C.E. Evidence from Roman regions to the north of the Alps suggests that horses from what is now Germany may have been the first to use horseshoes regularly, from around 100 C.E.\n\nOver the years horseshoe design has improved from the \"hipposandal\" used by the Romans\u2014which had a solid bottom and was strapped to a horse's hoof\u2014to the U-shaped metal plate used today. The earliest known mention of the iron horseshoe is in 910. The weight and shape of early horseshoes varies on their provenance, and the climate and terrain in which the horses had to move. Blacksmiths and farriers made and fitted horseshoes using nails, and their skills helped develop metallurgy during medieval times. Today, horseshoes are often made from steel and aluminum, but also come in copper, titanium, rubber, or plastic depending on what the horse is used for.\n\n----\n\nDome\n\nInvented: c. 100\n\nSummary: Roman engineers solve an architectural puzzle.\n\n\u2002\"...my own opinion is that the Pantheon's name is due to its round shape, like the sky.\" \u2014Cassius Dio, History of Rome (c. 220)\n\nDomes, like arches, present problems for architects and engineers: They remain unstable until the final stone is put in place and have to support their own weight without collapsing. It was the Romans who in circa 100 first solved these technical problems when they managed to build a true dome, that is, an unsupported half-sphere.\n\nThe greatest of these is the Pantheon in Rome, which was erected in circa 123. Roman engineers tackled the problem as if it was a series of circular barrel vaults, or arches, arranged in a circle across a central point, and used concrete as a building material, in this case a mixture of lime, pumice, pieces of rock, and volcanic ash. A template for each arch was erected on scaffolding and served as the mold for the poured concrete. The dome was built up in sections, with heavier concrete being used at the thicker base and lighter concrete toward the thinner top. The weight of the dome is concentrated on a ring at the top of the structure surrounding an opening that lets in the light, and reduces the weight at the top. The result is to push the weight of the dome toward its base and down to the floor below. Once the dome was completed and the concrete dry, the supports could be removed.\n\n----\n\nSuspension Bridge\n\nInvented: c. 100\n\nSummary: The Chinese suspend a bridge with chains.\n\n\u2002\"I have no quarrel with you, good Sir Knight, but I must cross this bridge.\" \u2014King Arthur, Monty Python and the Holy Grail (1975)\n\nPrimitive suspension bridges, in the form of vines and fiber ropes, have been used for many thousands of years throughout Asia, Africa, and South America, such as those by the Incas. It is thought that the iron chain first replaced these frailer materials in China in c. 100.\n\nThe walkways of early catenary bridges were directly fixed onto the chains that spanned a valley, but in fourth-century India the road deck was instead suspended from the main cables to create a horizontal pathway that was more easily negotiable than its sloping predecessors.\n\nBasic suspension bridges were used in military campaigns in Europe, but the first permanent example in the West was a primitive catenary bridge built over England's River Tees circa 1741. The idea caught on in the United States, and in 1801 James Finley built the first modern suspended-deck suspension bridge across Jacob's Creek in Pennsylvania.\n\nWire cable eventually replaced chains, and the first permanent suspension bridge to use wire cable was the St. Antoine Bridge built in Geneva, Switzerland, in 1823. Steel was used in early constructions but the cost was prohibitively high until the Bessemer steelmaking process was developed in 1855. John A. Roebling made great improvements in the reliability of bridges, and his Brooklyn Bridge of 1883 remainsan iconic suspension bridge.\n\n----\n\nPaper\n\nInvented: 105\n\nSummary: Ts'ai Lun initiates papermaking.\n\n\u2002\"Paper can convey a private warning, a public threat, secret temptation, open defiance...\" \u2014Eric Frank Russell, Wasp (1957)\n\nIn 105 whenTs'ai Lun (50-121), a courtier in the Chinese Imperial court, invented paper, little did he realize that he was opening one of the most epoch-making chapters in history. He refined and popularized the process of mixing tree fibers and wheat stalks with the bark of a mulberry tree, then pounding them together and pouring the mixture onto a woven cloth to create a lightweight writing surface. His blended, fibrous sheets were an improvement over bamboo and wood, which were awkward and heavy, and silk, which was expensive. Successive Chinese dynasties conspired to keep his invention secret, and it was not until the start of the seventh century that papermaking techniques began to appear in Japan and Korea.\n\nWith the capture of Chinese paper merchants by Arab soldiers during the Battle of Talas in 751, the knowledge of papermaking soon spread across the Arab world, and first appeared in Europe in Moorish Spain early in the twelfth century.\n\nIn Europe, paper began a centuries-long battle for prominence with parchment until the invention of movable type in the fifteenth century led to a steep rise in literacy and a demand for the production of books that parchment could no longer satisfy. The eighteenth century saw paper made from linen and cotton rags that were replaced by wood and other vegetable pulps in the early nineteenth century.\n\n----\n\nWheelbarrow\n\nInvented: c. 231\n\nSummary: Zhuge Liang's invention makes light of moving heavy loads.\n\n\u2002\"To carry stones and takings of garden to places, appointed to receive 'em or, to carry earth....\" \u2014Francis Gentil, The Solitary Gardener (1706)\n\nThe wheelbarrow is reputed to have been invented by a Chinese chancellor, Zhuge Liang (181-234) during the Han Dynasty, who used the device in military campaigns to transport supplies for injured soldiers. It was said to have been kept secret because of the advantages it gave the Chinese over their enemies.\n\nIt was also used for early Chinese agriculture, which was said to have been thirty times more efficient than that in Europe. Designed to transport heavy loads, wheelbarrows are now used in the construction industry as well as in gardening.\n\nA wheelbarrow is a small cart, with one or two wheels, designed to be pushed by one person using two handles at the rear. Chinese wheelbarrows often had two wheels, and the Chinese sometimes attached sails to them so that the wind could take part of the load, as is recorded by European travelers of the sixteenth century.\n\nWheelbarrows were seen in Europe in the twelfth century, as evidenced by a stained-glass window at Chartres Cathedral in France, dating around 1220. This is believed to be the earliest image of a wheelbarrow in Western Europe. A manuscript illumination of 1286 also shows the European wheelbarrow. This design differed from the Chinese one in that the wheel was moved from the center to the front of the box, and the propelling power was at the rear.\n\nDesigns of wheelbarrow have been developed in recent years, such as British inventor James Dyson's Ballbarrow of 1974 that uses a spherical plastic wheel, and is easier to steer than those models based on the conventional wheel design.\n\n----\n\nTrebuchet\n\nInvented: c. 500\n\nSummary: The Chinese invent a rock-hurling machine.\n\n\u2002\"The trebuchet was the dominant siege weapon... lasting 100 years after the arrival of gunpowder\" \u2014University of Arkansas website\n\nThetrebuchet was an ancient form of artillery that first appeared in China in the fifth century B.C.E. The weapon of mass destruction of its time, it was an improvement on the catapult Unlike other catapults, such as the mangonel that uses twisted rope to provide power, the trebuchet uses a counterweight to provide its force. The trebuchet dominated long-range artillery until the sixteenth century.\n\nThe main arm of a trebuchet is attached to a fulcrum in such a way that the end holding the counterweight is much closer to the fulcrum than the end that holds the projectile. As the counterweight is released, the short end of the arm drops downward rapidly. Because of the longer length on the other side of the fulcrum, the end holding the projectile is flung upward in an arc at a much faster rate, giving considerable velocity to any missile thrown from it. This effect is usually increased by adding a sling to the firing end that also swings outward while firing, effectively increasing the power of the trebuchet.\n\nTrebuchets were far more powerful and accurate than earlier catapults and, by the time they appeared in the Mediterranean region, around 1100, they had evolved into terrifying machines of war that could be easily maneuvered to lay siege to castles with strong fortifications. They were primarily used to batter down stone walls by repeatedly firing at points of weakness. Boulders weighing as much as 300 pounds (140 kg) were pounded into fortified walls.\n\nThe trebuchet also served as an early form of biological warfare in that ordure, diseased animals, and rotting corpses were launched into besieged towns and forts. Not only did these spread disease, but having former comrades raining down from the sky had a powerfully negative impacton morale.\n\n----\n\nHorse Collar\n\nInvented: c. 500\n\nSummary: A Chinese device increases horse power.\n\nMost inventions are remarkable because they appear to be ahead of their time, revelatory events that transform the world into which they appear. The horse collar seems to be somewhat the opposite, for it is difficult to see why it was not invented earlier.\n\nThe problem to be solved is obvious: A horse wearing a simple harness can pull a load weighing about 135 pounds (60 kg), but any heavier load forces the harness on to the horse's windpipe, and restricts its ability to breathe. Therefore, while horses had been domesticated, mounted, saddled, and harnessed by around 100\u2014and so could be ridden for pleasure, work, or warfare\u2014their role as a beast of burden was necessarily limited, and was to remain so for another 400 years.\n\nIt was not until circa 500 that a Chinese camel driver had the bright idea of devising a padded collar, which was quickly used also on horses. It took the form of a rigid construction that sat low on the horse's chest and rose round its neck to rest on its withers or shoulders. The top of the collar supported a pair of curved metal or wood hames, to which the harness was attached. The collar reduced pressure on the windpipe and allowed the horse to use its full strength, thus allowing it to push forward with its hindquarters into the collar rather than pull the weight with its shoulders.\n\nThis new design of collar reached Europe circa 920, and soon revolutionized agriculture. Horses replaced oxen as the main beasts of burden, pulling plows, harrows, harvesting machines, and other agricultural implements, as well as farm carts and wagons.\n\n----\n\nQuill Pen\n\nInvented: c. 580\n\nSummary: Spanish record the \"pen that wrote history.\"\n\nThe first specific reference to a quill pen is found in the writings of St. Isidore of Seville around 580, although pens made of bird feathers are likely to have been used even earlier. The quill pen was the main writing tool in the Western world until the invention of the fountain pen in the nineteenth century. The quill's development was assisted by the rise of Christianity because its fine script was suitable for the promulgation of religion, as well as lending itself to otherdocuments in increasingly dense text.\n\nAlthough the outer wing feathers of many birds could be used, those of the goose and crow were preferred. A slit would be made in the base of the quill to allow ink to flow to the nib, with goose quills especially adept at holding the ink. The composition and size of goose quills also allowed the nib to be sliced to a broad edge, and then sharpened to an extremely fine point Quill pens quickly became blunt, and needed to be recut frequently in order to maintain their edge. The feathers were taken only from live birds\u2014those taken from the left wing best suited the right-handed scribe because they curved outward to the right side. Each bird could supply around ten good quills. The quill was of such importance that goose farms were prevalent across Europe.\n\nThe United States Supreme Court began a tradition of using quill pens in 1801, and its Chief Justices continued to write with them until well into the 1920s. Today white quills are still placed on attorneys' tables when the court is in session. By 1850, quill pen usage was starting to decline as the quality of steel nibs improved.\n\n----\n\nToilet Paper\n\nInvented: c. 589\n\nSummary: The Chinese revolutionize personal hygiene.\n\n\u2002\"Paper on which there are... the names of sages, I dare not use for toilet purposes.\" \u2014Yan Zhitui, The Family Instructions of Master Yan (589)\n\nThe earliest recorded use of toilet paper comes from China in the sixth century when government official and scholar Yan Zhitui warned against using paper printed with philosophical utterances for the wiping of bottoms. By the end of the fourteenth century, when the rest of the world was using water, the Chinese were producing more than 700,000 sheets of aromatic toilet paper a year for the Imperial court.\n\nPrior to the advent of the first commercially packaged, premoistened toilet paper by Joseph Gayetty of New York City in 1857, how people used to clean themselves depended to a large degree on where and how they lived, and their standing in society. Coconut shells were used widely throughout an egalitarian Hawaii, while lace and hemp proved popular within the French aristocracy. In ancient Rome combining rosewater with wool was common among the upper classes; colonial Americans used corncobs and old almanacs; while the ends of old anchor cables proved an unpopular but not uncommon option for Spanish and Portuguese maritime sailors of the seventeenth and eighteenth centuries.\n\nToilet paper was manufactured on a roll for the first time in the United States by the Scott Paper Company in 1890. In 1935 the Northern Tissue Company began to advertise \"splinter-free\" paper, and a softer two-ply toilet paper made its debut in 1942.\n\n----\n\nSpinning Wheel\n\nInvented: c. 700\n\nSummary: Indians accelerate the spinning process.\n\nThe origins of the spinning wheel remain unsure, but the machine is thought to have been invented around 700 in India, where it was used to turn fibers into thread or yarn that were then woven into cloth. Earlier hand-spinning methods were superseded by mounting the spindle horizontally and rotating it by slowly turning a large wheel with the right hand. The fiber was held at an angle in the operator's left hand to produce the necessary twist.\n\nThe spinning wheel reached Europe in the Middle Ages, becoming part of a cottage industry that used simple hand-operated tools. It persisted in this context until the eighteenth century.\n\nIn Britain the new cotton industry was modeled on the old woolen cloth industry. The most complicated apparatus was the loom, worked by a single weaver and normal'y kept in an upstairs room where a window provided natural light. The weavers were usually men who used yarn produced by a number of women, known as \"spinsters,\" who did the spinning. With the advent of waterpower, this early cottage industry eventually grew into a large-scale factory operation. In 1733 John Kay invented the flying shuttle that enabled the weaving process to become faster, and the Industrial Revolution saw the process become increasingly mechanized.\n\nModern spinning wheels use electrical and mechanical means to rotate the spindle, automatic methods to draw out fibers, and devices to work many spindles together at high speeds. Other technologies that offer faster yarn production include friction spinning and airjets.\n\n----\n\nTidal Mill\n\nInvented: c. 787\n\nSummary: Irish monks harness tidal waterpower.\n\n\u2002\"Much water goeth by the mill that the miller knoweth not of.\" \u2014Proverb\n\nIn a tidal mill, incoming water enters and fills the millpond through sluices and is then channeled out at low tide to turn the mill wheel, thus powering the millstones, and crushing the grain to flour. The first known tidal mill, dating around 787, was built on Strangford Lough in northern Ireland, and was used by monks to grind corn for the nearby monastery.\n\nTidal mills were used along Europe's Atlantic coast in the Middle Ages, where the high tidal ranges ensured generous payback for the millers. The number of suitable sites was limited, and the mills could only operate for a certain period after each high tide, but their output was predictable compared to weatherdependent windmills and traditional watermills.\n\nThe popularity of tidal mills waned with the arrival of the steam engine, until in 1966 French engineers harnessed the tides to generate electricity. The Rance estuary in northern France was dammed by a barrage housing twenty-four turbines capable of producing power from both the ebb and the flow of the tide. Other schemes have been developed since, but the specific site requirements and the environmental considerations around the tidal basin are limiting.\n\nModern alternatives to the barrage approach are to construct underwater turbines, either on a riverbed or seabed, or to hang them from tethered surface buoys that rotate in the tidal stream.\n\n----\n\nGunpowder\n\nInvented: c. 800\n\nSummary: The Chinese trigger the race toward firearms.\n\n\u2002\"We owe to the Middle Ages the two worst inventions of humanity \u2014romantic love and gunpowder.\" \u2014Andre Maurois, novelist and writer\n\nFew inventions can have instigated as much misery to humankind as that of the seemingly innocuous gunpowder. Created by Chinese alchemists in the ninth century, gunpowder Consists of a mixture of ground saltpeter (potassium nitrate), charcoal, and sulfur in approximate proportions of 75, 15, and 10 by weight. Known as \"black powder,\" its exposure to an open flame produces an explosion that can propel an object great distances when contained in a tube closed at one end. The Chinese experimented with different levels of saltpeter content to design rockets. Arab chemists acquired knowledge of gunpowder in the thirteenth century, rapidly employing it for military purposes, including the production of a gun made from a bamboo tube reinforced with iron. The spread of information arrived in Europe, where gunpowder was manufactured in larger grains of uniform size to control the speed of burning, and advances in metallurgy witnessed the rise of the cannon and handheld firearms.\n\nBy the late nineteenth century, \"black powder\" had been replaced by nitrocellulose, resulting in a smoother, more powerful explosion from a firearm with little smoke deposit. Smokeless powder accounts for most gunpowder produced today, usually in single-base powder (nitrocellulose) or double-base powders (nitrocellulose and nitroglycerin).\n\n----\n\nBanknote\n\nInvented: c. 806\n\nSummary: The Chinese Tang Dynasty persuades people to accept paper money.\n\n\u2002\"My notion of a wife at 40 is that a man should be able to change her, like a banknote, for two 20s.\" \u2014Warren Beatty, actor, producer, and director\n\nWhen Marco Polo traveled to China in the late thirteenth century he was astonished to see the locals use paper money instead of coins. Prompted by a copper shortage, the Tang Dynasty (618-907) introduced this new monetary system in 806, more than 800 years before the first European banknotes.\n\nWhile commodity money (the trading of goods that have an intrinsic value, such as gold and cattle) has been around since the dawn of civilization, the first standardized coinage is thought to have appeared in Lydia (western Asia Minor) in the seventh century B.C.E. This was the first time that the nominal value of money was higher than the worth of its inherent material. Ancient Greek historian Herodotus criticized the \"gross commercialism\" that this system induced.\n\nSwedish bank Stockholms Banco issued the first European banknotes in 1660. Once again, a shortage of copper was to blame. Customers had loaned copper to the bank, but demanded it back when their coins' copper content was reduced, making the copper more valuable than the coins. Unable to respond to the demand, the institution came up with promissory banknotes to solve their liquidity problem.\n\nThe Chinese were the first to discover the risks of using money without inherent worth. By 1020 the cost of imported goods, coupled with bribes given to potential invaders, had forced the government to issue more and more notes, thereby fueling inflation. By 1455 paper money had become so devalued that the Ming Dynasty (1368-1644) decided to get rid of it altogether, leaving the world without circulating banknotes for another 200 years.\n\n----\n\nWoodblock Printing\n\nInvented: c. 868\n\nSummary: A Chinese woodblock-printed masterpiece speaks of an earlier tradition.\n\n\u2002\"...good woodblock printing rests upon the perfection of drawing and painting, of color and line.\" \u2014Hiroshi Yoshida, Japanese Woodblock Printing (1939)\n\nWoodblock printing first appeared in China during the Tang Dynasty in the ninth century and was initially used in the production of textiles and Buddhist texts and amulets, A text or image'was transferred to a thin layer of paper that was then glued face down onto a wooden surface using rice paste. The lines would then be cut out by the block maker. Only those portions of a page or pattern to be inked were left untouched on the block's surface, with the remainder carved away along the grain using a fist knife known as a quan dao. Dense hardwoods such as birch, pear, or jujube were used because they withstood moisture and insects yet their regular, fine grains lent themselves to easy engraving and printing. Once a block was completed, the ink was rubbed onto the surface of the raised lines, and a skilled artisan could produce 1,000 or more sheets a day, thus ushering in the era of mass-produced booksand manuscripts.\n\nThe world's oldest extant woodblock-printed book that carries the date of its production is the Diamond Sutra, an Indian Buddhist Sanskrit text originally dating to 400, and later translated into Chinese and block-printed in ink on paper by an artisan, Wang Jie, on May 11, 868. It was discovered in a sealed cave in northwestern China by the archeologist Sir Marc Aurel Stein in 1907. However, it is by no means the oldest example of block printing. The degree of technical perfection in the Diamond Sutra suggests that the practice of woodblock printing had been long established by the time of its production.\n\nWoodblock printing continued to be popular in East Asia well into the nineteenth century.\n\n----\n\nRocket\n\nInvented: c. 904\n\nSummary: Chinese \"fire arrows\" herald rocketry.\n\n\u2002\"At the campaign of Yuzhang, he ordered his troops to propel the 'flying fire'on the besieged city....\" \u2014Compendium of Important Military Techniques (1044)\n\nIn 904 at the siege ofYuzhang, in southeastern China, attacking troops were ordered to launch \"flying fire\" on the city gates, burning them down and allowing their army to enter and capture the city. This is the first use of \"fire arrows,\" a term that originally meant an arrow carrying a tub of gunpowder that would explode when the arrow impacted.\n\nThe Compendium of Important Military Techniques (1044), written by Tseng Kung-Liang, gives details of how to launch fire arrows by gunpowder rather than using bows. By 1232, when the Chinese were fighting the Mongols, a much more recognizable rocket was being made using the exploding tubes to propel the arrows. The tubes were capped at the top, but open at the bottom, and tied to the top of an arrow that, when lit, would ignite the powder and produce thrust. Whether the rockets themselves did much physical damage in the war is unclear, but the psychological effect was formidable. After seeing it used against them, the Mongols quickly developed their own versions that they used throughout their empire, and this spread the technology across the Middle East and on to Europe. By the twelfth century rockets arrived in European arsenals, reaching Italy by 1500, and then Germany, and later England. The use of the Iron Rocket against the British in India in the eighteenth century led to the development of the technology.\n\n----\n\nCanal Lock\n\nInvented: c. 984\n\nInventor: Qiao Weiyo (China)\n\nSummary: Qiao Weiyo devises the pound lock.\n\n\u2002\"To see barges waiting... at a lock affords a fine lesson in how easily the world may be taken.\" \u2014Robert Louis Stevenson, An Inland Voyage (1878)\n\nLocks interrupt a canal or river with stepped stretches of still water, thus reducing currents in the waterway and conserving deep water for passage. The forerunner of today's lock was the flash lock, already in use by the first century B.C.E. in China, whereby part of a dam would be temporarily opened to allow passage of a vessel. Those traveling downstream were carried on the resulting surge of water, whereas those sailing in the opposite direction hauled the vessel against the torrent. Such an arrangement was dangerous and resulted in the loss of large quantities of water downstream for every vessel passing, a circumstance not appreciated by mill owners reliant on the supply.\n\nIn 984, during the construction of China's Grand Canal, engineer Qiao Weiyo noted that in placing two flash locks 750 feet (229 m) apart, he had created an intermediate stretch of water that could be held at the level of either the upper or lower reach of the waterway, and thus the pound lock, or chamber lock, was born. Following that breakthrough, a significant improvement was the development of mitered lock gates in sixteenth-century Italy, perhaps based on the designs of Leonardo da Vinci. The miter uses the pressure of the high water on the upper side of the gate to create a secure seal until the water levels have equalized. This allowed the constructions required to withstand pent-up water to be less massive.\n\n----\n\nLens\n\nInvented: c. 984\n\nInventor: Ibn al-Haytham (Iraq)\n\nSummary: Ibn al-Haytham's treatise establishes optical science.\n\nThe earliest lenses were made of circular pieces of rock crystal or semiprecious stone, such as beryl and quartz, which were ground and polished so that they produced a magnified image when looked through. The oldest known lens artifact was one made of rock crystal dating from around 640 B.C.E. and excavated in Nineveh, near the modern city of Mosul, Iraq. The most common form was circular and thicker in the middle than around the edge, and having both its front and back surfaces the same shape.\n\nThe modern convex lens developed from the ancient Greek burning glass. Here a spherical vase of water would be used to concentrate the rays of the sun onto a small area, which heated up. The heat was used to ignite fires in temples or to cauterize wounds.\n\nThe Iraqi mathematician and optics engineer Ibn Sahl (c. 940-1000) wrote the treatise On Burning Mirrors and Lenses (984) in which he set out his understanding of how curved mirrors and lenses bend and focus light, using what is now known as Snell's law to calculate the shape of lenses. But the Iraqi Ibn al-Haytham (965-1039), also known as Alhazen, is regarded as \"the father of optics\" for his treatise, the Book of Optics, (1011-1021), in which he proved that rays of light travel in straight lines, explained how the lens in. the human eye forms an image on the retina, and described experiments with a pinhole camera.\n\nIn the thirteenth century convex lenses were used in spectacles to correct farsightedness. The use of concave lenses, which disperse the light as opposed to concentrating it, to correct for nearsightedness, came in the early fifteenth century.\n\n----\n\nSextant\n\nInvented: c. 994\n\nInventor: Abu-Mahmud al-Khujandi (Iran)\n\nSummary: Abu-Mahmud al-Khujandi measures the altitude of the sun above the horizon.\n\nIranian astronomical observer and instrument designer Abu-Mahmud al-Khujandi (circa 940-1000) constructed the first known mural sextant, with a radius of 66 feet (20 m), on an accurate north-south facing wall in Ray, near modern Tehran, Iran. The name \"sextant\" refers to the fact that the instrument had an angular scale that was 60 degrees in length, one sixth of a circle. (When measuring latitude, one minute is equal to one sixtieth of a degree.)\n\nThe instrument was designed to measure the altitude of the sun above the horizon at noon on the days of both the summer and winter solstice, the two dates in theyear when this angle has its maximum and minimum value. From the average of these two angles, an observer could determine his or her latitude\u2014the angular distance between the equator and the observation site.\n\nThe height of the sun in the sky was measured by looking at the shadow it cast on an accurate scale. The Al-Khujandi scale was so accurate that the latitude that he obtained was correct to a tiny fraction of a degree. Other famous mural sextants followed, including the Fakhri sextant with a radius of approximately 118 feet (36 m) constructed by Iranian Ulugh Beg in Samarkand, Uzbekistan, in around 1420. More modern astronomical sextants are smaller and pivoted at the balance point. They can be moved to measure the angular separations of stars and planets.\n\nHandheld nautical sextants have become common in the last three centuries. They are fitted with adjustable mirrors and are used to measure the altitudes of celestial bodies.\n\n----\n\nMovable Type\n\nInvented: 1041\n\nInventor: Bi Sheng (China)\n\nSummary: Bi Sheng advances printing by creating characters on movable clay tablets.\n\n\u2002\"...for printing hundreds or thousands of copies, it was marvelously quick.\" \u2014Shen Kuo, Dream Pool Essays (1088)\n\nIn 1041, in the best traditions of China's inventive and technologically vibrant Song Dynasty (960-1280 C.E.), an alchemist named Bi Sheng shaped a series of reusable, moistened clay 'tablets, inscribed an individual Chinese character upon the surface of each one, fired them to harden and make them permanent, and in the process invented movable type. Printers then took the characters and laid them within an iron framecoated with a mix of resin, turpentine, wax, and paper ash, arranging the characters to reflect what was to become the printed page.\n\nUnlike the Western alphabet that requires the generation and arrangement of only twenty-six characters, Bi Sheng worked in a language with over 5,000 distinct characters. Many of these needed several pieces of type to complete, and all of them required the making of multiple copies. The copies were wrapped in paper and stored within wooden framed cases when not in use, ordered according to the first syllable of their pronunciation. Like Johannes Gutenberg hundreds of years later, Bi Sheng failed to receive recognition for his invention until long after his death, despite-his efforts being recorded by the great Chinese scientist Shen Kuo in his series of Dream Pool Essays.\n\nThe multiplicity of Chinese characters and symbols was one reason for the failure of Bi Sheng's invention to impact significantly upon Chinese society, in contrast to Gutenberg's press in fifteenth-century Europe. Another problem was that clay tablets were manifestly unsuitable for large-scale printing and were not at all durable. The limitations of clay led eventually to the invention in Korea of metal, movable type, -which accelerated the spread of printing in Asia in the early thirteenth century.\n\n----\n\nTower Clock\n\nInvented: 1094\n\nInventor: Su Song (China)\n\nSummary: Su Song builds a technological marvel.\n\n.. the comparison of the rotary movements... will show no discrepancy or contradiction....\" Su Song, The Rotation ofanArmillary Sphere (1092)\n\nThe world's first water-driven astronomical clock tower was by far the most advanced astronomical instrument of its day. Its designer was Su Song (1020\u2014 1101), who oversaw the project with the aid of mathematician Han Gong-lian. The elaborate, 40-foot (12 m), water-powered, mechanically driven clock had bronze castings, precision gears, gear rings, and pinions. A bronze armillary sphere with a celestial globe mounted below allowed the sun, moon, and selected stars to be seen through a sighting tube.\n\nThe tower was a three-level, pagoda-like structure powered by thirty-six buckets attached to a central wheel, each of which would trip a lever and tilt forward at a predetermined point to engage the clock's\n\ncomplex system of gears and counterweights. Song's greatest achievement, however, was an ingenious escapement mechanism that converted this energy discreetly from a pendulum to the gears in a concept vital in the construction of clocks, and a technology unknown to Europeans until late in the thirteenth century. This technology was a precursor to the mechanical escapement, which enabled the manufacture of all-mechanical clocks that could tell time with far greater precision.\n\n----\n\nChain Drive\n\nInvented: 1094\n\nInventor: Su Song (China)\n\nSummary: Su Song's clock hides a brilliant innovation.\n\nChinese government official Su Song (1020-1101) was also a naturalist, cartographer, astronomer, horologist, and engineer. His greatest legacy was the clock tower he built in Kaifeng. In 1086 the emperor had ordered the construction of an \"armillary clock\" to keep time and track celestial bodies. A finished structure was completed in 1094, and consisted of three levels. The upper level contained a rotating armillary sphere that allowed astrological observations through sighting tubes; the middle level had a bronze celestial globe; and the lower level had mechanically timed manikins that would exit doors at fixed times of the day.\n\nPerhaps most significant, however, was the clock's innovatory driving system. At the heart of the clock tower was the tian ti, or \"celestial ladder.\" This is the oldest known endless power-transmitting chain drive. The chain transmitted the power from a water wheel to turn the armillary sphere and power the clock.\n\nDrive belts had been present in China for approximately 1,000 years before Song's chain drive. However, such belts were primitive, haphazard affairs and lacked the precision necessary todrivea clockand armillary sphere. The chain links fitted sprockets and were not subject to stretching or slippage. Chain drive is now used in a wide range of mechanical devices, especially in vehicles such as bicycles, but it was not until several centuries after Song's innovation that Europeans independently discovered the technology.\n\nThe clock was captured and dismantled by invading Jurchens from Manchuria who overran Kaifeng in 1127. It is one of the great lost artifacts of the medieval age. However, Song's 1092 treatise (Essentials of a New Method for Mechanizing the Rotation of an Armillary Sphere and a Celestial Globe) survived, with illustrations and descriptions of the clock.\n\n----\n\nCannon\n\nInvented: c. 1128\n\nSummary: The Chinese develop bronze cannons from primitive bamboo forerunners.\n\n\u2002\"Shells are made of east iron... and are sent flying toward the enemy camp from an eruptor\" \u2014Jiao Yu and Liu Ji, Fire Dragon Manual (c. 1368-1398)\n\nDuring the Chinese Song Dynasty (circa 960-1279), artillery engineering exploded, as it were, with the development of the ancestor of the cannon: flamethrowing \"fire lances\" made of bamboo. When gunpowder at one end was ignited, it forced sand, lead pellets, or shards of pottery at the enemy.\n\nWhen metal later replaced bamboo, probably in the early 1100s, these lances became \"fire tubes\" or \"eruptors.\" The oldest record of them is a painting, dated to 1128. The early Chinese cannons could throw a ball about 50 yards (45 m). A century later they had become powerful enough to breach city walls, and were made of bronze. According to the historian of Chinese technology Joseph Needham, cannon warfare took a great step forward with the development of cannonballs that fitted the tube's bore precisely, enabling more control. Later cannons were made of cast iron, and some were wheeled.\n\nCannon technology spread and was developed in Europe; the Scots defended Stirling Castle with cannons in 1341, and three cannons were used at the battle of Crecy-en-Ponthieu in 1346 by England's King Edward III, who had more than a hundred of them, in London. Such early European cannons were small, but by the end of the Hundred Years' War (1337-1453) giant ones were available, known as \"bombards.\" Mons Meg, a bombard built in 1457, survives at Edinburgh Castle in Scotland; with a 22-inch (56 cm) caliber barrel, it is capable of firing gunstones weighing 331 pounds (150 kg) nearly 2 miles (3.2 km).\n\nFrom the sixteenth century, lighter cannons capable of more accurate fire were developed, and these gradually evolved into modern artillery pieces, such as the howitzer used to great effect in the American Civil War (1861-1865).\n\n----\n\nFireworks\n\nInvented: c. 1150\n\nSummary: The Chinese invent explosive entertainment.\n\nFireworks, familiar now in sound-and-light shows on dark evenings, to celebrate festivals and to entertain, were invented in China around 1,000 years ago, following the invention of gunpowder in the first century C.E. Bamboo tubes, filled with gunpowder, were thrown onto fires to create explosions at religious festivals, perhaps in the belief that the noise they made would scare off evil spirits. It is highly likely that some of these little bombs shot like rockets out of the fire, propelled by the gases they produced.\n\nThe next step seems likely to have been to attach such charged bamboo tubes to sticks and fire them with bows. The earliest evidence of devices that could be described as firework rockets comes from a written report of the battle of Kai-Keng in 1232 during the war between China and Mongolia, in which the Chinese attacked with \"arrows of flying fire.\" After Kai-Keng, the Mongols began to make rockets as well, and probably tookthese with them on theirtravels to Europe.\n\nThere is documentary evidence for experiments involving rockets in Europe throughout the thirteenth to fifteenth centuries. English Franciscan friar and philosopher Roger Bacon (circa 1214-1294) reported on his experiments to improve gunpowder and increase the range of rockets, and, in France, Jean Froissart (circa 1337-1405) commented that rockets could be fired more accurately if launched from tubes.\n\nFor the first 700 years of their existence, fireworks were available only in one color (yellow), until the French chemist Claude Berthollet discovered potassium chlorate in around 1800 and began the development of new colors for fireworks.\n\n----\n\nArabic Numerals\n\nInvented: c. 1202\n\nInventor: Fibonacci (Algeria)\n\nSummary: Fibonacci promotes Hindu-Arabic numbers.\n\n\u2002\"The idea seems so simple that its significance and importance is no longer appreciated.\" \u2014Pierre-Simon Laplace (1749-1827), mathematician\n\nIn 1202 Leonardo Pisano (c.1170-c.1240), known as Fibonacci, published his seminal work Liber abaci (\"Book of the Abacus\") and thus popularized Hindu-Arabic numbers in Europe. Although born in Italy, Fibonacci grew up in what is modern-day Beja, Algeria. Taught by Arab teachers, Fibonacci came in contact with our modern numeral system, which was devised in ancient India yet virtually unknown in Europe.\n\nUntil then the Roman numeral system had been prevalent throughout the continent. The system had been-an improvement on the first recorded numbers found in Egypt\u2014simple representative strokes for each digit, and a special symbol for ten\u2014as well as the Greek (Attic) method of recording the first letters of the numeral names. In the Hindu-Arabic base ten system, on the other hand, the single digits were represented by symbols whose value depended on placement (i.e., 2 in 200 being ten times greaterthan 2 in 20).\n\nThe first known inscriptions of these numbers date from the third century B.C.E., although whether they were used in a place-value system isn't clear. As early as the seventh century C.E. the system had reached the Arab world, recorded by mathematicians such as Al-Khwarizmi. The advent of the printing press in the fifteenth century accelerated the proliferation of Hindu-Arabic numerals, which over the centuries has become the closest thing to a universal human language.\n\n----\n\nCrankshaft\n\nInvented: c. 1206\n\nInventor: Ismail Al-Jazari (Mesopotamia)\n\nSummary: Al-Jazari sets rotational energy to work.\n\n\u2002\"Types of machines... came to my notice offering possibilities for types of marvelous control.\" \u2014Al-Jazari, Book of Knowledge (1206)\n\nIslamic scholar Al-Jazari (1150-1220) lived in what was northern Mesopotamia\u2014today's northeastern Syria and Iraq. A brilliant inventor, he made one of the most significant contributions to human engineering in 1206 by devising the world's first crankshaft. This conceptually simple device converts rotary into reciprocating motion, and vice versa, but it is now used in a huge number of modern machines, including automobiles. Put simply, the Industrial Revolution could not have happened without it.\n\nThe crankshaft is perhaps most commonly recognized today in modern motor engines, and is among Al-Jazari's more famous inventions. In today's cars it receives force from firing pistons that move in a linear fashion back and forth and, through movable bearings, rotates around its axis, thus converting the pistons' energy into rotation output for the wheels.\n\nAl-Jazari's original invention was designed to pump water from wells for irrigation, with cattle employed to provide the energy\u2014quite a contrast from the modern interpretation of the technology. Despite the difference in complexity, the principle behind the crankshaft remains the same more than 800 years after Al-Jazari first thought of it.\n\n----\n\nCamshaft\n\nInvented: c. 1206\n\nInventor: Ismail Al-Jazari (Mesopotamia)\n\nSummary: Al-Jazari transforms rotational power.\n\nWhen the great Islamic scholar Al-Jazari (1150-1220), published in 1206 his Kitab ff ma'rifat al-hiyal al-handasiyya IBook of Knowledge of Ingenious Mechanical Devices), it included a description of a device that could change rotational motion into reciprocating motion: the camshaft. This invention consists of a shaft that has oval-shaped lobes attached to it, which turn with the shaft itself. Because of their noncircular shape, these \"cams\" appear to oscillate when the shaft spins on its axis. If a cam is positioned next to a valve, as it is in the example of the internal-combustion engine, then, as the camshaft turns, the longest end of the cam will depress, and hence open, the valve each time the shaft makes a turn. Before that, the camshaft played an important role in many medieval technologies. In windmills and waterwheels, for example, camshafts transformed rotational power into the energy and modes of action needed to mill corn, saw wood, or hammer metal.\n\nIn modern times the camshaft is best known as an integral part of the internal-combustion engine. When fuel within each combustion chamber of an engine explodes, the mixture of combusting fuel and air expands and drives a piston that is connected to a crankshaft, thus translating the piston's motion into the energy needed to propel a car, lift a weight, or perform some other form of work. A camshaft\u2014or two camshafts, depending on the engine's design\u2014 controls the valves that allow new fuel into each combustion chamber, as well as the valves that release exhaust gases from the previous fuel ignitions.\n\nIn an engine the camshaft is connected to the crankshaft by a timing belt that allows precise coordination ofthefiring of the combustion chambers with the intake of fuel and output of exhaust.\n\n----\n\nAutomaton\n\nInvented: c. 1206\n\nInventor: Ismail Al-Jazari (Mesopotamia)\n\nSummary: Al-Jazari creates the automaton that anticipates today's industrial robots.\n\n\u2003\"'Obedience...\n\n\u2003Makes slaves of men, and, of the human frame\n\n\u2003A mechanized automaton.\" \u2014Percy Bysshe Shelley, \"Queen Mab\" (1813)\n\nMost people think of self-operating machines as twentieth-century inventions. Although Isaac Asimov coined the word \"robotics\" in 1942, and Grey Walter built the first electronic autonomous robots in 1948, the first automaton for which we have good evidence was a boat with four mechanical musicians. It was built more than eight hundred years ago by Islamic scholar Al-Jazari (1150-1220).\n\nAl-Jazari, considered by some to be the father of robotics, wrote his Kitab fi ma'rifatal-hiyalal-handasiyya (Book of Knowledge of Ingenious Mechanical Devices) in about 1206, while he was the palace chief engineer in Diyarbakir (located in the southeast of present-day Turkey). The book describes a boat he constructed that floated on the palace lake and entertained guests at parties with music from a flute, a harp, and two drums played by automatons. The drummers contained rotating cylinders with movable pegs. As the cylinder rotated, the pegs would strike levers that caused the drums to be played. Changing the number and location of the pegs produced different rhythms, and so the automaton was entirely programmable.\n\nAutomatons created in subsequent centuries, mainly for entertainment purposes, continued to play musical instruments, along with other activities that could be recreated in a sufficiently realistic manner.\n\nToday, factories increasingly use robots\u2014 essentially automatons powered by electricity\u2014for jobs that require speed, precision, strength, and/or endurance. Robots build cars, package goods, manufacture circuit boards, and perform many other tasks. Almost a million robots were in operation around the world in 2007, and the International Federation of Robotics expects this number to reach 1.2 million by the end of 2010.\n\nAl-Jazari created this water-pouring automaton for the amusement ofUrtugid Dynasty princes.\n\n----\n\nSpectacles\n\nInvented: c. 1250\n\nSummary: Venetians create the first European glasses.\n\n\u2002\"...this invention enables good sight and is one of the most useful of arts... the world possesses.\" \u2014Fra Giordano da Rivalto, sermon (1305)\n\nIn the first century the Roman philosopher and dramatist Seneca used a glass sphere full of water resting on his reading material to magnify the letters, and this method was certainly used by farsighted monks a millennium later. Glass blowers in Venice produced lenses that were used as magnifying glasses, and in Europe in the late thirteenth century these were being used in pairs, one for each eye, the holding frame being made of wood or horn.\n\nSalvino D'Armate of Pisa (1258-1312) and the friar Alessandro da Spina (d. 1313) of Florence are often given the credit for the invention of spectacles, in the year 1284, but Marco Polo, in 1270, saw elderly Chinese using spectacles and, when asked, they credited the invention to Arabs in the eleventh century. The Chinese were also using smoky quartz as simple nonmagnifying sunglasses atthat time.\n\nThe first spectacles used convex lenses and corrected for presbyopia (farsightedness). In 1451 the German cardinal Nicholas of Cusa introduced spectacles with concave lenses that corrected for myopia (nearsightedness). The explanation as to why the lenses worked was given by Johannes Keplerin his 1604 treatise on optics. By around 1730 a London optician, Edward Scarlett, perfected spectacle arms that hook behind the ears, although it was some time before this became the preferred design.\n\n----\n\nLand Mine\n\nInvented: c. 1277\n\nSummary: The Chinese pioneera concealed weapon.\n\n\u2002\"The fuse starts from the bottom... black powder is compressed into it to form an explosive mine.\" \u2014Jiao Yu and Liu Ji, Fire Dragon Manual (c. 1368-1398)\n\nLand mines\u2014explosive weapons triggered by pressure or proximity\u2014have been in use for many hundreds of years, and as such their exact history is somewhat clouded. There is evidence to suggest, however, that the first self-contained land mines for military purposes were used in China in 1277 against Mongol invaders. Today their use has prompted great controversy, due to the high civilian casualties that can be caused many years after conflict has ended.\n\nThe name \"mine\" is derived from their original use in Europe in the Middle Ages as \"tunnel mines.\" During the siege of a castle or fort, tunnels would be dug under the walls and explosives detonated just beneath them in a bid to cause them to collapse. True anti-\n\npersonnel land mines were introduced in China by the Middle Ages. The mines were detonated either by the pressure of someone walking over them, or by operation from afar, and appeared in a variety of designs. However, their use in warfare was restricted by a scarcityofammunition.\n\nThe mine emerged at the beginning of the sixteenth century in Europe in the form of a shallow pit of gunpowder, with a \"charge\" made from flint that would ignite the explosive. In later centuries mines were used to slow advancing troops, especially in the Boer War and World War I. The twentieth century saw a great proliferation of their use.\n\n----\n\nScythe\n\nInvented: c. 1300\n\nSummary: This European invention increased productivity and liberated workers from the sickle.\n\n\u2002\"The scy the was faster to use than the ancient, short handled, curved, serrated blade sickle.\" \u2014The Countryside Museum website\n\nThe scy the is often ranked among the world's most significant advances in agricultural implements of the past thousand years. Its appearance on the farms of Europe in the latter half of the thirteenth century was to profoundly revolutionize agricultural production. Initially used as a grass cutter to gather hay, it was later used to harvest grain. Consisting of a curved blade, sharpened on the inside of the curve, and a long wooden handle (called a snath), the scy the allowed the reaper to stand upright while cutting grass\u2014a vast improvement over the short-bladed sickle, which required the userto stoop uncomfortably as he cut.\n\nA worker using a sickle, which was essentially unaltered in design since its emergence in around 5000 B.C.E., could harvest at best only three-quarters of an acre (0.3 ha) per day, while the use of a scy the increased the production of grain harvesting to more than an acre (0.4 ha) per day. Its ergonomic design and its way of operating as a kind of lever gave it more power than the backbreaking sickle, and by the sixteenth century the scy the had all but replaced the sickle as the preferred tool for harvesting\u2014as well as the weapon of choice in many a peasant rebellion.\n\nBy the late eighteenth century a series of wooden pegs had been added along the snath, which allowed grain to be cut and their stalks gathered in one motion for bundling into sheaves, an innovation that effectively doubled the farmer's productivity. The scy the remained the dominant tool for grain harvesting until the invention of the mechanical horsedrawn reaper in 1831, which could do as much reaping in a day as ten men with scythes.\n\n----\n\nMusket\n\nInvented: c. 1300) Summary: Using gunpowder, Chinese gunsmiths invent a deadly rival for the longbow.\n\n\u2002\"The impact of Chinese firearms in terms of warfare and territorial expansion was profound.\" \u2014Sun Laichen, Asia Research Institute\n\nA musket is a smoothbore firearm loaded from the muzzle and fired from shoulder-level. It is larger than an arquebus and often fired from a rest on which it can be pivoted from side to side. It is difficult to pin down with certainty when the musket was invented, although according to ancient Chinese texts it was some time in the fourteenth century. Basic cannons had been fashioned by the Chinese, and Chinese weapons experts were the first to produce a device that was recognizable as a musket, but it was when this technology met the greater metallurgical prowess of the Ottoman Empire (and laterthat of the European powers) that a revolution in warfare took place.\n\nIt took a long time for muskets to become established; early muskets in particular took a long time to reload, could not reliably pierce armor, and were expensive and unreliable. Crucially, a cheap and deadly accurate alternative already existed: A longbow and arrows could be constructed relatively easily from locally available materials. Yet from the sixteenth century onward, Europeans, and in particular the Portuguese, were producing muskets and cannons and exporting them to Asia.\n\nBy the seventeenth century, the musket's reliability and ease of use had improved, and it enjoyed one distinct advantage over the longbow: It did not require a highly trained soldier or nobleman to use it. Despite initial resistance to this \"cheapening\" of \"noble\" warfare, the aristocracy quickly realized that enemy forces were utilizing firearms to deadly effect, and also that the vast majority of casualties were now not people of their own class, but the more expendable common man. This pattern of warfare continued and intensified through the centuries, reaching a bloody peak in World War I.\n\n----\n\nProduction Line\n\nInvented: c. 1320\n\nSummary: The Venetians initiate mass production.\n\n\u2002\"The Arsenal of Venice's work force continually produced new innovations for the Venetian fleet.\" \u2014Gregory Sheridan, The Imperial Age of Venice (1970)\n\nThe division of labor into many discrete tasks in a production line increased efficiency and output and enabled the mass production of high quality goods. Nowhere was this better exemplified than in the Venice Arsenal factory, where standardized parts and specialized tasks gave the Venetians a speed advantage in building warships, firearms, and, as a result, their empire.\n\nIn 1574, King Henry III of England had the privilege of seeing this formidable first factory construct complete galley ships in less than a day. With their efficient and organized approach, the Arsenal's thousands of workers manufactured complicated war tools 600 years before the start of the Industrial Revolution. The Arsenal was expanded on several occasions throughout its lifetime but was originally built as a shipyard in 1104. By 1320, the workers carried out specialized tasks in the production of ships. At its peak, the Arsenal employed around 16,000 people, the largest workforce in Europe. After Venice was annexed by Italy in 1875\u20141878, the Arsenal underwent further expansion. During the late 1800s it was the site of construction for several of the Italian Navy's most powerful ships.\n\n----\n\nRain Gauge\n\nInvented: 1441\n\nInventor: Jang Yeong-Sil (Korea)\n\nSummary: Jang Yeong-Sil measures rainfall.\n\nIn the fifteenth century Korea was a drought-plagued realm, and King Sejong (1397-1450) wished to levy land taxes based on an assessment of each farmer's potential harvest. To this end a nationwide network of rain gauges was established and the local magistrates of every village were commanded to report the rainfall to the central government.\n\nIn 1441 each village was provided with a standard cylindrical container, 17 inches (43 cm) high and 7 inches (17 cm) wide, that was mounted on a stone stand; a special ruler was used to measure the depth of rainwater that entered the gauge over a specific time. Its inventor was a civil-servant scientist, Jang Yeong-Sil. Needless to say, the method of rain measurement was rather labor-intensive. The Chinese, meanwhile, had used a similar technique to measure snowfall in 1247 C.E.\n\nIn 1662 Sir Christopher Wren (1632-1723) invented the \"pluviometer,\" a mechanical, self-emptying, tipping-bucket rain gauge. It consisted of two small, well-balanced buckets that collected rain sequentially. When a specific amount of water had fallen into one of the buckets\u2014usually about 0.03 inches (0.1 cm)\u2014it tipped over, emptied itself, and produced a mechanical signal. Also, a hole was punched into a slowly moving paper tape as the bucket tipped. The second bucket then started to collect rain, only to tip over when full. The more signals recorded, the greater the rainfall.\n\nCare had to be taken in positioning Wren's gauge. It had to be sufficiently high off the ground to avoid splashes and animals, and be well away from trees, fences, and buildings to prevent shadowing and an unrepresentatively low reading. Heated gauges are now used when hail and snow are expected.\n\n----\n\nCoiled Spring\n\nInvented: c. 1450\n\nInventor: Peter Henlein (Germany)\n\nSummary: Henlein perfects the heart ofclockwork.\n\n\u2002\"...a piece of work which excites the admiration of the most learned mathematicians.\" \u2014Cosmographica Pomponii Melae (1511)\n\nOften in history one critical invention leads to another that overshadows the first. This was true of the German locksmith Peter Henlein, the inventor of the portable or pocket watch. He created this sometime between 1504and 1508, and it could operate for up to forty hours before it needed rewinding.\n\nHenlein's work was made possible by the invention, more than fifty years earlier, of a single piece of metal that, when in a certain shape, would use the metal's natural elasticity to both absorb and release a force applied to it: the humble coiled spring. History does not recall who first created this most useful invention, but a small number of examples of spring-driven clocks have survived from the early fifteenth century.\n\nThe coiled spring's ability to store energy was what made it perfect to power clockwork devices. Winding up a clock, or watch, costs physical energy as the spring becomes compressed. Clockwork gears then allow that energy to be gradually released while supplying a steady, if tiny, flow of power to a clock.\n\nHenlein, and others, had to overcome various problems in their early models. A good spring is created from a single ribbon of steel of uniform thickness that can be squeezed without breaking. The delicate preheating required to temper coiled springs was difficult, and perfecting the formula was an important step in metallurgy.\n\n----\n\nArquebus\n\nInvented: c. 1450\n\nSummary: The Spanish create the handheld cannon.\n\nIn the middle of the second millennium C.E. the battlefield was dominated by armored cavalry and the romantic concept of the chivalrous knight in armor. However, a technological innovation was about to take place that would completely change warfare. The invention in question was called the \"hackenbushce,\" or arquebus, probably a derivative of the Dutch word haakbus, meaning \"hook-gun.\" The arquebus was one of the first effective examples of a handheld firearm.\n\nBy this time, using gunpowder to fire projectiles was not a new idea. Cannons had existed since the early 1300s, and smaller \"hand-cannons\" had developed to complement these. These early firearms were basically small cannons mounted on poles or on crossbow stocks, and were fired by touching the venthole with a match, which would ignite the powder and fire the projectile.\n\nThe particular innovation of the arquebus, which cannot be attributed to one person but is probably of Spanish origin, lay in the use of a pivoting mechanism with the slow-burning match at one end that allowed the arquebusier, or shooter, to hold and aim the weapon with both hands, and then simply pull the other end of the pivoting lever to touch the match to the powder and fire the weapon. This mechanism was, of course, an early forerunner of the trigger, ubiquitous on modern guns, and by freeing both hands allowed the weapon to be fired with greater accuracy.\n\nDespite this advantage, the arquebus was still grossly inaccurate when compared to the longbow or crossbow, but it still caught on, probably due to the fact that use of the arquebus was relatively easy to learn; where the longbow took years of study and considerable physical strength to master, the gun could be fired by almost anyone.\n\n----\n\nAnemometer\n\nInvented: c. 1450\n\nInventor: Leon Battista Alberti (Italy)\n\nSummary: Alberti measures wind speed with an effective new instrument.\n\n\u2002\"None of our modem craftsmen (except Alberti) has known how to write about these subjects.. \u2014Giorgio Vasari, Lives of the Artists (1550)\n\nDevised by Leon Battista Alberti (1404-1472), the anemometer was a simple instrument to measure wind speed. It had a rectangular metal plate attached to a horizontal axis with a hinge, so that in the wind the metal plate lifted, giving an indication of relative wind speed that could be measured crudely on a curved scale bar below the plate. In light winds, the plate would move slightly on its hinge; in stronger winds, the plate would lift further. Alberti describes and illustrates this device in his book, The Pleasure of Mathematics (1450). The well-educated son of a wealthy merchant, Alberti was an accomplished artist, athlete, horserider, musician, mathematician, cryptographer (inventing the cipher disc), classicist, writer, cleric, and architect. He was a true Renaissance polymath, created by the intellectual culture prevailing in the Italian cities at the time.\n\nAs an artist and an architect, Alberti was inspired py Filipppo Brunelleschi's use of linear perspective and his great design for the dome of Florence Cathedral, where Alberti was a canon. In turn, Alberti's work, including the anemometer, inspired Leonardo da Vinci, who made drawings of it and saw its valueln his designs forflying machines.\n\nAlberti's simple design served its users for more than 200 years, until a British scientist, Robert Hooke (1635-1703), reinvented it in 1664, placing the moving plate beneath the curved scale bar to ensure more accurate measurements. Almost two centuries passed before the four-cup windmill anemometer was invented, in 1846, by the Irish astronomer John Thomas Romney Robinson (1792-1842).\n\n----\n\nPrinting Press with Movable Metal Type\n\nInvented: c. 1450\n\nInventor: Johannes Gutenberg (Germany)\n\nSummary: Gutenberg's innovatory press vastly increases the dissemination of information.\n\n\u2002\"It shall scatter the darkness of ignorance, and cause a light... to shine amongst men.\" \u2014Johannes Gutenberg, printer\n\nWriting was an important step in the advancement of civilization, but few books were produced and they reached a limited number of people. Such books were usually of a religious nature, handwritten in Latin, and copied by clerks for the clergy and the nobility. It was only when the printing press was developed that knowledge and ideas were spread more widely.\n\nThe earliest form of press incorporated a wooden block with raised letters on one side. Such blocks were arranged in a frame and inked, so that when pressed onto paper an impression of the letters was produced. Unfortunately the blocks disintegrated with use, and so could not produce many copies; it was very timeconsuming for craftsmen to produce new blocks for letters and illustrations.\n\nIn 1450 Johannes Gutenberg (circa 1400-1468), a German printer, developed a technique where letters produced from molds of metal alloy were arranged into words, then locked together using a template to produce a whole page of typeface. This was sufficiently robust to print many hundreds of identical pages and hence the production of books became widespread, enabling more people to learn to read and increasing the demand for reading material.\n\nGutenberg's press would have had limited usefulness without appropriate inks. Before his time, simpler printing methods made use of water-based inks, and Gutenberg himself introduced more robust oil-based inks, including colored inks that were printed experimentally in some copies of his bible.\n\nFlatbed-printing methods were eventually replaced by rotary presses, and by the end of the twentieth century computerto plate (CTP) technology was used, in which material was sent directly from a computerto a printing plate.\n\nNotes:\n\n- The impact on society of Gutenberg's press was comparable to that of the Internet today.\n\n----\n\nToothbrush\n\nInvented: c. 1498\n\nSummary: The Chinese introduce a dental savior.\n\nThe forerunner of the modern bristle toothbrush is generally believed to have originated in fifteenth century China. A Chinese encyclopedia dating to 1498 describes the short, coarse bristles from the neck of a Siberian wild boar being embedded in a handle made from animal bone, which was then used to clean the teeth. In the seventeenth century, Chinese traders took the brush to Europe, where its popularity flourished despite boar hairs being considered too rough for sensitive European gums. Softer horsehair bristles were seen as an alternative, although boar bristles remained the most common fiber.\n\nThe toothbrush was not humankind's first attempt at dental hygiene. \"Toothsticks\" dating back to 3000 B.C.E. have been uncovered during excavations of Pharaonic tombs in Egypt. These are lengths of frayed twigs or fibrous wood from shrubs, used to clean between the teeth and freshen the breath. \"Chewing sticks\" made from aromatic shrubs for oral hygiene and to freshen the breath were also used by the Chinese in the sixteenth century.\n\nThe first mass-produced toothbrush was designed and marketed by the English inventor William Addis in 1780 using boar hairs and swine bristles attached to the end of a downsized cow's thigh bone. More geometric designs began to appear in the mid-1840s when bristles first began to be aligned in rows. Natural bristles continued to be used up until the invention of nylon by Dupont de Nemours in 1938. The world's first electric toothbrush appeared in 1939.\n\nThe toothbrush is one of the oldest implements still used by humanity, regularly finishing above more fancied inventions\u2014such as the car and the personal computer\u2014on people's lists of the things they simply could not do without.\n\n----\n\nGlass Mirror\n\nInvented: c. 1505\n\nSummary: The Venetians transform glass reflectivity.\n\n\"The world has become uglier since it began to look into a mirror every day.\"\n\nKarl Kraus, journalist, poet, and playwright\n\nPrimitive peoples would have found their reflections in the surface of still ponds, while mirrors used in early Greek and Roman civilizations and in Europe during the Middle Ages were highly polished pieces of metal that reflected light off their surfaces. However, the real leap forward for vanity occurred during the early sixteenth century, when the Venetians developed a method of backing a plate of flat glass with a thin layer of reflecting metal that was an amalgam of tin and mercury, much increasing the clarity of the reflection.\n\nThe earliest mirrors were hand mirrors used for personal grooming, and later as objects of household decoration with frames made of ivory, silver, or carved wood. The chemical process of coating a glass surface\n\nwith metallic silver, from which modern techniques of mirror-making were developed, was discovered by Justus von Liebig in 1835. English brothers Robert and James Adam designed large and elaborate fireplaces that used mirrors to great effect. In the nineteenth century, mirrors were incorporated into pieces of furniture, such as wardrobes and sideboards.\n\nIn modern times, mirrors are used in scientific apparatus such as telescopes, cameras, and lasers and in industrial applications. Mirrors designed for electromagnetic radiation with wavelengths other than that of visible light are also used in manufacturing, especially of optical instruments\n\n----\n\nPocket Watch\n\nInvented: c. 1508\n\nInventor: Peter Henlein (Germany)\n\nSummary: Henlein makes the first pocket-sized timepiece.\n\n\u2002\"Peter Henlein... maxes from a little iron a pocket clock with a lot of wheels.\" \u2014Johannes Cocleus, historian\n\nThe world's first portable timepiece, which came to be known as a \"pocket-clocke,\" was made in Nuremberg, Germany, between 1504 and 1508 by the former apprentice locksmith and clockmaker Peter Henlein (c. 1479-1542). The miniaturization of timepieces began with the invention of the coiled spring in Italy in the late 1450s along with the development of various escapement mechanisms. However, the real breakthrough proved to be Henlein's invention of the balance spring, which greatly improved the precision of a watch's spring-driven interior.\n\nHenlein's new pocket watch measured only a few inches in diameter, chimed on the hour, and could run for up to forty hours before it required rewinding. It was driven by scaled-down steel wheels and hand-forged springs that, despite representing a huge technological leap forward, were nonetheless persistently inaccurate. The coiled springs unwound at a varying speed, causing the watch to slow as the mainspring unwound. Early springs also had a maddening tendency to break when tightly wound, although later refinements such as cam springs were added to compensate for inherent irregularities.\n\nIt took Henlein ten years to develop his first pocket watch (this and his subsequent timepieces would go on to become known as his \"Nuremberg eggs\"). The high cost of the innovation saw the pocket watch become largely a status symbol of the upper classes, yet the popularity of the pocket watch was to continue for 400 years, not least as a formal gift of readily perceived worth, until the invention of the wristwatch in the early twentieth century.\n\n----\n\nEtching for Print\n\nInvented: c. 1510\n\nInventor: Daniel Hopfer (Germany)\n\nSummary: Hopfer simplifies printmaking.\n\n\u2002\"He is praised as an innovator, yet he is also maligned as derivative and labeled a mere craftsman.\" \u2014Freyda Spira, historian\n\nAs a decorative technique, etching had been in use for many years before the birth of Daniel Hopfer (1470-1536), possibly since antiquity. His innovation was to apply the method to printmaking. The etching process begins by covering a metal plate with a waxy material called a ground. Lines are then scratched into the ground with a needle to expose bare metal where the artist wants lines to appear on the print. The plate is then washed with (ordipped into) acid, which cuts into the exposed metal, leaving lines etched in the plate.\n\nThe longer the plate is submerged, the deeper the incision, and the darker the lines wi'l appear on the print. For a more sophisticated finished print, the process can be repeated to allow for different tones within the piece. Once ready, the plate is covered in ink that is then wiped away, leaving ink only in the incisions and rough areas. The plate is covered by a sheet of wet paper and passed through a press. The pressure of the press forces the paper into the incisions, leaving a mirror image of the plate on the paper.\n\nHopfer's technique was influential because it was easy. Another way of making prints is to engrave, but this requires metalwork skills. The only prerequisite for etching is to be able to \"draw\" into the ground.\n\n----\n\nSand Casting\n\nInvented: c. 1540\n\nInventor: Vannoccio Biringucci (Italy)\n\nSummary: Biringuccio revives ancient skills.\n\nSand casting with molten metal ranks as one of the oldest of the manufacturing technologies. For many years it was a dark art and its mysteries were known only to a select few. A sixteenth-century Italian metallurgist and arms maker, Vannoccio Biringuccio (1480-c. 1539), would change this with his seminal work, De la pirotechnia (1540). Published in Venice a year after Biringuccio's death, the book is a veritable encyclopedia of metallurgical knowledge and constitutes some of the earliest printed information on sand casting and foundry techniques in general.\n\nBorn in Siena, Biringuccio, under the patronage of an Italian merchant politician and part-time tyrant, Pandolfo Petrucci, traveled widely throughout Italy and Germany, accumulating the information and experiences that he would summarize in his book.\n\nDuring a typical sand-casting operation, a model or \"pattern\" of the item to be cast is positioned in a frame. Sand, moistened to bind it together, is then pressed closely around the pattern. This moist sand mix is a critical feature of the process and through the years various binding agents have been adopted, some of them quite unusual. Biringuccio himself recommended the use of human urine and the dregs from beer vats for the purpose.\n\nWhen the frame is full and the sand rammed down, it is turned over and another frame temporarily attached. The process is then repeated, the frames separated, and the model carefully removed, leaving a cavity in each of the sand boxes that represents one half of the item to be cast. Channels (\"sprues\" and \"runners\") are cut into the sand to allow molten metal to be poured into the mold, and air to escape during the pouring. The frames are now securely reassembled together and the metal is poured.\n\n----\n\nCondom\n\nInvented: c. 1560\n\nInventor: Gabriele Falloppio (Italy)\n\nSummary: Falloppio invents the prophylactic sheath.\n\n\u2002\"The condom is an armor against enjoyment and a spider web against danger\" \u2014Madame de Sevigne, writer\n\nThe Italian anatomist Gabriele Falloppio (1523-1562) posthumously published the first description of the condom in De Morbo Gallico (1564), a treatise on syphilis. To help counter the spread of the sexually transmitted disease, Falloppio invented a linen sheath that, when dipped in a solution of salt, formed a protective barrier during intercourse. To attract the ladies, the condoms were secured by pink ribbons. Falloppio claimed that none of the 1,1 OO men who used the device became infected with syphilis.\n\nThis is not to say Falloppio's condom was the first. Cave paintings from Combarelles in France and drawings from ancient Egypt have been found depicting men wearing condoms. Over the years condoms have been made from oiled paper, thin leather, fish bladders, and even tortoiseshell.\n\nBy 1844 Charles Goodyear (of tire fame) had patented a process for the vulcanization of rubber, where intense heat transformed rubber into a strong, elastic material. The first condoms to be made of vulcanized rubber were as thick as bicycle tires with seams running down their sides. In the 1880s an updated manufacturing process led to condoms being produced by dipping glass molds into liquid latex. This process removed the seam, thus making condoms an altogether more practical prospect.\n\n----\n\nJointed Artificial Limb\n\nInvented: c. 1564\n\nInventory: Ambroise Pare (France)\n\nSummary: Pare initiates modern prosthetics.\n\nThe jointed prosthetic limb originated in the 1500s and steadily improved in the next five centuries. Credit for the invention goes to Ambroise Pare (circa 1510-1590), a French barber-surgeon better known for some of his earlier achievements. For example, during the siege of Turin (1536-37) he realized that gunshot wounds were not poisonous and did not need to be cauterized with boiling oil. In his book of 1545, La Method de traicter les playes faites par les arquebuses et aultres bastons a feu (The Method of Treating Wounds Made by Arquebuses and Other Guns), Pare recommended simple dressings and ointments. The Frenchman also promoted the tying off of blood vessels to prevent hemorrhage during surgery (ligaturation), which had been practiced for more than a thousand years but had fallen into disuse.\n\nPare then invented a prosthetic limb for above-the-knee amputees, to be fitted to the thigh. It incorporated a kneeling peg leg with a knee joint that cou'd be released by a thong running to the hip. Pare went on to devise a hand for a French Army captain to use in battle. Called \"Le Petit Lorrain,\" its thumb was fixed but the fingers operated by springs and catches.\n\nA similar hand had previously been devised for Gotz von Berlichingen, a knight who had garnered a romanticized reputation as the \"German Robin Hood\" for his kidnapping of nobles and attacking merchant convoys for booty. Later he led a section of rebels during the Peasant's War of 1525, but he quit before their ultimate defeat. In 1504 he lost his right arm when \"friendly\" cannon fire during the siege of Landshut struck his sword and it fell and severed his arm. He lost his hand as a result but gained another moniker: \"The Knight of the Iron Hand.'\n\n----\n\nGraphite Pencil\n\nInvented: c. 1564\n\nSummary: The English invent an erasable marker.\n\n\u2002\"A short pencil is more reliable than the longest memory.\" \u2014Proverb\n\nThe graphite pencil was invented in England in 1564 following the discovery of an extensive deposit of pure graphite at Seathwaite Fell near Borrowdale in Cumbria. The Borrowdale deposit was so pure it could be cut into sheets and subsequently into tiny squareprofile lengths. The material left a darker mark than other less pure graphite composites, possessed a greasy texture, was extremely brittle, and quickly dirtied the hands of the user, thus requiring some form of protective sheath. However, the fact that it could be erased made it a popular alternative to ink.\n\nThe first known account of a graphite pencil was written in 1565 by the German scientist Konrad von Gesner. He described a rudimentary lead pencil \"enclosed in a wood holder,\" and it was not until the 1660s that a Keswick joiner hollowed out a piece of wood to create the forerunner of today's graphite-rod pencil. Graphite was known as blacklead or plumbago (Latin for \"lead ore\") until the new name was coined by the Swedish chemist K. W. Scheele as a footnote to his Treatise on Fossils (1779).\t.\n\nThe Seathwaite Fell deposit remains the purest deposit of graphite ever found. It was so valuable and easily extracted that in 1752 the British parliament passed a law making the theft of graphite punishable by imprisonment. The first commercial production of pencils began in Nuremberg, Germany, in 1761.\n\n----\n\nTheodolite\n\nInvented: c. 1571\n\nSummary: Digges facilitates the triangulation process.\n\nAn instrument designed for measuring horizontal and vertical angles, the theodolite is of critical importance to the surveying profession. Comprising a telescopic lens that can tilt on both horizontal and vertical axes, the theodolite is essential in \"triangulation,\" a long-established technique for surveying tracts of land. The distance between two points is measured, to become the baseline of a triangle. The theodolite is placed at one end of the line and used to determine the angle to a predefined distant point (which makes the third corner of the triangle). The instrument is then moved to other end of the baseline, where a second angle is measured to that same point. Simple trigonometry is then employed to calculate accurately the length of the othertwo sides.\n\nThe word theodolite first appears in a surveying textbook, A Geometric Practice Named Pantometria (1571) by mathematician and scientist Leonard Digges. Although tools for measuring angles had existed for centuries, it was Digges who introduced an \"altazimuth\" instrument\u2014one that could be moved on two perpendicular axes. The inventor himself died penniless twelve years before the publication of his book. His historical standing can be attributed to his son, Thomas, who worked tirelessly to continue his father's work, and who would become a significant figure in his own right, popularizing the principles of modern science.\n\nThere have since been many technological refinements, namely Jesse Ramsden'sGreatTheodolite of 1797, used in the Principal Triangulation of Great Britain\u2014the original Ordnance Survey.'\n\nNotes:\n\n- Ramsden's highly accurate Great Theodolite was first commissioned for the survey of southern Britain.\n\n----\n\nGregorian Calendar\n\nInvented: 1582\n\nInventor: Luigi Lilio (Italy)\n\nSummary: Lilio resets the Catholic clock.\n\nThe Julian year (introduced by Julius Caesar in 45 B.C.E.) contained exactly 365.25 days and had a leap year every fourth year (when the year number was divisible by four). But the actual year is 365.24219879 days long and thus the Roman calendar gradually became out of step with reality. By the sixteenth century, the calendar was ten days adrift from the seasons.\n\nIn 1576 Pope Gregory XIII assembled a commission of astronomers, mathematicians, and clergy, and this advisory body eventually adopted a plan suggested by the Calabrian physician Luigi Lilio, who was also known as Aloysius Lilius. On February 24, 1582, the pope declared that Thursday, October 4, 1582, was to be followed by Friday, October 15. From that date, century leap years would only be allowed if the year number was exactly divisible by 400. Thus, 2000 was a leap year, to be followed by 2400, 2800, and so on.\n\nRoman Catholic countries immediately adopted the Gregorian Calendar, but the Protestant and Greek Orthodox countries would have none of it. Norway and Denmark finally changed their minds in 1700. Great Britain and its colonies, including the United States, eventually followed, in 1752. In that year, in those territories the day after September 2 was September 14. Japan changed to the Gregorian calendar in 1873, Russia adopted it in 1918 after the Revolution, and Greece waited until 1923.\n\nThere are still minor problems. By 13000 the calendar will be ten days out of step again. And the fact that the Earth's spin rate is slowly decreasing in a complicated fashion means that the system should be subtracting a day about every 2,000 years.\n\n----\n\nStocking Frame\n\nInvented: 1589\n\nInventor: William Lee (England)\n\nSummary: Lee mechanizes knitting.\n\n\u2002\"The privilege of making stockings for everyone is too important to grant to any individual.\" \u2014Queen Elizabeth I to William Lee\n\nWilliam Lee (circa 1550-1610), a clergyman from Nottinghamshire, England, invented the stocking frame in 1589. One story suggests that he invented it to relieve his mother and sisters of the burden of knitting; another has it that a girl was showing more interest in her knitting than in him.\n\nKnitted fabrics are constructed by the interlocking of a series of loops, with each row of loops caught into the previous row. The stocking frame allowed production of a complete row of loops, held by a long bar similar to a knitting needle; a second bar opposed it, and each loop, picked up by a piece of wire, was transferred to the first bar.\n\nLee's first machine, which produced coarse wool stockings, was refused a patent by Queen Elizabeth I. An improved machine produced silk stockings of finer texture, but again she refused, saying she was concerned for the livelihoods of hand knitters.\n\nKing Henry IV of France encouraged new industries, so Lee and his brother James moved nine hand frames to Rouen. They prospered until Henry IV's assassination in 1610, after which Louis XIII imposed restrictions on foreign industries. The Lees returned to England, where James set up workshops in London.\n\nWilliam Lee died in Paris in 1610. 'today's knitting industry, while employing machinery driven by computers, still incorporates many of his ideas.\n\n----\n\nMicroscope\n\nInvented: c. 1590\n\nInventor: Hans and Zacharias Janssen (Dutch)\n\nSummary: Hans and Zacharias Janssen combine lenses in the first compound microscope.\n\n\u2002\"Nature composes some of her loveliest poems for the microscope and the telescope.\" \u2014Theodore Roszak, academic and historian\n\nThe earliest microscope was no more than a single small lens that magnified between six and ten times. Zacharias Jansen and his father, Hans, a lens maker, experimented with combinations of lenses and realized that greater magnification could be obtained by an inversion of the telescope. Their compound microscope combined a magnifying objective lens (the one closest to the object being investigated) with an eye lens at the opposite end of a tube. A focusing device was added by the Italian Galileo Galilei.\n\nThe circulation of blood through capillaries was observed by the Italian physiologist Marcello Malpighi (1624-1694). The popularity of microscopes was greatly enhanced by the publication of Micrographic (1655) by English scientist Robert Hooke. The Dutchman Anthoni van Leeuwenhoek (1632-1723) used a microscope to count the number of threads in woven cloth, and his refined instrument could magnify 270 times. Van Leeuwenhoek's microscope only had a single lens with a radius of curvature of roughly 0.7 millimeters. He was the first to see microorganisms and blood cells. Of the 500 microscopes manufactured by van Leeuwenhoek, about ten still survive.\n\nIn the eighteenth century, improved glass, coupled with multiple objective lenses with smaller focal lengths that could see much finer detail, led to much better microscopes. Stages were added so that samples under investigation could be held securely. The nineteenth century brought the familiar microscope form with its firmly mounted, vibration-free optical tube.\n\n----\n\nNewspaper\n\nInvented: 1605\n\nInventor: Johann Carolus (Germany)\n\nSummary: Carolus publishes the world's earliest printed news.\n\n\u2002\"A newspaper consists of just the same number of words, whether there be any news in it or not.\" \u2014Henry Fielding, novelist\n\nIn 1605 Johann Carolus (1575-1634) published the first printed issue of Relation aller Furnemmen und gedenckwurdigen Historien in Strasbourg, France, thereby giving the world its first newspaper.\n\nSimilar concepts had been around for more than 1,500 years. Julius Caesar established the Acta Diurna\u2014a newsletter carved on stone or metal\u2014for the citizens of Rome, ana, almost 800 years later in 713, the Chinese Tang Dynasty published the Kaiyuan Za Bao, a news bulletin handwritten on silk.\n\nInitially Carolus copied his newsletters by hand and sold them to rich subscribers. But in order to make his publication affordable to more people, and thus increase his revenue, he bought a printing shop in 1604. Despite his modern approach, Relation did not survive, so today the Dutch daily Haarlems Dagblad (after merging with the Oprechte Haarlemsche Courant from 1656) is the world's oldest existing newspaper.\n\nInitially the medium was viewed skeptically by some. Benjamin Harris found out as much when he tried to establish the United States's first newspaper, Publick Occurrences, Both Forreign and Domestick, in 1690. The paper was meant to be \"furnished once a moneth (or if any Glut of Occurrences happen, oftener).\" But he was forced to abandon this plan after only one issue when outraged government officials decided that his publication contained \"reflections of a very high order\" and had been printed \"Without the least Privity or Countenance of Authority.\"\n\nWhile the Internet now poses a danger to many newspapers, more than a billion people worldwide still read a daily newspaper in print every day\n\nNotes:\n\n- The 1609 edition of Relation is the oldest surviving newspaper, owned by Heidelberg University.\n\n----\n\nTelescope\n\nInvented: c. 1609\n\nInventor: Hans Lippershey (Dutch)\n\nSummary: Lippershey develops an instrument for examining the heavens.\n\n\u2002\"Reaching the dim boundary... we measure shadows, and we search among ghostly errors...\" \u2014Edwin Hubble, The Realm of the Nebulae (1936)\n\nThe legend goes that, playing one day in their father's spectacle shop, two Dutch children realized that if they looked through both a concave lens close to their eye and a concave lens held at arm's length, the local church tower was greatly magnified. Their father, Hans Lippershey (circa 1570-1619), then mounted the two lenses in a tube and tried to sell the device to the Dutch Army. Whether the credit for this invention should go to Lippershey or to, for example, Zacharius Janssen or Jacob Metius, or even the Englishman Leonard Digges, has become a matter of considerable debate. At the very least, Lippershey is generally credited with popularizing the device, and creating and disseminating designs for the first practical telescope. Soon similar instruments, known as \"Dutch Trunks,\" were appearing all over Europe.\n\nThe Italian astronomer and physicist Galileo Galilei heard about the new device when he was in Venice in May 1609. Returning to his university in nearby Padua, he made a telescope that magnified by about twenty times and had a field of view of about one-tenth of a degree. Using this, he discovered that the sun had spots, Jupiter was accompanied by four satellites, Venus had phases, and the moon was mountainous. These results he published in March 1610 in his work, Siderius Nuncius (The Sidereal Messenger).\n\nTelescopic astronomy never looked back. By 1611, the German astronomer Johannes Kepler was using a telescope consisting of two convex lenses, an instrument that gave greater magnification but an inverted image. In 1668 the English genius Sir Isaac Newton invented the reflecting telescope, which uses a curved mirror rather than a large lens to collect and focus light, thus eliminating the problem of severe chromatic aberration.\n\nNotes:\n\n- The telescope with which Galileo explored the solar system is held at the Museo della Scienza, Florence.\n\n----\n\nFlintlock\n\nInvented: c. 1612\n\nSummary: An unknown French gunsmith devises a mechanism for igniting gunpowder.\n\n\u2002\"Political power... grows out of the barrel of a gun... \u2014Mao Zedong, political leader\n\nThe basic mechanism from which the traditional flintlock originated is thought to have first appeared on a firearm made for King Louis XIII of France. The name of the French courtier Marin Le Bourgeoys appears on the flintlock, and it is thought to have been made in about 1612.\n\nThe flintlock works as follows. First, the hammer of the gun, which holds a piece of flint, is pulled back or rotated to the half-cock position. Gunpowder is poured into the barrel, followed by ammunition\u2014 often a steel ball\u2014and both are pressed into position with a ramrod. A small amount of finely ground gunpowder is then placed in a compartment below the hammer, known as the flashpan. The hammer is then pulled back or rotated to the full-cock position, and the gun is ready to be fired. When the trigger is pulled, the hammer springs forward and its flint hits the frizzen, a curving piece of steel. The frizzen moves aside to expose the gunpowder in the flashpan, and sparks from the flint ignite the gunpowder in the flash pan; this, in turn, explodes the main gunpowder charge, which projects the ball out of the barrel.\n\nAnyone wishing to discharge a round of ammunition successfully anytime in the seventeenth or eighteenth centuries was obliged to master the sequence of actions required by the flintlock mechanism. Even the fastest experts took about fifteen seconds to load and fire a flintlock weapon.\n\nThe flintlock is responsible for a number of phrases in the English language still in use today. \"Lock, stock, and barrel\" and \"going off half-cocked\" both have their origins in flintlock operation.\n\n----\n\nCigarette\n\nInvented: 1614\n\nSummary: Beggars in Seville find a new way to smoke.\n\nWhen Christopher Columbus arrived in the Americas in 1492 he was struck by the locals' indulgence in an unfamiliar habit. The Mayans had been smoking dried tobacco leaves since the first century B.C.E., and by the time the Spanish sailors discovered the New World the custom had spread throughout the continent. Possibly thinking their foreign visitors divine, the indigenous Arawaks offered Columbus and his men some of the leaves\u2014who immediately threw them away.\n\nOne member of the crew, Rodrigo de Jerez, was not as skeptical, though, and very soon he also \"drank\" the dried tobacco leaves wrapped in palm or maize, thus becoming the first European smoker. Back home, his newly acquired habit frightened his compatriots so muchthat the Inquisition put him in jail.\n\nOver the next few centuries the practice gradually spread all over the world, but to a mixed reception. Initially European doctors praised its medicinal properties\u2014the French ambassador to Portugal, Jean Nicot de Villemain (who gave nicotine its name) even described it as \"a panacea.\" Soon, however, people were beginning to realize its dangers and ban it. Mexico was the first country to outlaw smoking in places of worship, in 1575, and Turkey, Russia, and China temporarily declared the habit to be a crime punishable by execution in the 1630s.\n\nA few years before that, in 1614, Seville in southern Spain had become the center of cigar making. It was here, in the same year, that beggars created the first cigarettes by taking leftover tobacco from cigars and rolling it in paper. However, snuff, cigars, and pipes remained more popular than cigarettes in the West for another 250 years, but then British soldiers fighting in the Crimean War (1853-1856) were won over by the cigarettes smoked by their Turkish allies.\n\n----\n\nSlide Rule\n\nInvented: c. 1622\n\nInventor: William Oughtred (England)\n\nSummary: Oughtred creates a ready-reckoner.\n\n\u2002\"A computer who must make many difficult calculations usually has a slide rule close at hand.\" \u2014Pickett manual\n\nThe slide rule is a mechanical device used to carry out complicated mathematical functions. It is based on two logarithmic scales that move parallel to each other and are aligned according to the desired calculation. To multiply two numbers, for example, the logs are added and raised to the power ten; to divide, the logs are subtracted.\n\nIn 1620 Edmund Gunter (1581-1626), an English clergyman and Gresham College Professor of Astronomy, produced a logarithmic scale and used dividers to take off specific distances to do the calculations. William Oughtred (1574-1660), mathematician and rector of Albury, did away with the dividers by using two sliding Gunter rules side by side in circa 1622 and described his circular slide rule in Circles of Proportion and the Horizontal Instrument (1632). Sliding different distances multiplied and divided by different quantities. Seth Partridge (16171689) invented the modern slide rule in which the inner scale (the slide) is held by, and moves within, the outer scales, known as the stock or body of the rule.\n\nIn 1775 John Robertson added a cursor (an etched line in a transparent sliding attached plate) so that settings could be noted and transferred to any of a series of parallel scales. By 1815, P. M. Roget had added log-log scales, enabling powers, exponentials, and roots to be assessed easily.\n\n----\n\nMechanical Calculator\n\nInvented: c. 1623\n\nInventor: Wilhelm Schickard (Germany)\n\nSummary: Schickard automates the manipulation of figures.\n\n\u2002\"It computes the given numbers automatically; adds, subtracts, multiplies, and divides.\" \u2014Wilhelm Schickard\n\nEarly inventions to speed up calculations focused on manual solutions such as Napier's bones, which consisted of multiplication tables inscribed onto bones for calculating sums. Seeing John Napier's work, the German polymath Wilhelm Schickard (1592-1635) created a mechanical calculator that automated the process of calculation and incorporated Napier's bones. In 1623, he designed and built the \"calculating clock.\" At around the size of a typewriter, it could handle numbers of up to six digits in length.\n\nThe calculator used a direct gear drive and rotating wheels to add and subtract. When a wheel made a complete turn, the wheel adjacent rotated one-tenth of a turn. Dials on the lower part of the machine were turned one way to perform addition, and the opposite way to perform subtraction. These dials were joined by teeth-bearing internal wheels that carried one digit every time the wheel passed from nine to zero. The upper part of the machine used Napier's bones to multiply and divide. The machine was fitted with a bell that rang when a calculation produced a result of more than six digits (and was thus too long to display).\n\nSchickard began building a replica of his calculating clock for astronomer Johannes Kepler but it was never completed because a fire engulfed his workshop. He gave Kepler detailed instructions on how to build the calculator, but then Schickard and his family died of the plague in the 1630s and the prototype was lost. It was not until the 1950s that a sketch of the calculating clock was discovered among Kepler's papers in Russia, proving that Schickard was the originator of the mechanical calculator.\n\n----\n\nVernier Scale\n\nInvented: 1631\n\nInventor: Pierre Vernier (France)\n\nSummary: Vernier refines micro measurement.\n\n\u2002\"There are... fixed boundaries, beyond and about which that which is right cannot exist.\" \u2014Horace, Satires, Book 1 (35 B.C.E.)\n\nVernier callipers are a sliding, adjustable-jaw device for measuring distances of a few centimeters to an accuracy of 0.01 centimeters. A main (ruler) scale is marked off with 0.1 centimeter divisions. Sliding parallel and alongside the main scale is a much smaller vernier scale on which ten divisions are equally spaced over 0.9 centimeters of the main scale. To subdivide the 0.1 centimeter division on the main scale into ten, the user has to select the nearest vernier division that is in line with one of the main scale divisions.\n\nThe scale was invented by French scientist and engineer Pierre Vernier (1580-1637), and the details were published in his 1631 book, La Construction, I'usage, et les proprietes du quadrant nouveau de mathematiques {The Construction, Uses, and Properties of a New Mathematical Quadrant), published in Brussels. Vernier was interested in cartography and surveying, and his vernier was first used on the circular scale of a quadrant theodolite. The scale enabled angles to be measured with ease to an accuracy of one minute of arc (one-sixtieth of a degree).\n\nUnfortunately, dividing a circular scale into an equal number of uniform degrees was a matter of considerable complexity and vernier scales did not become a common adjunct to angle-measuring devices such as telescopes and theodolites until the early nineteenth century.\n\n----\n\nScrew Micrometer\n\nInvented: 1635\n\nInventor: William Gascoigne (England)\n\nSummary: Gascoigne improves precise measurements.\n\nWilliam Gascoigne (1612-44) was an English mathematician and astronomer, renowned for making scientific instruments. He was intrigued by the vernier scale and saw its potential for measuring the angular distances between stars.\n\nIn circa 1635, while working on precision optics, he noticed that a thread from a spider's web had become trapped at the exact focal point of two lenses, and that he could therefore see it sharply. This inspired him to create a thin marker that could be placed at the focal point of a lens. He added a second linear marker so that, when he looked through his telescope lens, two parallel lines could be seen within the field of view.\n\nOne of the markers he linked to a very fine screw thread, which could be used to adjust the distance between the two markers\u2014the other of which would remain fixed. As the angular size of the field of view of a telescope was known, Gascoigne's invention enabled precise measurements to be made of the positions of astronomical objects in the sky.\n\nGascoigne's micrometer revolutionized accurate measurements in astronomy, but there were other uses to be discovered for this device, beside acting as a finely calibrated telescope sight.\n\nBritish engineer James Watt, best known for his invention of the steam engine, adapted Gascoigne's idea in 1776 to produce a handheld micrometer screw gauge that measured actual sizes of small objects. By replacing the markers with callipers, and by knowing the size of the threads on the screw which adjusted them, he was able to add measuring wheels to the head of the screw. This allowed minute adjustments and measurements to be made. Watts's instrument significantly advanced the ability of manufacturers to make machine parts of precise dimensions.\n\n----\n\nBarometer\n\nInvented: 1643\n\nInventor: Evangelista Torricelli (Italy)\n\nSummary: Torricelli researches atmospheric pressure.\n\nInterest in atmospheric pressure arose when miners and well-diggers realized that pumps and siphons would only raise water to a maximum distance of about 33 feet (10 m). Hearing that the Grand Duke of Tuscany had a suction pump that could not raise water as far as he wanted, the Italian physicist Evangelista Torricelli (1608-1647) investigated the problem in 1643, creating what is known as the Torricelli tube.\n\nImagine that you have such a tube of straight glass, 40 inches (100 cm) long, sealed at one end and filled with mercury, and you carefully invert this tube, keeping the open end dipped in a reservoir of mercury. The mercury will retreat down the tube leaving a vacuum at the top. The height of mercury above the reservoir level will be about 30 inches (75 cm), and the weight of the mercury in the tube will be supported by the pressure exerted by the Earth's atmosphere as it presses down on the mercury in the reservoir.\n\nAt the time, many natural philosophers were interested in the properties of the vacuum, and the Torricelli tube was a common demonstration experiment at their meetings. Blaise Pascal (16231662) fitted the tube with a graduated scale around the 1660s, and what was a one-off demonstration device developed into an important instrument for measuring the variations of atmospheric pressure.\n\nPascal asked his brother-in-law to carry a mercury barometer up the nearby Puy-de Dome mountain and learned that atmospheric pressure decreases with height. Edmund Halley quantified the decrease as being exponential. People at the time noted how the pressure changes with the weather, and the barometer, in various forms, has been an essential tool in weather forecasting since the nineteenth century.\n\n----\n\nVacuum Pump\n\nInvented: 1650\n\nInventor: Otto von Guericke (Germany)\n\nSummary: Guericke exploits the vacuum.\n\n\"h vacuum is a hell of a lot better than some of the stuff that nature replaces it with.\"\n\nTennessee Williams, Caton a Hot Tin Roof (1955)\n\nA vacuum is an empty space containing nothing, not even air. Anything containing a vacuum has a much lower pressure on its inside t|pan its outside, and this creates a tremendous force. Otto von Guericke (1602-1686), a German scientist, was the first to experiment with the power of the vacuum. In his experiments, he filled containers with water and then used a suction pump to remove the water while trying to avoid letting in any air. Wood was useless for this as it leaked air, so he used glass or metal containers. To minimize air intake, Guericke put his container in another layer of water as it was easier to stop water leakage than air leakage. The inward pressure on the containers was often so great that they would collapse. Further trials\n\nled Guericke to the conclusion that spherical containers were optimal because their smooth shape avoided weak points in the structure. To prove the power of his discovery, Guericke demonstrated to Emperor Ferdinand III that neither fifty men nor teams of horses could pull apart two copper hemispheres that contained a vacuum.\t.\n\nIn science vacuums are most commonly used for their ability to create a truly empty space, enabling the study of particles without the confusion of air. They are essential in many machines used in industry for pumping liquids and other materials, moving objects, and powering heavy machinery.\n\n----\n\nPendulum Clock\n\nInvented: 1656\n\nInventor: Christiaan Huygens (Dutch)\n\nSummary: Huygens uses the pendulum to improve timekeeping accuracy.\n\n\u2002\"While fancy, like the finger of a clock, runs the great circuit, and is still at home.\" \u2014William Cowper, \"The Winter Evening\" (1785)\n\nAround 1602 Galileo Galilei noticed that the swing period of a pendulum was nearly independent of the amplitude of the oscillation, and this became the most important discovery in the history of horology. In 1656 Dutch mathematician and astronomer Christiaan Huygens (1629-1695) was the first to use a pendulum as a regulating oscil'ator in a clock.\n\nThe swing period of a pendulum is only a function of :ts length and the local gravitational field, unlike the verge and balance (foliot) oscillator, which it replaced, which had an oscillation period that depended on the force exerted by the driving spring.\n\nWithin years of Huygens's discovery, weight-driven pendulum clocks were appearing all over Europe. To provide a sufficient distance for the weights to fall, and to accommodate a reasonably long pendulum\u2014a two-second tick-tock requires a pendulum 3 feet (1 m) long--these clocks were put in long floor-standing cases. These \"grandfather\" clocks were reliable to an impressive (in those days) twenty seconds a day. Around 1670 the invention of the anchor escapement led to improvements in timekeeping by enabling the amplitude of the pendulum oscillation to be reduced.\n\nIn 1676 the more fragile dead-beat escapement was introduced to high-accuracy regulat'ng clocks. This escapement gave the pendulum a \"push\" only when it was near its vertical position. Coupled with a pendulum made of bars of different metals (usually brass and steel), it ensured that the length did not change as the temperature changed. The accuracy improved to about one second per day, an important aid in the work of astronomical observatories.\n\n----\n\nMagic Lantern\n\nInvented: c. 1659\n\nInventor: Christiaan Huygens (Dutch)\n\nSummary: Huygens makes the first image projector.\n\n\u2002\"...a Ianthorn, with pictures on glass, to make strange things appear on a wall, very pretty.\" \u2014Samuel Pepys, diarist\n\nThe \"magic\" lantern was used to project still images onto a wall or sheet and was an early version of the slide projector. The idea has been understood for many centuries. Light, shining through a translucent picture, will project the image onto a light-colored flat surface. The earliest reference to the use of a lantern to project images is in Liber Instrumentorum by Giovanni de Fontana, written around 1420.\n\nOptics developed rapidly in Europe during the seventeenth century. As early as 1659, Dutch scientist Christiaan Huygens (1629-1695) had made a lantern with a lens to focus the light and produce a sharp image. Danish mathematician Thomas Walgensten (1627-1681) traveled throughout Europe in the 1660s, selling the lantema magica. Numerous designs survive from this period and, in 1663, optician John Reeves of London was making and selling lanterns. The diarist Samuel Pepys (1633-1703) boughtonefrom Reeves in 1666.\n\nDuring the eighteenth century, improvements in lenses, light sources, and mirrors transformed the magic lantern into a powerful projector. Showmen traveled throughout Europe putting on elaborate \"phantasmagoria\" shows, using magic lanterns to present ghost and horror stories.\n\n----\n\nHygrometer\n\nInvented: 1664\n\nInventor: Francesco Folli (Italy)\n\nSummary: FolIi measures air humidity.\n\nThe most sticky, hot, and humid places in the world tend to be found in Southeast Asia, near coastal regions around the equator. Anyone who is not used to the heavy, damp, often motionless air can find them to be very uncomfortable places to live.\n\nHumidity, the moisture content of the air, tends to be high in these places because the heat of the sun causes the air to absorb increased moisture from the surrounding seas and oceans\u2014the air in cold latitudes is relatively dry. But it was not until the 1600s that people were able to measure air humidity.\n\nTechnically, Leonardo da Vinci designed the first crude hygrometer in the 1440s, but in 1664 the first practical hygrometer, used to measure the moisture content of air, was invented by the Italian scientist Francesco Folli (1624-1685). Folli's invention was a finely decorated device, made of brass, that contained a mounted paper ribbon acting as a hygroscopic (moisture-absorbing) indicator. When the ribbon changed in length as a result of changes in its water volume, a simple mechanical system moved a pointer on a central brass dial marked with a graduated scale. The pointer indicated variations in humidity.\n\nSome modern hygrometers still use principles very similar to those of Folli's original design. One commonly seen improvement of the original is that blond human hair, rather than paper ribbon, is the medium used to expand and contract in response to variations in atmospheric moisture.\n\nHowever, there are now many different types of hygrometer. The most common is the dry and wetbulb psychrometer, which compares readings of dry and water-immersed thermometers. Others use semiconductors to measure changes in electrical resistance, which is affected by humidity.\n\n----\n\nPressure Cooker\n\nInvented: 1679\n\nInventor: Denis Papin (France)\n\nSummary: Papin's \"steam digester\" prefigures the modern cooking vessel.\n\n\u2002\"Papin doth not think... that any thing better can be made for such things, as must be stew'd....\" \u2014Denis Papin, Philosophical Transactions (1683-1775)\n\nThere is a story that when French scientist and inventor Denis Papin (1647-1712) first demonstrated his wonderfully named \"digester\" to London's Royal Society in 1679, the device'exploded. So another invention swiftly came into being: Papin's safety valve, which went on to have other applications.\n\nBy 1682, a refined version of the steam digester proved excellent at cooking food and making nutritious bones soft and tasty. After a demonstration dinner at the Royal Society in that year, one guest, leading horticulturalist John Evelyn, noted in his diary that food served up from the digester was among \"the most delicious that I have ever seen or tasted.\"\n\nPapin was an interesting character of diverse scientific interests. Trained in medicine as a young man, he had long been interested in food preservation. His tightly sealed digester vessel showed how atmospheric pressure affected boiling points. Under high pressure, water in the vessel produced steam that cooked food quickly at temperatures far higher than those possible in a saucepan. The cooked food was meltingly soft, its nutrients and flavor were preserved, and the cooker used little fuel. Papin quickly saw that the impoverished were among those who would benefit greatly from his device.\n\nPapin went on to experiment with similar principles in various important early steam-engine prototypes that he developed. Meanwhile his digester also informed the history of the autoclave (whose uses include sterilizing medical instruments) and became the modern pressure cooker, which still works very much to his template.\n\n----\n\nUniversal Joint\n\nInvented: 1676\n\nInventor: Robert Hooke (England)\n\nSummary: Hooke joins rotating shafts together.\n\nThe name of Robert Hooke (1635-1703) pops up frequently in the late seventeenth century. This was a time when a small number of scientists led the whole world in new discoveries across various scientific fields, and of this distinguished group Hooke was one of the most accomplished.\n\nThe English polymath discovered the laws of physics that govern elasticity and now bear his name. He was the first person to use the word \"cell\" to describe the basic building blocks that made up living things. In addition, Hooke was also a top architect\u2014 even collaborating on projects with Sir Christopher Wren. But among all of his achievements it was his often overlooked invention of the universal joint that opened up whole new possibilities to the world of applied mechanics.\n\nLike many inventions, the universal joint evolved as the solution to a problem that the inventor had encountered personally. Hooke was a serious astronomer and recognized that the best way to improve knowledge of the universe was by building Petter and more accurate equipment. But some of his projects, which involved turning sma'I screws at angles to gears with teeth, were beyond the contemporary level of manufacturing.\n\nIn 1676, while working on a way to operate an adjusting arm for his helioscope, he created the first working model of a joint that allowed power to be transmitted from one rotating shaft to another. Critically, his joint allowed for the two shafts to be at angles to each other, and maintain the angle while rotating. This made it possible, for the first time, for a rotating shaft essentially to be able to go around corners, opening up a new world of possibilities for machine designs of all types.\n\n----\n\nCentrifugal Pump\n\nInvented: 1689\n\nInventor: Denis Papin (France)\n\nSummary: Papin improves mine ventilation.\n\n\u2002\"Today, centrifugal pumps and compressors have reached efficiency levels above 90 percent.\" \u2014Abraham Engeda, Michigan State University\n\nThe centrifugal pump works by drawing in a fluid (a liquid or gas) at the center of a cylindrical chamber that contains a rotating impeller with vanes. This forces the fluid to rotate outward toward the wall of the cylinder before flowing into an outlet pipe. The rotation of the fluid causes the liquid to leave with a higher velocity and pressure than when it entered.\n\nThe centrifugal pump was invented by French scientist Denis Papin in 1689 as he attempted to solve the problem of ventilating mines. Papin's device was used to pump air through mines and was also applied to furnaces, where it was known as the Hessian bellows. The basic centrifugal pump was improved by John Appold, who carried out an exhaustive study on the effect of blade shape on pump efficiency. He found that curved vanes on the impeller drastically increased the pump's efficiency. At the Great Exhibition of 1851, Appold showed his improved design, which was nearly three times more efficient than that of its nearest rival. The new design propelled the development of the centrifugal impeller, which found applications in compressors as well as pumps.\n\nCentrifugal pumps are currently used in areas of power generation, water supply, and general industry. They are widely used in the petroleum and chemical industries because they are relatively inexpensive and can handle large volumes of fluid.\n\n----\n\nMetronome\n\nInvented: 1696\n\nInventor: Etienne Loulie (France)\n\nSummary: Loulie's device sounds out musical tempo.\n\n\u2002\"Tempoi parendum. (One should be compliant with the times.)\" \u2014Maxim of Theodosius II\n\nThe tempo of a piece of music, that is, the number of beats per minute, can be established using a metronome, a type of compact, adjustable, loud clock. The most common type Is powered by simple clockwork and has a vertical metal rod that swings from side to side making a loud clicking sound at every swing. The rate of swing can be adjusted by moving a small weight up or down the swinging bar. Up decreases the tempo, and down increases it. This helps musicians not only establish the intended beat, but also maintain it throughout a musical piece.\n\nThe first metronome was made in 1696 by the Parisian Etienne Loulie (1654-1702). This required a single-weighted pendulum, similar to that of a grandfather clock. It had no clock escapement to maintain the pendulum in motion, so it only gave the musician the beat for a limited time. In 1812 Dietrich Nikolaus Winkel invented a version in Amsterdam. His breakthrough was the realization that a short, 8-inch (20 cm) metal pendulum, weighted both above and below the pivot, could be made to sound out a low tempo of forty to sixty beats per minute. Johann M\u00e4lzel patented the well-known small portable metronome in 1816 using Winkel's basic design. The first composer to mark his music with the expected metronome-regulated tempo was Ludwig van Beethoven, in around 1817.\n\nNeedless to say, electronic metronomes now vie with the mechanical version. These include sophistications such as additional sounds, and can sound out complicated time signatures, such as 5/4, that are beyond the range of their predecessors.\n\n----\n\nSteam Pump\n\nInvented: 1698\n\nInventor: Thomas Savery (England)\n\nSummary: Savery uses steam to drain floodwater from mine shafts.\n\n\u2002\"...such an engine may be made large enough to do the work of ten, fifteen, or twenty horses...\" \u2014Thomas Savery, The Miner's Friend (1702)\n\nCoal mining is difficult and risky work, and one of the dangers in the mine shafts is flooding. While this is something modern equipment can easily handle, the best remedy for flooding in the late seventeenth century was baling with a bucket. The problem caught the attention of English military engineer Thomas Savery (c. 1650-1715), who set out to make draining faster and easier. Savery's solution was to fight fire with fire, or in this case, fight water with steam.\n\nSteam's power had been revealed by French physicist Denis Papin and his pressure cooker in 1679. Papin had observed that bottled-up steam lifted the cooker's lid, and he envisioned steam doing the same to a piston in an engine. Papin's work inspired Savery to put steam to work in the mines. In 1698 Savery patented \"The Miner's Friend,\" a rudimentary steam engine for pumping waterfrom mine shafts.\n\nSavery's device used pressurized steam to farce water up a drainage pipe placed with one end in the flooded shaft. Savery's pumping system had dozens of parts\u2014drainage pipes, valves, boilers, connector pipes, steam delivery pipes, condensers, furnaces\u2014 and one big limitation: distance. Floodwater would only travel as far as it was forced by the pressure of the steam. Savery's pump had a limit of about 25 feet (7.6 m), which curtailed its use in underground mining.\n\nThe distance limitation of Savery's pump was solved by Thomas Newcomen's atmospheric steam engine, but Savery's patent barred Newcomen from manufacturing his machine. The inventor went into business with Savery to avoid legal difficulties, and soon their engines were highly sought after.\n\n----\n\nSeed Drill\n\nInvented: 1701) Inventor: Jethro Tull (England)\n\nSummary: Tull achieves eightfold productivity by transforming how seeds are sown.\n\n\u2002\"When tillage begins, other arts follow. The farmers therefore are the founders of human civilization.\" \u2014Daniel Webster, American statesman, 1840\n\nEnglish farmer Jethro Tull (1674-1741) despaired at the waste of seeds that resulted from sowing them by scattering. Seeds would falftoo close together, or onto stony ground, lie at differing depths, and plants would grow with no soil between them from which the crop could be weeded, tended, and harvested.\n\nTull's horsedrawn wooden seed drill improved on this situation and resulted in crop yields of up to eight times those where the seeds had been scattered. A shaped wooden drill dug an even groove of the right depth into the soil and seeds from the hopper mounted above it trickled into the groove, evenly spaced by the forward movement of the horse. Tull mounted three drills alongside each other in the machine, and so could plant three rows of seeds at a time, leaving space between these triple rows.\n\nAs a young man, Tull traveled in continental Europe in what were the early years of the Age of Enlightenment and was inspired by some of the scientific ideas he encountered. Although he is best known for inventing the seed drill, he also introduced the use of workhorses instead of cattle, invented a horsedrawn hoe, and developed the design of the plow in ways that are still in use today.\n\nSome of his ideas proved controversial at the time, and his observation that crop nutrients are released from the soil by pulverization turned out to be misguided, but much of what he achieved established the foundations of modern agriculture in Britain, Some decades before the start of the industrial and agricultural revolutions.\n\n----\n\nCoke-based Iron Smelting\n\nInvented: 1709\n\nInventor: Abraham Darby I (England)\n\nSummary: Darby revolutionizes iron making.\n\nBefore the introduction of plastics, iron was one of the most multipurpose materials, used to make almost everything. However, the only pure iron on Earth fell from space as meteorites, and that is far too rare to rely on. Most iron has been pushed up to the Earth's crust by activity in the planet's core, but this has reacted with many other elements, resulting in iron ore, rather than pure elemental iron. The process of separating iron from ore is called smelting: The ore is heated to a temperature at which it becomes a liquid, and then the metal is separated from the waste.\n\nCharcoal is one of the few materials that burns hot enough to melt iron. In Britain the iron industry originally moved around the country, burning forests and then moving on, but by the seventeenth century the industry was running out of trees and wood was becoming much more expensive. Also, charcoal is soft, which means that the furnaces had to be smal, and iron could never be mass-produced. An alternative was needed.\n\nCoal was no good because elements from it get into the iron and make it weak, but in the same ways that charcoal can be made from wood, coal can produce a material ca'ied coke. Coke was cleaner than the alternatives and, in 1709, ironmaster Abraham Darby I (1678-1717) built the first coke-fired blast furnace. He was the first of three generations of Abraham Darbys to perform pioneering works in the iron industry. The purity of the iron made it stronger and the use of coke allowed bigger furnaces. Soon large quantities of iron were available cheaply in Britain, playing an important role in the Industrial Revolution and in making Britain one of the dominant world powers at that time.\n\n----\n\nAtmospheric Steam Engine\n\nInvented: 1712\n\nInventor: Thomas Newcomen (England)\n\nSummary: Newcomen improves mine drainage.\n\n\u2002\"Those who admire modern civilization usually identify it with the steam engine...\" \u2014George Bernard Shaw, playwright and writer\n\nThomas Newcomen (1663-1729), a Devonshire blacksmith, developed the first successful steam engine in the world and used it to pump water from mines. His engine was a development of the thermic syphon built by Thomas Savery, whose surface condensation patents blocked his own designs.\n\nNewcomen's engine allowed steam to condense inside a water-cooled cylinder, the vacuum produced by this condensation being used to draw down a tightly fitting piston that was connected by chains to one end of a huge, wooden, centrally pivoted beam. The other end of the beam was attached by chains to a pump at the bottom of the mine. The whole system was run safely at near atmospheric pressure, the weight of the atmosphere being used to depress the piston into the evacuated cylinder.\n\nNewcomen's first atmospheric steam engine worked at Conygree in the West Midlands of England. Many more were built in the next seventy years, the initial brass cylinders being replaced by larger cast iron ones, some up to 6 feet (1.8 m) in diameter. The engine was relatively inefficient, and in areas where coal was not plentiful was eventually replaced by doubleacting engines designed by James Watt (1736-1819). These used both sides of the cylinders for power strokes and usually had separate condensers.\n\n----\n\nMercury Thermometer\n\nInvented: 1714\n\nInventor: Dante Gabriel Fahrenheit (Poland)\n\nSummary: Fahrenheit initiates the standardized measurement of temperature.\n\n\u2002\"Scientists should return to the plainness... of Observations on material and obvious things.\" \u2014Robert Hooke, Micrographia (1664)\n\nIn a mercury thermometer, mercury in a small glass bulb expands into an evacuated, linear, uniform crosssection glass tube; the amount of expansion is used to measure the temperature of'the bulb. Dante Gabriel Fahrenheit (1686-1736) left Gdansk, Poland, and eventually became a glassblower and scientific instrument maker in the Netherlands. His first glass thermometer (1709) used alcohol as the expanding fluid, but this has a limited temperature difference between its freezing and boiling points. In 1714 Fahrenheit turned to mercury, a liquid metal that expands uniformly over normal temperature ranges.\n\nFahrenheit insisted that thermometer results should be universally reproducible, and similar temperatures should be represented by the same number. To this end he introduced, in 1724, three \"fixed\" points and eight graduations on his thermometer tube. Zero degrees was the lowest temperature that he could obtain in the laboratory, the temperature of a mixture of water, water ice, and ammonium chloride. Thirty-two was the temperature of an ice/pure water mixture, and ninety-six degrees was the normal temperature of a human body. From 1717 Fahrenheit was selling thermometers from a base in Amsterdam, and these, and his temperature scale, became widely used throughout Britain, the Netherlands, and Germany.\n\nMore recently the Fahrenheit scale has been defined using the freezing and boiling points of pure water, at normal atmospheric pressure, as 32 and 212 degrees (0 and 100\u00b0C). Here our typical body temperature becomes 98.6\u00b0F (37\u00b0C).\n\n----\n\nPadlock\n\nInvented: 1720\n\nInventor: Christopher Polhem (Sweden)\n\nSummary: Polhem devises a portable lock that effectively resists tampering.\n\n\u2002\"Lock-and-key n. The distinguishing device of civilization and enlightenment.\" \u2014Ambrose Bierce, writer and journalist\n\nPrimitive padlocks have been around since medieval times, but their design left them prone to force or picking. In 1720, Swedish inventor Christopher Polhem (1661-1751) conjured up a lock that was much more resistant to the dexterous hands of lockpickers.\n\nPolhem was one of the most gifted mechanical engineers of his day. After studying mathematics, physics, and engineering at Uppsala University, he set up as a clock repairer. His ingenuity was soon spotted by important patrons, including King Charles XI of Sweaen. Polhem went on to design many intricate devices both small (watch mechanisms) and large (industrial machinery). Perhaps his most enduring invention, however, was the padlock.\n\nHis basic design comprises an elliptical cast iron body containing a series of rotating disks. When locked, the disks fit into grooves on the shackle (the U-shaped bar on top of the padlock), preventing its release from the body. Notches on the discs can be aligned with those on the shackle by rotating the correct key, thus releasing the shackle and allowing the lock to be opened.\n\nThe Swedish inventor's device became known as the Polhem lock, or Scandinavian lock, and Polhem started a factory in Stj\u00e4rnsund to produce it. The Scandinavian lock came to dominate the market. The design was later strengthened by the American locksmith Harry Soref, who founded the Master Lock Company in 1921. A modified version of this design is still in use today. For his many achievements, Polhem has been honored by appearing on the back of the 500 Swedish kronor note.\n\n----\n\nPitot Tube\n\nInvented: 1732\n\nInventor: Henri Pitot (France)\n\nSummary: Pitot measures air and liquid flow rates.\n\nThe Pitot (pronounced pea-tow) tube is an eighteenthcentury invention still flying high amid twenty-first-century technology. Designed by French astronomer, engineer, and mathematician Henri Pitot (1695-1771), this deceptively simple device is essentially a differential pressure gauge and can be used for a variety of flow-rate or speed-measuring purposes.\n\nPitot's pet interest was water flow, and his personal research led him to conclude that much of the accepted wisdom of the day was incorrect. He would not accept, for example, the prevailing theory that, other things being equal, the speed of flowing water increased with depth. His tube, demonstrated at the French Academy of Sciences in 1732, would show that he was right: it does not.\n\nAs well as being used in a fixed position to determine the flow rate of a liquid or gas, the L-shaped tube may be attached to a boat or airplane to measure the craft's forward speed. In all cases, the tube functions by registering the difference between the ambient pressure surrounding it and the pressure created by the flow into it (the \"impact\" pressure), which will increase with speed. The resulting comparative measurements can be displayed via suitable instrumentation. Various improvements to the basic design have been made over the years, although Henri Darcy's 1858 design is more or less the one still in use today.\n\nToday, variations of, and uses for, Pitot's amazing little tube continue to grow; multiport versions exist to enable the measurement of the impact and static pressures at different points. They can be seen on Formula 1 racing cars and spacecraft. They have even been configured to perform an additional role as an aircraft antenna.\n\n----\n\nBaby Carriage\n\nInvented: 1733\n\nInventor: William Kent (England)\n\nSummary: Kent creates a child's amusement.\n\n\u2002\"Nobody outside of a baby carriage... believes in an unprejudiced point of view.\" \u2014Lillian Hellman, playwright\n\nThe first known design for a baby carriage was produced in 1733 by William Kent (c. 1685-1748), the renowned English landscape-garden designer. Today the baby carriage is an essential tool for any family with children, but it was originally intended as an entertainment. Kent, who as a designer could turn his hand from furniture to ladies clothes as well as gardens, was commissioned by the third Duke of Devonshire to design something to amuse his children. He produced a shell-shaped vehicle in which a baby could sit, with an attached harness designed to fit a small pony, a dog, or a goat.\n\nBaby carriages quickly became popular among the wealthy as fashionable toys. Gradually changes were made to their design, with one of the most significant being the addition of handles, which allowed a person to push the vehicle. The carriages became more popular in the 1840s when Queen Victoria bought three of the new push-style versions from Hitchings Baby Store of Ludgate Hill.\n\nThe next breakthrough came in 1889 with a new design created by William H. Richardson, who devised a special joint that enabled the bassinet to be turned to face the handles, as seen in many modern designs. He also improved the axles enabling the wheels to turn individually allowing for great maneuverability. Many of his design features are still used today.\n\n----\n\nFlying Shuttle\n\nInvented: 1733\n\nInventor: John Kay (England)\n\nSummary: Kay vastly speeds up the weaving process.\n\nArcheologists have found a model of a loom in an Egyptian tomb from 4,000 years ago. Yet the development of loom technology was slow until 1733, when John Kay (1704-1780) invented the flying shuttle.\n\nLooms interlace two sets of yarn or threads together to form cloth. The first set of threads is placed lengthwise along the loom and is called the warp. The second set of threads is called the weft. The weft is carried between the warp threads by a shuttle. In traditional looms, weavers passed the shuttle through the warp by hand, and it was a slow process. Kay's flying shuttle moved on wheels in a track through the warp when the weaver pulled a cord. This was much faster than hand weaving, and could also be used to create much wider fabrics than previously possible.\n\nKay did not receive much benefit from his invention because weavers saw the flying shuttle as a threat to their livelihoods. They believed\u2014incorrectly as it turned out\u2014that the demand for doth was constant, so if looms were more efficient, fewer weavers would be needed. Although manufacturers were glad to use Kay's invention, they did not pay him any royalties. Kay died a poor man in 1780.\n\nThe flying shuttle created a huge demand for yarn. At the time, yarn spinning was a slow process done by hand. Over the next fifty-five years, inventors worked on machines to increase the productivity of spinners. These included the spinning jenny, the water frame, and the spinning mule. All these inventions made cotton items affordable to many more people.\n\nNotes:\n\n- Eighteenth-century weavers' shuttles had rollers and were iron-tipped to reduce friction.\n\n----\n\nFranklin Stove Circulating Fireplace\n\nInvented: 1742\n\nInventor: Benjamin Franklin (US)\n\nSummary: Franklin invents a safer and more efficient way of heating wooden buildings.\n\n\u2002\"The use of these fireplaces in very many houses... is a great saving of wood to the inhabitants.\" \u2014Benjamin Franklin, statesman and scientist\n\nBefore inventing the lightning rod and bifocal lenses, American statesman and polymath Benjamin Franklin (1706-1790) had turned his attention to keeping peoples' homes warm and safe. In the eighteenth century many homes in the United States, built of wood and heated by open hearths, were at great risk of fire. This had concerned Franklin since at least 1735, when he organized the first volunteer fire department in his adopted home town of Philadelphia, Pennsylvania. He also called for building regulations to include minimum safety standards in fireplace design\u2014modern standards are still based on them.\n\nIn 1742 he designed a new stove that he called the \"Pennsylvania fireplace\"; it was later called the \"Franklin stove\" or \"circulating fireplace.\" The stove was a box lined with metal that stood away from the wall, improving efficiency compared to the standard fireplace where much of the heat was lost to the wall behind it. He also added flat plates or \"baffles\" at the stove's rear to improve the flow of air. The only flaw, later fixed by Franklin, was that smoke had to escape through the base of the stove, and it filled the room.\n\nThe stove was first manufactured by Franklin's friend Robert Grace, but the inventor refused to patent the device in order to keep the technology freely available\u2014a story that is often cited as an early example of open-source development.\n\nThe freedom to tinker with Franklin's design was explored in the 1780s by David Rittenhouse, who added an L-shaped chimney. History has preferred to call it the Franklin stove nonetheless, and there are many in use to this day.\n\n----\n\nLeyden Jar\n\nInvented: 1745\n\nInventor: Pieter van Musschenbroek (Dutch)\n\nSummary: Van Musschenbroek demonstrates that electricity can be stored and then discharged.\n\n\u2002\"My whole body was shaken as though by a thunderbolt.\" \u2014Pieter Van Musschenbroek, physicist\n\nIn 1745 the Dutch physicist Pieter van Musschenbroek (1692-1791) took a sealed glass vial partially filled with water, passed a conducting wire through a cork at one end and attached it to a nearby Wimshurst friction machine, which generated a static charge. The glass jar, called a Leyden Jar in honor of the inventor's home town and university, absorbed the charge, demonstrating for the first time that electricity could be produced and stored successfully and then discharged through the exposed wire to any grounded object. Musschenbroek tested the device by holding the jar in one hand and touching the charged, exposed wire with the other. He received such a shock that he swore not even a promise of the entire French nation could persuade him to do so again.\n\nThe Leyden jar created a sensation within the worldwide scientific community. The American inventor Benjamin Franklin called it \"Musschenbroek's wonderful bottle.\" A year later the English physician William Watson, using a modified Leyden jar, successfully transmitted an electric spark along a wire stretched across the River Thames. The precise nature and makeup of electricity proved elusive until the discovery of the electron by J. J. Thompson in 1897.\n\nThough cumbersome and grossly inefficient by modern standards, this forerunner of the modern capacitor represented the eighteenth century's single most significant advance in the understanding and harnessing of electricity. It facilitated a greater understanding of the nature of conductivity and led to a more mathematical approach in the study of the attraction of electrified bodies.\n\nThe original Leyden jar of 1745 was made of glass and had metal foil coatings inside and out.\n\n----\n\nElectroscope\n\nInvented: 1748\n\nInventor: Jean-Antoine Nollet (France)\n\nSummary: Nollet's device detects and measures electric charge.\n\n\u2002\"The electron... crystallizes out of Schrodinger's mist like a genie emerging from his bottle.\" \u2014Sir Arthur Eddington, Nature of the Physical World\n\nJean-Antoine Nollet (1700-1770) was the first professor of experimental physics at the University of Paris. At that time electrostatics was a topic of great interest.\n\nNollet's electroscope was'designed to detect and crudely measure electric charge. An insulated charge sensor protruded into a cylindrical container, the ends of which were closed by two flat glass windows. The bottom of the sensor (the part in the cylinder) was fitted with two leaves of metal foil (usually gold). If the sensor's opposite, extruding end was brought into contact with a negatively charged body, electrons were repelled into the two leaves and they separated. The degree of separation was a function of the size of the charge. A second negatively charged body contacting the extruding end would cause the leaves to separate more, whereas a positively charged body subsequently applied to the same end wou'd cause the separation to decrease.\n\nEarlier electroscopes were mainly used to investigate the amount of charge that could be produced by hand-cranked or foot-treadled frictional electrostatic machines. Here, a globe of glass was charged by rubbing it with a soft material.\n\nNollet was interested in the causes of electrostatic repulsion and attraction and the speed with which electric current flowed. He once estimated the latter by discharging the charge contained in a large Leyden jar through a line of 200 Carthusian monks who were connected to each other by iron wires 25 feet (7.6 m) long. As all the monks leaped with shock at the same time, he concluded that electricity traveled speedily, and could travel a long distance.\n\n----\n\nWater Pillar Pump\n\nInvented: 1749\n\nInventor: J\u00f3zsef K\u00e1roly Hell (Hungary)\n\nSummary: Hell drains mines with water power.\n\nDuring a period spanning the sixteenth and nineteenth centuries, the Slovakian mining town of Banska Stiavnica rose to fame both as a major source of gold and silver and as a center of excellence in the technologies needed to extract those precious metals. The area became synonymous with advances in ore extraction and processing.\n\nFundamental among the many problems that mining engineers had to overcome at that time was the removal of water from shafts several hundred yards deep. Human and animal power played its part in no small measure; by the end of the seventeenth century, close to a thousand men and hundreds of horses were toiling around the clock to keep the existing pumping systems working. Steam-powered systems were put to the test. However, it was asked that if an abundance of water was the problem, why not work with water, exploit its energy potential, and turn it into the solution? J\u00f3zsef Hell, senior mining engineer and son of the equally talented Matej Kernel Hell, would become preeminent in the successful implementation of this revolution with his \"water pillar\" or \"water column\" pump designs.\n\nHell's first pump, constructed in 1749 at Banska Stiavnica's Leopold mine shaft, was a positive displacement \"engine,\" utilizing a system of pistons and valves quite similar to a steam engine. Instead of steam, however, hydraulic pressure, developed by a column of water obtained from a surface reservoir, was used. It comprised a single, vertical cylinder with a control system using simple rods and hammers that directly operated two-way valves. A second pump could be installed beneath the first, so that the same primary water supply could be used to drive them both and pump water from an even lower level.\n\n----\n\nLightning Rod\n\nInvented: 1752\n\nInventor: Benjamin Franklin (US)\n\nSummary: Franklin proves lightning is electricity.\n\n\u2002\"Electrical fire would be drawn out of a cloud silently, before it could come near enough to strike.\" \u2014Benjamin Franklin, statesman and scientist\n\nAmerican statesman and inventor Benjamin Franklin (1706-1790) was particularly interested in electricity and set up a small laboratory in his house to investigate its properties. His interest soon switched from electricity to lightning after he noticed similarities between the two. Many scientists had previously noticed a link, but none had managed to prove it.\n\nOn a stormy night in 1752, he conducted a lifethreatening experiment to demonstrate that lightning is the result of an electrical buildup. He constructed a kite that carried a metal spike and flew it into the thunderstorm. The kite had a key attached near the bottom of the ribbon and Franklin noticed that it sparked as he brought his knuckles close to it. Franklin had shown that lightning was a form of electricity and he went on to use this knowledge to design a lightning rod to protect buildings. The iron rod was between 6 and 10 feet (2 and 3 m) in length, and provided a path of least resistance for the lightning, channeling it safely to the ground. He later showed that sharp rods were betterthan blunt ones for the purpose.\n\nRecently it was suggested that the kite experiment was a hoax and that Franklin would have been killed if he had actually been struck by lightning. Some suggest the experiment was real but the sparks observed were actually from an electrical field and not a lightning strike.\n\n----\n\nLinnaean Taxonomy\n\nInvented: 1753\n\nInventor: Carolus Linnaeus (Sweden)\n\nSummary: Linnaeus classifies all plant life.\n\nLinnaean taxonomy is the system of classification of living organisms that is used throughout the biological sciences. Its inventor, Carolus Linnaeus (1707-1778), spent most of his career in Uppsala, Sweden. Starting with the plant kingdom, Linnaeus created a hierarchy in which plants are grouped, according to similarities in their appearance, into twenty-five phyla, and then each phylum into classes, and these in turn into orders, families, genera, and species. The first description of this system was published by Linnaeus in 1753, in a two-volume work, Species Plantarum. He later applied the same principles to animals and minerals.\n\nThe most important feature of Linnaean taxonomy is a system known as binomial (or two-name) nomenclature. The first name identifies the genus to which the organism belongs; the second name, its unique species: for example, the common daisy is Bellis perennis. If necessary, the family, order, and phylum to which a genus belongs can be looked up in a floral taxonomy reference book.\n\nLinnaeus collected, studied, and classified plants and animals, publishing his findings in successive editions of Systema Naturae. The first edition, published in 1735, was just eleven pages long; the tenth edition, published in 1758, detailed 4,400 species of animals and 7,700 plant species. Linnaean taxonomy, although developed a hundred years before Darwin's theory of evolution, proved to be robust and effective even as scientists have explored the evolutionary relationships between organisms. More recently, comparisons of the genetic codes of individual species have led to some reclassification of plants and animals, but the essential concepts of Linnaean taxonomy remain entirely valid today.\n\n----\n\nBimetallic Strip\n\nInvented: 1755\n\nInventor: John Harrison (England)\n\nSummary: Harrison utilizes metal expansion.\n\n\u2002\"Some people change their ways when they see the light, others when they feel the heat.\" \u2014Caroline Schroeder, pianist\n\nThe bimetallic bar was invented by the Yorkshire clockmaker John Harrison (1693-1776), and was used in his third and fifth chronometers to cancel out thermally induced variations in the balance springs.\n\nImagine two straight strips of metal bar\u2014steel and brass, say\u2014riveted, brazed, or welded together along their length. Brass expands by nineteen parts in a million for every increase in temperature of 1.8\u00b0F (1\u00b0C), and steel by thirteen parts. Heating the bar will make one metal expand more than the other and cause the bar to bend. In the above example, the brass will be on the outer side of the curve. Cooling the bar will cause it to curve the other way, with the steel on the outside.\n\nA spiral bimetallic strip unwinds or tightens as a function of temperature; a cheap, robust thermometer may be made by attaching a pointer. Strips are also used in clocks, forming the circular rim of the balance wheel, where the size of the wheel changes in a way that compensates for temperature variations in the strength of the controlling spring. But by far the most common usage is as a temperature-sensitive contact breaker in thermostatically controlled devices such as refrigerators, ovens, and irons. The fact that the metals conduct electricity means that the moving end of the strip can be used to open and close an electrical switch that is connected to a heater or cooler.\n\n----\n\nMarine Chronometer\n\nInvented: 1761\n\nInventor: John Harrison (England)\n\nSummary: Harrison's invention enables mariners to checktheir longitude at sea.\n\n\u2002\".. every great captain... became lost at sea despite the best available charts and compasses.\" \u2014Dava SobeL Longitude (1995)\n\nOne way of calculating the difference between a longitude at sea and a known longitude (of Greenwich, say) was to ascertain the mean solar time on the ship, by astronomical observations, and compare it with the time at Greenwich. To this end a clock was needed that accurately kept Greenwich time despite being rocked back and forth by the ship. In 1714 the British government offered a \u00a320,000 prize (about \u00a31,000,000 today) to anyone who could find longitude at sea to an accuracy of 0.5 degrees.\n\nYorkshireman John Harrison (1693-1776) decided that an accurate clock was the answer. He built his first marine chronometer in 1735. This spring-driven clock was regulated by two connected balances that oscillated in opposite directions, thus eliminating all the effects of the ship's motion. Intentional variations in the lengths of the balance springs also compensated for temperature changes.\n\nHarrison's third chronometer (1759) had a bimetallic temperature compensator and a remontoire to ensure that the escapement driving force was constant. Harrison's fourth chronometer (1761) embodied all his improvements into a large \"pocket\" watch, about 5 inches (13 cm) in diameter.\n\nThis watch was carried to Jamaica on board HMS Deptford in 1761. The clock error over the journey was about five seconds, equivalent to a longitude error of about one sixtieth of a degree. The ship's position was thus known to an accuracy of 1.5 miles (2 km). Harrison finally got all his prize money in 1773, and soon every ship was carrying his instrument\n\n----\n\nSpinning Jenny\n\nInvented: 1764\n\nInventor: James Hargreaves (England)\n\nSummary: Hargreaves transforms cotton spinning.\n\n\u2002\"The Industrial Revolution... opened an age of... production for the needs of the masses.\" \u2014Ludwig von Mises, economist\n\nSpinner and carpenter James Hargreaves (1720-1778) invented this multispool spinning wheel as a way of increasing the productivity of his cotton factory in Lancashire. The \"spinning jenny\" had eight spindles, all of which could be operated by a single person, who rolled a beam back and forth over the yarn until it was the correct thickness. The machine increased the production of spun yarn eightfold. One story has it that a daughter of Hargreaves knocked over a spinning wheel, and he noticed that it continued to work perfectly well. This led him to consider a machine with multiple spindles, all in an upright position.\n\nThe machine was so successful that yarn prices fell, upsetting the spinning community in the area. Several spinners broke into Hargreaves's house and destroyed his machines, causing him to move to Nottingham where, in 1767, he began making spinning jennies. Three years later he applied for a patent for his invention but failed in his attempt to sue local manufacturers who were using copies of his machine. Hargreaves died in 1778, the year Samuel Crompton invented an even more efficient spinning machine that was dubbed the \"spinning mule.\"\n\n----\n\nSurveyor's Perambulator Wheel\n\nInvented: 1765\n\nInventor: Isaac Fenn\n\nSummary: Fenn facilitates land surveying.\n\nBy the time Isaac Fenn was granted a patent, in 1765, for his distance-measuring hodometer, the device had existed, in various forms and with By the time Isaac Fenn was granted a patent, in 1765, for his distance-measuring hodometer, the device had existed, in various forms and with various names, for centuries. In Roman times it was called an odometer and comprised little more than a wheel that could be pushed along, coupled to a mechanical system for counting the number of revolutions the wheel made, and thus the distance it had traveled.\n\nThe eighteenth and nineteenth century saw the mapping of India and the division of vast tracts of land into farms in regions such as the United States and Australia. Reasonably accurate surveying and distance measurement became important. The surveyor's perambulator wheel (the \"waywiser\" or trundle wheel) was in everyday use. The accuracy of this device was good on a smooth surface such as a pavement or macadamed road. On rough terrain, such as farmland, wheel bounce and slippage became a problem and surveyors had to apply a series of corrections to the readings. For very accurate work, the surveyor had to resort to a tape or chain measure.\n\nA typical eighteenth-century waywiser would have a wheel diameter of around inches (80 cm), equating to a circumference of around feet (2.5 m). This meant that two revolutions of the wheel would equate to one pole (an old English measure of length and area). A central dial with two hands, much like a clock, was attached to the unit. The bigger hand made one sweep every 320 poles\u2014this marking 1 mile (1.6 km). The shorter hand indicated the total number of miles traversed.\n\nToday, professional trundle wheels are extremely accurate and are likely to sport an LCD display and onboard digital storage/manipulation of data.\n\n----\n\nSteam Engine with Separate Condenser\n\nInvented: 1765\n\nInventor: James Watt (Scotland)\n\nSummary: Watt drives steam power forward with a technological breakthrough.\n\n\u2002\"I have now made an engine that shall not waste a particle of steam. It shall be boiling hot.\" \u2014James Watt to his friend John Robison\n\nScottish engineer James Watt (1736-1819) was responsible for some of the most important advances in steam-engine technology. Steam engines had been in use since the 1710s, mainly to pump water from mines. These machines depended upon steam condensing inside a large cylinder after the cylinder was cooled with cold water. As the steam condensed, it took up less space, allowing atmospheric pressure to push down on a movable piston inside the cylinder.\n\nIn 1765 Watt made the first working model of his most important contribution to the development of steam power; he patented it in 1769. His innovation was an engine in which steam condensed outside the main cylinder in a separate condenser; the cylinder remained at working temperature at all times. Watt made several other technological improvements to increase the power and efficiency of his engines. For example, he realized that, within a closed cylinder, low-pressure steam could push the piston instead of atmospheric air. It took only a short mental leap for Watt to design a double-acting engine in which steam pushed the piston first one way, then the other, increasing efficiency still further.\n\nWatt's influence in the history of steam-engine technology owes as much to his business partner, Matthew Boulton (1728-1809), as it does to his own ingenuity. The two men formed a partnership in 1775, and Boulton poured huge amounts of money into Watt's innovations. From 1781, Boulton and Watt began making and selling steam engines that produced rotary motion; all previous engines had been restricted to a vertical, pumping action. Rotary steam engines were soon the most common source of power for factories, becoming a major driving force behind Britain's Industrial Revolution.\n\nNotes:\n\n- Watt's separate steam condenser allowed the main cylinder to remain hot, bringing great fuel economy.\n\n----\n\nWater Frame\n\nInvented: 1769\n\nSummary: Arkwright's innovation accelerates the rate of textile mass production.\n\n\u2002\"One machine produced in an hour what had previously taken hundreds of person-hours.\" \u2014Robert Clark, University of East Anglia\n\nPreston wigmaker Sir Richard Arkwright (1732-1792) patented a new cotton-spinning machine in 1769, Around that time people were racing to find a fast and inexpensive way to produce good-quality cotton for the textiles industry, James Hargreaves had created the \"spinning jenny\" between 1764 and 1767, but this simply mimicked the action of a hand-turned spinning wheel and could not produce high-quality cotton thread, Arkwright's \"water frame\" would become a major catalyst for the Industrial Revolution.\n\nWhile working as a wigmaker, Arkwright became interested in the spinning of cotton. He enlisted the help of clockmaker John Kay, who had worked previously with Thomas Highs on another spinning machine that had been halted by a lack of funds. Together, Arkwright and Kay built a prototype horsepowered spinning frame, which they patented in 1769, The frame drastically sped up the process of spinning cotton, producing both weft (filling yarn) and high-quality waft suitable for hosiery.\n\nRealizing the potential for large-scale production, Arkwright perfected a model powered by waterwheel, one that became known as the \"water frame,\" Although Arkwright is heralded as the inventor of the water frame, many believe that it was actually Highs who came up with the original design. It is thought that, while working with Kay, Arkwright obtained the secret to Highs's design and went on to use it for his water frame. This model could not be operated within workers' homes, so in 1771 Arkwright built the first textiles factory in Cromford, Derbyshire, marking the beginning of textile mass-production.\n\n----\n\nVenetian Blind\n\nInvented: 1769\n\nSummary: Beran patents a window covering.\n\nPrecisely where or when the very first Venetian blinds appeared has long been a point of some conjecture. Slatted blinds made from various timbers were popular throughout northern Italy in the mid to late-1700s; these consisted of slats held together by strips of fabric rather than corded cloth, and the angle of the slats could be adjusted with the use of a tilting device, not unlike what is in use today. When freed Venetian slaves took Venetian blinds to France in the 1790s, the window coverings soon became known to the French as les Persiennes (the Persians).\n\nIn fact, by the 1700s Italy had already enjoyed a long association with the Venetian blind. Archeologists have uncovered slatted window coverings amid the ruins of Pompeii, with the individual slats being fashioned from marble. Farther to the east, the earliest window coverings unearthed in modern Iran (previously known as Persia) have been dated to 4000 B.C.E.; these were made from clay tiles. To the south, on the Mediterranean island of Crete, shutters made from an amalgam of alabaster and marble have been found among ruins attributed to the ancient Minoan civilization (2600-1100 B.C.E.).\n\nIn England, Venetian blinds were patented by Edward Beran in London on December 11, 1769. A century later they became highly popular with the Victorians as an alternative to curtains, which had become heavy, cumbersome, and unfashionable.\n\nThe modern method of adjusting the angle of the slats while keeping them synchronized and parallel was invented in 1841 by John Hampson of New Orleans, Louisiana. Blinds made from wood continued to remain popular until the development by Joe Hunter and Henry Sonnenberg of the 2-inch (50 mm) aluminumslat in the mid-1940s.\n\n----\n\nCaterpillar Tracks\n\nInvented: 1770\n\nInventor: Richard Lovell Edgeworth (England)\n\nSummary: Edgeworth patents continuous tracks.\n\n\u2002\"They come and pushed me off. They come with the cats... the Caterpillar tractors.\" \u2014The Grapes of Wrath, Nunally Johnson screenplay\n\nWhen you want to navigate areas where the terrain is uneven and muddy, what better solution than to take the road with you? This was precisely the conclusion of Englishman Richard Lovell Edgeworth (1744-1817) when he invented the \"portable railway,\" the earliest incarnation of a ful'-track vehicle. Although his 1770 patent is open to interpretation, it could describe anything from a vehicle with shoed wheels to a system similar to that seen today where continuous tracks run between front and rear wheels.\n\nThe nineteenth century saw a glut of patents filed for vehicles sporting tracks. However, they suffered from problems such as poor steering and a lack of materials capable of taking the stresses and strains exerted by the system. But perhaps the biggest stumbling block was insufficient propulsive power, a problem overcome only with the advent of the internal combustion engine. Despite this, full-track, steam-powered vehicles had their uses; the Western Alliance for example used them during the Crimean War (1853-1856).\n\nIt is believed that the name \"caterpillar track\" was shrewdly trademarked in the early 1900s by Benjamin Holt, founder of Holt Manufacturing, later Caterpillar Inc, after hearing a British soldier quip how the tracked vehicles crawled like a caterpillar. The caterpillar track now appears in designs created for many terrains.\n\n----\n\nSoda Water\n\nInvented: 1771\n\nInventor: Joseph Pristley (England)\n\nSummary: Priestley mixes carbon dioxide and water.\n\n\u2002\"Let us have wine and women, mirth and laughter/Sermons and soda-water the day after\" \u2014Lord Byron, Don Juan\n\nJoseph Priestley (1733-1804) grew up near a brewery in Yorkshire, England, and as a teenager saw carbon dioxide gas \"floating\" above deposits of fermenting grain. In 1771 this clergyman, philosopher, and chemist began to inject carbon dioxide, what he called \"fixed air,\" into small containers of water uncontaminated by the surrounding air. By agitating the mixture for thirty minutes he was able to cause the water to absorb its own volume of carbon dioxide, and so he created the world's first drinkable glass of carbonated water. In 1772 Priestley wrote a book detailing in part how he thought carbonated water could be used to retard food spoilage and reduce the incidence of scurvy on long ocean voyages. He also wrote a paper entitled Directions for Impregnating Water with Fixed Air.\n\nPriestley's considerable legacy includes writings on the nature of electricity, ethics, religious freedom, and extensive work on the nature of gases, which led to his discovery of oxygen in 1774. He never found the time, nor likely possessed the inclination, to pursue the commercial potential of his carbonated water.\n\nArtificially carbonated water mimicked the bubbles found in many natural springs. It was not until the invention of the soda fountain or carbonated drink dispenser by Samuel Fahnestock in 1819, however, that carbonated water achieved the kind of popularity it has today as the foundation of many soft drinks.\n\n----\n\nS-trap for Toilet\n\nInvented: 1775\n\nInventor: Alexander Cummings (Scotland)\n\nSummary: Cummings introduces the indoor toilet.\n\n\u2002\"And you shall have an implement and you shall dig with it and turn and cover your refuse.\" \u2014Deuteronomy 23:1 on camp sanitation\n\nWithout the toilet system, disease would be widespread and water undrinkable. It is an invention that is taken for granted in the modern world, but where would we be without it? Even though they began only as holes in the ground, toilets in various forms have been used since Babylonian times.\n\nA defining step in the long and complex history of the toilet was the S-trap system developed by Alexander Cummings, a watchmaker by trade. (Thomas Crapper is often given credit for the invention of the modern toilet; although he was involved in toilet production, it was Cummings who held the patent.) Cummings's design incorporated an S-shaped bend in the drainage pipe that created a water seal between\n\nflushes. This meant that foul odors were trapped below the water and could not escape into the air.\n\nLife improved immeasurably with the combined benefits of the flushing toilet and the closed sewer system. By blocking the odors of the sewer, Cummings made it possible to bring the toilet inside the house, and so he made the toilet desirable. Soon everyone who could afford one was happily flushing away.\n\nThe S-trap design is still used in toilets as an effective way to deal with odor. However, toilet design has since addressed other aspects of use\u2014in Japan, standard toilets are fitted with seat warmers, jets of cleansing water, and fully automated flushers.\n\n----\n\nSubmersible Craft\n\nInvented: 1775\n\nInventor: David Dushnell (US)\n\nSummary: Bushnell builds the first underwater vessel to be used for military purposes.\n\n\u2002\"I was obliged to rise up every few minutes to see that I sailed in the right direction.\" \u2014Sergeant Ezra Lee, pilot of Turtle\n\nIn 1775 Britain's North American colonies rebelled against British rule, precipitating a War of Independence. An enthusiastic American patriot, David Bushnell (1742-1824) of Saybrook, Connecticut, devised a secret weapon to counter the might of Britain's Royal Navy. He designed and built a submersible vessel to attack warships in harbor.\n\nBushnell's Turtle was an oval-shaped vessel of wood and brass, just large enough to hold one person. It had ballast water tanks that were filled to make it dive, then emptied with a hand pump to return to the surface. Two screw propellers, operated by foot pedals and a handle, allowed the operative to maneuver the vessel laterally and vertically underwater. Ingeniously, the inside of the submersible was lined with naturally luminescent wood to provide light for reading the instruments\u2014a compass and a depth meter.\n\nTurtle's weapon was an underwater gunpowder charge with a timer, in effect the first sea mine, although Bushnell called it a \"torpedo,\" after a stinging crampfish. A drill was provided for attaching the chargeto the hull ofa ship atanchor.\n\nTurtle was first sent into action on September 7, 1776. With an army volunteer, Sergeant Ezra Lee, at the controls, it was launched into New York harbor to attack the British flagship, HMS Eagle. Lee successfully brought Turtle up against the underside of Eagle's hull, but failed to attach the charge. Getting the drill to penetrate the ship's copper-sheathed hull while maintaining position in strong currents was beyond Lee's powers. The subsequent fate of Turtle is obscure, but it never achieved a successful attack.\n\n----\n\nBoring Machine\n\nInvented: 1775\n\nInventor: John Wilkinson (England)\n\nSummary: Wilkinson creates a vital tool for precise engineering in iron.\n\n\u2002\"One of the most hard-hearted, malevolent old scoundrels now living in Britain.\" \u2014Lord Dundonald on John Wilkinson\n\nThe boring machine, designed by John Wilkinson (1728-1808), was one of the foundations of the Industrial Revolution. The idea of mechanical boring was not new, but Wilkinson used it to bore better cannon with a greater degree of accuracy. More importantly, however, boring machines could be used to make precisely engineered cylinders for steam engines. Thanks to his collaboration with James Watt, inventor of the commercial steam engine, Wilkinson enjoyed a monopoly on the engine for several years, and they both became very wealthy men.\n\nAs Wilkinson's wealth grew, so did his eccentricities. He was a volatile character and was often criticized by his fellow industrialists, thanks to some shady business dealings and the implication that some of his ideas may have already been suggested by others. Some of his family relationships were strained too\u2014he was estranged from his father, and his spectacular fallout with his brother in the late 1780s caused the collapse of his steam-engine monopoly.\n\nIn his later years Wilkinson become increasingly obsessed with iron. He arranged an enormous and impractical iron coffin in which to be buried, and prophesied his supernatural return to his beloved furnaces seven years after his death. However, extraordinarily for his time, he gave pensions to old workers who had served him well, and he was held in high regard by his employees. After his death in 1808 he was commemorated in folksong by his ironworkers and, after seven years had passed, thousands turned up at his furnaces to see whether \"Iron Mad\" Wilkinson would \"live up to\" his prophecy.\n\n----\n\nSteamboat\n\nInvented: 1776\n\nInventor: Marquis de Jouffroy d'Abban (France)\n\nSummary: De Jouffroy d'Abbans powers a watercraft.\n\n\u2002\"The glory belongs to the author of the experiments made on the River Sa\u00f6ne at Lyons in 1783.\" \u2014Robert Fulton on De Jouffroy's steamboat\n\nIt is not uncommon for the American Robert Fulton (1765-1815) to be heralded as the inventor of the steamboat, but in actuality the true creative force behind its invention was a young French aristocrat, Claude-Franqois-Dorothee, Marquis de Jouffroy d'Abbans (1751-1832). DeJouffroy d'Abbans, according to legend, was wild and unruly, resulting in his incarceration in a military prison on the Isle of St. Marguerite. While he was there he studied the boats passing by and developed an interest in engineering.\n\nOn his release he went to Paris and studied with the Perier brothers, examining the Watt steam engine and devising methods in which it could be applied to propelling a vessel. He began workon an experimental boat, a steamship called the Palmipede, which he ran along the Doubs River in June and July 1776. The boat was not entirely successful, and he continued his experimental work, this time moving from Paris to Lyons. In 1783 his new model, the paddle steamer Pyroscaphe, was ready and ran for fifteen minutes along the Sa\u00f6ne against the current and to a crowd of scientists and spectators. The boat was a success and ran for sixteen months, but the French Academy of Sciences in Paris refused to acknowledge it and denied de Jouffroy d'Abbans his license. Finally, embittered and impoverished, the inventor retired to the Hotel des Invalides, where he died from cholera.\n\n----\n\nCircular Saw\n\nInvented: 1777\n\nInventor: Samuel Miller (England)\n\nSummary: Miller patents an innovatory form of saw.\n\nIn 1777 Samuel Miller of Southampton, England, received the first patent for a circular saw. His wind-powered machine's usefulness was limited, however, forwantofa more powerful energy source.\n\nThirty-six years later Tabitha Babbit, a Shaker woman from the Harvard Shaker village, invented a circular saw of her own. Her religious beliefs prevented her from seeking a patent, but the new invention became popular in her community. Babbit's saw was initially human-poweredt but waterwheels and steam were soon harnessed for added convenience and efficiency. Sawmills adopted the circular saw, and the tool was soon at the heart of the lumber industry.\n\nThe circular saw is a relatively simple device that dramatically improves on the efficiency of a standard handsaw, where half of each stroke is wasted effort. Circular saws cut by spinning circular serrated blades at high speeds into the timber passed through them.\n\nThe U.S. military, bolstering its technology for World War II, enlisted the saw manufacturer Skilsaw to develop a specialized saw for military use. Skilsaw's answer, the PS-12 military circular saw, could function in all conditions, including underwater, and came with a rugged camouflage paint job. The U.S. Navy put the saw into camouflaged boxes and began floating secret circular-saw units to predefined landing areas.\n\nNowadays the circular saw is an industrial staple. Portable circular saws allow users to saw small jobs, miter saws permit all angles of cutting, and table saws provide the backbone of most woodworking shops. Numerous blades have also been created to optimize saws for particular cutting purposes. Specialized blades, with intriguing names such as \"ripping,\" \"dado,\" and \"thin kerf,\" are designed to cut through materials as varied as brick, steel, and glass.\n\n----\n\nTumbler Lock\n\nInvented: 1778\n\nInventor: Robert Barron (England)\n\nSummary: Barron patents a thief-resistant lock.\n\n\u2002\"The lever tumbler lock... could still be picked. It merely required more skill and time.\" \u2014Jock Dempsey, blacksmith\n\nPeople depend on their locks and keys a lot more than they would like to admit. Without having to stand guard over their possessions from morning to night, they are free to pursue their lives away from their homes and businesses. Locks and keys existed before Robert Barron patented his tumbler lock in 1778, but the sheer number of people now carrying keys to tumbler locks testifies to the success of his invention.\n\nBarron's lock, which offered considerably improved security over any previous locks, was called a doubleacting tumbler and was very similar to many modern models. A tumbler, essentially a lever inside the lock, prevents the bolt of the lock from being opened unless it is raised to a certain height. Barron's lock employed two tumblers and these needed to be lifted to different heights for the bolt to be released.\n\nMost focused thieves could still pick the Barron lock if they had enough time, so in 1818 Jeremiah Chubb added a detecting feature in hopes of winning a reward of \u00a3100 offered by England's Portsmouth Dockyard. The detector consisted of either a spring or a specialized lever that would catch any tumbler that was raised too high. If an unlucky picker raised any tumbler higher than the detection point, the lock would jam shut, vanquishing the thief. The jammed lock would also alert the lock's owner, who could reset the lock simply by using the original key.\n\n----\n\nSpeech Synthesis\n\nInvented: 1779\n\nInventor: Christian Kratzenstein (Russia)\n\nSummary: Kratzenstein reproduces vowel sounds.\n\nThe earliest speech synthesizer was created by a Russian professor, Christian Kratzenstein (1723-1795). Between 1773 and 1779 Kratzenstein made acoustic resonators and produced vowel sounds by connecting them to organ pipes.\n\nA contemporary in Vienna, Wolfgang von Kempelen, produced a more advanced machine in 1791. His \"acoustic mechanical speech machine\" was able to produce single sounds and even words or short phrases. He is best known for an earlier invention, a chess-playing machine named \"The Turk.\" This consisted of a cabinet, housing (apparently) just cogs and wheels, and a manikin with movable arms. One could not see the legless human chess player concealed inside. Once this hoax was exposed, his legitimate speech machine was discredited as well.\n\nAlexander Graham Bell became interested in speech synthesis after he saw a replica of one of Von Kempelen's speech machines. When young, Bell had taught his pet terrier to stand between his legs and growl while he manipulated the dog's vocal tract by hand. He was eventually able to produce \"How are you, Grandmamma?\"\n\nJoseph Farber improved on Von Kempelen's machine by adding a mechanical tongue and a pharyngeal cavity that could be manipulated as well. It was powered by bellows and controlled by a keyboard and could sing as well as produce speech.\n\nThe first electrical speech synthesizer was the VODER, developed by Homer Dudley and presented at the 1939 World's Fair. It saw more utility as the VOCODER, which reduced ordinary speech into a facsimile to reduce the bandwidth necessary for the telephonic transmission. This allowed a larger number of telephone calls to be transmitted over a line.\n\n----\n\nSpinning Mule\n\nInvented: 1779\n\nInventor: Samuel Compton (England)\n\nSummary: Crompton refines further the efficiency of mass-produced spun yarn.\n\nThe textile industry was one of the cornerstones of Britain's Industrial Revolution. The production process had changed little in centuries: yarn was spun skillfully on a human-powered wheel. Invariably performed by women and young children, it was hard work and provided little in the way of reward.\n\nBy the middle of the eighteenth century, as the demand for textiles for export grew, labor-saving devices enabling yarn to be spun at greater speed began to emerge. The two most significant developments were the water frame and the spinning jenny. The water frame used the principles of the water wheel to power the spinning frame, thus dramatically reducing the amount of human effort required; the spinning jenny, a multispool spinning wheel, boosted output by enabling a single worker to operate up to eight spools at once. In 1779 the inventor Samuel Crompton (1753-1827) combined the main features of both, creating the spinning mule. A multispooled, waterpowered spinning wheel, the mule could create a strong, thin yarn, high both in quality and consistency, suitable for any kind of textile. And it could do so at considerable speed.\n\nThe Industrial Revolution was a period of endless technical innovation, and as steam gradually became the ascendant form of power, the mule was duly converted. This gave rise to the widespread mass production of textiles, and the gradual appearance of the mighty factories that would come to dominate the Lancashire and Yorkshire landscapes.\n\n----\n\nArgand Lamp\n\nInvented: 1780\n\nInventor: Ami Argand (Geneva)\n\nSummary: Argand revolutionizes the oil lamp, starting a worldwide hunt for the sperm whale.\n\n\u2002\"In the Argand... the air and the gas were brought into contact by means of numerous small orifices.\" \u2014The Mechanics' Magazine (1854)\n\nFuel-burning lamps had been used for hundreds of years without significant improvement. Then, in 1780, Swiss scientist Aime Argand (1750-1803) invented a lamp that would revolutionize the lives of two species\u2014Homo sapiens and Physeter macrocephalus.\n\nArgand studied chemistry under the French chemist Antoine-Laurent de Lavoisier, who discovered that oxygen was required for burning. Argand's lamp used a hollow wick to draw more air to the inside of the flame and had a glass cylinder around the wick to increase the flow of air outside the flame. Argand also provided a way to lower or raise the wick to decrease or increase the size of the flame and thus the amount of light the lamp produced. Because of the additional oxygen, the flame burned at a higher temperature, which produced much more light. It also burned most of the carbon particles that had dirtied and dimmed older oil lamps. The glass protected the flame from air currents, which kept the amount of light steady.\n\nArgand found that sperm whale oil produced the best flame, up to ten times brighter than candles. Since Argand lamps provided a reliable source of light after nightfall, the demand for whale oil rocketed.\n\nIn 1794, during the French Revolution, Lavoisier was executed and Argand's patent was taken away, allowing anyone to make Argand lamps. He died in London in 1803, after having spent the rest of his life experimenting on bones, coffin wood, and graveyard plants in an attempt to find the elixir of long life. Until kerosene lamps arrived in the 1850s, the sperm whale continued to be killed in large numbers for its oil.\n\n----\n\nIron Rocket\n\nInvented: 1780\n\nSummary: The Indians extend the range of war rockets.\n\nThe use of rockets in warfare began with the Chinese, who first developed the technology around the thirteenth century. Their new \"fire arrows\" were successfully deployed against the Mongols, and it was not long before the rest of the world began to experiment with them.\n\nDuring the eighteenth century, the British and the French were fighting over India, each keen to possess its riches. Unfortunately forthem, they discovered that the inhabitants were not always happy to hand over their land. Tipu Sultan of Mysore in southern India fought the British with a tactic, developed by him and his father, of using rocket brigades against the British infantry. The Mysoreans perfected the use of the rockets in the battlefield, developing the technology so that they could fire them over much greater distances than British weapons could achieve.\n\nThe European rockets were wooden, so they could only survive so much thrust before breaking apart. Tipu Sultan's rockets were constructed from a tube of iron, making them much stronger than wooden rockets. This extra strength meant they could withstand more thrust and fly much farther, giving the Mysoreans a tactical advantage in the field. The sheer numbers of rockets deployed, not to mention their noise and drama, disoriented the British infantry, and the rockets aimed directly at the infantry caused significant casualties.\n\nImpressed by these rockets, the British took hundreds back to reverse engineer them. New British rockets were used at Boulogne, Copenhagen, and against the Americans at Fort Washington, with the words \"rockets' red glare\" eventually being included in the first verse of the American national anthem.\n\n----\n\nCompound Steam Engine\n\nInvented: 1781\n\nInventor: Jonathan Hornblower (England)\n\nSummary: Hornblower introduces compound cylinders.\n\n\u2002\"Engine control requires an intelligent man, an honest man, a sober man, a steady man...\" \u2014Isambard Kingdom Brunel, engineer\n\nFhe steam in early steam engines was used only once; after it had pushed back the piston it was discharged into the atmosphere, a more efficient process allowed the steam to expand in two or more stages. These \"compound\" engines had two or more cylinders. After the steam had been expanded in the high-pressure cylinder the exhaust steam was then used to push back the piston of a following, larger-circumference, low-pressure cylinder. The two pistons were connected with cranks that enabled them to work at the required different phases. With correct size scaling, the power output per cylinder could be equalized, and the engine ran smoothly. As these systems were\n\nrather complicated, they were mainly used in industrial and marine engines. Some compound railway locomotives were bu;lt, but the tough operating conditions made them difficultto maintain.\n\nJonathan Hornblower (1753-1815) was originally an employee of Boulton and Watt and designed the first compound steam engine in 1781. Unfortunately, the early compounds were no more economical than simple single-cylinder engines. The concept was then revised by the Cornish engineer Arthur Wolf, who obtained a patent in 1805. Problems with the high-pressure cylinder meant that few such engines were used until the mid-nineteenth century."}