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During the sixteenth and seventeenth centuries, Athena was used as a symbol for female rulers. In his book "A Revelation of the True Minerva" (1582), Thomas Blennerhassett portrays Queen Elizabeth I of England as a "new Minerva" and "the greatest goddesse nowe on earth". A series of paintings by Peter Paul Rubens depict Athena as Marie de' Medici's patron and mentor; the final painting in the series goes even further and shows Marie de' Medici with Athena's iconography, as the mortal incarnation of the goddess herself. The Flemish sculptor Jean-Pierre-Antoine Tassaert (Jan Peter Anton Tassaert) later portrayed Catherine II of Russia as Athena in a marble bust in 1774. During the French Revolution, statues of pagan gods were torn down all throughout France, but statues of Athena were not. Instead, Athena was transformed into the personification of freedom and the republic and a statue of the goddess stood in the center of the Place de la Revolution in Paris. In the years following the Revolution, artistic representations of Athena proliferated.
A statue of Athena stands directly in front of the Austrian Parliament Building in Vienna, and depictions of Athena have influenced other symbols of Western freedom, including the Statue of Liberty and Britannia. For over a century, a full-scale replica of the Parthenon has stood in Nashville, Tennessee. In 1990, the curators added a gilded forty-two-foot (12.5 m) tall replica of Phidias's "Athena Parthenos", built from concrete and fiberglass. The Great Seal of California bears the image of Athena kneeling next to a brown grizzly bear. Athena has occasionally appeared on modern coins, as she did on the ancient Athenian drachma. Her head appears on the $50 1915-S Panama-Pacific commemorative coin. Modern interpretations. One of Sigmund Freud's most treasured possessions was a small, bronze sculpture of Athena, which sat on his desk. Freud once described Athena as "a woman who is unapproachable and repels all sexual desires since she displays the terrifying genitals of the Mother". Feminist views on Athena are sharply divided; some regard her as "the ultimate patriarchal sell out ... who uses her powers to promote and advance men rather than others of her sex", while some feminists regard her as a symbol of female empowerment, In contemporary Wicca, Athena is venerated as an aspect of the Goddess and some Wiccans believe that she may bestow the "Owl Gift" ("the ability to write and communicate clearly") upon her worshippers. Due to her status as one of the twelve Olympians, Athena is a major deity in Hellenismos, a Neopagan religion which seeks to authentically revive and recreate the religion of ancient Greece in the modern world.
Athena is a natural patron of universities: At Bryn Mawr College in Pennsylvania, a statue of Athena (a replica of the original bronze one in the arts and archaeology library) resides in the Great Hall. It is traditional at exam time for students to leave offerings to the goddess with a note asking for good luck, or to repent for accidentally breaking any of the college's numerous other traditions. Pallas Athena is the tutelary goddess of the international social fraternity Phi Delta Theta. Her owl is also a symbol of the fraternity.
Amber Diceless Roleplaying Game The Amber Diceless Roleplaying Game is a role-playing game created and written by Erick Wujcik, set in the fictional universe created by author Roger Zelazny for his "Chronicles of Amber". The game is unusual in that no dice are used in resolving conflicts or player actions; instead a simple diceless system of comparative ability, and narrative description of the action by the players and gamemaster, is used to determine how situations are resolved. "Amber DRPG" was created in the 1980s, and is much more focused on relationships and roleplaying than most of the roleplaying games of that era. Most "Amber" characters are members of the two ruling classes in the "Amber" multiverse, and are much more advanced in matters of strength, endurance, psyche, warfare and sorcery than ordinary beings. This often means that the only individuals who are capable of opposing a character are from his or her family, a fact that leads to much suspicion and intrigue. History. Erick Wujcik wanted to design a role-playing game based on "Amber" for West End Games, and they agreed to look at his work. Wujcik intended to integrate the feel of the "Amber" setting from the novels into a role-playing game, and playtested his system for a few months at the Michigan Gaming Center where he decided to try it out as a diceless game. West End Games was not interested in a diceless role-playing game, so Wujcik acquired the role-playing game rights to "Amber" and offered the game to R. Talsorian Games, until he withdrew over creative differences. Wujcik then founded Phage Press, and published "Amber Diceless Role-playing" in 1991.
The original 256-page game book was published in 1991 by Phage Press, covering material from the first five novels (the "Corwin Cycle") and some details – sorcery and the Logrus – from the remaining five novels (the "Merlin Cycle"), in order to allow players to roleplay characters from the Courts of Chaos. Some details were changed slightly to allow more player choice – for example, players can be full Trump Artists without having walked the Pattern or the Logrus, which Merlin says is impossible; and players' psychic abilities are far greater than those shown in the books. A 256-page companion volume, "Shadow Knight", was published in 1993. This supplemental rule book includes the remaining elements from the Merlin novels, such as Broken Patterns, and allows players to create Constructs such as Merlin's Ghostwheel. The book presents the second series of novels not as additions to the series' continuity but as an example of a roleplaying campaign with Merlin, Luke, Julia, Jurt and Coral as the PCs. The remainder of the book is a collection of essays on the game, statistics for the new characters and an update of the older ones in light of their appearance in the second series, and (perhaps most usefully for GMs) plot summaries of each of the ten books. The book includes some material from the short story "The Salesman's Tale," and some unpublished material cut from "Prince of Chaos", notably Coral's pregnancy by Merlin.
Both books were translated into French and published by Jeux Descartes in 1994 and 1995. A third book, "Rebma", was promised. Cover art was commissioned and pre-orders were taken, but it was never published. Wujcik also expressed a desire to create a book giving greater detail to the Courts of Chaos. The publishing rights to the "Amber DRPG" games were acquired in 2004 by Guardians of Order, who took over sales of the game and announced their intention to release a new edition of the game. However, no new edition was released before Guardians of Order went out of business in 2006. The two existing books are now out-of-print, but they have been made available as PDF downloads. In June 2007 a new publishing company, headed by Edwin Voskamp and Eleanor Todd, was formed with the express purpose of bringing "Amber DRPG" back into print. The new company is named "Diceless by Design". In May 2010, "Rite Publishing" secured a license from Diceless by Design to use the rules system with a new setting in the creation of a new product to be written by industry and system veteran Jason Durall. The project Lords of Gossamer & Shadow (Diceless) was funded via Kickstarter in May 2013. In Sept 2013 the project was completed, and on in Nov 2013 Lords of Gossamer and Shadow (Diceless) was released publicly in full-color Print and PDF, along with additional supplements and continued support.
Setting. The game is set in the multiverse described in Zelazny's "Chronicles of Amber". The first book assumes that gamemasters will set their campaigns after the Patternfall war; that is, after the end of the fifth book in the series, "The Courts of Chaos", but uses material from the following books to describe those parts of Zelazny's cosmology that were featured there in more detail. The "Amber" multiverse consists of Amber, a city at one pole of the universe wherein is found the Pattern, the symbol of Order; The Courts of Chaos, an assembly of worlds at the other pole where can be found the Logrus, the manifestation of Chaos, and the Abyss, the source or end of all reality; and Shadow, the collection of all possible universes (shadows) between and around them. Inhabitants of either pole can use one or both of the Pattern and the Logrus to travel through Shadow. It is assumed that players will portray the children of the main characters from the books – the ruling family of Amber, known as the Elder Amberites – or a resident of the Courts. However, since some feel that being the children of the main characters is too limiting, it is fairly common to either start with King Oberon's death "before" the book begins and roleplay the Elder Amberites as they vie for the throne; or to populate Amber from scratch with a different set of Elder Amberites. The former option is one presented in the book; the latter is known in the Amber community as an "Amethyst" game. A third option is to have the players portray Corwin's children, in an Amber-like city built around Corwin's pattern; this is sometimes called an "Argent" game, since one of Corwin's heraldic colours is Silver.
System. Attributes. Characters in "Amber DRPG" are represented by four attributes: "Psyche", "Strength", "Endurance" and "Warfare". The attributes run from −25 (normal human level), through −10 (normal level for a denizen of the Courts of Chaos) and 0 (normal level for an inhabitant of Amber), upwards without limit. Scores above 0 are "ranked", with the highest score being ranked 1st, the next-highest 2nd, and so on. The character with 1st rank in each attribute is considered "superior" in that attribute, being considered to be substantially better than the character with 2nd rank even if the difference in scores is small. All else being equal, a character with a higher rank in an attribute will always win a contest based on that attribute. The Attribute Auction. A character's ability scores are purchased during character creation in an auction; players get 100 character points, and bid on each attribute in turn. The character who bids the most for an attribute is "ranked" first and is considered superior to all other characters in that attribute. Unlike conventional auctions, bids are non-refundable; if one player bids 65 for psyche and another wins with a bid of 66, then the character with 66 is "superior" to the character with 65 even though there is only one bid difference. Instead, lower bidding characters are ranked in ascending order according to how much they have bid, the characters becoming progressively weaker in that attribute as they pay less for it. After the auction, players can secretly pay extra points to raise their ranks, but they can only pay to raise their scores to an existing rank. Further, a character with a bid-for rank is considered to have a slight advantage over character with a bought-up rank.
The Auction simulates a 'history' of competition between the descendants of Oberon for player characters who have not had dozens of decades to get to know each other. Through the competitive Auction, characters may begin the game vying for standings. The auction serves to introduce some unpredictability into character creation without the need to resort to dice, cards, or other randomizing devices. A player may intend, for example, to create a character who is a strong, mighty warrior, but being "outplayed" in the auction may result in lower attribute scores than anticipated, therefore necessitating a change of character concept. Since a player cannot control another player's bids, and since all bids are non-refundable, the auction involves a considerable amount of strategizing and prioritization by players. A willingness to spend as many points as possible on an attribute may improve your chances of a high ranking, but too reckless a spending strategy could leave a player with few points to spend on powers and objects. In a hotly contested auction, such as for the important attribute of warfare, the most valuable skill is the ability to force one's opponents to back down. With two or more equally determined players, this can result in a "bidding war," in which the attribute is driven up by increments to large sums. An alternative strategy is to try to cow other players into submission with a high opening bid. Most players bid low amounts between one and ten points in an initial bid in order to feel out the competition and to save points for other uses. A high enough opening bid could signal a player's determination to be first ranked in that attribute, thereby dissuading others from competing.
Psyche in "Amber DRPG" compared to the "Chronicles". Characters with high psyche are presented as having strong telepathic abilities, being able to hypnotise and even mentally dominate any character with lesser psyche with whom they can make eye-contact. This is likely due to three scenes in the "Chronicles": first, when Eric paralyzes Corwin with an attack across the Trump and refuses to desist because one or the other would be dominated; second, when Corwin faces the demon Strygalldwir, it is able to wrestle mentally with him when their gazes meet; and third, when Fiona is able to keep Brand immobile in the final battle at the Courts of Chaos. However, in general, the books only feature mental battles when there is some reason for mind-to-mind contact (for example, Trump contact) and magic or Trump is involved in all three of the above conflicts, so it is not clear whether Zelazny intended his characters to have such a power; the combination of Brand's "living trump" powers and his high Psyche (as presented in the roleplaying game) would have guaranteed him victory over Corwin. "Shadow Knight" does address this inconsistency somewhat, by presenting the "living trump" abilities as somewhat limited.
Powers. Characters in "Amber DRPG" have access to the powers seen in the "Chronicles of Amber": "Pattern", "Logrus", "Shape-shifting", "Trump", and "magic". Each of the first four powers is available in an advanced form. Artifacts, Personal shadows and Constructs. While a character with Pattern, Logrus or Conjuration can acquire virtually any object, players can choose to spend character points to obtain objects with particular virtues – unbreakability, or a mind of their own. Since they have paid points for the items, they are a part of the character's legend, and cannot lightly be destroyed. Similarly, a character can find any possible universe, but they can spend character points to know of or inhabit shadows which are (in some sense) "real" and therefore useful. The expansion, "Shadow Knight", adds Constructs – artifacts with connections to shadows. Stuff. Unspent character points become good stuff – a good luck for the character. Players are also allowed to overspend (in moderation), with the points becoming bad stuff – bad luck which the Gamemaster should inflict on the character. Stuff governs how non-player characters perceive and respond to the character: characters with good stuff will often receive friendly or helpful reactions, while characters with bad stuff are often treated with suspicion or hostility.
As well as representing luck, stuff can be seen as representing a character's outlook on the universe: characters with good stuff seeing the multiverse as a cheerful place, while characters with bad stuff see it as hostile. Conflict resolution. In any given fair conflict between two characters, the character with the higher score in the relevant attribute will eventually win. The key words here are "fair" and "eventually" – if characters' ranks are close, and the weaker character has obtained some advantage, then the weaker character can escape defeat or perhaps prevail. Close ranks result in longer contests while greater difference between ranks result in fast resolution. Alternatively, if characters' attribute ranks are close, the weaker character can try to change the relevant attribute by changing the nature of the conflict. For example, if two characters are wrestling the relevant attribute is Strength; a character could reveal a weapon, changing it to Warfare; they could try to overcome the other character's mind using a power, changing it to Psyche; or they could concentrate their strength on defense, changing it to Endurance. If there is a substantial difference between characters' ranks, the conflict is generally over before the weaker character can react.
The "Golden Rule". "Amber DRPG" advises gamemasters to change rules as they see fit, even to the point of adding or removing powers or attributes. Reception. Steve Crow reviewed "Amber Diceless Roleplaying Game" in "White Wolf" #31 (May/June, 1992), rating it a 4 out of 5 and stated that "It is undoubtedly a game for experienced gamers. While I would not recommend "Amber" to novices, it is a must buy for experienced gamemasters and players looking for new challenges." In the June 1992 edition of "Dragon" (Issue 182), both Lester Smith and Allen Varney published reviews of this game. In Issue 65 of "Challenge", Dirk DeJong had a good first impression of the game, especially the information provided about the Amber family members and their various flaws and strengths. However he found that "The biggest problem with this endeavor, and its downfall, is the nature of the conflict systems. First, they are diceless, really diceless, and don't involve any sort of random factors at all, aside from those that you can introduce by roleplaying them out. Thus, if you get involved with a character who's better than you at sword-fighting, even if only by one point out of 100, you're pretty much dead meat, unless you can act your way out." DeJong also disagreed with the suggestion that if the referee and players disagreed with a rule to simply remove it from the game. "I thought the entire idea of using rules and random results was to prevent the type of arguments that I can see arising from this setup." DeJong concluded on an ambivalent note, saying, "If you love Zelazny and the Amber series, jump on it, as this is the premier sourcebook for running an Amber campaign. [...] Personally, I just can't get turned on by a system that expects me to either be content with a simple subtraction of numbers to find out who won, or to describe an entire combat blow by blow, just so that I can attempt some trick to win."
Loyd Blankenship reviewed "Amber" in "Pyramid" #2 (July/Aug., 1993), and stated that ""Amber" is a valuable resource to a GM - even if he isn't running an "Amber" game. For gamers who have an aspiring actor or actress lurking within their breast, or for someone running a campaign via electronic mail or message base, "Amber" should be given serious consideration." In his 2023 book "Monsters, Aliens, and Holes in the Ground", RPG historian Stu Horvath noted, "There hasn't been an RPG quite like "Amber", before or since. Bold though it was, the game didn't do very well commercially. The lack of dice became a flashpoint of controversy, with dice enthusiasts dramatically swearing off the game. That's a bit ridiculous, but it does get at a key hurdle "Amber" face: People "like" rolling dice. They've been doing it for thousands of years and a significant part of the appeal of RPGs is giving dice, often in sparkly colours, a toss." Community. Despite the game's out-of-print status, a thriving convention scene exists supporting the game. Amber conventions, known as "Ambercons", are held yearly in Massachusetts, Michigan, Portland (United States), Milton Keynes (England), Belfast (Northern Ireland) and Modena, Italy. Additionally, Phage Press published 12 volumes of a dedicated "Amber DRPG" magazine called "Amberzine". Some "Amberzine" issues are still available from Phage Press.
Athene (disambiguation) Athene or Athena is the shrewd companion of heroes and the goddess of heroic endeavour in Greek mythology. Athene may also refer to:
Alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have properties that differ from those of the pure elements from which they are made. The vast majority of metals used for commercial purposes are alloyed to improve their properties or behavior, such as increased strength, hardness or corrosion resistance. Metals may also be alloyed to reduce their overall cost, for instance alloys of gold and copper. A typical example of an alloy is 304 grade stainless steel which is commonly used for kitchen utensils, pans, knives and forks. Sometime also known as 18/8, it as an alloy consisting broadly of 74% iron, 18% chromium and 8% nickel. The chromium and nickel alloying elements add strength and hardness to the majority iron element, but their main function is to make it resistant to rust/corrosion. In an alloy, the atoms are joined by metallic bonding rather than by covalent bonds typically found in chemical compounds. The alloy constituents are usually measured by mass percentage for practical applications, and in atomic fraction for basic science studies. Alloys are usually classified as substitutional or interstitial alloys, depending on the atomic arrangement that forms the alloy. They can be further classified as homogeneous (consisting of a single phase), or heterogeneous (consisting of two or more phases) or intermetallic. An alloy may be a solid solution of metal elements (a single phase, where all metallic grains (crystals) are of the same composition) or a mixture of metallic phases (two or more solutions, forming a microstructure of different crystals within the metal).
Examples of alloys include red gold (gold and copper), white gold (gold and silver), sterling silver (silver and copper), steel or silicon steel (iron with non-metallic carbon or silicon respectively), solder, brass, pewter, duralumin, bronze, and amalgams. Alloys are used in a wide variety of applications, from the steel alloys, used in everything from buildings to automobiles to surgical tools, to exotic titanium alloys used in the aerospace industry, to beryllium-copper alloys for non-sparking tools. Characteristics. An alloy is a mixture of chemical elements, which forms an impure substance (admixture) that retains the characteristics of a metal. An alloy is distinct from an impure metal in that, with an alloy, the added elements are well controlled to produce desirable properties, while impure metals such as wrought iron are less controlled, but are often considered useful. Alloys are made by mixing two or more elements, at least one of which is a metal. This is usually called the primary metal or the base metal, and the name of this metal may also be the name of the alloy. The other constituents may or may not be metals but, when mixed with the molten base, they will be soluble and dissolve into the mixture.
The mechanical properties of alloys will often be quite different from those of its individual constituents. A metal that is normally very soft (malleable), such as aluminium, can be altered by alloying it with another soft metal, such as copper. Although both metals are very soft and ductile, the resulting aluminium alloy will have much greater strength. Adding a small amount of non-metallic carbon to iron trades its great ductility for the greater strength of an alloy called steel. Due to its very-high strength, but still substantial toughness, and its ability to be greatly altered by heat treatment, steel is one of the most useful and common alloys in modern use. By adding chromium to steel, its resistance to corrosion can be enhanced, creating stainless steel, while adding silicon will alter its electrical characteristics, producing silicon steel.
Some alloys, such as electrum—an alloy of silver and gold—occur naturally. Meteorites are sometimes made of naturally occurring alloys of iron and nickel, but are not native to the Earth. One of the first alloys made by humans was bronze, which is a mixture of the metals tin and copper. Bronze was an extremely useful alloy to the ancients, because it is much stronger and harder than either of its components. Steel was another common alloy. However, in ancient times, it could only be created as an accidental byproduct from the heating of iron ore in fires (smelting) during the manufacture of iron. Other ancient alloys include pewter, brass and pig iron. In the modern age, steel can be created in many forms. Carbon steel can be made by varying only the carbon content, producing soft alloys like mild steel or hard alloys like spring steel. Alloy steels can be made by adding other elements, such as chromium, molybdenum, vanadium or nickel, resulting in alloys such as high-speed steel or tool steel. Small amounts of manganese are usually alloyed with most modern steels because of its ability to remove unwanted impurities, like phosphorus, sulfur and oxygen, which can have detrimental effects on the alloy. However, most alloys were not created until the 1900s, such as various aluminium, titanium, nickel, and magnesium alloys. Some modern superalloys, such as incoloy, inconel, and hastelloy, may consist of a multitude of different elements.
An alloy is technically an impure metal, but when referring to alloys, the term "impurities" usually denotes undesirable elements. Such impurities are introduced from the base metals and alloying elements, but are removed during processing. For instance, sulfur is a common impurity in steel. Sulfur combines readily with iron to form iron sulfide, which is very brittle, creating weak spots in the steel. Lithium, sodium and calcium are common impurities in aluminium alloys, which can have adverse effects on the structural integrity of castings. Conversely, otherwise pure-metals that contain unwanted impurities are often called "impure metals" and are not usually referred to as alloys. Oxygen, present in the air, readily combines with most metals to form metal oxides; especially at higher temperatures encountered during alloying. Great care is often taken during the alloying process to remove excess impurities, using fluxes, chemical additives, or other methods of extractive metallurgy. Theory.
By adding another element to a metal, differences in the size of the atoms create internal stresses in the lattice of the metallic crystals; stresses that often enhance its properties. For example, the combination of carbon with iron produces steel, which is stronger than iron, its primary element. The electrical and thermal conductivity of alloys is usually lower than that of the pure metals. The physical properties, such as density, reactivity, Young's modulus of an alloy may not differ greatly from those of its base element, but engineering properties such as tensile strength, ductility, and shear strength may be substantially different from those of the constituent materials. This is sometimes a result of the sizes of the atoms in the alloy, because larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit marked differences in behavior even when small amounts of one element are present. For example, impurities in semiconducting ferromagnetic alloys lead to different properties, as first predicted by White, Hogan, Suhl, Tian Abrie and Nakamura.
Unlike pure metals, most alloys do not have a single melting point, but a melting range during which the material is a mixture of solid and liquid phases (a slush). The temperature at which melting begins is called the solidus, and the temperature when melting is just complete is called the liquidus. For many alloys there is a particular alloy proportion (in some cases more than one), called either a eutectic mixture or a peritectic composition, which gives the alloy a unique and low melting point, and no liquid/solid slush transition. Heat treatment. Alloying elements are added to a base metal, to induce hardness, toughness, ductility, or other desired properties. Most metals and alloys can be work hardened by creating defects in their crystal structure. These defects are created during plastic deformation by hammering, bending, extruding, et cetera, and are permanent unless the metal is recrystallized. Otherwise, some alloys can also have their properties altered by heat treatment. Nearly all metals can be softened by annealing, which recrystallizes the alloy and repairs the defects, but not as many can be hardened by controlled heating and cooling. Many alloys of aluminium, copper, magnesium, titanium, and nickel can be strengthened to some degree by some method of heat treatment, but few respond to this to the same degree as does steel.
The base metal iron of the iron-carbon alloy known as steel, undergoes a change in the arrangement (allotropy) of the atoms of its crystal matrix at a certain temperature (usually between and , depending on carbon content). This allows the smaller carbon atoms to enter the interstices of the iron crystal. When this diffusion happens, the carbon atoms are said to be in "solution" in the iron, forming a particular single, homogeneous, crystalline phase called austenite. If the steel is cooled slowly, the carbon can diffuse out of the iron and it will gradually revert to its low temperature allotrope. During slow cooling, the carbon atoms will no longer be as soluble with the iron, and will be forced to precipitate out of solution, nucleating into a more concentrated form of iron carbide (Fe3C) in the spaces between the pure iron crystals. The steel then becomes heterogeneous, as it is formed of two phases, the iron-carbon phase called cementite (or carbide), and pure iron ferrite. Such a heat treatment produces a steel that is rather soft. If the steel is cooled quickly, however, the carbon atoms will not have time to diffuse and precipitate out as carbide, but will be trapped within the iron crystals. When rapidly cooled, a diffusionless (martensite) transformation occurs, in which the carbon atoms become trapped in solution. This causes the iron crystals to deform as the crystal structure tries to change to its low temperature state, leaving those crystals very hard but much less ductile (more brittle).
While the high strength of steel results when diffusion and precipitation is prevented (forming martensite), most heat-treatable alloys are precipitation hardening alloys, that depend on the diffusion of alloying elements to achieve their strength. When heated to form a solution and then cooled quickly, these alloys become much softer than normal, during the diffusionless transformation, but then harden as they age. The solutes in these alloys will precipitate over time, forming intermetallic phases, which are difficult to discern from the base metal. Unlike steel, in which the solid solution separates into different crystal phases (carbide and ferrite), precipitation hardening alloys form different phases within the same crystal. These intermetallic alloys appear homogeneous in crystal structure, but tend to behave heterogeneously, becoming hard and somewhat brittle. In 1906, precipitation hardening alloys were discovered by Alfred Wilm. Precipitation hardening alloys, such as certain alloys of aluminium, titanium, and copper, are heat-treatable alloys that soften when quenched (cooled quickly), and then harden over time. Wilm had been searching for a way to harden aluminium alloys for use in machine-gun cartridge cases. Knowing that aluminium-copper alloys were heat-treatable to some degree, Wilm tried quenching a ternary alloy of aluminium, copper, and the addition of magnesium, but was initially disappointed with the results. However, when Wilm retested it the next day he discovered that the alloy increased in hardness when left to age at room temperature, and far exceeded his expectations. Although an explanation for the phenomenon was not provided until 1919, duralumin was one of the first "age hardening" alloys used, becoming the primary building material for the first Zeppelins, and was soon followed by many others. Because they often exhibit a combination of high strength and low weight, these alloys became widely used in many forms of industry, including the construction of modern aircraft.
Mechanisms. When a molten metal is mixed with another substance, there are two mechanisms that can cause an alloy to form, called "atom exchange" and the "interstitial mechanism". The relative size of each element in the mix plays a primary role in determining which mechanism will occur. When the atoms are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a "substitutional alloy". Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms respectively. In the case of the interstitial mechanism, one atom is usually much smaller than the other and can not successfully substitute for the other type of atom in the crystals of the base metal. Instead, the smaller atoms become trapped in the interstitial sites between the atoms of the crystal matrix. This is referred to as an "interstitial alloy". Steel is an example of an interstitial alloy, because the very small carbon atoms fit into interstices of the iron matrix.
Stainless steel is an example of a combination of interstitial and substitutional alloys, because the carbon atoms fit into the interstices, but some of the iron atoms are substituted by nickel and chromium atoms. History and examples. Meteoric iron. The use of alloys by humans started with the use of meteoric iron, a naturally occurring alloy of nickel and iron. It is the main constituent of iron meteorites. As no metallurgic processes were used to separate iron from nickel, the alloy was used as it was. Meteoric iron could be forged from a red heat to make objects such as tools, weapons, and nails. In many cultures it was shaped by cold hammering into knives and arrowheads. They were often used as anvils. Meteoric iron was very rare and valuable, and difficult for ancient people to work. Bronze and brass.
Amalgams. Mercury has been smelted from cinnabar for thousands of years. Mercury dissolves many metals, such as gold, silver, and tin, to form amalgams (an alloy in a soft paste or liquid form at ambient temperature). Amalgams have been used since 200 BC in China for gilding objects such as armor and mirrors with precious metals. The ancient Romans often used mercury-tin amalgams for gilding their armor. The amalgam was applied as a paste and then heated until the mercury vaporized, leaving the gold, silver, or tin behind. Mercury was often used in mining, to extract precious metals like gold and silver from their ores. Precious metals. Many ancient civilizations alloyed metals for purely aesthetic purposes. In ancient Egypt and Mycenae, gold was often alloyed with copper to produce red-gold, or iron to produce a bright burgundy-gold. Gold was often found alloyed with silver or other metals to produce various types of colored gold. These metals were also used to strengthen each other, for more practical purposes. Copper was often added to silver to make sterling silver, increasing its strength for use in dishes, silverware, and other practical items. Quite often, precious metals were alloyed with less valuable substances as a means to deceive buyers. Around 250 BC, Archimedes was commissioned by the King of Syracuse to find a way to check the purity of the gold in a crown, leading to the famous bath-house shouting of "Eureka!" upon the discovery of Archimedes' principle.
Pewter. The term pewter covers a variety of alloys consisting primarily of tin. As a pure metal, tin is much too soft to use for most practical purposes. However, during the Bronze Age, tin was a rare metal in many parts of Europe and the Mediterranean, so it was often valued higher than gold. To make jewellery, cutlery, or other objects from tin, workers usually alloyed it with other metals to increase strength and hardness. These metals were typically lead, antimony, bismuth or copper. These solutes were sometimes added individually in varying amounts, or added together, making a wide variety of objects, ranging from practical items such as dishes, surgical tools, candlesticks or funnels, to decorative items like ear rings and hair clips. The earliest examples of pewter come from ancient Egypt, around 1450 BC. The use of pewter was widespread across Europe, from France to Norway and Britain (where most of the ancient tin was mined) to the Near East. The alloy was also used in China and the Far East, arriving in Japan around 800 AD, where it was used for making objects like ceremonial vessels, tea canisters, or chalices used in shinto shrines.
Iron. The first known smelting of iron began in Anatolia, around 1800 BC. Called the bloomery process, it produced very soft but ductile wrought iron. By 800 BC, iron-making technology had spread to Europe, arriving in Japan around 700 AD. Pig iron, a very hard but brittle alloy of iron and carbon, was being produced in China as early as 1200 BC, but did not arrive in Europe until the Middle Ages. Pig iron has a lower melting point than iron, and was used for making cast-iron. However, these metals found little practical use until the introduction of crucible steel around 300 BC. These steels were of poor quality, and the introduction of pattern welding, around the 1st century AD, sought to balance the extreme properties of the alloys by laminating them, to create a tougher metal. Around 700 AD, the Japanese began folding bloomery-steel and cast-iron in alternating layers to increase the strength of their swords, using clay fluxes to remove slag and impurities. This method of Japanese swordsmithing produced one of the purest steel-alloys of the ancient world.
While the use of iron started to become more widespread around 1200 BC, mainly because of interruptions in the trade routes for tin, the metal was much softer than bronze. However, very small amounts of steel, (an alloy of iron and around 1% carbon), was always a byproduct of the bloomery process. The ability to modify the hardness of steel by heat treatment had been known since 1100 BC, and the rare material was valued for the manufacture of tools and weapons. Because the ancients could not produce temperatures high enough to melt iron fully, the production of steel in decent quantities did not occur until the introduction of blister steel during the Middle Ages. This method introduced carbon by heating wrought iron in charcoal for long periods of time, but the absorption of carbon in this manner is extremely slow thus the penetration was not very deep, so the alloy was not homogeneous. In 1740, Benjamin Huntsman began melting blister steel in a crucible to even out the carbon content, creating the first process for the mass production of tool steel. Huntsman's process was used for manufacturing tool steel until the early 1900s.
The introduction of the blast furnace to Europe in the Middle Ages meant that people could produce pig iron in much higher volumes than wrought iron. Because pig iron could be melted, people began to develop processes to reduce carbon in liquid pig iron to create steel. Puddling had been used in China since the first century, and was introduced in Europe during the 1700s, where molten pig iron was stirred while exposed to the air, to remove the carbon by oxidation. In 1858, Henry Bessemer developed a process of steel-making by blowing hot air through liquid pig iron to reduce the carbon content. The Bessemer process led to the first large scale manufacture of steel. Steel is an alloy of iron and carbon, but the term "alloy steel" usually only refers to steels that contain other elements— like vanadium, molybdenum, or cobalt—in amounts sufficient to alter the properties of the base steel. Since ancient times, when steel was used primarily for tools and weapons, the methods of producing and working the metal were often closely guarded secrets. Even long after the Age of Enlightenment, the steel industry was very competitive and manufacturers went through great lengths to keep their processes confidential, resisting any attempts to scientifically analyze the material for fear it would reveal their methods. For example, the people of Sheffield, a center of steel production in England, were known to routinely bar visitors and tourists from entering town to deter industrial espionage. Thus, almost no metallurgical information existed about steel until 1860. Because of this lack of understanding, steel was not generally considered an alloy until the decades between 1930 and 1970 (primarily due to the work of scientists like William Chandler Roberts-Austen, Adolf Martens, and Edgar Bain), so "alloy steel" became the popular term for ternary and quaternary steel-alloys.
After Benjamin Huntsman developed his crucible steel in 1740, he began experimenting with the addition of elements like manganese (in the form of a high-manganese pig-iron called "spiegeleisen"), which helped remove impurities such as phosphorus and oxygen; a process adopted by Bessemer and still used in modern steels (albeit in concentrations low enough to still be considered carbon steel). Afterward, many people began experimenting with various alloys of steel without much success. However, in 1882, Robert Hadfield, being a pioneer in steel metallurgy, took an interest and produced a steel alloy containing around 12% manganese. Called mangalloy, it exhibited extreme hardness and toughness, becoming the first commercially viable alloy-steel. Afterward, he created silicon steel, launching the search for other possible alloys of steel. Robert Forester Mushet found that by adding tungsten to steel it could produce a very hard edge that would resist losing its hardness at high temperatures. "R. Mushet's special steel" (RMS) became the first high-speed steel. Mushet's steel was quickly replaced by tungsten carbide steel, developed by Taylor and White in 1900, in which they doubled the tungsten content and added small amounts of chromium and vanadium, producing a superior steel for use in lathes and machining tools. In 1903, the Wright brothers used a chromium-nickel steel to make the crankshaft for their airplane engine, while in 1908 Henry Ford began using vanadium steels for parts like crankshafts and valves in his Model T Ford, due to their higher strength and resistance to high temperatures. In 1912, the Krupp Ironworks in Germany developed a rust-resistant steel by adding 21% chromium and 7% nickel, producing the first stainless steel.
Others. Due to their high reactivity, most metals were not discovered until the 19th century. A method for extracting aluminium from bauxite was proposed by Humphry Davy in 1807, using an electric arc. Although his attempts were unsuccessful, by 1855 the first sales of pure aluminium reached the market. However, as extractive metallurgy was still in its infancy, most aluminium extraction-processes produced unintended alloys contaminated with other elements found in the ore; the most abundant of which was copper. These aluminium-copper alloys (at the time termed "aluminum bronze") preceded pure aluminium, offering greater strength and hardness over the soft, pure metal, and to a slight degree were found to be heat treatable. However, due to their softness and limited hardenability these alloys found little practical use, and were more of a novelty, until the Wright brothers used an aluminium alloy to construct the first airplane engine in 1903. During the time between 1865 and 1910, processes for extracting many other metals were discovered, such as chromium, vanadium, tungsten, iridium, cobalt, and molybdenum, and various alloys were developed.
Prior to 1910, research mainly consisted of private individuals tinkering in their own laboratories. However, as the aircraft and automotive industries began growing, research into alloys became an industrial effort in the years following 1910, as new magnesium alloys were developed for pistons and wheels in cars, and pot metal for levers and knobs, and aluminium alloys developed for airframes and aircraft skins were put into use. The Doehler Die Casting Co. of Toledo, Ohio were known for the production of "Brastil", a high tensile corrosion resistant bronze alloy.
Artistic revolution Throughout history, forms of art have gone through periodic abrupt changes called artistic revolutions. Movements have come to an end to be replaced by a new movement markedly different in striking ways. Scientific and technological. 1 Not all artistic revolutions were political. Sometimes, science and technological innovations have brought about unforeseen transformations in the works of artists. The stylistic revolution known as Impressionism, by painters eager to more accurately capture the changing colors of light and shadow, is inseparable from discoveries and inventions in the mid-19th century in which the style was born. Michel Eugène Chevreul, a French chemist hired as director of dyes at a French tapestry works, began to investigate the optical nature of color in order to improve color in fabrics. Chevreul realized It was the eye, and not the dye, that had the greatest influence on color, and from this, he revolutionized color theory by grasping what came to be called the law of simultaneous contrast: that colors mutually influence one another when juxtaposed, each imposing its own complementary color on the other. The French painter Eugène Delacroix, who had been experimenting with what he called broken tones, embraced Chevreul's book, "The Law of Contrast of Color" (1839) with its explanations of how juxtaposed colors can enhance or diminish each other, and his exploration of all the visible colors of the spectrum. Inspired by Chevreul's 1839 treatise, Delacroix passed his enthusiasm on to the young artists who were inspired by him. It was Chevreul who led the Impressionists to grasp that they should apply separate brushstrokes of pure color to a canvas and allow the viewer's eye to combine them optically.
They were aided greatly in this by innovations in oil paint itself. Since the Renaissance, painters had to grind pigment, add oil and thus create their own paints; these time-consuming paints also quickly dried out, making studio painting a necessity for large works, and limiting painters to mix one or two colors at a time and fill in an entire area using just that one color before it dried out. In 1841, a little-known American painter named John G. Rand invented a simple improvement without which the Impressionist movement could not have occurred: the small, flexible tin tube with removable cap in which oil paints could be stored. Oil paints kept in such tubes stayed moist, usable, and portable. For the first time since the Renaissance, painters were not trapped by the time frame of how quickly oil paint dried. Paints in tubes could be easily loaded up and carried out into the real world, to directly observe the play of color and natural light, in shadow and movement, to paint in the moment. Selling the oil paint in tubes also brought about the arrival of dazzling new pigments - chrome yellow, cadmium blue - invented by 19th century industrial chemists. The tubes freed the Impressionists to paint quickly, and across an entire canvas, rather than carefully delineated single-color sections at a time; in short, to sketch directly in oil - racing across the canvas in every color that came to hand and thus inspiring their name of "impressionists" - since such speedy, bold brushwork and dabs of separate colors made contemporary critics think their paintings were mere impressions, not finished paintings, which were to have no visible brush marks at all, seamless under layers of varnish.
Pierre-Auguste Renoir said, “Without colors in tubes, there would be no Cézanne, no Monet, no Pissarro, and no Impressionism.” Finally, the careful, hyper-realistic techniques of French neo-classicism were seen as stiff and lifeless when compared to the remarkable new vision of the world as seen through the new invention of photography by the mid-1850s. It was not merely that the increasing ability of this new invention, particularly by the French inventor Daguerre, made the realism of the painted image redundant as he deliberately competed in the Paris diorama with large-scale historical paintings. The neo-classical subject matter, limited by Academic tradition to Greek and Roman legends, historical battles and Biblical stories, seemed oppressively clichéd and limited to artists eager to explore the actual world in front of their own eyes revealed by the camera - daily life, candid groupings of everyday people doing simple things, Paris itself, rural landscapes and most particularly the play of captured light - not the imaginary lionizing of unseen past events. Early photographs influenced Impressionist style by its use of asymmetry, cropping and most obviously the blurring of motion, as inadvertently captured in the very slow speeds of early photography.
Edgar Degas, Claude Monet, Pierre-Auguste Renoir - in their framing, use of color, light and shadow, subject matter - put these innovations to work to create a new language of visual beauty and meaning. Faking revolution: the CIA and Abstract Expressionism. Their initial break with realism into an exploration of light, color and the nature of paint was brought to an ultimate conclusion by the abstract expressionists who broke away from recognizable content of any kind into works of pure shape, color and painterliness which emerged at the end of the Second World War. At first thought of as primitive, inept works - as in "my four year old could do that - these works were misunderstood and neglected until given critical and support by the rise of art journalists and critics who championed their work in the 1940s and 50s, expressing the power of such work in aesthetic terms the artists themselves seldom used, or even understood. Jackson Pollock who pioneered splatter painting, dispensing with a paint brush altogether, soon became lionized as the angry young man in a large spread in "Life" magazine.
In fact, in a deliberate, secret and successful effort to separate artistic revolutions from political ones, abstract expressionists like Pollock, Robert Motherwell, Willem de Kooning and Mark Rothko, while seemingly difficult, pathbreaking artists, were in fact secretly supported for twenty years by the Central Intelligence Agency (CIA) in a Cold War policy begun in 1947 to prove that the United States could foster more artistic freedom than the Soviet bloc. "It was recognized that Abstract Expressionism was the kind of art that made Socialist Realism look even more stylized and rigid and confined than it was," said former CIA case worker Donald Jameson, who finally broke the silence on this program in 1995. Ironically, the covert CIA support for these radical works was required because an attempt to use government funds for a European tour of these works during the Truman administration led to a public uproar in conservative McCarthy-era America, with Truman famously remarking, "If that's art, I'm a Hottentot." Thus, the program was hidden under the guise of fabricated foundations and the support of wealthy patrons who were actually using CIA funds, not their own, to sponsor traveling exhibitions of American abstract expressionists all over the world, publish books and articles praising them and to purchase and exhibit abstract expressionist works in major American and British museums. Thomas Braden, in charge of these cultural programs for the CIA, in the early years of the Cold War, had formerly been executive secretary of the Museum of Modern Art, America's leading institution for 20th century art and the charges of collusion between the two echoed for many years after this program was revealed, though most of the artists involved had no idea they were being used in this way and were furious when they found out.
Agrarianism Agrarianism is a social and political philosophy that advocates for rural development, a rural agricultural lifestyle, family farming, widespread property ownership, and political decentralization. Those who adhere to agrarianism tend to value traditional forms of local community over urban modernity. Agrarian political parties sometimes aim to support the rights and sustainability of small farmers and poor peasants against the wealthy, powerful and famous in society. Philosophy. Some scholars suggest that agrarianism espouses the superiority of rural society to urban society and the independent farmer as superior to the paid worker, and sees farming as a way of life that can shape the ideal social values. It stresses the superiority of a simpler rural life in comparison to the complexity of urban life. For example, M. Thomas Inge defines agrarianism by the following basic tenets: History. The philosophical roots of agrarianism include European and Chinese philosophers. The Chinese school of Agriculturalism (农家/農家) was a philosophy that advocated peasant utopian communalism and egalitarianism. In societies influenced by Confucianism that had as its foundation that humans are innately good, the farmer was considered an esteemed productive member of society, but merchants who made money were looked down upon. That influenced European intellectuals like François Quesnay, an avid Confucianist and advocate of China's agrarian policies, in forming the French agrarian philosophy of physiocracy. The physiocrats, along with the ideas of John Locke and the Romantic Era, formed the basis of modern European and American agrarianism.
Types of agrarianism. Jeffersonian democracy. The United States president Thomas Jefferson was an agrarian who based his ideas about the budding American democracy around the notion that farmers are "the most valuable citizens" and the truest republicans. Jefferson and his support base were committed to American republicanism, which they saw as being in opposition to monarchy, aristocracy, clericalism and corruption, and which prioritized morality and virtue, exemplified by the "yeoman farmer", "planters", and the "plain folk". In praising the rural farmfolk, the Jeffersonians felt that financiers, bankers and industrialists created "cesspools of corruption" in the cities and should thus be avoided. The Jeffersonians sought to align the American economy more with agriculture than industry. Part of their motive to do so was Jefferson's fear that the over-industrialization of America would create a class of wage slaves who relied on their employers for income and sustenance. In turn, these workers would cease to be independent voters as their vote could be manipulated by said employers. To counter this, Jefferson introduced, as scholar Clay Jenkinson noted, "a graduated income tax that would serve as a disincentive to vast accumulations of wealth and would make funds available for some sort of benign redistribution downward" and tariffs on imported articles, which were mainly purchased by the wealthy. In 1811, Jefferson, writing to a friend, explained: "these revenues will be levied entirely on the rich... . the rich alone use imported articles, and on these alone the whole taxes of the general government are levied. the poor man ... pays not a farthing of tax to the general government, but on his salt."
There is general agreement that the substantial United States' federal policy of offering land grants (such as thousands of gifts of land to veterans) had a positive impact on economic development in the 19th century. Agrarian socialism. Agrarian socialism is a form of agrarianism that is anti-capitalist in nature and seeks to introduce socialist economic systems in their stead. Zapatismo. Notable agrarian socialists include Emiliano Zapata who was a leading figure in the Mexican Revolution. As part of the Liberation Army of the South, his group of revolutionaries fought on behalf of the Mexican peasants, whom they saw as exploited by the landowning classes. Zapata published the Plan of Ayala, which called for significant land reforms and land redistribution in Mexico as part of the revolution. Zapata was killed and his forces crushed over the course of the Revolution, but his political ideas lived on in the form of Zapatismo. Zapatismo would form the basis for neozapatismo, the ideology of the Zapatista Army of National Liberation. Known as "Ejército Zapatista de Liberación Nacional" or EZLN in Spanish, EZLN is a far-left libertarian socialist political and militant group that emerged in the state of Chiapas in southmost Mexico in 1994. EZLN and Neozapatismo, as explicit in their name, seek to revive the agrarian socialist movement of Zapata, but fuse it with new elements such as a commitment to indigenous rights and community-level decision making.
Subcommander Marcos, a leading member of the movement, argues that the peoples' collective ownership of the land was and is the basis for all subsequent developments the movement sought to create: ...When the land became property of the peasants ... when the land passed into the hands of those who work it ... [This was] the starting point for advances in government, health, education, housing, nutrition, women's participation, trade, culture, communication, and information ...[it was] recovering the means of production, in this case, the land, animals, and machines that were in the hands of large property owners." Maoism. Maoism, the far-left ideology of Mao Zedong and his followers, places a heavy emphasis on the role of peasants in its goals. In contrast to other Marxist schools of thought which normally seek to acquire the support of urban workers, Maoism sees the peasantry as key. Believing that "political power grows out of the barrel of a gun", Maoism saw the Chinese Peasantry as the prime source for a Marxist vanguard because it possessed two qualities: (i) they were poor, and (ii) they were a political blank slate; in Mao's words, "A clean sheet of paper has no blotches, and so the newest and most beautiful words can be written on it". During the Chinese Civil War and the Second Sino-Japanese War, Mao and the Chinese Communist Party made extensive use of peasants and rural bases in their military tactics, often eschewing the cities.
Following the eventual victory of the Communist Party in both wars, the countryside and how it should be run remained a focus for Mao. In 1958, Mao launched the Great Leap Forward, a social and economic campaign which, amongst other things, altered many aspects of rural Chinese life. It introduced mandatory collective farming and forced the peasantry to organize itself into communal living units which were known as people's communes. These communes, which consisted of 5,000 people on average, were expected to meet high production quotas while the peasants who lived on them adapted to this radically new way of life. The communes were run as co-operatives where wages and money were replaced by work points. Peasants who criticised this new system were persecuted as "rightists" and "counter-revolutionaries". Leaving the communes was forbidden and escaping from them was difficult or impossible, and those who attempted it were subjected to party-orchestrated "public struggle sessions," which further jeopardized their survival. These public criticism sessions were often used to intimidate the peasants into obeying local officials and they often devolved into little more than public beatings.
On the communes, experiments were conducted in order to find new methods of planting crops, efforts were made to construct new irrigation systems on a massive scale, and the communes were all encouraged to produce steel backyard furnaces as part of an effort to increase steel production. However, following the Anti-Rightist Campaign, Mao had instilled a mass distrust of intellectuals into China, and thus engineers often were not consulted with regard to the new irrigation systems and the wisdom of asking untrained peasants to produce good quality steel from scrap iron was not publicly questioned. Similarly, the experimentation with the crops did not produce results. In addition to this the Four Pests Campaign was launched, in which the peasants were called upon to destroy sparrows and other wild birds that ate crop seeds, in order to protect fields. Pest birds were shot down or scared away from landing until they dropped from exhaustion. This campaign resulted in an ecological disaster that saw an explosion of the vermin population, especially crop-eating insects, which was consequently not in danger of being killed by predators.
None of these new systems were working, but local leaders did not dare to state this, instead, they falsified reports so as not to be punished for failing to meet the quotas. In many cases they stated that they were greatly exceeding their quotas, and in turn, the Chinese state developed a completely false sense of success with regard to the commune system. All of this culminated in the Great Chinese Famine, which began in 1959, lasted 3 years, and saw an estimated 15 to 30 million Chinese people die. A combination of bad weather and the new, failed farming techniques that were introduced by the state led to massive shortages of food. By 1962, the Great Leap Forward was declared to be at an end. In the late 1960s and early 1970s, Mao once again radically altered life in rural China with the launching of the Down to the Countryside Movement. As a response to the Great Chinese Famine, the Chinese President Liu Shaoqi began "sending down" urban youths to rural China in order to recover its population losses and alleviate overcrowding in the cities.
As a response to the Great Chinese Famine, the Chinese President Liu Shaoqi began "sending down" urban youths to rural China in order to recover its population losses and alleviate overcrowding in the cities. However, Mao turned the practice into a political crusade, declaring that the sending down would strip the youth of any bourgeois tendencies by forcing them to learn from the unprivileged rural peasants. In reality, it was the Communist Party's attempt to reign in the Red Guards, who had become uncontrollable during the course of the Cultural Revolution. 10% of the 1970 urban population of China was sent out to remote rural villages, often in Inner Mongolia. The villages, which were still poorly recovering from the effects of the Great Chinese Famine, did not have the excess resources that were needed to support the newcomers. Furthermore, the so-called "sent-down youth" had no agricultural experience and as a result, they were unaccustomed to the harsh lifestyle that existed in the countryside, and their unskilled labor in the villages provided little benefit to the agricultural sector.
Furthermore, the so-called "sent-down youth" had no agricultural experience and as a result, they were unaccustomed to the harsh lifestyle that existed in the countryside, and their unskilled labor in the villages provided little benefit to the agricultural sector. As a result, many of the sent-down youth died in the countryside. The relocation of the youths was originally intended to be permanent, but by the end of the Cultural Revolution, the Communist Party relented and some of those who had the capacity to return to the cities were allowed to do so. In imitation of Mao's policies, the Khmer Rouge of Cambodia (who were heavily funded and supported by the People's Republic of China) created their own version of the Great Leap Forward which was known as "Maha Lout Ploh". With the Great Leap Forward as its model, it had similarly disastrous effects, contributing to what is now known as the Cambodian genocide. As a part of the Maha Lout Ploh, the Khmer Rouge sought to create an entirely agrarian socialist society by forcibly relocating 100,000 people to move from Cambodia's cities into newly created communes.
As a part of the Maha Lout Ploh, the Khmer Rouge sought to create an entirely agrarian socialist society by forcibly relocating 100,000 people to move from Cambodia's cities into newly created communes. The Khmer Rouge leader, Pol Pot sought to "purify" the country by setting it back to "Year Zero", freeing it from "corrupting influences". Besides trying to completely de-urbanize Cambodia, ethnic minorities were slaughtered along with anyone else who was suspected of being a "reactionary" or a member of the "bourgeoisie", to the point that wearing glasses was seen as grounds for execution. The killings were only brought to an end when Cambodia was invaded by the neighboring socialist nation of Vietnam, whose army toppled the Khmer Rouge. However, with Cambodia's entire society and economy in disarray, including its agricultural sector, the country still plunged into renewed famine due to vast food shortages. However, as international journalists began to report on the situation and send images of it out to the world, a massive international response was provoked, leading to one of the most concentrated relief efforts of its time.
Notable agrarian parties. Peasant parties first appeared across Eastern Europe between 1860 and 1910, when commercialized agriculture and world market forces disrupted traditional rural society, and the railway and growing literacy facilitated the work of roving organizers. Agrarian parties advocated land reforms to redistribute land on large estates among those who work it. They also wanted village cooperatives to keep the profit from crop sales in local hands and credit institutions to underwrite needed improvements. Many peasant parties were also nationalist parties because peasants often worked their land for the benefit of landlords of different ethnicity. Peasant parties rarely had any power before World War I but some became influential in the interwar era, especially in Bulgaria and Czechoslovakia. For a while, in the 1920s and the 1930s, there was a Green International (International Agrarian Bureau) based on the peasant parties in Bulgaria, Czechoslovakia, Poland, and Serbia. It functioned primarily as an information center that spread the ideas of agrarianism and combating socialism on the left and landlords on the right and never launched any significant activities.
Europe. Bulgaria. In Bulgaria, the Bulgarian Agrarian National Union (BZNS) was organized in 1899 to resist taxes and build cooperatives. BZNS came to power in 1919 and introduced many economic, social, and legal reforms. However, conservative forces crushed BZNS in a 1923 coup and assassinated its leader, Aleksandar Stamboliyski (1879–1923). BZNS was made into a communist puppet group until 1989, when it reorganized as a genuine party. Czechoslovakia. In Czechoslovakia, the Republican Party of Agricultural and Smallholder People often shared power in parliament as a partner in the five-party pětka coalition. The party's leader, Antonín Švehla (1873–1933), was prime minister several times. It was consistently the strongest party, forming and dominating coalitions. It moved beyond its original agrarian base to reach middle-class voters. The party was banned by the National Front after the Second World War. France. In France, the Hunting, Fishing, Nature, Tradition party is a moderate conservative, agrarian party, reaching a peak of 4.23% in the 2002 French presidential election. It would later on become affiliated to France's main conservative party, Union for a Popular Movement. More recently, the Resistons! movement of Jean Lassalle espoused agrarianism.
Hungary. In Hungary, the first major agrarian party, the small-holders party was founded in 1908. The party became part of the government in the 1920s but lost influence in the government. A new party, the Independent Smallholders, Agrarian Workers and Civic Party was established in 1930 with a more radical program representing larger scale land redistribution initiatives. They implemented this program together with the other coalition parties after WWII. However, after 1949 the party was outlawed when a one-party system was introduced. They became part of the government again 1990–1994, and 1998–2002 after which they lost political support. The ruling Fidesz party has an agrarian faction, and promotes agrarian interest since 2010 with the emphasis now placed on supporting larger family farms versus small-holders. Ireland. In the late 19th century, the Irish National Land League aimed to abolish landlordism in Ireland and enable tenant farmers to own the land they worked on. The "Land War" of 1878–1909 led to the Irish Land Acts, ending absentee landlords and ground rent and redistributing land among peasant farmers.
Post-independence, the Farmers' Party operated in the Irish Free State from 1922, folding into the National Centre Party in 1932. It was mostly supported by wealthy farmers in the east of Ireland. Clann na Talmhan (Family of the Land; also called the "National Agricultural Party") was founded in 1938. They focused more on the poor smallholders of the west, supporting land reclamation, afforestation, social democracy and rates reform. They formed part of the governing coalition of the Government of the 13th Dáil and Government of the 15th Dáil. Economic improvement in the 1960s saw farmers vote for other parties and Clann na Talmhan disbanded in 1965. Kazakhstan. In Kazakhstan, the Peasants' Union, originally a communist organization, was formed as one of first agrarian parties in independent Kazakhstan and would win four seats in the 1994 legislative election. The Agrarian Party of Kazakhstan, led by Romin Madinov, was founded in 1999, which favored the privatization of agricultural land, developments towards rural infrastructure, as well as changes in the tax system in agrarian economy. The party would go on to win three Mäjilis seats in the 1999 legislative election and eventually unite with the Civic Party of Kazakhstan to form the pro-government Agrarian-Industrial Union of Workers (AIST) bloc that would be chaired by Madinov for the 2004 legislative election, with the AIST bloc winning 11 seats in the Mäjilis. From there, the bloc remained short-lived as it would merge with the ruling Nur Otan party in 2006.
Several other parties in Kazakhstan over the years have embraced agrarian policies in their programs in an effort to appeal towards a large rural Kazakh demographic base, which included Amanat, ADAL, and Respublica. Since late 2000s, the "Auyl" People's Democratic Patriotic Party remains the largest and most influential agrarian-oriented party in Kazakhstan, as its presidential candidate Jiguli Dairabaev had become the second-place frontrunner in the 2022 presidential election after sweeping 3.4% of the vote. In the 2023 legislative election, the Auyl party for the first time was represented the parliament after winning nine seats in the lower chamber Mäjilis. The party raises rural issues in regard to decaying villages, rural development and the agro-industrial complex, the issues of social security of the rural population, and has consistently opposed the ongoing rural flight in Kazakhstan. Latvia. In Latvia, the Union of Greens and Farmers is supportive of traditional small farms and perceives them as more environmentally friendly than large-scale farming: Nature is threatened by development, while small farms are threatened by large industrial-scale farms.
Lithuania. In Lithuania, the government led by the Lithuanian Farmers and Greens Union was in power between 2016 and 2020. Poland. In Poland, the Polish People's Party ("Polskie Stronnictwo Ludowe", PSL) traces its tradition to an agrarian party in Austro-Hungarian-controlled Galician Poland. After the fall of the communist regime, PSL's biggest success came in 1993 elections, where it won 132 out of 460 parliamentary seats. Since then, PSL's support has steadily declined, until 2019, when they formed Polish Coalition with an anti-establishment, direct democracy Kukiz'15 party, and managed to get 8.5% of popular vote. Moreover, PSL tends to get much better results in local elections. In 2014 elections they have managed to get 23.88% of votes. The right-wing Law and Justice party has also become supportive of agrarian policies in recent years and polls show that most of their support comes from rural areas. AGROunia resembles the features of agrarianism. Romania. In Romania, older party parties from Transylvania, Moldavia, and Wallachia merged to become the National Peasants' Party (PNȚ) in 1926. Iuliu Maniu (1873–1953) was a prime minister with an agrarian cabinet from 1928 to 1930 and briefly in 1932–1933, but the Great Depression made proposed reforms impossible. The communist administration dissolved the party in 1947 (along with other historical parties such as the National Liberal Party), but it reformed in 1989 after they fell from power.
The reformed party, which also incorporated elements of Christian democracy in its ideology, governed Romania as part of the Romanian Democratic Convention (CDR) between 1996 and 2000. Serbia. In Serbia, Nikola Pašić (1845–1926) and his People's Radical Party dominated Serbian politics after 1903. The party also monopolized power in Yugoslavia from 1918 to 1929. During the dictatorship of the 1930s, the prime minister was from that party. Ukraine. In Ukraine, the Radical Party of Oleh Lyashko has promised to purify the country of oligarchs "with a pitchfork". The party advocates a number of traditional left-wing positions (a progressive tax structure, a ban on agricultural land sale and eliminating the illegal land market, a tenfold increase in budget spending on health, setting up primary health centres in every village) and mixes them with strong nationalist sentiments. United Kingdom. In land law the heyday of English, Irish (and thus Welsh) agrarianism was to 1603, led by the Tudor royal advisors, who sought to maintain a broad pool of agricultural commoners from which to draw military men, against the interests of larger landowners who sought enclosure (meaning complete private control of common land, over which by custom and common law lords of the manor always enjoyed minor rights). The heyday was eroded by hundreds of Acts of Parliament to expressly permit enclosure, chiefly from 1650 to the 1810s. Politicians standing strongly as reactionaries to this included the Levellers, those anti-industrialists (Luddites) going beyond opposing new weaving technology and, later, radicals such as William Cobbett.
A high level of net national or local self-sufficiency has a strong base in campaigns and movements. In the 19th century such empowered advocates included Peelites and most Conservatives. The 20th century saw the growth or start of influential non-governmental organisations, such as the National Farmers' Union of England and Wales, Campaign for Rural England, Friends of the Earth (EWNI) and of the England Wales, Scottish and Northern Irish political parties prefixed by and focussed on Green politics. The 21st century has seen decarbonisation already in electricity markets. Following protests and charitable lobbying local food has seen growing market share, sometimes backed by wording in public policy papers and manifestos. The UK has many sustainability-prioritising businesses, green charity campaigns, events and lobby groups ranging from espousing allotment gardens (hobby community farming) through to a clear policy of local food and/or self-sustainability models. Oceania. Australia. Historian F.K. Crowley finds that:
The National Party of Australia (formerly called the Country Party), from the 1920s to the 1970s, promulgated its version of agrarianism, which it called "countrymindedness". The goal was to enhance the status of the graziers (operators of big sheep stations) and small farmers and justified subsidies for them. New Zealand. The New Zealand Liberal Party aggressively promoted agrarianism in its heyday (1891–1912). The landed gentry and aristocracy ruled Britain at this time. New Zealand never had an aristocracy but its wealthy landowners largely controlled politics before 1891. The Liberal Party set out to change that by a policy it called "populism." Richard Seddon had proclaimed the goal as early as 1884: "It is the rich and the poor; it is the wealthy and the landowners against the middle and labouring classes. That, Sir, shows the real political position of New Zealand." The Liberal strategy was to create a large class of small landowning farmers who supported Liberal ideals. The Liberal government also established the basis of the later welfare state such as old age pensions and developed a system for settling industrial disputes, which was accepted by both employers and trade unions. In 1893, it extended voting rights to women, making New Zealand the first country in the world to do so.
To obtain land for farmers, the Liberal government from 1891 to 1911 purchased of Maori land. The government also purchased from large estate holders for subdivision and closer settlement by small farmers. The Advances to Settlers Act (1894) provided low-interest mortgages, and the agriculture department disseminated information on the best farming methods. The Liberals proclaimed success in forging an egalitarian, anti-monopoly land policy. The policy built up support for the Liberal Party in rural North Island electorates. By 1903, the Liberals were so dominant that there was no longer an organized opposition in Parliament. North America. The United States and Canada both saw a rise of Agrarian-oriented parties in the early twentieth century as economic troubles motivated farming communities to become politically active. It has been proposed that different responses to agrarian protest largely determined the course of power generated by these newly energized rural factions. According to Sociologist Barry Eidlin:"In the United States, Democrats adopted a co-optive response to farmer and labor protest, incorporating these constituencies into the New Deal coalition. In Canada, both mainstream parties adopted a coercive response, leaving these constituencies politically excluded and available for an independent left coalition."These reactions may have helped determine the outcome of agrarian power and political associations in the US and Canada.
United States of America. Kansas. Economic desperation experienced by farmers across the state of Kansas in the nineteenth century spurred the creation of The People's Party in 1890, and soon-after would gain control of the governor's office in 1892. This party, consisting of a mix of Democrats, Socialists, Populists, and Fusionists, would find itself buckling from internal conflict regarding the unlimited coinage of silver. The Populists permanently lost power in 1898. Oklahoma. Oklahoma farmers considered their political activity during the early twentieth century due to the outbreak of war, depressed crop prices, and an inhibited sense of progression towards owning their own farms. Tenancy had been reportedly as high as 55% in Oklahoma by 1910. These pressures saw agrarian counties in Oklahoma supporting Socialist policies and politics, with the Socialist platform proposing a deeply agrarian-radical platform:...the platform proposed a "Renters and Farmer's Program" which was strongly agrarian radical in its insistence upon various measures to put land into "The hands of the actual tillers of the soil." Although it did not propose to nationalize privately owned land,
with the Socialist platform proposing a deeply agrarian-radical platform:...the platform proposed a "Renters and Farmer's Program" which was strongly agrarian radical in its insistence upon various measures to put land into "The hands of the actual tillers of the soil." Although it did not propose to nationalize privately owned land, it did offer numerous plans to enlarge the state's public domain, from which land would be rented at prevailing share rents to tenants until they had paid rent equal to the land's value. The tenant and his children would have the right of occupancy and use, but the 'title' would remind in the 'commonwealth', an arrangement that might be aptly termed 'Socialist fee simple'. They proposed to exempt from taxation all farm dwellings, animals, and improvements up to the value of $1,000. The State Board of Agriculture would encourage 'co-operative societies' of farmers to make plans f or the purchase of land, seed, tools, and for preparing and selling produce.
and improvements up to the value of $1,000. The State Board of Agriculture would encourage 'co-operative societies' of farmers to make plans f or the purchase of land, seed, tools, and for preparing and selling produce. This agrarian-Socialist movement would be inhibited by voter suppression laws aimed at reducing the participation of voters of color, as well as national wartime policies intended to disrupt political elements considered subversive. This party would peak in power in 1914. Back-to-the-land movement. Agrarianism is similar to but not identical with the back-to-the-land movement. Agrarianism concentrates on the fundamental goods of the earth, on communities of more limited economic and political scale than in modern society, and on simple living, even when the shift involves questioning the "progressive" character of some recent social and economic developments. Thus, agrarianism is not industrial farming, with its specialization on products and industrial scale.
Angle In Euclidean geometry, an angle or plane angle is the figure formed by two rays, called the "sides" of the angle, sharing a common endpoint, called the "vertex" of the angle. Two intersecting curves may also define an angle, which is the angle of the rays lying tangent to the respective curves at their point of intersection. Angles are also formed by the intersection of two planes; these are called "dihedral angles". In any case, the resulting angle lies in a plane (spanned by the two rays or perpendicular to the line of plane-plane intersection). The magnitude of an angle is called an angular measure or simply "angle". This measure, for an ordinary angle, is often visualized or defined using the arc of a circle centered at the vertex and lying between the sides. Two different angles may have the same measure, as in an isosceles triangle. "Angle" also denotes the angular sector, the infinite region of the plane bounded by the sides of an angle. "Angle of rotation" is a measure conventionally defined as the ratio of a circular arc length to its radius, and may be a negative number; the arc is centered at the center of the rotation and delimited by any other point and its image after the rotation.
History and etymology. The word "angle" comes from the Latin word , meaning "corner". Cognate words include the Greek () meaning "crooked, curved" and the English word "ankle". Both are connected with the Proto-Indo-European root "*ank-", meaning "to bend" or "bow". Euclid defines a plane angle as the inclination to each other, in a plane, of two lines that meet each other and do not lie straight with respect to each other. According to the Neoplatonic metaphysician Proclus, an angle must be either a quality, a quantity, or a relationship. The first concept, angle as quality, was used by Eudemus of Rhodes, who regarded an angle as a deviation from a straight line; the second, angle as quantity, by Carpus of Antioch, who regarded it as the interval or space between the intersecting lines; Euclid adopted the third: angle as a relationship. Identifying angles. In mathematical expressions, it is common to use Greek letters (α, β, γ, θ, φ, . . . ) as variables denoting the size of some angle (the symbol is typically not used for this purpose to avoid confusion with the constant denoted by that symbol). Lower case Roman letters ("a", "b", "c", . . . ) are also used. In contexts where this is not confusing, an angle may be denoted by the upper case Roman letter denoting its vertex. See the figures in this article for examples.
The three defining points may also identify angles in geometric figures. For example, the angle with vertex A formed by the rays AB and AC (that is, the half-lines from point A through points B and C) is denoted or formula_1. Where there is no risk of confusion, the angle may sometimes be referred to by a single vertex alone (in this case, "angle A"). In other ways, an angle denoted as, say, might refer to any of four angles: the clockwise angle from B to C about A, the anticlockwise angle from B to C about A, the clockwise angle from C to B about A, or the anticlockwise angle from C to B about A, where the direction in which the angle is measured determines its sign (see "). However, in many geometrical situations, it is evident from the context that the positive angle less than or equal to 180 degrees is meant, and in these cases, no ambiguity arises. Otherwise, to avoid ambiguity, specific conventions may be adopted so that, for instance, always refers to the anticlockwise (positive) angle from B to C about A and the anticlockwise (positive) angle from C to B about A.
Types. Individual angles. There is some common terminology for angles, whose measure is always non-negative (see "): The names, intervals, and measuring units are shown in the table below: Vertical and angle pairs. When two straight lines intersect at a point, four angles are formed. Pairwise, these angles are named according to their location relative to each other. A transversal is a line that intersects a pair of (often parallel) lines and is associated with "exterior angles", "interior angles", "alternate exterior angles", "alternate interior angles", "corresponding angles", and "consecutive interior angles". Combining angle pairs. The angle addition postulate states that if B is in the interior of angle AOC, then formula_2 I.e., the measure of the angle AOC is the sum of the measure of angle AOB and the measure of angle BOC. Three special angle pairs involve the summation of angles: Measuring angles. The size of a geometric angle is usually characterized by the magnitude of the smallest rotation that maps one of the rays into the other. Angles of the same size are said to be "equal" "congruent" or "equal in measure".
In some contexts, such as identifying a point on a circle or describing the "orientation" of an object in two dimensions relative to a reference orientation, angles that differ by an exact multiple of a full turn are effectively equivalent. In other contexts, such as identifying a point on a spiral curve or describing an object's "cumulative rotation" in two dimensions relative to a reference orientation, angles that differ by a non-zero multiple of a full turn are not equivalent. To measure an angle θ, a circular arc centered at the vertex of the angle is drawn, e.g., with a pair of compasses. The ratio of the length s of the arc by the radius r of the circle is the number of radians in the angle: formula_3 Conventionally, in mathematics and the SI, the radian is treated as being equal to the dimensionless unit 1, thus being normally omitted. The angle expressed by another angular unit may then be obtained by multiplying the angle by a suitable conversion constant of the form , where "k" is the measure of a complete turn expressed in the chosen unit (for example, for degrees or 400 grad for gradians):
formula_4 The value of thus defined is independent of the size of the circle: if the length of the radius is changed, then the arc length changes in the same proportion, so the ratio "s"/"r" is unaltered. Units. Throughout history, angles have been measured in various units. These are known as angular units, with the most contemporary units being the degree ( ° ), the radian (rad), and the gradian (grad), though many others have been used throughout history. Most units of angular measurement are defined such that one turn (i.e., the angle subtended by the circumference of a circle at its centre) is equal to "n" units, for some whole number "n". Two exceptions are the radian (and its decimal submultiples) and the diameter part. In the International System of Quantities, an angle is defined as a dimensionless quantity, and in particular, the radian unit is dimensionless. This convention impacts how angles are treated in dimensional analysis. The following table lists some units used to represent angles. Signed angles.
It is frequently helpful to impose a convention that allows positive and negative angular values to represent orientations and/or rotations in opposite directions or "sense" relative to some reference. In a two-dimensional Cartesian coordinate system, an angle is typically defined by its two sides, with its vertex at the origin. The "initial side" is on the positive x-axis, while the other side or "terminal side" is defined by the measure from the initial side in radians, degrees, or turns, with "positive angles" representing rotations toward the positive y-axis and "negative angles" representing rotations toward the negative "y"-axis. When Cartesian coordinates are represented by "standard position", defined by the "x"-axis rightward and the "y"-axis upward, positive rotations are anticlockwise, and negative cycles are clockwise. In many contexts, an angle of −"θ" is effectively equivalent to an angle of "one full turn minus "θ"". For example, an orientation represented as −45° is effectively equal to an orientation defined as 360° − 45° or 315°. Although the final position is the same, a physical rotation (movement) of −45° is not the same as a rotation of 315° (for example, the rotation of a person holding a broom resting on a dusty floor would leave visually different traces of swept regions on the floor).
In three-dimensional geometry, "clockwise" and "anticlockwise" have no absolute meaning, so the direction of positive and negative angles must be defined in terms of an orientation, which is typically determined by a normal vector passing through the angle's vertex and perpendicular to the plane in which the rays of the angle lie. In navigation, bearings or azimuth are measured relative to north. By convention, viewed from above, bearing angles are positive clockwise, so a bearing of 45° corresponds to a north-east orientation. Negative bearings are not used in navigation, so a north-west orientation corresponds to a bearing of 315°. Related quantities. For an angular unit, it is definitional that the angle addition postulate holds. Some quantities related to angles where the angle addition postulate does not hold include: Angles between curves. The angle between a line and a curve (mixed angle) or between two intersecting curves (curvilinear angle) is defined to be the angle between the tangents at the point of intersection. Various names (now rarely, if ever, used) have been given to particular cases:—"amphicyrtic" (Gr. , on both sides, κυρτός, convex) or "cissoidal" (Gr. κισσός, ivy), biconvex; "xystroidal" or "sistroidal" (Gr. ξυστρίς, a tool for scraping), concavo-convex; "amphicoelic" (Gr. κοίλη, a hollow) or "angulus lunularis", biconcave.
Bisecting and trisecting angles. The ancient Greek mathematicians knew how to bisect an angle (divide it into two angles of equal measure) using only a compass and straightedge but could only trisect certain angles. In 1837, Pierre Wantzel showed that this construction could not be performed for most angles. Dot product and generalisations. In the Euclidean space, the angle "θ" between two Euclidean vectors u and v is related to their dot product and their lengths by the formula formula_5 This formula supplies an easy method to find the angle between two planes (or curved surfaces) from their normal vectors and between skew lines from their vector equations. Inner product. To define angles in an abstract real inner product space, we replace the Euclidean dot product ( · ) by the inner product formula_6, i.e. formula_7 In a complex inner product space, the expression for the cosine above may give non-real values, so it is replaced with formula_8 or, more commonly, using the absolute value, with formula_9 The latter definition ignores the direction of the vectors. It thus describes the angle between one-dimensional subspaces formula_10 and formula_11 spanned by the vectors formula_12 and formula_13 correspondingly.
Angles between subspaces. The definition of the angle between one-dimensional subspaces formula_10 and formula_11 given by formula_16 in a Hilbert space can be extended to subspaces of finite dimensions. Given two subspaces formula_17, formula_18 with formula_19, this leads to a definition of formula_20 angles called canonical or principal angles between subspaces. Angles in Riemannian geometry. In Riemannian geometry, the metric tensor is used to define the angle between two tangents. Where "U" and "V" are tangent vectors and "g""ij" are the components of the metric tensor "G", formula_21 Hyperbolic angle. A hyperbolic angle is an argument of a hyperbolic function just as the "circular angle" is the argument of a circular function. The comparison can be visualized as the size of the openings of a hyperbolic sector and a circular sector since the areas of these sectors correspond to the angle magnitudes in each case. Unlike the circular angle, the hyperbolic angle is unbounded. When the circular and hyperbolic functions are viewed as infinite series in their angle argument, the circular ones are just alternating series forms of the hyperbolic functions. This comparison of the two series corresponding to functions of angles was described by Leonhard Euler in "Introduction to the Analysis of the Infinite" (1748).
Angles in geography and astronomy. In geography, the location of any point on the Earth can be identified using a "geographic coordinate system". This system specifies the latitude and longitude of any location in terms of angles subtended at the center of the Earth, using the equator and (usually) the Greenwich meridian as references. In astronomy, a given point on the celestial sphere (that is, the apparent position of an astronomical object) can be identified using any of several "astronomical coordinate systems", where the references vary according to the particular system. Astronomers measure the "angular separation" of two stars by imagining two lines through the center of the Earth, each intersecting one of the stars. The angle between those lines and the angular separation between the two stars can be measured. In both geography and astronomy, a sighting direction can be specified in terms of a vertical angle such as altitude /elevation with respect to the horizon as well as the azimuth with respect to north.
Astronomers also measure objects' "apparent size" as an angular diameter. For example, the full moon has an angular diameter of approximately 0.5° when viewed from Earth. One could say, "The Moon's diameter subtends an angle of half a degree." The small-angle formula can convert such an angular measurement into a distance/size ratio. Other astronomical approximations include: These measurements depend on the individual subject, and the above should be treated as rough rule of thumb approximations only. In astronomy, right ascension and declination are usually measured in angular units, expressed in terms of time, based on a 24-hour day.
Acoustics Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics technology may be called an acoustical engineer. The application of acoustics is present in almost all aspects of modern society with the most obvious being the audio and noise control industries. Hearing is one of the most crucial means of survival in the animal world and speech is one of the most distinctive characteristics of human development and culture. Accordingly, the science of acoustics spreads across many facets of human society—music, medicine, architecture, industrial production, warfare and more. Likewise, animal species such as songbirds and frogs use sound and hearing as a key element of mating rituals or for marking territories. Art, craft, science and technology have provoked one another to advance the whole, as in many other fields of knowledge. Robert Bruce Lindsay's "Wheel of Acoustics" is a well-accepted overview of the various fields in acoustics.
History. Etymology. The word "acoustic" is derived from the Greek word ἀκουστικός ("akoustikos"), meaning "of or for hearing, ready to hear" and that from ἀκουστός ("akoustos"), "heard, audible", which in turn derives from the verb ἀκούω("akouo"), "I hear". The Latin synonym is "sonic", after which the term sonics used to be a synonym for acoustics and later a branch of acoustics. Frequencies above and below the audible range are called "ultrasonic" and "infrasonic", respectively. Early research in acoustics. In the 6th century BC, the ancient Greek philosopher Pythagoras wanted to know why some combinations of musical sounds seemed more beautiful than others, and he found answers in terms of numerical ratios representing the harmonic overtone series on a string. He is reputed to have observed that when the lengths of vibrating strings are expressible as ratios of integers (e.g. 2 to 3, 3 to 4), the tones produced will be harmonious, and the smaller the integers the more harmonious the sounds. For example, a string of a certain length would sound particularly harmonious with a string of twice the length (other factors being equal). In modern parlance, if a string sounds the note C when plucked, a string twice as long will sound a C an octave lower. In one system of musical tuning, the tones in between are then given by 16:9 for D, 8:5 for E, 3:2 for F, 4:3 for G, 6:5 for A, and 16:15 for B, in ascending order.
Aristotle (384–322 BC) understood that sound consisted of compressions and rarefactions of air which "falls upon and strikes the air which is next to it...", a very good expression of the nature of wave motion. "On Things Heard", generally ascribed to Strato of Lampsacus, states that the pitch is related to the frequency of vibrations of the air and to the speed of sound. In about 20 BC, the Roman architect and engineer Vitruvius wrote a treatise on the acoustic properties of theaters including discussion of interference, echoes, and reverberation—the beginnings of architectural acoustics. In Book V of his ("The Ten Books of Architecture") Vitruvius describes sound as a wave comparable to a water wave extended to three dimensions, which, when interrupted by obstructions, would flow back and break up following waves. He described the ascending seats in ancient theaters as designed to prevent this deterioration of sound and also recommended bronze vessels (echea) of appropriate sizes be placed in theaters to resonate with the fourth, fifth and so on, up to the double octave, in order to resonate with the more desirable, harmonious notes.
During the Islamic golden age, Abū Rayhān al-Bīrūnī (973–1048) is believed to have postulated that the speed of sound was much slower than the speed of light. The physical understanding of acoustical processes advanced rapidly during and after the Scientific Revolution. Mainly Galileo Galilei (1564–1642) but also Marin Mersenne (1588–1648), independently, discovered the complete laws of vibrating strings (completing what Pythagoras and Pythagoreans had started 2000 years earlier). Galileo wrote "Waves are produced by the vibrations of a sonorous body, which spread through the air, bringing to the tympanum of the ear a stimulus which the mind interprets as sound", a remarkable statement that points to the beginnings of physiological and psychological acoustics. Experimental measurements of the speed of sound in air were carried out successfully between 1630 and 1680 by a number of investigators, prominently Mersenne. Inspired by Mersenne's "Harmonie universelle" ("Universal Harmony") or 1634, the Rome-based Jesuit scholar Athanasius Kircher undertook research in acoustics. Kircher published two major books on acoustics: the "Musurgia universalis" ("Universal Music-Making") in 1650 and the "Phonurgia nova" ("New Sound-Making") in 1673. Meanwhile, Newton (1642–1727) derived the relationship for wave velocity in solids, a cornerstone of physical acoustics (Principia, 1687).
Age of Enlightenment and onward. Substantial progress in acoustics, resting on firmer mathematical and physical concepts, was made during the eighteenth century by Euler (1707–1783), Lagrange (1736–1813), and d'Alembert (1717–1783). During this era, continuum physics, or field theory, began to receive a definite mathematical structure. The wave equation emerged in a number of contexts, including the propagation of sound in air. In the nineteenth century the major figures of mathematical acoustics were Helmholtz in Germany, who consolidated the field of physiological acoustics, and Lord Rayleigh in England, who combined the previous knowledge with his own copious contributions to the field in his monumental work "The Theory of Sound" (1877). Also in the 19th century, Wheatstone, Ohm, and Henry developed the analogy between electricity and acoustics. The twentieth century saw a burgeoning of technological applications of the large body of scientific knowledge that was by then in place. The first such application was Sabine's groundbreaking work in architectural acoustics, and many others followed. Underwater acoustics was used for detecting submarines in the first World War. Sound recording and the telephone played important roles in a global transformation of society. Sound measurement and analysis reached new levels of accuracy and sophistication through the use of electronics and computing. The ultrasonic frequency range enabled wholly new kinds of application in medicine and industry. New kinds of transducers (generators and receivers of acoustic energy) were invented and put to use.
Definition. Acoustics is defined by ANSI/ASA S1.1-2013 as "(a) Science of sound, including its production, transmission, and effects, including biological and psychological effects. (b) Those qualities of a room that, together, determine its character with respect to auditory effects." The study of acoustics revolves around the generation, propagation and reception of mechanical waves and vibrations. The steps shown in the above diagram can be found in any acoustical event or process. There are many kinds of cause, both natural and volitional. There are many kinds of transduction process that convert energy from some other form into sonic energy, producing a sound wave. There is one fundamental equation that describes sound wave propagation, the acoustic wave equation, but the phenomena that emerge from it are varied and often complex. The wave carries energy throughout the propagating medium. Eventually this energy is transduced again into other forms, in ways that again may be natural and/or volitionally contrived. The final effect may be purely physical or it may reach far into the biological or volitional domains. The five basic steps are found equally well whether we are talking about an earthquake, a submarine using sonar to locate its foe, or a band playing in a rock concert.
The central stage in the acoustical process is wave propagation. This falls within the domain of physical acoustics. In fluids, sound propagates primarily as a pressure wave. In solids, mechanical waves can take many forms including longitudinal waves, transverse waves and surface waves. Acoustics looks first at the pressure levels and frequencies in the sound wave and how the wave interacts with the environment. This interaction can be described as either a diffraction, interference or a reflection or a mix of the three. If several media are present, a refraction can also occur. Transduction processes are also of special importance to acoustics. Fundamental concepts. Wave propagation: pressure levels. In fluids such as air and water, sound waves propagate as disturbances in the ambient pressure level. While this disturbance is usually small, it is still noticeable to the human ear. The smallest sound that a person can hear, known as the threshold of hearing, is nine orders of magnitude smaller than the ambient pressure. The loudness of these disturbances is related to the sound pressure level (SPL) which is measured on a logarithmic scale in decibels.
Wave propagation: frequency. Physicists and acoustic engineers tend to discuss sound pressure levels in terms of frequencies, partly because this is how our ears interpret sound. What we experience as "higher pitched" or "lower pitched" sounds are pressure vibrations having a higher or lower number of cycles per second. In a common technique of acoustic measurement, acoustic signals are sampled in time, and then presented in more meaningful forms such as octave bands or time frequency plots. Both of these popular methods are used to analyze sound and better understand the acoustic phenomenon. The entire spectrum can be divided into three sections: audio, ultrasonic, and infrasonic. The audio range falls between 20 Hz and 20,000 Hz. This range is important because its frequencies can be detected by the human ear. This range has a number of applications, including speech communication and music. The ultrasonic range refers to the very high frequencies: 20,000 Hz and higher. This range has shorter wavelengths which allow better resolution in imaging technologies. Medical applications such as ultrasonography and elastography rely on the ultrasonic frequency range. On the other end of the spectrum, the lowest frequencies are known as the infrasonic range. These frequencies can be used to study geological phenomena such as earthquakes.
Analytic instruments such as the spectrum analyzer facilitate visualization and measurement of acoustic signals and their properties. The spectrogram produced by such an instrument is a graphical display of the time varying pressure level and frequency profiles which give a specific acoustic signal its defining character. Transduction in acoustics. A transducer is a device for converting one form of energy into another. In an electroacoustic context, this means converting sound energy into electrical energy (or vice versa). Electroacoustic transducers include loudspeakers, microphones, particle velocity sensors, hydrophones and sonar projectors. These devices convert a sound wave to or from an electric signal. The most widely used transduction principles are electromagnetism, electrostatics and piezoelectricity. The transducers in most common loudspeakers (e.g. woofers and tweeters), are electromagnetic devices that generate waves using a suspended diaphragm driven by an electromagnetic voice coil, sending off pressure waves. Electret microphones and condenser microphones employ electrostatics—as the sound wave strikes the microphone's diaphragm, it moves and induces a voltage change. The ultrasonic systems used in medical ultrasonography employ piezoelectric transducers. These are made from special ceramics in which mechanical vibrations and electrical fields are interlinked through a property of the material itself.
Acoustician. An acoustician is an expert in the science of sound. Education. There are many types of acoustician, but they usually have a Bachelor's degree or higher qualification. Some possess a degree in acoustics, while others enter the discipline via studies in fields such as physics or engineering. Much work in acoustics requires a good grounding in Mathematics and science. Many acoustic scientists work in research and development. Some conduct basic research to advance our knowledge of the perception (e.g. hearing, psychoacoustics or neurophysiology) of speech, music and noise. Other acoustic scientists advance understanding of how sound is affected as it moves through environments, e.g. underwater acoustics, architectural acoustics or structural acoustics. Other areas of work are listed under subdisciplines below. Acoustic scientists work in government, university and private industry laboratories. Many go on to work in Acoustical Engineering. Some positions, such as Faculty (academic staff) require a Doctor of Philosophy.
Subdisciplines. Archaeoacoustics. Archaeoacoustics, also known as the archaeology of sound, is one of the only ways to experience the past with senses other than our eyes. Archaeoacoustics is studied by testing the acoustic properties of prehistoric sites, including caves. Iegor Rezkinoff, a sound archaeologist, studies the acoustic properties of caves through natural sounds like humming and whistling. Archaeological theories of acoustics are focused around ritualistic purposes as well as a way of echolocation in the caves. In archaeology, acoustic sounds and rituals directly correlate as specific sounds were meant to bring ritual participants closer to a spiritual awakening. Parallels can also be drawn between cave wall paintings and the acoustic properties of the cave; they are both dynamic. Because archaeoacoustics is a fairly new archaeological subject, acoustic sound is still being tested in these prehistoric sites today. Aeroacoustics. Aeroacoustics is the study of noise generated by air movement, for instance via turbulence, and the movement of sound through the fluid air. This knowledge was applied in the 1920s and '30s to detect aircraft before radar was invented and is applied in acoustical engineering to study how to quieten aircraft. Aeroacoustics is important for understanding how wind musical instruments work.
Acoustic signal processing. Acoustic signal processing is the electronic manipulation of acoustic signals. Applications include: active noise control; design for hearing aids or cochlear implants; echo cancellation; music information retrieval, and perceptual coding (e.g. MP3 or Opus). Architectural acoustics. Architectural acoustics (also known as building acoustics) involves the scientific understanding of how to achieve good sound within a building. It typically involves the study of speech intelligibility, speech privacy, music quality, and vibration reduction in the built environment. Commonly studied environments are hospitals, classrooms, dwellings, performance venues, recording and broadcasting studios. Focus considerations include room acoustics, airborne and impact transmission in building structures, airborne and structure-borne noise control, noise control of building systems and electroacoustic systems. Bioacoustics. Bioacoustics is the scientific study of the hearing and calls of animal calls, as well as how animals are affected by the acoustic and sounds of their habitat.
Electroacoustics. This subdiscipline is concerned with the recording, manipulation and reproduction of audio using electronics. This might include products such as mobile phones, large scale public address systems or virtual reality systems in research laboratories. Environmental noise and soundscapes. Environmental acoustics is the study of noise and vibrations, and their impact on structures, objects, humans, and animals. The main aim of these studies is to reduce levels of environmental noise and vibration. Typical work and research within environmental acoustics concerns the development of models used in simulations, measurement techniques, noise mitigation strategies, and the development of standards and regulations. Research work now also has a focus on the positive use of sound in urban environments: soundscapes and tranquility. Examples of noise and vibration sources include railways, road traffic, aircraft, industrial equipment and recreational activities. Musical acoustics. Musical acoustics is the study of the physics of acoustic instruments; the audio signal processing used in electronic music; the computer analysis of music and composition, and the perception and cognitive neuroscience of music.
Psychoacoustics. Many studies have been conducted to identify the relationship between acoustics and cognition, or more commonly known as psychoacoustics, in which what one hears is a combination of perception and biological aspects. The information intercepted by the passage of sound waves through the ear is understood and interpreted through the brain, emphasizing the connection between the mind and acoustics. Psychological changes have been seen as brain waves slow down or speed up as a result of varying auditory stimulus which can in turn affect the way one thinks, feels, or even behaves. This correlation can be viewed in normal, everyday situations in which listening to an upbeat or uptempo song can cause one's foot to start tapping or a slower song can leave one feeling calm and serene. In a deeper biological look at the phenomenon of psychoacoustics, it was discovered that the central nervous system is activated by basic acoustical characteristics of music. By observing how the central nervous system, which includes the brain and spine, is influenced by acoustics, the pathway in which acoustic affects the mind, and essentially the body, is evident.
Speech. Acousticians study the production, processing and perception of speech. Speech recognition and Speech synthesis are two important areas of speech processing using computers. The subject also overlaps with the disciplines of physics, physiology, psychology, and linguistics. Structural Vibration and Dynamics. Structural acoustics is the study of motions and interactions of mechanical systems with their environments and the methods of their measurement, analysis, and control. There are several sub-disciplines found within this regime: Applications might include: ground vibrations from railways; vibration isolation to reduce vibration in operating theatres; studying how vibration can damage health (vibration white finger); vibration control to protect a building from earthquakes, or measuring how structure-borne sound moves through buildings. Ultrasonics. Ultrasonics deals with sounds at frequencies too high to be heard by humans. Specialisms include medical ultrasonics (including medical ultrasonography), sonochemistry, ultrasonic testing, material characterisation and underwater acoustics (sonar). Underwater acoustics. Underwater acoustics is the scientific study of natural and man-made sounds underwater. Applications include sonar to locate submarines, underwater communication by whales, climate change monitoring by measuring sea temperatures acoustically, sonic weapons, and marine bioacoustics.
Atomic physics Atomic physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. Atomic physics typically refers to the study of atomic structure and the interaction between atoms. It is primarily concerned with the way in which electrons are arranged around the nucleus and the processes by which these arrangements change. This comprises ions, neutral atoms and, unless otherwise stated, it can be assumed that the term "atom" includes ions. The term "atomic physics" can be associated with nuclear power and nuclear weapons, due to the synonymous use of "atomic" and "nuclear" in standard English. Physicists distinguish between atomic physics—which deals with the atom as a system consisting of a nucleus and electrons—and nuclear physics, which studies nuclear reactions and special properties of atomic nuclei. As with many scientific fields, strict delineation can be highly contrived and atomic physics is often considered in the wider context of atomic, molecular, and optical physics. Physics research groups are usually so classified.
Isolated atoms. Atomic physics primarily considers atoms in isolation. Atomic models will consist of a single nucleus that may be surrounded by one or more bound electrons. It is not concerned with the formation of molecules (although much of the physics is identical), nor does it examine atoms in a solid state as condensed matter. It is concerned with processes such as ionization and excitation by photons or collisions with atomic particles. While modelling atoms in isolation may not seem realistic, if one considers atoms in a gas or plasma then the time-scales for atom-atom interactions are huge in comparison to the atomic processes that are generally considered. This means that the individual atoms can be treated as if each were in isolation, as the vast majority of the time they are. By this consideration, atomic physics provides the underlying theory in plasma physics and atmospheric physics, even though both deal with very large numbers of atoms. Electronic configuration. Electrons form notional shells around the nucleus. These are normally in a ground state but can be excited by the absorption of energy from light (photons), magnetic fields, or interaction with a colliding particle (typically ions or other electrons).
Electrons that populate a shell are said to be in a bound state. The energy necessary to remove an electron from its shell (taking it to infinity) is called the binding energy. Any quantity of energy absorbed by the electron in excess of this amount is converted to kinetic energy according to the conservation of energy. The atom is said to have undergone the process of ionization. If the electron absorbs a quantity of energy less than the binding energy, it will be transferred to an excited state. After a certain time, the electron in an excited state will "jump" (undergo a transition) to a lower state. In a neutral atom, the system will emit a photon of the difference in energy, since energy is conserved. If an inner electron has absorbed more than the binding energy (so that the atom ionizes), then a more outer electron may undergo a transition to fill the inner orbital. In this case, a visible photon or a characteristic X-ray is emitted, or a phenomenon known as the Auger effect may take place, where the released energy is transferred to another bound electron, causing it to go into the continuum. The Auger effect allows one to multiply ionize an atom with a single photon.
There are rather strict selection rules as to the electronic configurations that can be reached by excitation by light — however, there are no such rules for excitation by collision processes. Bohr Model of the Atom. The Bohr model, proposed by Niels Bohr in 1913, is a revolutionary theory describing the structure of the hydrogen atom. It introduced the idea of quantized orbits for electrons, combining classical and quantum physics. Key Postulates of the Bohr Model 1. Electrons Move in Circular Orbits: • Electrons revolve around the nucleus in fixed, circular paths called orbits or energy levels. • These orbits are stable and do not radiate energy. 2. Quantization of Angular Momentum: • The angular momentum of an electron is quantized and given by: where: • formula_2 Mass of the electron. • formula_3 Velocity of the electron. • formula_4 Radius of the orbit. • formula_5 Reduced Planck’s constant (formula_6). • formula_7 Principal quantum number, representing the orbit. 3. Energy Levels: • Each orbit has a specific energy. The total energy of an electron in the formula_8th orbit is:
where formula_10 is the ground-state energy of the hydrogen atom. 4. Emission or Absorption of Energy: • Electrons can transition between orbits by absorbing or emitting energy equal to the difference between the energy levels: where: • formula_12 Planck’s constant. • formula_13 Frequency of emitted/absorbed radiation. • formula_14 Final and initial energy levels. History and developments. One of the earliest steps towards atomic physics was the recognition that matter was composed of "atoms". It forms a part of the texts written in 6th century BC to 2nd century BC, such as those of Democritus or "" written by . This theory was later developed in the modern sense of the basic unit of a chemical element by the British chemist and physicist John Dalton in the 18th century. At this stage, it was not clear what atoms were, although they could be described and classified by their properties (in bulk). The invention of the periodic system of elements by Dmitri Mendeleev was another great step forward. The true beginning of atomic physics is marked by the discovery of spectral lines and attempts to describe the phenomenon, most notably by Joseph von Fraunhofer. The study of these lines led to the Bohr atom model and to the birth of quantum mechanics. In seeking to explain atomic spectra, an entirely new mathematical model of matter was revealed. As far as atoms and their electron shells were concerned, not only did this yield a better overall description, i.e. the atomic orbital model, but it also provided a new theoretical basis for chemistry
(quantum chemistry) and spectroscopy. Since the Second World War, both theoretical and experimental fields have advanced at a rapid pace. This can be attributed to progress in computing technology, which has allowed larger and more sophisticated models of atomic structure and associated collision processes. Similar technological advances in accelerators, detectors, magnetic field generation and lasers have greatly assisted experimental work. Beyond the well-known phenomena which can be describe with regular quantum mechanics chaotic processes can occur which need different descriptions.
American Sign Language American Sign Language (ASL) is a natural language that serves as the predominant sign language of Deaf communities in the United States and most of Anglophone Canada. ASL is a complete and organized visual language that is expressed by employing both manual and nonmanual features. Besides North America, dialects of ASL and ASL-based creoles are used in many countries around the world, including much of West Africa and parts of Southeast Asia. ASL is also widely learned as a second language, serving as a lingua franca. ASL is most closely related to French Sign Language (LSF). It has been proposed that ASL is a creole language of LSF, although ASL shows features atypical of creole languages, such as agglutinative morphology. ASL originated in the early 19th century in the American School for the Deaf (ASD) in Hartford, Connecticut, from a situation of language contact. Since then, ASL use has been propagated widely by schools for the deaf and Deaf community organizations. Despite its wide use, no accurate count of ASL users has been taken. Reliable estimates for American ASL users range from 250,000 to 500,000 persons, including a number of children of deaf adults (CODA) and other hearing individuals.
Signs in ASL have a number of phonemic components, such as movement of the face, the torso, and the hands. ASL is not a form of pantomime, although iconicity plays a larger role in ASL than in spoken languages. English loan words are often borrowed through fingerspelling, although ASL grammar is unrelated to that of English. ASL has verbal agreement and aspectual marking and has a productive system of forming agglutinative classifiers. Many linguists believe ASL to be a subject–verb–object language. However, there are several alternative proposals to account for ASL word order. Classification. ASL emerged as a language in the American School for the Deaf (ASD), founded by Thomas Gallaudet in 1817, which brought together Old French Sign Language, various village sign languages, and home sign systems. ASL was created in that situation by language contact. ASL is influenced by its forerunners, yet linguistically distinct. The influence of French Sign Language (LSF) on ASL is readily apparent; for example, it has been found that about 58% of signs in modern ASL are cognate to Old French Sign Language signs. However, that is far less than the standard 80% measure used to determine whether related languages are actually dialects. That suggests nascent ASL was highly affected by the other signing systems brought by the ASD students although the school's original director, Laurent Clerc, taught in LSF. In fact, Clerc reported that he often learned the students' signs rather than conveying LSF:
It has been proposed that ASL is a creole in which LSF is the superstrate language and the native village sign languages are substrate languages. However, more recent research has shown that modern ASL does not share many of the structural features that characterize creole languages. ASL may have begun as a creole and then undergone structural change over time, but it is also possible that it was never a creole-type language. There are modality-specific reasons that signed languages tend towards agglutination, such as the ability to simultaneously convey information via the face, head, torso, and other body parts. That might override creole characteristics such as the tendency towards isolating morphology. Additionally, Clerc and Thomas Hopkins Gallaudet may have used an artificially constructed form of manually coded language in instruction rather than true LSF. Although the United States, the United Kingdom, and Australia share English as a common oral and written language, ASL is not mutually intelligible with either British Sign Language (BSL) or Auslan. All three languages show degrees of borrowing from English, but that alone is not sufficient for cross-language comprehension. It has been found that a relatively high percentage (37–44%) of ASL signs have similar translations in Auslan, which for oral languages would suggest that they belong to the same language family. However, that does not seem justified historically for ASL and Auslan, and it is likely that the resemblance is caused by the higher degree of iconicity in sign languages in general as well as contact with English.
American Sign Language is growing in popularity in many states. Many high school and university students desire to take it as a foreign language, but until recently, it was usually not considered a creditable foreign language elective. ASL users, however, have a very distinct culture, and they interact very differently when they talk. Their facial expressions and hand movements reflect what they are communicating. They also have their own sentence structure, which sets the language apart. American Sign Language is now being accepted by many colleges as a language eligible for foreign language course credit; many states are making it mandatory to accept it as such. In some states however, this is only true with regard to high school coursework. History. Prior to the birth of ASL, sign language had been used by various communities in the United States. In the United States, as elsewhere in the world, hearing families with deaf children have historically employed ad hoc home sign, which often reaches much higher levels of sophistication than gestures used by hearing people in spoken conversation. As early as 1541 at first contact by Francisco Vásquez de Coronado, there were reports that the Indigenous peoples of the Great Plains widely spoke a sign language to communicate across vast national and linguistic lines.
In the 19th century, a "triangle" of village sign languages developed in New England: one in Martha's Vineyard, Massachusetts; one in Henniker, New Hampshire, and one in Sandy River Valley, Maine. Martha's Vineyard Sign Language (MVSL), which was particularly important for the history of ASL, was used mainly in Chilmark, Massachusetts. Due to intermarriage in the original community of English settlers of the 1690s, and the recessive nature of genetic deafness, Chilmark had a high 4% rate of genetic deafness. MVSL was used even by hearing residents whenever a deaf person was present, and also in some situations where spoken language would be ineffective or inappropriate, such as during church sermons or between boats at sea. ASL is thought to have originated in the American School for the Deaf (ASD), founded in Hartford, Connecticut, in 1817. Originally known as "The American Asylum, At Hartford, For The Education And Instruction Of The Deaf And Dumb", the school was founded by the Yale graduate and divinity student Thomas Hopkins Gallaudet. Gallaudet, inspired by his success in demonstrating the learning abilities of a young deaf girl Alice Cogswell, traveled to Europe in order to learn deaf pedagogy from European institutions. Ultimately, Gallaudet chose to adopt the methods of the French Institut National de Jeunes Sourds de Paris, and convinced Laurent Clerc, an assistant to the school's founder Charles-Michel de l'Épée, to accompany him back to the United States. Upon his return, Gallaudet founded the ASD on April 15, 1817.

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