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the roads and paths leading to or near the post, ascertaining their breadth and practicability for cavalry and cannon, and ensure a ready and constant communication with the adjoining posts and videttes, by signals during the day -- by patrols during the night. He should examine all ravines that might cover the approach of an enemy, and all the points from which he is most likely to be attacked. This will prevent all surprises, and should he be assailed during the night, enable him to act with promptness and decision.
An intelligent officer upon an outpost, even without intrenching tools, may materially strengthen his post. A tree felled with judgment, brushwood cut to a certain distance, pointed stakes, about breast high, placed on the point most assailable, may be attended with the greatest advantages, and can be effected with the common hatchet, or axe, with which the soldiers are provided for the purpose of cutting fire-wood.
Unexpected obstacles, within point-blank musket shot of the place attacked, embarrass and discourage an enemy ; and an officer who is on the defensive, should multiply them within that distance as much as possible.
Guards are not to presume to molest any persons coming to camp with provisions, and are, on no account, to exact or receive any thing for their free passage.
When a deserter comes in from the enemy, he is immediately to be sent, under a proper escort, to the officer commanding the outposts, who, after ascertaining from him such facts as relate to his own post, will immediately forward him to head quarters.
The videttes or sentinels on outposts are to be placed so as to best observe the approach of the enemy, and at tne same time, communicate by signal with each other and with their respective posts. At night, or in thick weather, they will be doubled.
Officers, soldiers, and followers of the camp, are not, on any account, to be suffered to pass the outposts, unless they are on duty, or present a regular permit from head quarters.
Persons bearing a fag of truce from the enemy, are to be treated with attention and civility ; but, as communications of that nature are frequently designed to gain intelligence, and for reconnoisance, the most strict and efficacious means must be adopted to frustrate such consequences.
44 PART IV. REGULATIONS.
The camp and quarter guards are for the better security of the camp, as well as for preserving good order and discipline.
Every regiment will furnish a camp and quarter guard. The camp guard to consist of one Lieutenant, one Sergeant, one Corporal, one drummer, and twenty-seven privates ; and the quarter guard, of one Corporal and nine privates.
The camp guard of the front line will be posted four hundred and twelve feet in front of it, and that of the second line, the same distance in the rear of the second line, each opposite to the centre of the regiment.
Each camp guard will post nine sentinels, viz. two before the guard, two on the right, and two on the left. These six sentinels, with those from the other regiments in the line, form a chain in the front and rear of the camp ; two sentinels before the colours and arms, and .one before the marquee of the commanding officer of the regiment.
To complete the chain of sentinels around the camp, the Adjutant General or staff officer at head quarters, will order two flank guards to be detailed from the line, to consist of a commissioned officer and as many men as may be necessary for that purpose.
The intention of the camp guards being to form a chain of sentinels around the camp, in order to prevent improper persons entering, or soldiers going out of camp, the commanding officers of brigades will add to, or diminish them, so as to answer this purpose.
The quarter guard is to be posted twelve feet in the rear of the line of wagons, and will furnish three sentinels, viz. one at the guard, and one behind the centre of each wing of the regiment. |
passing tlirougli this set of surfaces it would be of little use conducting the gases into flues, for they would be found practically cool, having nearly all their useful heat abstracted by the water tubes as is intended. A sectional boiler is also at an advantage (perhaps more to the maker than anyone else) in the fact that different powers are made up by varying the numl)er of sections. With the boiler illustrated, a middle section heats about 1000 feet of 4-inch pipe, and the boiler is made up in five sizes, that is, with five to nine sections, the latter heating 7000 feet of 4-inch pipe. There are three sizes of snndler sections made, suited for more moderate requirements. (This boiler is also made to be heated by gas.) The fire bars are
of the rocking type, and are operated by the lever shown in front outside.
What is undoubtedly the finest known example of a cast l)oiler, either in this country or in America, is Keith’s “ Python,” shown on the accompanying plate. It derives its name from the fact that it can be readily lengthened or shortened ; this is effected by the addition or abstraction of sections, it being, as will be seen, a sectional boiler.- A considerable deoree of coura2;e is needed
O O
in undertaking the manu- FiG. 401. Fig. 402. facture of a boiler such as
this, as tlie cost of patterns and general preparation is really enormous. The boiler, however, luas a steady demand, notwithstanding its size preventing 'its being an everyday requirement. It is used for large heating works, being capable of dealing with 24,000 feet (over 4 miles) of 4-iuch pipe ; and is also used in heating the water for public baths, and other large requirements. The sections from the front to the rear have slo]3ing and vertical cross tubes, between which the flames and heated gases pass before reaching the flue. The exterior of the boiler is made to receive non-conducting compound to prevent loss of heat. The furnace is fitted with rocking bars.
Vi/vVvV'ViVNm
=fOHb/V
S CLINKER
O^R
L^YVKOK
>s
WARMING BUILDINGS BY HOT WATER.
American Cast-Iron Boilers. -- The description of boilers would not be complete without reference to one or two typical American designs, for these are now finding their way into this country and gradually meeting with some degree of favour.
Figs. 401 and 402 are elevation and section of the “ Ideal Junior ” * (meaning the smaller make of “ Ideal ” boiler, there being three patterns bearing this name). This is
Fig. 403.
Fig. 404.
a taper-sided npright cylindrical boiler, with corrugated interior to increase the heating surface, and the flow-pipe connection is made at the top edge of the water-way as shown in Fig. 401. The central water-way in the upper part of the boiler is not put with the smallest sizes, it being provided as a means to increase the power of the boiler.
* These and the succeeding illustrations are of the “ Ideal ” boilers as imported b}' the American Radiator Company, 113 Queen Victoria Street, London.
3 X
PLUMBING AND SANITATION.
Figs. 403 and 404 are elevation and section of tlie “ Ideal Portable ” boiler, a more powerful type than the last. This boiler is made sectional, as will be seen. The utmost use is made of the heat and gases before they can reach the chimney, as the apertures through which they pass are not in line with one
Fig. 405.
another. The joints between the sections are made with taper “push” nipples, and this method of jointing is spoken of as the best that can possibly be devised. A description of this nipple and the joint it makes will be found a few pages further on, where the sectional joints of radiators are described.
This boiler has the fire box corrugated; in fact, every possilile means is usually adopted with American boilers with a view to get the utmost effective heating surface
WARMING BUILDINGS BY HOT WATER. |
Seeing there are no Coaches at Siam, he was carried in a very neat Chair which he brought with him from France. . The Bifhop took one like to thofe which the Superiors of the Talapoins ufe ; the Abbot de Choifi was carried in a Palanquin, and the Gentlemen went on Horfeback, the Barcalons
‘ Lodgings were above a large quarter of a League
from the Ambafladors Palace, tho there be but three Streets betwixt them, but they are extreamly long, all paved with Brick and bordered on each fide with low houfés, behind which there are trees that caft a fhade into the Streets, and which make pleafant walks when the heat is over. The Barcalons Houle is large, but built of Wood, as moft of the Houfes of Sam are, with this difference that it hath three Roofs one over another, which are the badge of his Dignity. It was then furrounded with water by reafon of the Inundation, and the entry into it was over a Bridge which Landed upon a Terrafs. A great many. Mendarins made a Lane at the entry into the Bridge; and all allighted except the Ambaflador, who was carried over tothe Terrafs, from whence he entred into the Hall where the Ambaflador gives Audience. He came to receive the Ambaflador at the Hall-door, and conduéted him to the end of it, wherehe made him fit down in an Armed Chair oppofite to his own. ‘The Bifhop and Ab- bot de Choifi had alfo Chairs brought them to fit in by the Ambaffador; and the Gentlemen ftood at his back. ‘The Converfation lafted not long ;
N 2 all
A Voyage toSiam. Book IV.
all th e difcourfe was about matters indifk ferent, and fo the Ambaffador returned in rhe famz mannéras he went,
‘The Aimbaflador had been told fo much of: the Pagod of the Palace, and of the Idols that are in It, that he had a great mind to fee them; and feeing in every thing they were ready to pleale him, a proper day was pitched upon, when they might be all fhewn to him at leifure, about eight a pa in the Morning he was conducted to the Palace, where the Lord Conftance expected him. Having crofled over eight or nine Courts,we came at length to the Richeft and moft Celebrated Paged ‘of the Kingdom, it is covered with Ealin, et à is a kind of a very white Metal betwixt T'inn and Lead, with three Roofs one over another. Atthe door of ir, there is on the one hand a Cow, and: on the other a moft hideous Monfter, - This Pagod is pretty long, but very narrow, and when‘oneis within it, there is nothi ing to be feen but Gold. ‘The Pillars,’ Walls, Cibk: ing and all the Figures are’ fo well gilt, that all foi to be cove sped with plates of Gold. ‘The building is pretty like to our Churches, and fupported by thick Pillars. “Advancing forwards within it you find a kind cf Altar upon which there are three or feur Figures of beaten Gold near about the heighth of a Man; fome of them ftand, and others are fitting crof-leoved after the manuer of the Siamefe. ‘Bey ond that theféis a kind os Quire, where they Keep the richeft and moft precious Pagod or Ido! of the Kingdom, for that a name given indifierently to es Teste
the Idol thacis within it: ‘That Statue is ftanding and ihe head of it reaches up to the Roof.
Ie
ESS catia SS == Seas
Book. IV.
It is about five and forty foot high and feven or eight broad; but’ what is moft fu ipriling, It is all of Gold. Of the bignefs it is, the’ Mais of it mutt needs contain above an hundred picks of that Metal} and be worth at leaft twelve Millions fix hundred thoufand Livers. “They aus chat. this Prodigious Coloflus was-caft in ‘the
A Voyage to Siam.
os fame sur
where it ftands and that afterwards they built the
Temple over it. It cannot be compreherded,where thofé eens otherwifè poor enough could hnd fo much Gold ; but it muft needs touch one to the quick to as one fingle [doi richer than all the ang |
98. The filling of bulbs in this manner is very often required in certain trains of research, and amongst others in organic analysis. Hence it is necessary to point out one or two circumstances requiring attention in the operation. When the bulb is about four-fifths full, and the attempt is made to fill it by applying heat whilst it is immersed in the liquid, it will perhaps be found that the bubble of air ex¬ pands and contracts as its temperature changes, but docs not go out of the vessel; the fluid which enters remaining, by capillary attraction, in the narrower part of the
jj top, and consequently passing out again upon the A re-elevation of temperature. But in such a case it h~\ is necessary, before the heat is applied, to make this ( j portion of the fluid and the air change places, which \J is easily done: for this purpose the tube, with its contents, should be held by the upper part, and suf¬ fered to hang as it were below the hand; a swing of a foot or two in extent should then be given to it, so as to produce centrifugal force; all the fluid will descend except that which is contained in the narrowest part of the neck, and the air will take its place ; the tube and bulb should then be heated to expel more air, and fresh fluid suffered to enter, which is to be treated in the same way if required. If anything renders it inexpedient to subject the whole tube to this motion, the bulb can be withdrawn, and being held by the wire or in the hand, can then be shaken in the same way and with the same effect.
Digitized
Sect. II.]
FLUIDS HEATED IN TUBES.
99. In the next place the fluid may be volatile, and subject to waste by repeated elevations of temperature in an open tube ; but in such circumstances it is easy to close the tube effectually by the fore-finger of the left hand, whilst the thumb and second fingpr are occupied in holding it (919) : the heating and cooling are then to be performed with- CjeT} out allowing the end to be unclosed, and no waste is occasioned.
100. This point of manipulation will require a little prac¬ tice to allow of all the advantage being derived from it which it is capable of affording in other operations; but when required, a volatile fluid, ether for example, may be heated until its vapour has a force of two or even three atmospheres, if the tube be strong enough, and be retained there for a quarter of an hour, or more, without any loss. The portion of common air in the tube is to be allowed to escape or not, according to circumstances (919), and may be made use of at times, as will be found by practice, to pre¬ vent the accession of heat to the fingers.
101. Returning to the fluid with which the bulb has been filled:--upon removing the latter when cold, allow its exterior to drain as much as possible; the wire must then be taken off, the surface wiped, and the bulb put upon a cork stand (67), and weighed. As the vessel will then be required full of water, it must be emptied of the fluid. For this purpose replace the wire handle, invert the bulb, hold¬ ing its aperture within the mouth of the tube to which its contents are to be restored, and apply a little heat: a part of the liquid will be forced out, or indeed the whole if it be volatile; if not, on cooling, a bubble of air will enter, and a second and third application of heat will displace the whole of the contents. On introducing a portion of water and dis¬ placing it, and repeating this two or three times, the bulb will be sufficiently cleansed; it may then be filled entirely with water, and weighed when cold as before. The weights of equal bulks of the fluid and water are now known, and the specific gravity readily obtained by calculation.
Go^ 'gle
Original from
NEW YORK PUBLiC
SPECIFIC GRAVITY BULBS--DRIED.
{Seot. II. |
opposite the screw, and abutting against them an oblong piece of glass. The strain now is different, resembling the breakingload of a bridge. It will be seen how the coloured figures also differ, and how exactly the " lines of strain " are optically represented on the screen.
Other transparent substances will give the same effects. A glass trough, made the size of a slide, open at one end and filled with clear cold jelly, will show beautiful phenomena if a rectangular piston is pushed in at the end so as to compress it. So will a glycerine "jujube," if compressed in any manner; but a still better plan, if a slab from which the lozenges are cut can be obtained, is to tie back the studs of the opticalstage, pass the slab of elastic matter through, and extend it with the two hands, of course at an angle of 45° with the polariser and analyser. A strip of thin transparent india-rubber
282 LIGHT [CHAP.
will show similar phenomena when stretched. If neither is handy, soak some gelatine in cold water for a few hours, and then melt it with about two-thirds its' weight of glycerine, and pour out upon a smooth stone or iron slab, greased, to cool. The composition will be something like that which printers use for their rollers, but clearer ; and an oblong slab passed through the slide-stage (kept clear by tying back the studs), and stretched, gives beautiful colour phenomena. Not much time must be wasted over such jelly, or it will melt with the heat of the lantern, unless this is absorbed by a water cell.
Heat applied to glass produces the same effects, owing to its expansive powers. Even one of the plain glass discs, fixed with a spring wire in one of the frames and held momentarily on alternate sides (so as not to crack it), with its centre over a small spirit-flame, will show a black cross, and transmit light through the rest when the analyser is crossed. But much better effects than this can be obtained. Make a " shell " of sheet-iron, like A B, Fig. 177, with a square hole in each side, i-J inches square, the parallelogram measuring 4 by 2\ inches, so as to go in the slide-stage. A little bit turned over from top and bottom at A A, one end, makes a "stop" for adjustment. Cut a piece of wood, c c, such size and shape that the edge of one of the thick glasses made for the press just described, "jams" into the shallow notch, and when wood and all are pushed in against the end stop, A, the glass stands central with the apertures. Fit a small bar of iron so as to slide in over the top edge of the glass. Having adjusted all except the bar of iron in the stage, and made the iron a dull red heat, slide it in over the glass ; at once fringes of light and darkness, and presently of colour, spread over the screen.1
1 The private student needs no expensive apparatus for this class of experiments. As a boy, many, many years ago, I first made the above experiment in the following manner. A dinner plate was inverted on a bare polished mahogany table, and on this was laid a rather massive square bar of heated iron. On this was " stood on edge " a 2-inch square of plate glass,
XII]
EFFECTS OF HEAT
In glass made red hot and suddenly cooled, these beautiful effects are permanent. Such are called chilled or unannealed glasses, and cost from 45*. to *js. 6d. each, of various sizes and patterns. In making them, the great thing is to cool rapidly round the edges, and to start with a red heat. A square block made red hot, and stood on one edge on an iron smooth sur-
FIG. 177. -- Apparatus for Heating Glass.
face, while any mass of smooth metal is balanced on the top edge, will after cooling show very good phenomena, especially if slid on to fresh cold surfaces till cold. A good chilled glass gives coloured figures particularly vivid, and the figures can always be foretold. The most instructive shapes are a circular |
The materials in general use are brick, stone, and earth or PiB6. The Building Act requires that the materials of walls should be of brick, stone, or artificial stone, and no tind)er to be used in them, except such aa is necessaiy for planking, bridging, or piling the foundation ; and for templets, chains, and bonds, and also the ends of girders, beams, puriins, binding and trimming joists, or other principal timbers, observing alwaya to leave Si inches of solid brickwork between the ends and aides of such timbers and the timben of adjoining buildings.
103. The thickness of waUs must, of eourse, be regulated by the height and number of stories in the mansion, and the materials, whether of stone or bricks. It is to be observed that-in bride walls the thickness is, in some degree, regulated by the siae of the bricks : thus a wall may be 1, 2, or 3 bricto, or U, 2|, 3i^ dec., but it cannot be 1|, Si» dto., since the bricto cannot be cot properly. In stone walls there is no such limitetion.
BINT0 on ns njitmcm or wBj>uro.
104. Th€ kwt$t pari tf He watU U itekmMlf etMei iU frstmg, trtdeh •hottld be ooDfliderably thicker than the watt above, diminiahing to that of the walls by a set-off in each coune as it riaea. This, aa well as the thickness of the wall, ia rifulated by the Building Act, aod there can be no better rule than to attend to its instmotiona, even when the building is out of ita limita. In the first, seoend, and third rates, the footing must have a width ^^ at least nine inches more than the thickncaa of the waU above, and the top '^* 37. of it shall be at least six indies below the suiftce of the lowest ground or adjoining area, and at least 18 inches below the suiftce of the lowest floor in the house.
106. Ptutif f»aUM are those which divide one house from another ; they must be built with good hncks, and the Building Aet ia veiy particular in requiring them to be of a certain thickness, according to the several rates. No eztemal wall can be converted into aparty waU.
106. Wkem wUnu %• emfkytd, the architect most be guided partly by the strength of his materials. The operatioa of proparing the scaffolding, and raising the wall with strict adherence to the dimenaiooa marked in the woridng drawings, are subjects of too technieal a natmra^ be entered into hare, and most be left, in a great measure, to the akill of the tradesmen, superintended by the surveyor. A Urn general hints may be mentioned aa things to be attended to. Care being taken toprovide the beet bricks and mortar, and that the briokbcrer uaes what is teohnicaUy catted tiie proper bond in building, the watt ahould not be nm up too hast^, althongh most persons are desirous of expedition ; in particular, one part ahould never he worked up higher than another above a few feet at a time, aince aU waUs aettle or shrink a little when ntswly built, on account of the softness of the mortar, and if the work be carried up too rapidly, cracks are apt to occur from unequal settling.
107. Jk iry tsea£icr H i$ luefiU 49 wd tie irkkt before they are laM down, in order that the mortar may adhere to them better; «id care should be taken that the bricklayer fill in properly the cavities that may happen in the centre of the wall, which they are apt to neglect. WaUs ahould not be built in frosty weather, since, if the mortar should happen to fieese while it is wet or new, it viriU, on thawing, crumble, and its adhesive property be totaUy destroyed ; therefore such wall wiU have no strength or durability. In stormy and rainy weather, the top of the new waU should, if possible, be covered witfi straw or boards. |
Morocco Leather.--Goat or sheep skins are to be cleansed, have their hair removed, and to be limed as in the before-mentioned processes. They are then to undergo a partial fermentation by a bath of bran and water, and afterwards to be immersed in another bath of white figs and water, where they are to remain for five or six days. It is now necessary to dip them in a solution of salt and water, to fit them for dyeing. To communicate a red colour, the alum and cochineal bath is to be used for sheepskins 5 for black, sumach and iron liquor, as before; and for yellow, the bath is to be composed of alum and the pomegranate bark. The tanning, dressing, and graining are the same as for sheep-skins.
Russia Jcather. -- Calf-skins being steeped in a weak bath of carbonate of potass and water, are well cleaned and scraped, to have the hair and dirt removed. They are now immersed in another bath, containing dog and pigeon’s dung in water. Being thus freed from the alkali, they are thrown into a mixture of oatmeal and water, to undergo a slight fermentation. To tan these hides it is necessary to use birch bark instead of oak bark; and during the operation they are to be frequently handled or agitated. When tanned and perfectly dry, they are made pliable by oil and much friction; they are then rubbed over gently with birch tar, which gives them that agreeable odour peculiar to this kind of leather, and which secures them against the attacks of moths and worms. This odour the leather will preserve for many years; and on account of 1t Russia leather is much used in binding books. The marks or intersecting lines on this leather are given to it by passing over its grained surface 8 oe iron
B24
WORKSHOP RECEIPTS,
cylinder, bound round by wires. To dye this leather of a black colour, it is to be rubbed over, after tanning, with a solution of acetate, or pyrolignite of iron; to dye it red, alum and Brazil wood are used,
Another Russia Leather.--Deer and goat skins are cleaned and dressed in the same manner as sheep-skins, and then put into a bath of bran in a state of fermentation with water, for three days. Each skin is then put mto a wooden tray, where, being spread out, it receives a portion of a liquor composed of honey and water. When the skin has combined with this liquid, it is immersed in very salt brine for a short time, and is then dried. To dye it red, it is to be made up in bags, and dipped in a bath of cochineal water and alkalis; it is now to be immersed in a solution of alum, and then tanned with sumach. To give this leather a brilliant and more lasting red, it is dipped in an infusion or decoction of valls, instead of sumach. When to be dyed yellow, the berries of buckthorn or the flowers of wild camomile are used. The graining of this leather is given by an iron instrument of great weight, having a number of blunt points.
Lanning Nets.--Put 1 cwt. of oak branches, and 1 cwt. of spent bark, from any tannery, into 100 galls. of water, and so in proportion for a greater or less quantity. After boiling the same till reduced to about 80 galls., take the branches and spent bark from the copper, and then immerse as many nets, sails, or other articles, as are required, into the liquor left in the copper, taking care that they are completely covered. Boil the whole together for about three hours, then remove the fire, and allow the liquor to get cool; after which remove the nets, sails, or other articles from the furnace, and hang them to dry,
Tanning Sheep or other Skins with the Wool on.--All frarments of flesh must be scrupulously removed with a knife, taking care not to cut or bruise the inner skin; then dry with towels, and lay the skin on a flat board or slab. With hot water, soft-soap, and a hard brush, thoroughly scrub the inside of the skin. |
BOILERS, STEAM. During the last ten years no special improvements have been made in the construction of steam-boilers in the direction of improving their economy of fuel ; in fact, further progress in this direction is scarcely possible in boilers fired with anthracite coal, since many years ago boilers were made which have given results equal to about 80 per cent of the theoretical efficiency of the fuel. As the chimney gases carry off as a minimum about 15 per cent of the heat of the fuel, and losses due are generally not less than 5 per cent, it is readily seen that the margin left for further saving is extremely slight. As a lb. of pure carbon is capable of generating 14,500 thermal units, equivalent to an evaporation of 15 lbs. of water from and at 212° per lb. of carbon, an efficiency of 80 per cent is equal to an evaporation of 12 lbs. of water from and at 212° per lb. of combustible. IIow nearly this result has been reached in actual test is shown bv the results of the boilers tested at the Centennial Ex- hibition at Philadelphia in 1876. Out of fourteen boilers tested, the five highest in the list. in order of economy, gave results as follows (Reports of the Judges of Grouj) XX, Centennial Exhibition Reports) :
NAME OF BOILER.
Coal burned per sq. ft. of grate per hour
Water evaporated per sq. ft. of heating surface per hour
Temperature of rtue gases
Water evaporated per lb. of combustible from and at 212°
9 T6
BAbeock & Wilcox.
Galloway.
These boilers were of different types, as shown in Vol. 1 of this work.
The Firmenich, Root, and Babcock & Wilcox boilers were of the water-tube type. ^ The Lowe boiler was an externallv fired, horizontal tubular boiler of peculiar design. The Smith boiler was a horizontal tubular boiler with a set of water-tube appendages in the furnace, and the Gallowav boiler was an internally fired shell-boiler with conical-shaped water-tubes crossing the large internal flue. Results with anthracite coal exceeding 12 lbs. evaporation from and at 212' per lb. of combustible have been frequently reported, but they are scarcely credible, since they would require an efficiency of over 80 per cent, and an allowance for the heat carried off in"the chimney gases less than't he actual and necessary loss. With semi-bituminous coal, however, containing less than 20 per cent volatile matter, the theoretical heatuig value being greater than 14,500 heat units, an evaporation of even V.i lbs. from and at 212° is not impossil)le: but this assumes a perfect combustion of the coal in the furnace, which can scarcely be reached in practice with ordinary boiler-furnaces on account of some of the gases evolved from the coal being chilled by the inm surfaces of the boiler, and therefore escaping unburned. A result of 12-o lbs. with Cumberland coal is. however, frequently obtained, and this with quite a variety of tvpes of boiler. It may be stated as a general proposition that any boiler, of whatever type (1), in the furnace of which the coal is thoroughly burned with no greater excess of air tlian is necessary to effect complete combustion, giving consequently the highest practically attainable temperature in the furnace (2), which has its heating surface in a clean condition, so placed as to be completely and uniformly passed over by the currents of heated gases, and (8) sufficient extent of heating surface so that it will absorb all the available heat in the gases above the temperature of the steam, is capable of giving the maximum economical result which can be obtained in the best type of boiler. |
CHAPTER I.
ON THE CIRCULATION AND COMPRESSION OF WATER, AND THE INCLINATION AND LEVEL OF PIPES, ETC.
Cause of Circulation of the Water -- Inclination of the Pipes -- Necessity for Air Vents-- Open and Close Boilers -- Pressure of Water -- Expansive Power of Steam -- Effect produced on the Circulation by increased Height of the Pipe -- Compression of Water -- Branch Pipes -- Variations in Level of Pipes 9
CHAPTEE II.
ON THE MOTIVE POWER AND VELOCITY OF CIRCULATION OP
WATER.
On the Motive Power of the Water -- On increasing the Motive Power -- Velocity of Circulation -- Circulation of Water below the Boiler -- Direct and Reversed Circulation -- Air Vents -- Supply Cisterns -- Expansion of Pipes, &c 24
CONTENTS.
CHAPTER III.
ON THE RELATIVE SIZES OP PIPES, AND THE USE OF STOP-COCKS AND VALVES.
FACE
On the Eesistance by Friction -- Eelative Size of Main Pipes and Branch Pipes -- Vertical and Horizontal Main Pipes -- Small Connecting Pipes -- Branch Pipes at different Levels -- Stop-Cocks and Valves -- Their Use and proper Size -- Their place supplied by Cisterns -- Inconvenience of them -- Remedies 51
CHAPTER IV.
ON TEMPERATURE, PIPES AND BOILERS, DURABILITY OF MATERIAL, AND FUEL.
Permanence of Temperature -- Rates of Cooling for different-sized Bodies -- Proper Sizes for Pipes -- Relative Size of Pipes and Boiler -- Various Forms of Boilers, and their Peculiarities -- Boilers heated by Gas -- Objections against contracted Waterway in Boilers -- Proper Size of Boilers for any given lengths of Pipe -- What constitutes a good and efficient Boiler -- Durability of different materials for Boilers -- Effect of Impure Fuel 63
CHAPTER V.
ON FURNACES, THEIR CONSTRUCTION, AND MODES OF FIRING.
On the Construction of Furnaces -- Combustion dependent on Size of Fire Bars -- Furnace Doors, and other parts of Furnaces -- Proportionate Area of Furnace Bars to the Fuel consumed -- Confining the Heat within the Furnace -- Directions for Building the Furnace for different Boilers -- Advantage of large Furnaces -- Modes of Firing -- Size of Chimneys 88
CONTENTS. XI
CHAPTER VI.
ESTIMATE OF THE HEATING SURFACE BEQUIRED TO WARM ANY DESCRIPTION OF BUILDINGS.
PACK
Heat by Combustion -- Quantity of Heat from Coal -- Specific Heat of Air and Water -- Measure of Effect for Heated Iron Pipe -- Cooling Power of Glass -- Effect of Vapour -- Quantity of Pipe required to warm a given space -- Time required to heat a Building -- Facile Mode of Calculating the quantity of Pipe required in any Building -- Quantity of Coal consumed 105
CHAPTER VII.
ON VARIOUS HOT-WATER APPARATUS.
Various Modifications of the Hot -water Apparatus -- Kewley's Siphon Principle -- The High-pressure System -- Holmes' and Coffey's Modifications -- Eckstein and Busby's Rotary Float Circulator -- Fowler's Thermo-siphon -- Price's improved Hotwater Boxes -- Rendle's Tank System -- Corbett's Trough System for Evaporation -- Theory of Evaporation 131
CHAPTER VIII.
GENERAL REMARKS ON HOT-WATER APPARATUS.
General Summary of the Subject -- Points requiring particular attention -- Abstraction of Air from the Pipes -- Vertical Alteration of Level -- Effect of Elbows in Compensating unequal Expansions of the Pipe -- Different Floors heated by one Main Pipe from the Boiler -- Method of connecting Coils to Main Pipes -- Reduced Effect from Pipes laid in Trenches -- Effect of Cold Currents of Air in neutralizing Heating Apparatus -- Heating Apparatus placed in Vaults -- Cements for Joints -- Sediment in Boilers -- Use of Salt in Pipes to prevent Freezing -- Deposition of Vapour in inhabited Rooms -- Ne- cessity for Ventilation -- Construction of Dryingrooms . 163
Xll CONTENTS.
CHAPTER IX.
ON APPARATUS FOE BATHS AND DOMESTIC SERVICE.
PAGE |
This mineral is fcarce. It is diftinguifhable from black lead by its more fliining fcaly appearance, and marks paper with a more brilliant flroke ; and, as it refembles no other fubdance, it does not require to beaflayed.
MOON STONE. The moon done is of a clear white colour, approaching to that of milk. When looked at in a certain pofition, it reflefts a drong light, like the mother of pearl; and fome fpecimens exhibit fpots of a carnation colour. It is found in obtufe-angular pieces, which fometimes have a quadrangular figure. Its frafture is evidently foliated. It is very hard, and in other refpeds agrees with common feltfpar. Probably it is the androdamas of Pliny ; the common girafole of the Italians; and the water opal of Ceylon. It is fometimes clafied with the opal, and by others with the cat’s-eye.
This done is of the chalcedony or pfeudo-opal kind ; it refle&s a whitifh light, with fome various fhades of a few intermixed colours on a blueifii bottom, like the (hining face .of the moon, when it is high enough not to become reddifh by the interference of the earthy vapours.
The rainbow-done, or iris, feems to be nothing elfe than a moon-done, in which the yellow, purple, and blue reflected rays are the mod confpicuous. Magellan.
MOOR-STONE. See Granite.
3T
MORTAR.
M O R
( 5o6 )
M O U
MORTAR. See Lime. Alfo a well-known inftrument for pulverizing,.
MOSAIC GOLD. See Aurum Musivum. Alfo Tin.
MOSS. See Archil.
MOTHER WATER, or MOTHER LEY. When fea-water, or anyother fplution containing various falts, is evaporated, and the cryftals taken out ; there always remains a fluid containing deliquefcent falts, and the impurities if prefent. This is called the mother- water, and requires to be varioufly treated according to the nature of its contents. Inflammable matters are deftroyed by evaporation to drynefs and ignition in an open veflfel. The faline matters may be afterwards taken up by the addition of pure water. In other instances the mother- water is largely diluted, and fuch additions made as may either precipitate part of its contents, or form fuch new combinations as the operator is defirous of procuring. See Magnesia ; alfo Analysis.
MOULD. See Arable Land, Earth Vegetable, and Marle.
MOUNTAIN. When we contemplate the furface of the globe in populous diftrids, our attention is chiefly direded to the agency of man, and thofe energies of focial life, which produce, modify, and change the profpedt around us. But when we enter the wild and romantic fcene of a mountainous country, we are every where ftruck with the veftiges of operations carried on by the powers of nature, through a long feries of ages, and upon a fcale prodigioufly greater than any to which the works of man can be extended. We meditate on the furrounding fcene with an emotion refembling that produced by the view of a pile of ruins long fince gone to decay. We endeavour to inveftigate what may have been the original ftate of t,he pile, and, for want of information, our conclufions are for the moft part little better founded than thofe of an amufing reverie. If the life of man had permitted the philofopher to follow, during the revolution of centuries, that variety of changes produced on the furface of the earth by the numerous agents which alter it, we (hould at this time have been in pofleffion of the moft valuable information refpeding thefe great phenomena : but confined as we are to a fmall fpot of the univerfe, we fix our attention for the tranfient moment of our exiftence upon operations of prodigious duration, far remote from their commencement, or termination. It is no wonder dien that, in many inftances, we find it difficult to comprehend, and in many more to imitate, thefe vaft procefles. |
But what thefe organic powers are, of which the: underftanding makes ufe in its operations, has not yet: been refolv’d or determin'd, fecing the natural philofo-. phers fay, that if one man reafons better than another, , it comes from the underftanding’s being an organic: power, and better difpos'd in one than another, and not: for any other reafon: for rational fouls and their caparcities (when feparated from their bodies) are of equal! perfectionand knowledge. And Ariftofle himielf gives: weight to this argument, when he proves that the un-- derftanding is. better, as the memory is worfe; and on) the other hand, that the more the memory advances and | rifes to a point, the more the underftanding fails and de-- clines; and therefore Ariffotle demands, Why the old! have fo bad a memory, and fo good an underftanding ;; and the young a good memory, with a bad underftand-. ing? Experience alfo furnifhes us with inftances, that: when the temperament and good difpofition of the brain are deftroy’d by ficknefs, we often lofe the ufe of the: operations of the underftanding, while thofe of the me-- mory and imagination remain unimpair’d; which could | never be, if the underftanding had not a particular inftru- - ment by its felf, diftin@ from that of the other powers.. What I fhall anfwer to this, is, That when the brain is; obferv’d to be moifter than it fhould, the eafinefs to re-- ceive and retain in the memory improves; but when: the reprefentation of the fpecies is not fo vivid, nor fo) good, it is, without comparifon,. better effected with drineís, which is light and clear, than with moifture, , which is dark and troubled; infomuch, that the under-- ftanding fails in its operations, from the clouds and ob-: {curity of the fpecies. Quite contrary, thofe who are of adry brain, have not a memory that receives and retains i well; but in recompence, are provided with an imagi-.
nation!
proper for different Capacities. ¡ES nation which helps them to fee clearly the figures, becaufe of the light which attends the drineí, and it is that of which the underftanding has moft necd, according to Heraclitus’s laying, The dry light makes the foul wife. What darkneís, and what mifts, moifture (preads over the objects, and what light, drineís brings long with it, may be eafily obferved in the night, when the fouth and north winds blow: the firft darkens and overcafts the ftars, and the other renders them bright and clear. The fame things fall out with regard ta the figures and fpecies in the memory, infomuch that itis not to be admired, that the underftanding fometimes blunders, and. fometimes hits right, according as thefe fpecies and figures which, it makes ufe of im fpeculation, prove either clear or obíture, without any neceflity of its being therefore a faculty tied to its organs, or of any defeét to be imputed to it. |
PREFACE.
The recent alterations in the Examining Statute will give, we may hope, a powerful impulse to studies in Physical knowledge. Let us therefore consider what branches in that department seem best adapted to forward the great objects proposed in an Academic education. The study of any branch of Physical knowledge forms a healthful exercise of the mental powers, and supplies the mind with interesting information ; and, stimulating to continued thought and observation, calls into action those purer intellectual energies, which, in proportion to their perfection and intensity, constitute the happiness of man, and elevate his taste and conceptions above the low range of sensual gratifications. But those habits of close attention, abstraction, and patient investigation, which an University education is expected to generate, are far more likely to be assisted and strengthened by studies of Physical Science, grounded on systems of strict reasoning and connected argument, than by showy attainments in the light superficial departments. Some acquaint-
PREFACE.
ance with the general principles of Chemistry, with the all-pervading agencies and the general laws established by it, appears a necessary first step in Physical researches, somewhat in the manner of the Grammar and Dictionary being required in attaining a knowledge of Latin or Greek. Superior encouragement will, I trust, be held out to the four regular branches of Natural Philosophy, from the superior value of the knowledge they convey, and the strict reasoning and mathematical demonstration by which that knowledge is attained. I shall therefore venture an observation on the line of argument, or reasoning, by which in many cases we must be content to reach our conclusions. Though sincerely rejoicing that the Book of Nature will no longer be a closed volume to many of our Students, we must remember the paramount importance of a correct acquaintance with the Book of Grace, and of a disposition to acquiesce in its revelations. We must, therefore, not wish those studies in ancient Classical Literature to be in any way superseded, which have hitherto constituted the main feature in an Oxford education ; I mean, more particularly, an intimate acquaintance with the History of Thucydides, and the Ethical Works of Aristotle. In those Ethical Works, an exhibition is laid open of the governing principles, actuating motives, and prevailing habits of man's moral constitution, more fiill, accurate, and minute, than is to be found in any other work of any age or nation. The Student, regularly and
PREFACE. 3 |
See, I have carefully separated the cotyledons. Do you perceive, at the pointed end of the seed, a little body G? Look at it closely, very closely ; it is really a miniature plant. One can distinguish, without great difficulty, a tiny root R, or radicle (Fig. 26), a minute stalk T, and, on the top, a very small bud. And the cotyledons C, O', of what use are they? They are simply the first two leaves of the plant. Were we to put the little fruit (the almond) in the earth, the radicle R would become the root T, and the plumule G would grow up to form the plant. As for the cotyledons, their history is more complicated, and we will hereafter see what becomes of them when we study germination.
II. Structure of Palm-Trees.
11. We have, in a general way, gone over the history of our pear-tree and its fruit. I now wish to examine with you another tree, one altogether different from the foregoing, a palm-tree. Unfortunately, none grow in the northern part of this country except in hot-houses. To find one growing we should be obliged to go to some warm climate. In the Southern States, however, is found the palmetto, which is a small kind of palm, and what we shall learn of the palm applies also to the palmetto.
You may ask, But why, then, choose the palm-tree? There are in this country many other trees, -- the oak, elm, poplar, etc. Quite true ; but what I have told you concerning the pear-tree is applicable to all those trees , nay, even to all the trees of our country except the palmetto. All these have a trunk thicker at the base than at the top , -- a conical trunk, to use the geometrical expression ; all have a bark, and wood harder in the centre, and rings fitting into one an¬ other, and pith; their stems all bear branches or twigs, which come from buds situated at the axillae of the leaves , all of them also bear seeds that have two cotyledons.
But a palm-tree is altogether different , and it is for that
What is seen at the pointed end of the seed? What do you perceive there ? What are the two cotyledons? What would happen if we were to put the whole fruit in the ground? State the general characteristics of the trees of our country.
PALM-TREES.
reason I find it necessary to tell you about it. Fortunately, I have been able to procure some good engravings that will help you to follow my description.
12. General Aspect. -- Observe in the first place the gen¬ eral appearance of the tree (Fig. 27) ; how different it is from those of our forests. iVo branches are to be seen along the trunk , and only on the top A we find a tuft of leaves , long, strong, and stiff.
The trunk B itself is from TOP TO BOTTOM OF EQUAL THICKNESS ; it is cylindri¬ cal, not conical. From the top, beneath the leaves, great bunches of flowers hang down.
This palm-tree is, as you may judge by comparing it with the Arab passing on
camel-back, about forty-five FlG- 27.-- Palm-tree. Trunk from top to .£» . tj- • , ii x bottom of the same dimensions (cylin-
teet high, it is a tall tree, dricai).
but close to it is a young
one C, not more than nine feet high, although its trunk is
Fig. 28. -- Trunk of palmtree. The scars indicate the place where the leaves have fallen off.
Fig. 29. -- Transverse cut of the trunk of a palmtree. No pith, no cir¬ cles of wood fitting into one another, no bark.
Fig. 30. -- Longitudinal cut of the trunk of a palm-tree, showing the hard, black fila¬ ments which give strength to the trunk.
What difference exists between the branches of the palm-tree and those of other trees? In the trunks? What other great difference is there between a palm-tree and our trees? What palm grows in the United States, and where ?
PLANTS.
as thick as that of its elder brother ; strange to say, however tall it may grow , it never will be thicker than at present. This, then, is another great difference between the palm-tree and onr oaks, elms, apple-trees, etc. |
The same principles which have governed the successive developments of small arms have applied to cannon, with some modifications or additions. The power of being able to reach your enemy at a continually increasing distance, of being able to strike him with greater and greater certainty, of being able to do him more and more harm, and of accomplishing all this with the minimum of inconvenience and difficulty to oneself--this is the problem which for several centuries the artillerist has set himself to solve ; and these conditions may be said to apply to all classes of ordnance, heavy and light But the con¬ ditions imposed in the two cases are very different. In the case of the light gun, the object generally is to destroy men ; in the case of the heavy gun, although the ultimate object is to carry destruction and dismay among the per¬ sonnel of your enemy, that object can generally only be attained through the destruction of his mathieL Again, while there is practically hardly any limit to the size of the heavy gun, except the endurance of the weapon itself, the field-gun has to be of a weight no greater than will permit of its easy and rapid transport on a campaign, and from one part of a field to another. Lieut. Hime, R.A., in an interesting paper on Field Artillery, in the Proceedings of the Royal Artillery Institution, observes that “ motion is the essential difference between the two great branches of the artillery service, being as necessarily included in the conception of field artillery, as it is necessarily ex¬ cluded from the notion of garrison artillery. The latter is the artillery of rest, the former is the artillery of motion ; and an immovable field artillery is a contradiction in terms.” Marshal Marmont used to say, “ Le premier m^rite de Partillerie, apr£s la bravourie des canoniers et la justesse du tir, c’est la mobility.” It would seem that this proposition might be fitly reversed--for no amount of gallantry, no amount of accuracy, would compensate for an absence of mobility. Gustavus Adolphus, at any rate, acted upon this principle, for, as Lieut Hime tells us, he resolved at the commencement of the Thirty Years' War to increase the mobility of his field artillery “at all hazards,” and he actually took the extraordinary step of introducing leather guns of great mobility, but of inferior accuracy as compared with the iron guns then in vogue.
E 2
52 ARMS OF THE BRITISH SERVICE .
These leather guns did good service before they dropped into disuse.
Therefore, it is important to insist upon this fundamental distinction between field and garrison (or naval) artillery --the necessary mobility of the former.
But it would not do to divide artillery into two great groups, separated by a hard and fast line. On the con¬ trary--while in the one direction field artillery shades off into mountain artillery, and garrison artillery developes into the monster turret guns, which are moved on huge turn-tables within the cupola or turret--the two classes of field and garrison meet on common ground, and almost imperceptibly shade off one into the other in guns of position and siege guns.
If we were required to classify artillery at all, we should adopt some such distribution as the following :--
i. Mountain guns.
) («) Horse artillery.
*• Field s uns - \ (i) Field artillery
3. Guns of position.
4. Siege guns.
5. Garrison and broadside giins.
6. Turret guns.
Most of these classes admit of further subdivision--for there are mortars, howitzers, carronades, shell-guns, and guns proper ; there are also smooth-bore and rifled guns. It is evident, therefore, that an exhaustive treatment of every detail of this large subject is impossible within the limits of the present volume. We shall therefore not attempt to deal with each subdivision or class of weapon in detail, but will take the more salient points of the different systems in the order in which they occur to us. |
The process of mashing by manual labour or machinery, performed as expeditiously as possible, and not continued a minute longer than is necessary to cause the wrhole of the malt to be well divided and mixed vfith the mashing menstruum, which may be generally effected in from ten to twenty minutes. The purport of which is, to prevent any absolutely unnecessary Iom of heat, (for which purpose also the process ought to be done under cover), and because of the conviction, that -agitation, in the case of malt, rather impedes than promotes solution.
Setting the taps to run off the first wort from the goods, at the end of half or three quarters of an hour, from the time the mashing process terminates, fur* nbhes as strong an extract as if allowed to remain a longer period on the goods, and by having a sufficient number of taps, each set to run off a small stream at the commencement, the wort maybe run off as clear, and more expeditiously, than with a single tap at a great speed. By such a method time and fuel b saved*
THE OLD SYSTEM, atmosphere ; and also by alloinring the goods to lose a portion of their heat, bejond the limits of necessity, the extractive powers of the second liquor, is considerabJy decreased.
The first and subsequent worts ran from the mash tun into the under back, where it remains generally until the whole is off, and sometimes longer, and is then pumped into the copper. The consequences are, that much heat, time, and fuel is lost, absorption of oxygen occurs, and labour and wear and tear of machinery is occasioned $ loss of extract by adhesion to the surface of a superfluous vessel ensues, and the room which such vessel occupies, its first cost, its wear and tear, &c. &c., may be dispensed with.
The second mashino^ liqrior is turned under the goods by some, and over by others, at a temperature varying^ from 160 to 190 deg., and sufficient in quantity to constitute a second boiled wort ; aud the process of mashing is renewed, for a variable period ; and after mashing, the wort is allowed to remain a considerable period on the goods, for the purpose of settling and becoming fine, and in expectation of the obtainment of a wort of greater strength thereby.
The disadvantages of such a process are, that a large quantity of gluten is dissolved, which is not needed. Labour and time is lost, the soluble extract of the malt is diffused through a larger quantity of water than can act as an extracting menstruum, a great portion of it nerer coming in contact with the malt, consequently a weak and inferior wort is the result. fiut such a mode of mashing may be more aptly and intelligibly illustrated by comparing it with the infusing of tea in the tea-pot, with water that does not boil, and too much of it.
THE NEW SYSTEM, eharrinj)^ the ^ort is prevented, and the ^oods are left at a proper heat, to receive the second liquor ; wherebj the second and all subsequent extracts are greater in strength, better in quality, and of his/her temperature, saving time and fuel throu^i^hout the 'whole process.
The first and subsequent worts run from the mash tun into one of the coppers which are placed below it, . and instead of diminishing, are constantly incroasin;^ in heat, while running down, by a gradual increase of the action of tlie fire in the furnace, so that by the time the whole of the wort is down, they may boil. By this method the objectionable particulars, stated as occurring^ by the old system, may be avoided, and the benefits accruing from despatch ensured. |
63. The radial moment .. •• 75
xvi ANALYTICAL TABLE
Art. **»
64. The centre of the system 78
65. Geometrical determination of the centre 79
66. Theorems on the radial moment 79
67. Amount of rotation necessary for bringing a non-equilibrium-
system into an equilibrium-system 80
SECTION 4. -- Composition and resolution of forces acting on a rigid body in any directions.
68. Composition of many forces acting on a rigid body .. .. 81
69. Another interpretation of the result 82
70. Conditions of equilibrium 84
71. Geometrical theorems in interpretation of the conditions of
equilibrium 85
72-75. Theorems concerning the action-lines and points of application of an equilibrium-system 87
76. Consideration of the case wherein R = 0, and a is finite .. 90
77. Consideration of the case wherein R is finite and G = 0 .. 91
78. Consideration of the invariant LX + MY + NZ 93
79. Resultant of a system of parallel forces 94
80. The centre of a system of parallel forces 96
81. Consideration of the case wherein R and G are both finite .. 97
82. The central axis; the central plane; and the central principal
moment 98
83. Another demonstration of the theorems 99
84. Certain other theorems concerning the central principal
moment 101
85. Theorems on moment-centres and momental planes .. .. 103
86. A more general investigation 104
87,88. Further theorems on moment-centres 105
SECTION 5. -- TJie reduction of a system of forces in space to two forces of translation.
89. The first demonstration of the possibility of the reduction .. 112
90. The second demonstration of the same ..113
91. A third demonstration 114
92. A fourth demonstration by means of the resultant of trans-
lation and of the central principal moment 116
93. Theorems concerning the two forces to which a system may
be reduced 118
SECTION 6. -- The equilibrium-axis of an equilibrium-system.
94. Definition of an equilibrium-axis ; and condition requisite
for its existence 120
OP CONTENTS. xv'i
Art. Page
95. Interpretation of the condition .. ..123
96. The condition when two lines not parallel are equilibrium-
axes 124
97. The introduction into a system of two equal forces acting in
opposite directions along parallel lines will satisfy the condition of an equilibrium-axis 125
98. Reduction of a system to two forces, which with two other
new forces shall be in equilibrium, and shall have an equilibrium-axis 127
SECTION 7. -- Stability and instability of equilibrium.
99. Explanation of stability, neutrality, continuity, instability,
of equilibrium 129
100. The theory of displacement 129
101. Case of two forces 130
102. Case of forces acting in one plane 132
103. Character of equilibrium dependent on the radial moment . 133
104. Examples illustrative of stability of equilibrium 134
105. Character of equilibrium of a body under the action of
many forces in space 135
106. Geometrical interpretation of the condition 137
107. Stability dependent on the radial moment 138
SECTION 8. -- Tlie principle of virtual velocities.
108. The principle stated) and deduced from the six equations of
equilibrium 140
109. Examples wherein the principle is applied 143
110. Gauss' theorem of least statical constraint 146
SECTION 9. -- Constrained equilibrium.
111. Firstly, when one point of the body is fixed .. .. ' .. 148
112. Secondly, when two points are fixed: indeterminateness of
the pressures on the points 148
113. Thirdly, when three or more points are fixed 150
114. When the body is in contact with a fixed surface .. .. 151
115. When the body is in contact with many surfaces .. .. 152
116. Equilibrium of many bodies under the action of given forces,
and in contact with each other 153
117. Examples of the preceding 154
SECTION 10. -- On friction.
118. The rationale of friction : the laws of friction 155
119. Problems involving friction 158
PRICE, VOL. III. C
xviii ANALYTICAL TABLE
CHAPTER IV.
OK GRAVITY, AND CENTRE OF GRAVITY. |
"VII. The Sceptical Chymist •, or Chymico-Phyfical Doubts and Paradoxes touching the. Experiments, whereby. Vulgar Spagyrifts are wonctto endeavour to - evince their Salt, Sulphur and Mercury to be the true Principles of Things \ to which, in this Edition, are fubjoined divers Experiments and Notes about the Produciblenefs of GtyHHVd/.Principlcs. . 458
VIII. Phyfiological Confiderations touching the Experiments wont to be employed to evince cither the four Peripatetic Elements, ox the three Cbymieal Principles of mixed Bodies. Part of the firft Dialogue. 464
j . The Sceptical Chymift. . Part J. 474
2. Part II. 493.
3. Part III. 5 10
4. Part IV. 520
5. Part V.. 543
6. Part VI. 561
IX. Experiments and Norcs about the Produciblenefs of Cbymieal Principles, being Parts of an Appendix defigned to be added to the Sceptical Cbymijl. 587
1. Of the Produciblenefs of Cbymieal Principles. Part I. Of Salt. 594.
2. Of the Produciblenefs of Spirits. Part II. 609
3. Of the Produciblenefs of Sulphurs. Part III. 620
4. Of the Production of Mercury. Part IV. 629
5. Of the Produciblenefs of Phlegm or Water. Part V. 651
6. Of the Produciblenefs of Earth. Part VI. 655
X. Experiments and Confiderations touching Colours, firft occafionally written among fome other E Gays to a Friend, and now. luffered to come abroad , as the Beginning of an Experimental Hiftory of Colours. • 6bz
1. The Experimental Hiftory of Colours. The firft Part. 66$
2. The Experimental Hiftory of Colours. Part II. Of the Nature of Whilenefs and Blacbtefs. 696
3. Experiment in Confort touching Whitenefs and Blackncfs. 708
4. 'I he Experimental Hiftory of Colours begun. Part II. Containing promiscuous Experiments about Cclcurs. 724
XL A ftiort Account of feme Obfervations made by Mr. Boyle about a Diamond that Chines, in the j6S
The
'oT the SIX VOLUMES. *cxxvii
The CONTENTS of the SECOND VOLUME.
3. g
OME Confiderations touching the Ufefulnefs of Experimental Natural Philofphy, propofed in a familiar Difcourfc to a Friend, by way of Invitation to
the Study or it. Page 7
Eljay I. The Ufefulnefs of Experimental Philofopby, principally as it re
atcs
~to the Mmd of Man.
2. I-iia. y 11. Or the lame. Ig
3. EfTay III- Containing a Continuation of the former. 30
4. EH'ay IV. Containing a requihtc Digrcflion concerning thole that would exclude the Deity lrom intermeddling with Matter. 36
5. Elfay V. Wherein the Difcourfc interrupted by the late Digreflion is rc- Bum and concluded 49
IT. Of the Ufefulnefs of jV*/«rd/ Pbilofopby. Part II. Sect I. Of its Ufefulnefs to Pbyjick. 64.
1. EfTay II. Offering fome Particulars relating to the Pathological Part of Pbyfck.' ~7<S
2. ~EfTay III. Containing fome Particulars relating to the Semdoitecl Part oT ~FT?Jyk. ■ 80
3. liflay IV. Prcfenting fome Things relating to the Hygieinal Part of Phyfick.
roj
4. Eflay V. Prcfenting fome Particulars, wherein Natural Philofophy may be ufeful to the Therapeutical Part of Phyfick. ' 113
5. An Appendix to the firft Section of the fecond Part. 202
III. Some Conliderations touching the Style of the Holy Scriptures, extracted from feveral Parts of a Difcourle concerning divers Particulars belonging to the Bible, written divers Years fince to a Friend. 247
IV. Occasional Reflections upon fcvcral Subjects, whereto is premifed a Difcourle about fuch kind of Thoughts. _
i. A Dilcourfc touching Occafional Meditations. 335 |
^s all Mathematical Demonftrations are abftradled, I do not quefUon their becoming eafier, when Experiments fet forth the Conclufions before our Eyes ; following therein the Example of the EngltJJj^ whofe Way of teaching Natural Philofophy, gave me occafion to think of the Method I have followed in this Work. I fhall always glory in treading in their Footfteeps, who, with the Prince of Philofophers for their Guide, have firft opened the Way to the Difcovery of Truth in philofophical Matters, difmiffing all feign'd Hypothefes out of Philofophy.
As to the Machines, I will fay thus much more by way of Advertifement : That moft of them have been made by a very ingenious Artift of this Town, and no unfkilful Philofopher, whofe Name is John Van Muffchenbroek, and who has a perfed: Knowledge of every thing that is here explain'd. Which Advertifement, I fuppofe, will not be difpleafing to thofe who may iiave a fancy to get fame of the fame Machines made for themfelves.
Vol. I. ^ T O
TO THE
R E A
CONCERNING THE
Second E d i t i o n«
'MEN I firjl intended to write thife Elements, my De-^ ftgn ims thst my Auditors Jhou'd be able to re'colleSi, with ^sfe^ fitch 'things as they had heard more largeiy explained' and demonfirated ; and that I might give an Idea of Natural Philofophyy treated of in a mathematical Ma7iTter, tofuch of my Readers, who were acquainted only with the firft Eilenmits of Geo- ?netry. Moreover, that this Book might be ufeful to Beginners, I. fafs'd over the more difficult Things,^ and often mentioned PropofitiotiSy^ which Ifaid were prov'd by Geometricians^.
But that the fecond Edition inight be likewife of fervice to fuch of my Evaders as were better acquainted with Mathematics, I annex' d- the mathematical Demonjirations of all fuch Propofitions,in the Scholiums to thofe Chapters, in which they .are meiitioii'd. And left this Jliou'd confound other Readers, I took care to have them printed in a. f mailer CharaSler.. Tet Ifo difpos' d of the whole, that what is prin-^ ted in a greater CharaSler makes a kind of feparate 'Treat ife.
Ldkewife in the Scholiums I delivered fome other Things, which cou'd not well be treated, of in the Body of the Work, tho" they relate fo 'What is explained, or ferve by way of UJuft ration.
The fecond EditionAs,.^ alfo in other refpeSis, more full and more accurate.
Many new Machines, and old- oftes improv'd, are exhibited in the: Plates y a?id the Expe7~imentSy^ and their Succefs, are f&t forth in this Edition with greater Care.
For we have here likewife more f idly explained, and have deliver' d^^ fupported, and illuftrated, with fever al new Experiments, our New Theory of Pereuffion, which is founded z^^o« Leibnitz 'i on rather Huygens'i DoSirine of innate Forces..
It was never my Way, nor is it now, however I may be pi'ovok'd^ toquarrel about the Truth.. That which appearstrMe to me, I defendaccording
Concerning the Second Edition. xi
'according to my beji Ability^ when there is occafton ; and to removf all Appearance of Contention^ as much as I am able, I have fo en~ deanjour' d to propofe the Argmnents which feem to me to be the Foundation of the fore-mention' d 'Theorys^ that Anfwers to Diffculties tnav from thence be cafily drawn ; and I have undertaken to anfwer but a few direSlly : And I leave the Reader to judge ^ whether the theories of Forces, and Percuffions, as well as of Refiftances and Retardations, of Bodies tnov'd in Fluids, dont exaBly agree with the Phcefiomena, and with one another.
As for my Work, every on^ may make ufe of it as he pkafeth, fo that he does not think that I am bound to anfwer whatfoever may be objeSted. As long as I look upon thofe ^Things to be true which I have written, I think I may very juJlJy beflent. |
This experiment shows that induction precedes discharge. All that we know about Fig. 113. the subject shows that this is a universal law, namely, that there must always be induction along the whole path between the conductors before discharge can take place. It is clear that this law ought to hold, for discharge is only the sudden breaking down of a state of strain, and there can be no breaking down of strain except where strain exists, and induction is strain.
The fact of a spark passing along any path shows that induction was previously taking place along that path. It does not, however, show that the whole induction was along that particular path even a very small fraction of a second before the discharge. The induction might have been, and probably was taking place along many paths. When, however, the insulator broke down at the weakest point, and the spark began to pass, the whole of the induction at once transferred itself to the line of discharge as being the path offering least resistance, and then the breaking down and relief of the strain was completed along that path.
Given, then, that induction precedes discharge, if we see curved discharges, we shall know that there was previously curved induction. Discharge often consists of a barrel-shaped bundle of sparks. (Fig. 114.) They are, in Fig- m- fact, the curved lines of force, or
lines of induction, or lines of strain, produced in visible shape. The centre lines are straight, and the strongest induction takes place along them ; but induction strong enough to produce discharge takes place in curved lines through all the particles on all sides of the centre line.
172. Lines of force are real. These lines of force are
L ines of Force. 2 1 3
real, and, I may almost say, tangible things. They can bo attracted and shaped by the hand and other conductors. If I place my knuckle near the lines, they bend out towards it. This means that the positively electrified particles of air induce negative electricity on my hand, and tlu-ii the two electricities attract each other, and displace the whole lino of force. It would be difficult to conceive the possibility of attracting an t( action at a distance."
Wo have shown that the induction is a state of strain, and wo have studied the direction of the strain. We now ask, what is its nature? Faraday showed experimentally that the lines of force attracted each other, so that, if a number of them were side by side forming a " bundle/' their mutual attraction drew them together as if the bundle had been tied up more tightly.
Maxwell has since pointed out that this is what occurs whenever a rope is mechanically stretched. The pull tending to lengthen the rope is accompanied by a pressure tending to make the rope thinner. To show this lateral pressure, we may uso an india-rubber tube (fig. 115). When wo stretch it the }<ides press on whatever is inside it. Whenever a mechanical Fig. n:.. tension occurs it is accompanied by a pressure at right angles to it.
Maxwell has shown mathematically that an electric induction acting as a tension along the lines of force is always accompanied by an exactly equal pressure at right angles to them. Electric induction, or tension, is a tension of exactly the same kind as the tension of a rope, and the medium which can support a certain induction force before breaking and allowing a spark to pass may be said to have n certain strength in exactly the same sense as a rope may be said to have a certain strength. Sir William Thomson has found that the electric strength of air at ordinary temperature and pressure is 9600 grains per square foot.
Finally, Mr. Do la Rue has actually seen in one of his vacuum tubes a star of light showing a rain of particles thrown off at right angles to the main discharge.
2 1 4 School Electricity.
QUESTIONS ON CHAPTEE XXIV.
1. Describe the actions between insulated electrified bodies. State when attraction occurs, when repulsion. |
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GENERAL AIMS OF THE TEACHER, AND FORM |
EMPORIA -- Pop., 5,000. Opera House. _E. Goodwin, mgr. S. c, 800. Prices, 75c., 50c., 35c. Ilium., elec. Volt., 220. System, alternating and direct, both 220.. M. M. Goodwyn, elect. Width prose, opening, 30 ft. Height, 14 ft. Depth, footlights to back wall, 30 ft. Distance, curtain line to footlights', 2 ft. Between side walls, 50 ft. Distance between fly girders, 50 ft. No grooves. Height to rigging loft, 18 ft. Depth under stage, 10 ft. No traps. No scene room. Theatre on ground floor, Harvey, stage carpenter, E. E. Goodwyn, billposter. Printing required, 3 stands, 12 3-sheets, 25 i-sheets, 50 ^-sheets. Dates to read, Armory Opera House. Transfer Go., Harvey. Express ofiice. Southern. Dr. McNair. physician. E. G. Palmer, lawyer. . . .Newspaper -- "Messenger," weekly, Thursday, Dr. L. Lofton .... Hotel -- Gentral, $2. Virginia, $2. ... Railroads --
Atlantic Goast Line, W. H. Hudson, agt. Southern, O, S. Hall, agt Publisher
of programme -- E. E, Goodwyn.
FARMVILLE -- Pop., 3,500. Farmville Opera House. J. L. Hart, mgr. and bus. mgr. S. c, 750. Ilium., elec. H. K. Bullock, elect. German Baker, stage carpenter. Theatre on second floor. J. L. Hart, bill-poster. ,. .Newspaper -- "Herald," weekly. Express, Southern.
FREDERICKSBURG-- Pop., 6.000. Opera House. Goldsmith & Hirsh, bus. mgrs. and press agts. Sam Ghaffee, stage carpenter. S. c, 700. Prices, 25c. to 75c. Ilium., gas. Width prose, opening, 30 ft, Height, 15 ft. Footlights to back wall, 35 ft. Gurtain line to footlights, 5 ft. Distance between side walls, 60 ft. Height of grooves from stage, 14 ft. Stage to rigging loft, 20 ft.^ 5 grooves. Depth under stage, 5 ft. 3 traps. Theatre on second floor. Printing required, 15 stands, 15 3-sheets, 100 lithos., 50 i-sheets, 50 3^-sheets. Dates read. Opera
House. Goldsmith & Hirsh, bill-posters Newspapers -- "Star," daily. "Free
Lance" and "Star," weekly and semi-weekly journal .... Hotels -- Exchange, $1.50, $1.25. Virginia and Dannehl .... Railroads-- Richmond, Fredericksburg & Poto-
VIRGINIA.-- Continued.
mac, C. C. Cox, agt. Potomac, Fredericksburg & Piedmont, S. G. Daniel, agt. Southern and Atlantic Coast Line. S. A. L. R. R. Transfer, Goldsmith & Hirsh. Express, Adams.
FRONT ROYAL-- Pop., 2,000. Davis Hall. King & Supinger, mgrs. S. c, 600. Ilium., elec. Edison system. Width prose, opening, 20 ft. Height, 12 ft. Footlights to back wall, 22 ft. Theatre on second floor. N. J. Kendrick, leader of orchestra. 5 in orchestra. C. G. Supinger, bill-poster .... Newspaper -- "Sentinel," Friday. .. .Hotels -- Strickler House and Afton Inn, $2 .... Railroads -- Norfolk & Western, R. M. Helm, agt.; Southern, J. A. Lehew, agt.
HAMPTON-- Soldiers' Home Theatre. Col. T. T. Knox, mgr. S. c., 1,384.
Ilium., elec. Width prose, opening, 32 ft. Height, 18 ft. Depth, footlights to back wall, 27 ft. Distance, curtain line to footlights, 2 ft. Distance between side walls, 72 ft. Distance between fly girders, 36 ft. Stage to rigging loft, 40 ft. Depth under stage, 7 ft. i trap, located right, center in 3. i bridge. Scene room. Prof. John Scully, leader of orchestra. 10 in orchestra. Printing required, 6 3-sheets and 10 dates. Dates to read. Soldiers' Home Theatre.
Armory. J. V. Bickford, mgr. S. c, 400. Prices, 25c. and 50c. Ilium., gas and elec. Stage, 30x22 f t .... Newspapers -- "Hampton Monitor" and "Newport News
Press," daily Hotel -- Soldiers' flome Railroad -- C. & O. Transfer Co., E.
B. Chiles. Express, Adams, American and U. S. |
by Pd, the distance of the power's line of action from F\ and B'F by Wd, the distance of the weight's line of action from F.
If the weight P equal 3 lbs., and the length of power-arm A'F be 4 ft. ; and the weight W equal 6 lbs., and the length of the weight-arm FB' be 2 ft.,
4x3 = 2x6,
i. 6., the product of the weight and weight-arm equals product of power and power-arm.
In the first and second classes, as ordinarily used, we gain power and lose time ; in the third class we lose power and gain time.
If a weight is attached to a beam or pole which rests upon
two supports, the beam acts as a lever of the
twoSi^Srti^ second class, and the part carried by either sui)-
port may be found by considering it as the power, and the other support as the fulcrum. If the weight rests on the middle of the beam, it is obvious that ea<;h support will bear half the burden. If, as shown in Fig. 47, the lo€ui is
Fig. 47.
Weight between Two Supports.
one third the length of the beam from A, the support, -4., will bear two thirds of the weight, and the other support, one third.
When a small force is required to sustain iSevSr ^ considerable weight, and it is not convenient to use a very long lever, a combination of levera, or a compound lever, is employed. "W^eo. «wic\\ ^ v^^x^xci
THE BALANCE.
is In equilibrium, the power, multiplied by the contJnued product of the alternate amiB of the levers, commencing from the power, is equal to the weight multiplied by the continued product of the alternate arms, commencing from the weight.
Pta. 48.
Tbe Balance.
If the long arms are 6, 4, and 5 feet, and each of the shoi arms 1 foot, then I pound at A will sustain 130 pounds at D.
The balance is a lever of the first class with equal arms. The bar, AB (Pig. 48\ Ilea a pair of Bcale-pana suspended from its enda. iA tbe middle an axis, n, made o£ steel snA ''
THE STEELYARD.
Fis.49.
knife edge, rests upon a hard surface, so that the friction may be the least possible ; this is the fulcrum.
The steelyard is a lever of the first class. The P is at M,
the F at C, and the TT at J). If SteelyBrd. the distance from the pivot of the
hook D to the pivot of the hook C be one inch, and from the pivot of the hook C to the notch where JS hangs be 12 inches, then 1 lb. at U will balance 12 lbs. at W. If the steelyard be reversed (Fig. 50), then the distance of the F from the W is only J as great, and 1 lb. at FJ will W^E
balance 48 lbs. at D. Two '^^ steelyard.
sets of notches on opposite sides of the bar corre^ spend to these different positions.
The compound lever consists of several levers so
connected that the short arm of the lSvw^ first acts on the long arm of the second, and
so on to the last of the series. If the distance of A (Fig. 51) from the F be four times that of 5, a P of 5 lbs. at A will balance a W of 20 lbs. at B. If the arms of the second lever are of the same comparative length, a P of 20 lbs. at C will balance 80 lbs. at E. In the third lever, a P of 80 lbs. at D will balance 320 lbs. at G. With this sys- •"
Fio. 6a
lll.MI'IIHIIIIIilll tllll
The Steelyard.
tem of three levers, 5 lbs. at A will accordingly balance 320 lbs. at G. To raise the W 1 ft., however, the P must move 64
ft. Thus what is Fig. 51.
The Compound Lever.
gained in power is
lost in time. In
the application of power by
means of levers of this class,
there is no creation of force;
on the contrary, there ia an
ppreciable loss of force because ot iriction.
THE WHEEL AND AXLE.
Hay scales are constructed upon the principle of the < pound lever. Congiderii^ the large mass on the platform ae power, its pressure is transmitted at the points P and J" (Fig. 52) """ '" |
Oxygenated lard is formed by melting one part of nitric acid with sixteen parts of axungia, stirring it with a glass rod, and leaving it over the tire till it throws up bubbles. The nitric acid is decomposed, the nitrogen is disengaged, and the oxygen combines with the fat, without giving it acidity. -- Alyon.
Shermaceti is a concrete oil, extracted from a species of the whale, the cacholot. It burns with a very white flame, and rises totally if distilled on a naked lire, assuming a reddish tinge, and losing its natural consistence by repeated distillations.
Alcohol dissolves it by the assistance of heat, but lets it fall 45 it cools. It is also dissolved by ether, uud by fli c fixed and
volatile oils. It seems to bear the same relation to fixed oHs which camphor does to the volatile oils, whilst wax seems to be analogous to their resins.
Urine is an excrementitious fluid, secreted by the kidneys: in its natural state, it is transparent, of a peculiar smell, a citron yellow colour, and a saline_taste. Besides the differences proceeding from peculiarity of habit, there are other differences in the urine, arising from other circumstances. That which is voided soon after copious drinking, is aqueous ; having hardly colour or smell, and is called crude urine , or urina potus : whereas that which is made after the sanguification, succeeding to a full meal, possesses all the characters of urine, and may be called the faces sanguinis.
By the spontaneous decomposition of urine, it soon loses its original smell, and acquires that of ammonia; which being also dissipated, the smell becomes very fetid and offensive, and the colour brownish : in this state it manifests much less acid Ilian when fresh.
By evaporating urine to the consistence of a syrup, and allowing it to stand in a cool place, crystals are formed. This precipitate of crystals has been called fusible salt, native salt , and microcosmic salt. It is chiefly composed of the phosphates of soda and of ammonia, and is used as a flux to the earths.
The analysis of urine is very difficultly accomplished, owing to the complication with the substances employed as re-agents, and to its vast susceptibility of change by the application of the slightest degree of heat, or even exposure to the air. A carefully conducted spontaneous evaporation, afterwards aided by heat, fermentation, the action of alcohol, and a close observation of the several appearances yielded by the action of various re-agents, are all necessary to ascertain the principles which urine contain.
According to Fourcroy , there are twelve principles which are constantly found in urine.
SOS |
Ulcers (Chronic).
GalT. enr.( 10-15 mUliamps.), v. 83.
Urethra, Inflammation or. Antiseptic irrigation, mercury bichloride soL, ii. 209; ntlroJeo/rtteer inject., ii. 210; thalKn tulphale injection, iL
Urethral Warts. Operation
for Removal, ii. 212.
Stricture or. Meatotemy, ii. 214; paseage of catheters, ii. 215; cutting, II. 216; resection. Ii. 21.4; electrolysis, ii. 219: oathcterism, urinary disinfection, ii. 220.
IK Female. Steel sound dllat., It. 148.
Urirr, Incontinence or.
Oteaine wi. 1-200, inj. Into blad., iv. 455; collin*onia ranad., tr. Xj at Supper and bed-time, W. 456; rhn* armnat./L act. TTi 5-15 d.i.d. Ir. 497.
Suppression or. Com *ilk JL exi. &H), iv. 453.
Urticaria. Fictitious. Hydrotherapy, ii. 339.
Uteriice Colic
Antipyri**, 2.0 gm., iv. 445.
Uterus, Adherent. RETRO- FLEXED AMD ReTKOTERTET).
Laparotomy and Alexander's op., hystororrhaphy. iv. 1%: vagi do- and recto-abdom. man! p., iv. 16.
Cancer of. Conium and lanolin inunct., iv. 457.
Carcinoma of,
Chian turpentine, iv. SO; (erebine ana oil tampons, iv. 30 ; vaginal hysterectomy, curetting or high amputation, iv. 31.
AUTHORS QUOTED.
Ulcer, Oastric-- Marian, L 307; Decker, i.
Electrical Treatment of Chrorio--
Meyer. Blackwood, v. 62. UlexirE Htdrobromate. Prtsiolocical
Actior of-- Rose -Bradford, Pinet, ir.
Umhilical Cord, Anomalous Villous Irsrr-
tior or-- B. 8. Sohultse, Schata, Pfluger,
T.41I.
Urited States, Localities or Mirer a l
Springs in-- Peale. v. 39. Urachus, Abnormal-- Freer, v. 428. Ureter-- Tuohmann, ii. 238. Ureters, Catheterizatior of-- Pawlik, iv.
148; H. A. Keller, Hirst, iv. 149. Urethra-- Etienne, Wright, Vincent, Cham-
plonuiere. Ii. 207. " Irflammatior or-- Chaxeaux, Ooll, iL 211 ;
Oberlander, 212. Urethra, Malforhatior of Male-- Voita-
ries,v.431 ; Yarjavoy. Malgalgne, Dionis,
Sabbatier. Berard. looker, v. 432. Stricture or. ir Female-- Van de Warker,
ir. 147 ; Herman, Horrock, Routh, Har-
don. iv. 148. Urethral Argtria-- Oriinfeld. ii. 213. Fever, Pernicious-- Monod, iL 220. Stricture-- Raney, Davenport, Otis, IL
215; von Antaf, IL215: Dagniao, Cham-
pionniere, Fleming, ii. 217. Stricture, Treatmert bt Resectiok or
-- Heusner, ii. 218. Uretdar-- LongovoL von Jaksch, Andrews,
iv. 510. Urethrocele. Vagihal-- Cheron. Iv. 134;
Emmet, iv. 135; Cheron. iv. 154. Urinalysis-- Millard, Posner, i. 497 : Esoa?h,
Maixner, i. 498; Thorion. i. 499; Vns-
llevski. Sohmledeberg, Holland, i. 500;
Le), Donaldson. Adams, i. 501: Jaffe,
Johnson, i. 5112; Rosenbaoh. Einhorn.
Kramer, i. 503; Bond. i. 504; Molisch,
i. 5116; Mehu. i. 5117; Holovtechiner.
Brensing. Arturo. i. 509 : Mossatelll and
ViteH. Rossbaeh. I. 510: Griffith. Bagin-
sky.i.5U: v. Jaksch, Hayem. i.512: Keeier
and Engel. I. 513: Lcuhe. Marshall, i.
514; Caxeneuve and Hugounenq. i.
615; Mvgoe, i. 516; Sehmiedeberg and
Meyer, "Kirk. I. 517 ; Marshall, i. 518 ;
Groeoo. i. 521; Ralfe. Anott. I. 522:
Charrin and Roger. Felts, i. 543 : M'dlle •,
i. 524; Rossbaeh. i. 525; Franco Ul.
Yamane. Baker. L 626; Bamberger,
Aberoromble. i. 527 ; Bruselius. Lehsen.
Damme. Kobler and Obermeyer. i. 52S ;
Handford. Barinsky. i. 529: K'ussner.
Silbermann. Schmidt. Sanders, i. 539;
Luoa, Lewin and Rnsn«r. i. 631. Urirart Disinfection-- Championneire, IL
Urirart Fistula in Frmale. Causation--
More-Madden. Roe. Hbhlmaan, ir. 149;
Prowltt. H. P. Wilson. Iv. 1W. Operation-- Sims. Olshansen. Tait. iv. 1M ;
Rydygier. Simon. Tillaux. Wolfior.
Jeannel. Molinier, W. Duncan, iv. 152;
More-Madden. Folet. Verneuil, Rose,
Hervieux, Michinard. iv. Wl. Prrparatort Treatment-- Boceman. ir.
150 ; 8onohon. Croom, Tillaux, Molinier.
Iv. 151. Ustilago Mathis. Prtsiolocical Action--
Dorland. iv. 546. Uterine Haemorrhage, Comparative Frb-
quenct of Causes or-- Davenport, iv.
Involution, Diagroscd bv tms Sound
--Sinclair, Charpentier, Mileon, Hansen,
iv. 240. Tents, Preservation of-- Dirner, Frai-
pont, iv. 10. Uterus, Arsbrce or. with Morr or Less |
lliis is the place to remark that it is rarely that the discharge is of the simple form (2), i,e., consists of a single continuous discharge; in bv far the great majori^ of caaes it consists of a series of partial discharges. With the inductorium, both varieties (1) and (3) may occur according to the length of the air space, the resistance of the whole secondary circuit, and so on. A number of very beautiful experiments have been made to illustrate these principles, which it would take us beyond our limits to describe. Good summaries of the results of Felici, Cazin and Lucas, Donders and Nyland, Ogden Rood and Alf. Mayer, will be found in Mascart and Wiedemann. Recent researches of a very important character have been made by Wttllner* and Spottiswocide' on the discharge in vacuum tubes. They employ the rotating mirror. It would be premature to attempt to sum up or criticise their results, suffice it to sav that they show an amount of a^pieement which augurs well for tne future of this blanch of electrical science. The striaa seem, according to them,
» Pogg. Ann., «* Jttbelbd.,»» 1874. « Proc, R. S., 1875-6, 7.
to play a more essential part in the phenomenon than was perhaps previously expected. Spottiswoodo, in fact, seems to incline to the view that all discharges naving a dark interval are really stratified, although, owing to their rapid motion, the strata may not be distin* guishable by the eye alone.
In connection with this subject it may be well to mention the early experiments of Wheatstone,^ to determine the socalled velocity of electricity in conducting circuits. Six balls, 1, 2, 3, 4, 5, 6, were arranged in a straight line on a board ; 2 and 5 were connected with the coatings of a charged Leyden jar ; discharge passed by spark from 2 to 1, then through a large metallic resistance to 3, thence by spark to 4, then through a large metallic resistance to 6, and thence by spark to 5. It was found, as Feddersen observed later, that the introduction of the metallic resistance increased the duration of the sparks at all the intervals, so that the images in the mirror were lines of small length ; but, in addition, the spark between 3 and 4 began a little later than the sparks at 1, 2 and 5, 6, which were simultaneous. From this the velocity of electricity has been calculated, by taking the interval * between the sparks to be the time which the electricity takes to travel through the metal unre bettveen the intervals. Faraday long ago pointed out that this interval depends on the capacity of the wire, and may vary very much according to circumstances. It is very great in submarine telegraph wires for instance (vide supra, p. 36). Accordingly, the values of the so-called velocity of electricity, which have been found by different observers, differ extremely.
The sketch we have just given of the disruptive discharge in rarefied gases must be regarded as the merest outline. There are many points of great importance to which we have not even alluded. Hittorf s investigation on what has been called the "resistance*' of different parts of a vacuum tube during the discharge has not been mentioned, although it led to results of much interest, which must come to be of great importance when the clue to an explanation of the whole phenomena has been found. The reader who desires to study the matter will find in Wiedemann an excellent account of Hittorf's work, with references to the original sources. We have not so much as raised the delicate and difi&cult questions concerning the spectroscopic characteristics of the discharge. A good part of this subject belongs indeed more properly to the science of Light.
Miscellaneous Effects, chiefly Mechanical. -- Owing to the
heat suddenly developed by the electric spark, and perhaps
to a specific mechanical effect as well, there is a sudden
dispersion in all directions of the particles of the dielectric.
This commotion may be shown very well by means of Kin- |
The Sextile or Trine of Mars and Venus. If Mars be fignificator, it is the afpeft of liberty and love; if Mars be out of his dignities, the native is vicious above meafure, loves gaming, wantonnefs, women, and all manner of lewdnefs and debauchery ; he is ill-natured, unlefs among his own party, and vvaftes and fpends his fortune upon women ; but, if Mars is in his dignities, it fliows one witty, ingenious, a fearcher-out of myfteries, and one who ftiall gain a confiderable fortune in the world. If Venus be fignificatrix, it is the afped of pride, vanity, and vain-glory : the native is comely, but bold, rafti, and adventurous, fearing nothing, aiming at great things, and promifing himfelf mountains, but perfefting little; and, if Venus be weak, the perfon is debauched, and guilty of many lewd adtions.
The
OF ASTROLOGY. 215
The Sextile or Trine of Mars and Mercury. If Mars be fignificator, it is the afped of confidence and craft ; the native has a pregnant fancy, capable of any thing ; prudent, fubtle, bold, very ingenious, eloquent, and ftudious in moft arts and fciences, yet fomething hafty, and fubjeft to pafiion, which being over, the man is good-humoured again. If Mercury be lignificator, the native is valiant, courageous, ingenious, a lover of military exercifes, phyfic, furgery, and chemiftry ; and may probably get a fortune by the fire, or dealing in martial commodities ; the native has generally a good opinion of himfelf.
The Sextile or Trine of Mars and Luna. If Mars be fignificator, it is the afpeft of loquacity and mutability ^ the native gets by the common people, or by travel, often changing his ftation or place of dwelling; he is turbulent, furious, and rafh, but is eafily perfuadcd again to a compla-.. cent humour. If Luna be fignificatrix, the native is paffionate, ambitious of honour, afpiring to great things, and purfijing them even to a precipice; and, when attained, they feldom continue with him; and the reafon is, becaufe of the mutability and changeablenefs of his own nature, mind, and difpofition, which beget a change of his fortunes.
The Sextile or Trine of Sol and Venus. If Sol be fignificator, it is the afpeft of candour and generofity ; the native is exceedingly goodnatured, of an heroic difpofition, having nothing but gallantry in all his aftions ; he gets by women, and has the favour of fome rich lady, by whom he meets either with a good fortune or promotion ; he is witty, ingenious, and of an adtive fancy. If Venus be fignificatrix, it is the afpe6l of grandeur and magnificence ; the native meets with court preferment, or has the favour of fome prince ; rifes to high honour and glory in the world ; of a good difpofition, yet a little paffionate, foon angry, and as quickly appeafed again ; of a free liberal difpofition, lofty, and a little given to pride and vain-glory ; but in general a fociable, merry, good-humoured, perfon.
The Sextile or Trine of Sol and Mercury. If Sol be fignificator, the native is proud, ambitious, conceited, yet very courteous, and without any feeming refentment ; pafTes over fmall afFrt)nts, left the taking notice of them Ihould be any prejudice to his grandeur ; he is nimble-witted, loquacious, and very good at invention. If Mercury be fignificator, the native feems to rife in the world wholly by his own wit and ingenuity, and without doubt will attain to a degree of honour above that of his birth and anceftors' quality.
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the glass tsbe, whkh, in place of settling JeTel, was, on the contrarf» fonnd to he settling in such a. manner as to giire it a very ioelined upper surface. The cause of this unexpected peculiarity was inquired into, and at once suspected to proceed from the unequal distrihution or action of light, one side of the tube heing more disposed to that iafluence than the other. To verify this conjecture, the tube was turned round in an opposite direetion to that influence* when the low side not only recov^ed itself, but very soon had an inclination upward, and, as often as the turning round was resorted to, the same effect was produced, for most sediment would persist in settling on the dark side of the tube, that being least agitated by the action of light. To render the cause of this phenomenon a fact no longer to be doubted, a slip of black paper was procured, in width about half the circumference of the glass cylinder, and to one side of which it was applied in order to exclude the light from that side, while it had free access to the other; the result was as anticipated, for it caused a very much increased deposit on the side shaded by the paper.
'*Thi8 variation, or ihclined settling, progressively decreased as the lighter part of the tube, through which the particles had to fall, became shortened by its filling up with sediment"
These interesting observations as to the effect of light upon the deposition of sediment are certainly confirmatory of the conclusion already arrived at -- that the density of the deposit from the same sample of river water may vary materially, according to the circumstances under which it is deposited.
Those of Lieutenant Marr. -- Lieutenant Manr's first sediment observations were continued during the months of April, May, and June, and a part of July, 1849. He thus reports the results :
** The quantity of silt has been ascertained by daily placing a known quantity of river water in a box, drawing off the water as it becomes dear, and weigh: ing (wjien dried) the earth thus deposited. The average quantity. of earth conti^ined in 100 cubic feet of river water is twelve and seven-tenths pounds/'
The fraction representing the proportion, by weight, of the*sediment to the water is 5^. This is certainly too large for a true yearly mean, on account of the turbid rise in the Missouri, which always occurs about this date. In 1856 the value for these months at Columbus was j^s^* while for the whole period of the observations it was only j^^j. Had not a very unusual flood of comparatively pure water from the Ohio occurred, the difference between these fractions would have'.heen much greater. (See preceding table of sediment at Golumbas.)
Second series. -- Lieutenant Marr's second series of observations upon Mississippi sediment were continued from March 1, 1850, to March 1, 1851. The foilowing extract from his report explains his method of taking them :
"A quantity of water has been daily obtained from the middle of the surface of the river, and two quarts of it placed in a barrel to settle. In bulk, the sediment thus obtained has been found to be in proportion to the water by which it was deposited as 1 to 2950."
Observations upon other rivers. -- The preceding observations are all that have been collected from which the proportion of sediment contained in Mississippi water may be determined. The following facts relative to European rivers are of value as affording a means of comparison.
MEASUREMENTS UPON EUROPEAN AND OTHER RIVERS. |
We are obliged, by the Light of Reafon, to difpofe in that Order the Parts that compofe the whole Univerfe, which we imagine to have been formed by the moft fimpie Ways. For all that had been faid is only grounded on the Idea of Extenfion, the Parts of which are fuppofed to move in the moft fimpie Motion, which is that in a Right Line. And when we examine by the Effects, whether we are miftaken in the Explication of Things by their Cauies, we are furprized to fee the Phenomena of Celeftial Bodies fo perfectly agreeing with our Ratiocinations. For we perceive all the Planets that are in the middle of a fmall Vortex turning upon their own Centre, as the Sun does, and fvvimming in the Vortex of the Sun, and about the Sun 5 the fmalleft and Leaft folid neareft to ir, and the moft folid at a greater diftance. We likewiie obferve, that there are lc»ne: as die Com :• is. which cannot remain in the Vortex of the Sun: And laftly, that there
are
Chap. IV. fixe Search after Truth. 6t
are feveral Planets, which have other fmaller turning about them, as the Moon does about the F.nrth: Jupiter has four of them, Mars has three, and perhaps Saturn has ib many, and ih lmall, that they refemblea continued Circle, of which the thicknefs cannot be perceived, bec-auie of their too vaft diftance. Thofe,;Planets being the biggeft^we can obferve;, , it may be iirugin'd. that they have been produced from Vortexes which Had a fufficient lhength to conquer others, before they were involved in the Yprtex we live in. ., ,
All thefe Planets turn upon their own Centre, the Earth within 24. hours, Mars within 2^. or thereabouts, Jupiter within about 10, &c. They all turn about the Sun, Mercury the neareit in about 4. Months-, Saturn the remoteft in about 30. Years, and thofe that are betwixt them i . 1 more or left time, which however keep not an exaft proportion with their diftance. For the matter in which they fwim makes a fwifter Circumvolution when 'tis nearer to the Sun, becaufe the Line of its Motion is then mortem When Mars is oppolite to. the Sun, he is then near enough to the Earth, but is at a vaft diitance from it when he is in Conjunction with him. The like may be faid of the other fuperiour Planets, as Saturn and Jupiter -, for the inferiour, as Venm and. Mercury are, to fpeak properly, never oppolite to the Sun. The Lines, which all the Planets feem to defcribe about the Earth, are no Circles^ but are very like Ellipfes, which Ellipfes feem very much to differ, becaufe of the different Situation of the Planets in reference to us. Jri mo'rt, whatever may be obferved with any certainty in the Heavens, touching the Motion of the Planets perfectly agrees with what has been faid of their Formation by the molt fimple ways. |
very much in their number in dilferent ovaria, but are very seldom so numerous as has just been stai have agreed that the ovaria prepare whatevi male supplies towards the formation of the festua ; and this is proved by the operation of spaying, which consists in the extirpation of the ovaria, aftei which the animal not only loses the power of conceiving, hut de sire is for ever extinguished. The outer coat of the ovaria, together with that of the uterus, is given by the peritoneum ; and whenever an ovum is passed into the Fallopian tube, a fissure is observed at the part through which it is supposed to have been transferred. These fissures healing, leave small longitudinal cicatrices on the surface, which are said to enable us to determine, whenever the ovarium is examined, the number of times a woman has conceived. The corpora lutea are oblong glandular bodies of a yellowish colour, found in the ovaria of all animals when preg nant, and, according to some, when they are salacious. They are said to be calyces, from winch the Impregnated ovum has dropped; and their number is always in proportion to the number of conceptions found in the uterus. They are largest and most conspicuous in the early state of pregnancy, and remain for some time alter delivery, when they gradually fade and wither till they disappear. The corpora lutea are very vascular, except at their centre, which is whitish; and in the middle of the white partis a small cavity, from which the impregnated ovum is thought to have immediately proceeded. The ovaria are the seat of a particular kind of dropsy, which most commonly happens to women at the time of the final cessation of the menses, though not unfrequently at a more early period of life. It is of the encysted kind, the fluid bring sometimes limpid and thin, and at others di and gelatinous. In some cases it has been found contained in one cyst, often in several ; and in oHieis the whole tumefaction has been composed of hydatids not lamer than grapes, The ovaria are also subject, espe cially a short time after delivery, to Inflammation, terminating in suppuration, and lo scirrhous and cancerous diseases, vviih considerable enlargement. In the former state, they generally adhere to some adjoining
part, as the uterus, rectum, bladder, or external Integuments, and the matter is discharged from the vug na by stool, by urine, or by an external abscess of the in teguments of the abdomen.
OVATl.'S. Ovate. Leaves, petals, seeds, &.c. are so called when of the shape of an egg cut lengthwise, the base being rounded, and broader than the extremity, a very common form of leaves ; as in Vinca major and Urtica pilulifera, and the petals of the Allium fla vum, and narcissus pBuedo-narcissus ; the receptacle of the Omphalea, and seeds of the liuercus.
OVIDI : ictus; from ovum, an egg, and
ductus, a canal.) The duct or canal through which the OVUm, or egg, passes. In the human species, the Fallopian tube is so called, which runs from the ovary to the bottom of the womb.
OVIPAROUS. (From ovum, an egg, and pario, to bring forth.) Animals which exclude their young in the egg, which are afterward hatched.
Ovo'rwm test r.. Egg-shells. A testaceous absorbent
Hi
ovu
ovu
OVULOM. Alittleega. See Ovum. O'VUM. 1. An egg. SeeJE^y.
a. 'i'lie vesicles in tlie ovarium of females are called the ova, or ovula. When fecundation takes place in one or more of these, they pass, after a short time, along the Fallopian tube into the uterus. |
Cleaning Bolting-Cloths. -- Various devices have been proposed for the purpose of keeping bolt¬ ing-cloths free from paste, etc. One of the best inventions is that of Messrs. Rathbun Brothers, of East Pembroke, N. Y. The contrivance consists of spring-bolts securely fastened to the insides of the cross-stripes on the tail end of the reel, to the inner end of which are attached strong cords of gut running directly under the cloth and fastened at the head. On the bridge-tree at the tail of the reel is secured a circle, to which is attached a steel-faced cam in such a way that it will turn back if the reel is turned backward, but if held in position it causes the spring-bolts to crowd in as the reel revolves. This slackens the cords, and as the spring-bolt passes the cam the reaction of the spring causes the cord to snap against the inside- of the cloth, thereby removing the flour and the impurities which have caught on the cloth, and causing them to fall back into the reel.
The Cogswell & Finn bolt-cleaner consists of a brush suspended over the reel by arms secured to a shaft. The reel is cleaned through its rotating in contact with the brush. H. L. B.
MILLING MACHINE. The milling machine has assumed a position of great importance in the manipulation of iron work, especially that of small dimensions. The advantages it possesses are as follows : 1. Having a rotary cutter, the cutting operation is, so far as the cutter is concerned, continu-
MILLING MACHINE.
ous. 2. The outline of the work assumes a form in exact truth with the outline of the cutting edges of the cutter. S. The machine being once adjusted, all the work operated upon therein will possess exact uniformity in size and form. 4. By varying the position of the work beneath the revolving cutter or cutters, pieces of work of uniformly irregular shape may be duplicated with an assurance of exactitude in both size and shape. 5. The only special skill required to operate the machine con¬ sists in maintaining the form of the cutters and in setting the work. For these reasons the milling machine is applied to every form of small work which will admit of manipulation by rotating cut¬ ters, more especially in the manufacture of sewing machines and rifles. Even screw-cutting taps may be threaded by milling tools.
The milling machine consists essentially of a framework carrying a spindle revolved by a conepulley, either alone or in combination with gear-wheels whereby to obtain more changes of speed and greater driving power to the cutter, the same frame carrying a table whereon chucks or work¬ holding devices of various forms and sizes may be fastened. The chuck or work-holding device is then traversed beneath the rotating cutter, or is sometimes made to revolve, or to revolve and traverse at the same time, as in the case of milling out the flutes of twist-drills. In rare cases the work is stationary and the milling cutter is traversed.
The Universal Milling Machine , made by the Brown & Sharpe Manufacturing Company, shown in Fig. 3004, and also in a full-page engraving, has proved one of the most successful yet devised for general purposes. The spindle 0 C, for carrying the cutters, has its journal-bearings in the frame A, which is made hollow, a shape giving great rigidity, and forming a closet for the tools and appur¬ tenances to the machine. The arbor for holding the cutters is separate, and fits into a conical hole provided in the spindle at O'. Over the spindle C O' is an arm H extending across over the spin¬ dle-cone, from the front to the rear bearing, and projecting toward the front of the machine, to which |
Ordinary air-dried peat contains from 20 to 30 per cent of its fffM weight of moisture. If dried in air in the most effective manner, it contain at least 15 per cent, of moisture; and even when dried in a stove, it seldoa holds less than 7 or 8 per cent.
The peats named in table No. 156 were subjected to distillation, wfaen they yielded water, tar, charcoal, and gas, in the proportions shown in table No. 158:--
Table No. 158. -- Products of Distillation of Irish Peat.
Description and Locality of Peat
Water.
Crude Tar.
Charcoal
Gas.
Nos. I and 2, Philipstown
99 3> Wood of Allen
„ 4, do.
„ 5, Ticknevin
, , 6, Upper Shannon
Averages
percent.
percent.
percent.
perccflt
3S-7
The tar, when re-distilled, yielded water, paraffine, oils, charcoal, and gtt. The water yielded chloride of ammonium, acetic acid, and wood-spirit
PEAT-CHARCOAL. -- TAN. 455
Power of Irish Peat, -- In peat of average composition, as given ve» the heating power is by rule 4, page 406,
fectlydiy, 145 (59 + 428 (6-^)) = 9951 units of heat;
J^^C^.r.' } '45 (44 + 4.^8 (4.5 - ?M) ) = 7435 units of heat
Deduct for evaporating the moisture, ^ lb.,
supplied at 62°; iii6**h-4 = 279 do. do.
Effective heating power 7156 do. do.
rhe total evaporative power of i lb. of fuel, evaporating at 212°, is follows: --
Perfectly dry. Containing « per
' ' cent, of moisture.
lien water is supplied at 62°, divisor 11 16**... 8.91 lbs. 6.41 lbs.
Do. do. 212°, do. 966**... 10.30 lbs. 7.41 lbs.
British and foreign peats are very much like Irish peat in composition ; principal variation takes place in the proportion of ash.
PEAT-CHARCOAL.
fhe charcoal of ordinary dried peat is very porous, and, in general, light [ fragile; but the charcoal of condensed peat is dense and solid. It DS easily but slowly : small incandescent pieces separated from the fire tinue to bum undl the whole of the carbon disappears. Good peat ds from 30 to 40 per cent of charcoal; and the charcoal when perfectly consists generally of from 85 to 90 per cent of carbon, and 10 to 15 cent of ash.
rhe heating power of one pound of peat -charcoal, containing 85 per t of carbon, by rule 4, page 406, is, 145 x 85 = 12,325 units of heat; ivalent to the evaporation, at 212**, of 1 1.04 lbs. of water supplied at 62% rf 12.76 lbs. supplied at 212°. The temperature of combustion is that caibon, 4877** F.
In France, the peat-charcoal of Essonne contains 18.2 per cent of ash. the Ardennes, Bar peat carbonized in ovens yields 44 per cent of charil; but this contains one-third volatile matter, one-fourth ash, and only per cent of carbon.
TAN.
Tan, or oak-bark, after having been used in the processes of tanning, is ned as fiieL The spent tan consists of the fibrous portion of the bark, xoiding to M. Pedet, five parts of oak-bark produce four parts of dry i; and the heating power of perfectly dry tan, containing 15 per cent of b, is 6100 English units; whilst that of tan in an ordinary state of dryness, Btaining 30 per cent of water, is only 4284 English units. The weight water evaporated at 212° by one pound of tan, equivalent to these heat- ;poweiS| is as follows: --
45* FUELS.-- STRAW, LIQUID FUELS.
Pafcctfldrr. ■^'SSS.^
Water supplied at 6a° 5.46 lbs. 3.84 lbs.
» >. ^iz" 6.31 „ 4.44 „
STRAW. The average tomposilion of wheat-straw is as follows: --
Water 14.13 percenL
Organic or combustible matter; consisting of 1 „
carbon, hydrogen, oxygen, and nitrogen.. J ' '^° " Ash '. 7.47 .,
Chemists have not, so far as the author has learned, thought it while to record the proportions of the organic elements. But it n supposed that the composition of straw is similarly proportioned to lluC peaL The weight of pressed straw is from 6 to 8 lbs. per cubic foot
LIQUID FUEl^ |
10. When added to earths, and particularly to thofe called verifiable earths, and expofed to a fufficient degree of heat, they and the earths become glafs. See Vitrification.
11. When added in a large proportion to the earths with which they are fufed or vitrified, they communicate to thefe earths all their own properties. See Liquor ij/Tlints.
j 2. They cfFervefce and unite with acids to the point of fituration more perfectly and more intimately than pure abforbent earths, and from this union refult different neutral falts.
13. They dccompofe all falts with bafes of earths, metals, or volatile alkali. They Separate thefe bafes, and unite with the acids of the falts, with which they form new neutral falts. This is an example of ftronger affinity, from whence refult a new decompoiltion and a new combination.
(c) Volatile alkali retains water fo ftronglv, that it cannot be obtained dry, unlefs by combining it with fixable air, and then it becomes crylhillizable. The fixed alkalies may be rendered dry by application of heat, but are only cryftallizable by help of fixable air. See Gas
(d) Mineral alkali does not deliquiate by expofure to air; but on the contrary, when cryftallized, it is apt to become dry, and to lofe the water which is neceffary to its cryftalline Hate.
(e) Concerning the effects of acids and alkalies on the color of < , 1 up of violets, Jet the note (d) Jubjoined to the article, Acid.
E 4 Alkaline
ALKALI
Alkaline faits being fubftances pretty fimple, as well as acids, are pov/crful folvents. They are capable of combining not only with all acids and with all earths, as we have faid, but alfo with fulphur and with oily matters. With fulphur they form a fulphureous feap, foluble in water, called liver of fulphur; which fee.
With oils, fat, refits, fee. they form compounds, which have been called fcaps. In each of thefe combinations, the alkali is a medium by which the inflammable fubftance, naturally unfoluble, and even immifcible in water, becomes inifcible and foluble in that liquid. See Soap.
Thefe faline fubftances can acf. alfo upon fpirit of wine, when they are deprived of all the water unneceflkyy to their effence as falts. Alkalies, in that ftate, applied to fpirit of wine, firft deprive it of its fuperfluous water ; afterwards, when in a proper proportion, they acl: upon its own fubftance, by combining with it, and caufing feveral alterations, and even a decompofition of its parts. See Spirit of Wine (Tartarised), and Tincture of Salt of Tartar.
Laftly, alkalies act upon metallic fubftances with more or lefs facility, according to their natures, and the different means employed ; which mall be mentioned under the feveral articles of the alkalies and metals.
N. B. All that has been faid above concerning alkalies, may be applied to all the feveral kinds of alkalies, even to thofe called 'Volatile, excepting thofe properties which depend upon fixity. Hence this article is applicable to alkalies in general. But it is neceftary to obferve, 1 that a very juft idea cannot be formed of thefe generalities, without entering into the details of what concerns the feveral kinds. See for the affinities of fixed alkali, and for its medicinal virtues, the word Alkali (Fixed Mineral).
ALKALI (FIXED VEGETABLE). Thisname is given to ail fixed alkalies obtained by burning any vegetable fubftances, and which have not the properties of the alkali, which is the bafis of common fait, which has been called the alkali of common fait, the marine alkali, mineral or foffil alkali.
The common method of obtaining fixed alkalies from vegetable fubftances, confifts in burning thefe fubftances freely and in open air, till they be reduced to afhes. See Combustion of Plants. After which thefe afhes are lixiviated with very pure water, till the water, comes from Them infipid. This lixivium is evaporated to drynefs ; and what remains is the fixed alkaline fait of the plant, which
- may
ALKALI |
HISTORY 159
The twenty-fifth anniversary of the founding of the College was signalized by the c<»iipletion and occupatioa of a building in which antple space for many years' growth was provided. The better accommodations gave an impulse to better work. Up to this time instruction had been given mainly by means of lectures, laboratory work being entirely optional. Laboratory courses in pharmacy, chenristry, and vegetable histolc^y were now made obligatory. A laboratory devoted entirely to prescription compounding was established in 1892. The excellence of the equipment in this department won for the College a medal and diploma at the World's Columbian Exposition.
The College was formally united with the University May 1, 1896, and is now conducted as the technical "School of Pharmacy of the University of Illinois." In the management of the School the Trustees and officers of the University have the assistance of an advisory board of pharmacists elected by the registered pharmacists of the state through the IllintMSi Phamtaceutical Association,
The School is situated near the business center of Chicago. In addition to the larger amphitheater, known as "Attfield Hall," which has a seating capacity of three hundred and fifty, the building occupied has a smaller hall especially fitted for lectures and demonstrations in chemistry, and capable of seating one hundred and fifty persons. The chemical and pharmaceutical laboratories, as well as the nucroscofMcal laboratory and the dispensing laboratory, are ccahmodious and well appointed.
The courses of instruction, covering two terms of seven months each, extending from September to April, inclusive, afford opportunities for a thoroiigh technical training, such as is necessary for the successful practice of pharmacy. The strt)jects taught are pharmacy, ch«nistry, botany, physiology, and materia medica.
The system of teachii^ includes lectures, demonstraticms, recitations, written and oral examinations, as well as individual instruction in actual woric in operative and dis-
I .... ...CjOoqIc
I60 SCHOOL OF PHABMACY
pensin^ pbzimacy, analytical cbetnistt?, use of the cocnpound microscope, etc Much time is devoted to laboratory practice.
REQUIREMENTS FOR ADMISSION
Applicants for admissioo must be at least sixteen years of age and must furnish evidence of their ability to prosecute the work of the course successfully.
The preliminary education should be equivalent to that required for entrance to a good high school.
Students who have pursued courses of study in odier colleges of pharmacy, or at the Universi^, will be given credit for such portions of their work as are equivalent to the work required by this School,
REQUIREMENTS FOR GRADUATION
The candidate for the degree of graduate in phznaacy must be twenty-one years of age, must have had four years' practical experience in pharmacy, including the period of attendance at School, and must have attended two full courses of instruction, the first of which may have been in some other reputable coU^e or school of pharmacy. He must have attended r^ularly the l^ioratory and lecture courses of this School, must pass the examinations, and must not have been absent more than five times during the term from either laboratory exercises or lectures in any* department
The candidate for the d^[ree of graduate in pharmacy, who presents himself for final examination before he has attained the age or practical experience required, will, if successful, receive a certificate of having finished the course, and will be awarded his diplonra when the requirements <^ age and experience are complied with.
Persons competent to fulfill the general requirements of admission to the University may be granted credit upon the
I ...._.■., Coot^lc
GRADUATIOH l6l
University courses for equivalent work satisfactorily completed at the School of Pliarmacy. |
608. Fbotorr^pl&y i^ the art of fixing the images of the on substances sensitive to light. The various photographic processes tMf be classed under three heads : photography on metal, photography oo paper, and photography on glass.
Wedgwood was the first to suggest the use of chloride of siUcr in fiiinjf the image, and Davy, by means of the solar microscope, obtained imagCJ of small objects on paper impregnated with chloride of silver ; but no tn«lW was kno^^m of preserving the images thus obtained, by preventing the furtber action of light. Niepce, in 18 14, obtained permanent images of the cwncja by coating glass plates with a layer of a varnish compK>scd of bitames di»* solved in oil of lavender. This process was tedious and incfficicnl, and il was not until 1839 that the problem was solved. In that year Di^nent described a method of fixing the images of the camera, which, with the subsequent improvements of Talbot and Archer, has rendered the art of pboM^ grraphy one of the most marv^ellous discoveries ever made, whether as to tibc beauty and perfection of the results, or as to the celerity with which the) »? produced.
In Daguerre's process, the Dagti€rrotypi\ the picture is produced QQt plate of copper coated with silver. This is tirst very carefully pol^hed^^v [ operation on which much of the success of the subsequent operations depends It is then rendered sensitive by exposing it to the action of ioditir vifiour. which forms a thin layer of iodide of silver on the surflicc, TTie phi fit to be exposed in the camera ; it is sensitive enough for views u I quire an exposure often minutes in the camera, but when greater required, as for portraits, &c., it is further exposed to the action of M rator^ such as bromine or hypobromite of calcium. All the 0|>efatjflm mtt« be performed in a room lighted by a candle, or by the dayhjjlu *dxni through yellow glass, which cuts off all chemical rays. The plate i>
from the action of Iigfcl placing it in a »mali »ci case provided with « tlw the sensitive side*
TJic third operation < sists in ex|)osing the \ plate to the action of I placing it in that pc«itid the camef a where the \ is produced with delicacy. For pboiQ purposes a of peculiar used The brass tuW i 545) contains an arh cnndcnstng lens.
l-'ijE* £*5
be moved by means of a rackwork motion, to ^Inch \s titled a milled I D. At the opposite end of the box is a gTOUOd-glBSS ptetc, E, which 1
Photographs on Paper,
ve» B, in which the case containing the plate also fits. The !jng placed in a proper position before the object, the sliding part is adjusted until the image is produced on the glass with the kaq)ne&s ; this is the case when the glass slide is exactly in the le 6nal adjustment is made by means of the milled head D. iss slide is then replaced by the case containing the sensitive slide which protects it is raised, and the plate exposed for a time, \Xk of which varies in different cases, and can only be hit exactly raclice The plate is then removed to a dark room. No change iblc to the eye, but those parts on which the light has acted have |bc property of condensing mercur}' : the plate is next placed exposed 10 the action of mercurial vapour at 60 or 70 degrees. cury is deposited on the parts affected, in the form of globules Ible 10 the naked eye. The shadows, or those parts on which bas not acted, remain covered with the layer of iodide of silver, dioved by treatment with hyposulphite of sodium, which disile of silver without affecting the rest of the plate. The plate is r»cr| in a solution of chloride of gold in hyposulphite of sodium, olves the silver, while some gold combines with the mercury and ic parts attacked, and greatly increases the intensity of the lustre. the light parts of the image arc those on which the mercury has ited« and the shaded those on which the metal has retained its |
(2.) Liquids, as water, transmit sound with much less velocity than solids. According to the experiments of Colladon and Sturm, which were made on the waters of the Lake of Geneva, the velocity of sound in water is about 4708 feet per second. The velocity of sound in water is determined by two individuals placed at a known distance from each other : one of them communicates vibrations to the water by striking two elastic bodies at a given instant, and the other, having his ear in contact with the water, notes the exact time when the sound is heard. The distance divided by the difference of time in seconds will give the velocity.
(3.) The velocity with ivhich air transmits sound has also been determined by experiment. Though, in consequence of the fact that the density, temperature, and moisture of the air vary at different times, there is a slight variation in the rate at which sound is propagated through it, yet at a medium pressure, and at a temperature of 60° F., sound travels about 1120* feet per second, or about one fourth as rapidly as in water, and only about one eighteenth the velocity with which it is transmitted in glass. The velocity of sound in air is determined by ascertaining the time required for it to pass over a known distance. In consequence of the almost instant passage of light through any considerable distance on the earth's surface, this may be effected by observing the flash of a musket at a certain distance, and noting the time which transpires before the report reaches the ear.
* The velocity of sound through air was determined in France, at the temperature of 329 F., to be 1086-1 feet per second. Its velocity, as determined about the same time in Holland, was 1089-42 feet per second; and, assuming that its velocity is increased 1-14 feet per second for an increase of one degree <>f temperature, the velocity at a temperature of 62i° F. would be, for the first, 112087, and for the second, 1124-19 feet per second; which latter is the rate which has been considered most correct. According to this rate, sound travels 12| miles per minute, or 765 miles per hour.
Which of the three forms of matter transmits sound with the greatest velocity ? How is the velocity of sound determined ?
232 NATURAL PHILOSOPHY.
If the air is moist, the velocity is slightly increased. A wind in the same direction in which the sound travels will increase, and in the opposite direction will diminish its velocity.
There is also a slight variation dependent on temperature. As the temperature is raised, the velocity of sound is increased about one foot (1-14 feet) for every degree. Sound, therefore, will travel faster in summer than in winter, faster during damp than during dry weather.
In consequence of the known rate at which sound travels, we may determine the distance at which any report is made, provided we are able to observe the cause of it. Thus we may observe the blows of a man's ax felling a tree at a distance, and by noting how many seconds intervene after we see the stroke before the sound reaches us, the exact distance may be known.
In this case, we often observe the tree to fall before the last stroke reaches the ear. The distance of a flash of lightning may be determined in the same way by counting the number of seconds which intervene between the flash and the thunder. The number of seconds between the flash and the report of a cannon, multipled by 1120 feet, will give the distance it is from us. |
bracket of eq. (5), with different lij^draulic radii, slopes, and values of w, according to Kutter's Formula ; from JS = i ft., for a small ditch or sluice wav (or a wide and shallow stream), to i? = 15 ft., for a river or canal of considerable size. Under each value of H are given two values of A ; one for a slope of y = .001, and the other for «" = .00005. All these values of A imply the use of the foot and second.
These values of A have been scaled by the writer from a diagram given in Jackson's translation of Kutter^s " JByd/ratdic Tahles^^'* and are therefore only approximate. The corre- 49ponding values of y, the coefficient of fluid friction, can be
computed from y = -^ .
.J ft.
Rs
ift.
R =
= 8ft.
i?s
:6ft.
£ = 16 ft.
for
for
for
for
for
for
for
for
for for
f"
f' »"
The formula used in designing the New Aqueduct for New York City, in 1885, by Mr. Fteley, consulting engineer, was [see (4)]
V {ft per sec.) = 142 VR{inft) X «, ... (7)
whereas Kutter's Formula gives for the same case {a circular^ section of 14 ft. diameter, and slope of 0.7 ft. to the mile), with n = 0.013,
V {ft. pe)' see) = 140.7 VIi(:inft) X s. . . . (8)
* The aqueduct has this circular fonn for a smaU portion, only, of its length; a " horseshoe" section of very nearly the same flowing capacity being given to the greater portion of the remainder.
762 MECHANICS OF ENGINEERING.
, To quote from a letter of Mr. L A. Shaler of the Aqueduct Corps of Engineers, *' Mr. Ftelej states that the cleanliness of the conduit (Sudbury) had much to do in affecting the flow. He found the flow to be increased by 7 or 8 per cent in a portion which had been washed with a thin wash of Portland cement."
Example 1. -- A canal 1000 ft. long of the trapezoidal section in Rg. 611 is required to deliver 300 cubic ft of water
per second with the water 8 ft. deep at all sections (i.e., with uniform motion), the slope of the bank being such that for a depth ,^^-8~~*f of 8 ft. the width of the water surface (or Fio. 611. length of air-profile) will be 20 ft; and the
coefficient for roughness being n = .020. What is the necessary slope to be given to the bed (slope of bed = that of surface, here) (ft., lb., sec.) ? The mean velocity
i? = C -=- J?" = 300 -7- i (20 + 8) 8 = 2.67 ft per sec
[So that the surface velocity of mid-channel in any section would probably be {c, nBx.) = ^ -5- 0.83 = 8.21 ft per sec. (eq.
The wetted perimeter
i^? = 8 + 2v'8" + 6' = 28ft.,
and therefore the mean hydraulic depth
= ^ = F^ w? = 112 -^ 28 = 4 ft
To obtain a first approximation for the slope, we may nse the value/* = .00795 given by Weisbach for a velocity of 2.67 ft. per sec., and obtain, from (3),
k = •00795X1000X28(2.67)' ^ ^ ^^^
112 X 2 X 32.2 '
i.e., 8 = h'^l = .000221.
TJNIFOBM MOTION IN OPEN CHANNEL. 763
With this value for the slope and 7? = 4 ft. (see ahove), we then have, from eq. (6) (patting n = .020),
with which valne of/* we now obtain
A = 0.200 feet; i.e., slope = « = .00020.
Example 2. -- If the bed of a creek falls 20 inches every 1500 ft. of length, what volume of water must be flowing to maintain a uniform mean depth of 4^ ft., the corresponding surface-width being 40 ft., and wetted perimeter 46 ft. ? The bed is '^ in moderately good order and regimen ;" use Kutter's Formula, putting n = 0.030 (ft. and sec).
First we have
VBs = a/(40x4J)h-(46x^) = .066,
while VSJK) =1.98, and the slope = « = |^ -4- 1500=.00111 ; hence
[41.6 + 1:M1 + :20281 1^0.066 _ L ^ .030 ^ .00111 J 104.43 X .066
*~ -. . r., ^ I .00281 "10.030 ~ 1.6685 '
^+r^-^+:ooiirJT98-
or
V = 4.13 ft. per sec.
Hence, also,
Q=:Fv = 40XHX 4.13 = 743.4 cub. ft. per sec
[N.B. Weisbach works this same example by eq. (3) with a value of/ taken from his own table, his result being v = 6.1
764 UECHANIGS OF ENGINEERING. |
tary body represents. The moment the particles of cosmical vapor met and united, -- in other words, condensation began, -- heat was generated. It was the great obstacle in the way of condensation. From the amount of heat represented by the present motion of the earth, the degree of heat of the original chaos can be determined. It is found that only the four hundred and fifty-fourth of the original force remains ; but if this remainder were converted into heat, as it would be if the planets were all to fall into the sun, and the whole system suddenly be brought to rest, it would raise the temperature of the entire mass to twenty-eight million degrees centigrade, or fifty million degrees Fahrenheit. When we consider that the highest temperature we are capable of attaining is by the oxhydrogen blow-pipe, and that this does not exceed three thousand six hundred degrees Fahrenheit, but is sufficient to not only melt, but vaporize, platinum, the most infusible of metals, we can at once learn the incomprehensibleness of fifty million degrees, or more than thirteen thousand times that number. If the entire mass of the system were pure coal, and at once lit up in terrific combustion, only the thirty-five hundredth part of this heat would be generated.
A simple calculation affords us a view of the result if the earth were suddenly stopped in its orbit. The momentum of a ponderous ball, eight thousand miles in diameter, hurled sixty-eight thousand miles an hour, is at once converted into heat. A rifle-ball arrested becomes too warm to touch.
Matter and Force. 109
The earth is raised to sixteen thousand five hundred and sixty degrees Fahrenheit, a temperature sufficient to convert its most obdurate minerals into vapor, into a vast cometary chaos. If arrested, it would fall into the sun ; and the degree of heat developed by such a catastrophe would be four hundred times greater, or six million six hundred and twenty-four thousand degrees Fahrenheit.
70. The Sun the Fountain of Life.
The heat of the sun's surface -- the great perpetual fountain of life -- has been estimated, from what appear to be correct data, to be from seven thousand to fifteen thousand times greater than the oxhydrogen blow-pipe. This incomprehensible temperature is maintained invariably, and an immense flood of light and heat radiated into space. Meeting the surface of the planets, it warms, enlightens, and sets at work the processes of life. It is the origin of living beings, who derive from its exhilarating rays all their motion, or living force, which stands directly correlated to sunlight and heat.
We are all children of the sun, from the humblest worm to the divinest man. All are storehouses of these forces, which can be at any time called forth. When^wood is burned, it is not newly created heat we produce, but the light and warmth of the sun exerted in building up the cells of the wood.
A diamond shines in the dark, after exposure to the sun's rays, from the absorption of those rays.
no Arcana of spiritualism.
Wonderful thought! when we burn the dark and shining coal, we set at liberty the sunlight and sunheat treasured up by plants in the dark age of mythically gigantic vegetation flourishing in the marshes of the coal period ! We create nothing. The coal is simply a treasury of the heat and light of the sun.
71. Beautiful is this Circle of Transformation.
The heat of the sun builds up a plant. It is a storehouse of these forces to the animal that eats and digests it. The original heat is liberated by the chemical action in its system ; and it is warmed thereby, and tremendous muscular power derived. The same chemical processes occur when wood is burned in the furnace of an engine. The treasured heat is reconverted to the original motion of the chaos of the beginning. Thus the force of the animal frame and of the engine are reproductions of the primal forces of the planetary bodies.
72. The Realm of Life. |
There are in the^vicinity of the City several establishments for the manufacture of Brick. Yet all of these but one turn out their Brick in the " old fashioned way." The Messrs. Knight Bros., in 1868, established extensive Yards on the south bank of the Cumberland lliver, immediately above the City Reservoir. They supplied themselves with "Gard's Improved Steam Brick Machine," employed some thirty hands, and manufactured superior kinds cf Building and Paving Brick. During the first six months of their operations, without running constantly, they turned out 500,000 Brick, but soon ran their capacity up to 3,000,000 per annum. At present these Works are not in full running order, from the fact that nearly all the Brick Layers in the City make their own Material, and the outside demand is not overly great, so that the amount now made will fall short of the last figures.
Broom Manufactories.
From actual insignificance, prior to the war, the manufacture of Brooms in Nashville has grown to be one of importance. We can well remember the time when the only Broom Makers in our country were nothing more than industrious old negroes who managed to do their work during leisure hours, and brought their goods to the City on their shoulders for sale. Who would have thought the prophet sane in those days had he have foretold that to-day Nashville would claim among her separate Manufactures a department devoted exclusively to Brooms. But, waiving all prolonged remarks as to what was, we are enabled to ]>resent some interesting, and, as we deem them, important facts relative to the business at present. If our farmers but knew that with an expenditure not exceeding $30 to the acre they could produce Broom Corn commanding as high as $300 per ton, and that it is a crop that requires but little labor and attention, pcrlia})s they would take it as granted that "a hint to the wise is sufficicnj," and plant accordingly. The Corn raised in Tennes-
188 NASHVILLE AND HER TRADE.
see is rceoiumended l)y dealers and ISIanufacturers as far prclbrable to that produced in other States, for many reasons, prominent among which are its qualities of durability and fineness of brush. It matures much earlier, and when avcII cured, always commands a better price than Northern-raised Corn. Thus far, the facilities for raising the crop have not been so good as in States North and West of us, but more attention is being j^aid to the business as each year roUsi round, and the result is profitable. The coming crop will, in all probability, be much larger than any previous one, since several hun-' dred bushels of Seed have been distributed by the dealers here to parties who have never grown it before. The first crop raised as a speciality in Tennessee, perhaps, was that of Mr. 11. A. Toon, during 1865, in Williamson County. His success was decided, and has stimulated and encouraged its culture here wonderfully. But we pass to the Manufactories. |
Insolvent Law of 1853 requires that assignments shall be for the benefit of all the creditors, or creditor may petition Judge of Probate for appointment of trustee of debtor's estate. All attachments made within sixty days preceding such assignment, or application, are dissolved. All conveyances by mortgage or otherwise, which shall have been made in view of insolvency are void. Debtor must make oath of the delivery of all property of every kind, in or out of the State, and that he has not conveyed or disposed of any property for the purpose of giving any preference in view of Insolvency. Debtor to receive a sum not exceeding $ 15 a week for support of himself and family, and for a time not exceeding six months. If the estate pay fifty per cent., debtor is to receive twenty-five per cent., amount not to exceed $ 1000. If the estate pay seventy-five per cent., or more, debtor shall be entitled to an absolute discharge. The household furniture to be included in debtor's inventory of the estate, but the court shall set off to debtor so much as is necessary for debtor and his family, not exceeding $ 300. Claims must be presented within six months. AH debts for labor performed within six months preceding institution of proceedings to be paid in full, if less than $25.
NEW YOEK.
Limitation of Actions. -- Actions upon a contract, obligation, or liability (express or implied) must be commenced within six years; and on judgments and sealed instruments, within twenty years. Where there are open and mutual accounts the cause of action shall be deemed to have commenced from the time of the last item charged in the account on the adverse side.
Actions are commenced by serving a summons upon the defendant The summons is subscribed by the plaintiiF, or
TG 7*
78 RECOVERY OF DEBTS IN NEW YORK.
his attorney, and direoted to the defendant, and requires him to answer the complaint, and serve a copy of his answer on tVie person whose name is subscribed to the summons, at a place within the State, within twenty days after the service of the summons. The plaintiff also inserts a notice in the summons, in an action on a contract for the recovery of money, that he will take judgment for a specified sum, if the defendant fails to answer in twenty days. In other actions, if defendant fail to answer in twenty days, the plaintiff will apply to the court for the relief demanded in the complaint. In actions affecting the title to real property, notice of a pendency of the action is given by filing with the clerk of the county a description of the property, and names of the parties.
Attachment. -- The real and personal property of a debtor, may be attached -- whenever such debtor, being an inhabitant of the State, shall secretly depart therefrom, with intent to defraud his creditors, or to avoid process of service, or keeps himself concealed with like intent ; or whenever a person, not being a resident of the state, shall be indebted on a contract made within the state , or to a creditor residing within the state although upon a contract made elsewhere. The application for attachment must be in writing, verified by the affidavit of the creditor, and the facts and circumstances established by the affidavit of two disinterested witnesses.
The plaintiff must give security, before the issuing of the warrant, to the effect, that if the defendant recover judgment, the plaintiff shall pay all costs and damages awarded to defendant, and all damages he may sustain by reason of the attachment, not exceeding the sum specified in the undertaldng, which shall be at least $250.
Any other creditor may become a party to the attachment, whose debt is then due, on filing with the officer an affidavit, specifying the sum due him, over and above all discounts, and expressing in a petition, his desire to be deemed an attaching creditor. |
texture; or are composed of nacre , or mother of pearl. It appears that the porcellaneous shells are composed ot carbonate of lime, cemented by a very small portion of gluten ; and that mother of pearl and pearl do not differ from these, except by a smaller portion of carbonate ot lime; which, instead of being simply cemented by animal gluten, is intermixed with, and serves to harden, a membranaceous or cartilaginous substance ; and this substance, even when deprived of the carbonate of lime, still retains the figure of the shell. These shells appear to be formed of various membranes applied .stratum super stratum, each membrane having a corresponding coat, or crust, or carbonate of lime. The inhabitants of these stratified shells increase their habitation by new strata, each stratum exceeding in extent those which were previously formed, the slfell becoming stronger in proportion as it is enlarged, and its number of strata denoting its age.
Mother of pearl, according to Merai-Gnillot, contains 66 carbonate of lime, 34 membrane. -- Ann. fie Chim. xxxiv. 71.
Tooth and bone being steeped in acids, the ossifying substances are dissolved : the enamel of the tooth is completely taken up by the acid, while the cartilage of the bony part of the tooth is left, as is the case with other bones, retaining the shape of the tooth, and a cartilage or membrane of the figure of the bone remains. These effects, as well as those from exposure to fire, show a similarity between enamel and the porcellaneous shells, as well as between the substance of tooth and bone, and shells composed of mother of pearl. Thus porcellaneous shells resemble enamel, in suffering a complete dissolution in acids, and not leaving any pulpy or cartilaginous matter; whilst shells of nacre, like bone, and the substance of tooth, part with their ossifying substances in certain acids, and their bases remain in the state of membrane or cartilage. The basis varying in different shells, and in different bones, in its degrees of inspissation, from a very attennuated gluten to a tough jelly, and from this to a perfectly organized membrane composed of
3C2 4
fibres, arranged according to the configuration of the shell or bone.
The cuttLe bone of the shops, appears m composition exactly to resemble shell, it consisting of various membranes, hardened by carbonate of lime, without the smallest mixture of phosphate.
The crust of the echinus approaches most nearly to the shells ot the eggs of birds, consisting of carbonate, with a 3mall proportion of phosphate of lime, cemented by gluten.
Merat-Guillot obtained from lobster crust 60 carbonate of lime, 14 phosphate of lime, 26' cartilage; and from eray-fish crust 6’0 carbonate of lime, 12 phosphate of lime, and 28 cartilage.-- Ann. de Chim. xxxiv. 71. |
The armature of a dynamo-electric machine usually consists of a series of coils of insulated wire or conductors, wrapped around or grouped on a central core of iron. The movement of these wires or conductors through the magnetic field of the machine produces an electric current by means of the electromotive forces so generated. Sometimes the field is rotated ; Sometimes both armature and field rotate.
The armatures of dynamo-electric machines are of a great variety of forms. They may for convenience be arranged under the following heads, viz.:
Cylindrical or drum-armatures, dis car matures, poleor-radial armatures, ring armatures, and spherical-armatures. For further particulars see above term-;. Armatures are also uivided
into classes according to the character of the magnetic field through which they move -- viz.: unipolar, bipolar, and multipolar armatures.
The English sometimes use the word cylindrical armature as a synonym of ring-armature.
A unipolar-armature is one whose polarity is never reversed. A bipolar -armature is one in which the polarity is reversed twice in every rotation; multipolar armatures have their polarity reversed a number of times in every rotation.
The term armature as applied to a dynamoelectric machine was derived from the fact that the iron core acts to magnetically . connect the two poles of the field magnets in the same manner that an ordinary armature connects the poles of a magnet.
Armature, Flat Ring A ring-armature with a core in the shape of a short cylindrical ring.
Armature, Oirder An armature
with an H -shaped or girder-like core. An H -shaped armature.
Armature, Intensity An old term
for an armature with coils of many turns and of a comparatively high resistance.
Armature, Lamination of Core of ^
-- A division of the iron core of the armature of a dynamo-electric machine or motor, so as to avoid the formation of eddy-currents therein. (See Core, Lamination of. Currents, Eddy)
Armature, Multipolar A dynamoelectric machine armature whose polarity is reversed more than twice during each rotation in the field of the machine.
Armature, Neutral A non-polarized
armature. (See Armature, Non-Polarized^
Armature, Neutral-Relay A relay
armature, consisting of a piece of soft iron, which closes a local circuit whenever its electro-magnet receives an impulse over the main line. (.See Armature, Polarized)
This term is applied in contradistinction to a polarized relay armature.
Armature, Non-Polarized -- An
armature of soft iron, which is attracted toward the poles of an electro-magnet on the comn''^
Arm.]
[Arm.
tion of the circuit, no matter in what direction the current passes through the coils.
The term non-poiarized is ustd in contradistinction to polarized armature. (See Armature, Polarized. )
Th non-polanztrd armature of a relay magnet is generally called the neutral relay arfnatttre.
Armature of a Cable, or Cable-Armature.
-- A term sometimes employed for the sheathing or protecting coat of a cable.
The term armor sheathing or coating is preferable.
Armature of a Condenser, or Condenser Armature. -- A term sometimes applied to the metallic plates of a condenser or Leyden jar.
The use of this term is unnecessary and I'l- advised. The term coating or piaie would appear to be preferable.
Armature of Holtz Machine, or Holtz- Machine Armature. -- The pieces of paper that are placed on the stationary plate of the Holtz and other similar electrostatic induction machines.
Armature Pockets.-- (See Pockets, Armature.)
Armature, Polarized An armature
which possesses ' a polarity independent of that imparted by the magnet pole near which it is placed.
In permanent magnets the armatures are made of soft iron, and therefore, by induction, become of a polarity opposite to that of the magnet poles that lie nearest them. They have, therefore, only a motion of at'raction toward such poles. (See Induction, Magnetic. ) |
Digiti;
OOl^TENTS.
CHAPTER I. Introduction.
PAGES
Domain of Pliysics. Some properties of matter. Physical measurements. Kinematics. Laws of accelerated motion. Composition of motions and velocities. Kinds of motion 1-24
CHAPTER n.
Molar Dynamics.
Force. Newton's Laws of Motion. Momentum. Measurement of force. Composition of forces. Moments of force. Center of mass. Curvilinear motion. The pendulum. Gravitation. Work, energy, and power. Machines. Properties of matter due to molecular forces 25-d7
CHAPTER m.
Dynamics of Fluids.
Law of transmission of pressure. Pascal's Principle. Atmospheric pressure. Boyle's Law. Barometer. Principle of Archimedes. Specific gravity 98-123
CHAPTER IV.
Molecular Dynamics. Heat.
Theory of heat. Sources of heat. Thermometry. Calorimetry. Specific heat. Laws of gaseous bodies. Fusion.- Latent heat. Artificial cold. Hygrometry. Diffusion of heat. Thermo-dynamics. Steam engine ,.,.., ^. . .,124-165
Vm CONTENTS.
CHAPTER V. Energry of Maes Vibration.
PAGES
Simple harmonic motion. Wave-motion. Sound-waves. Beenforcement of sound-waves. Pitch. Composition of wave-forms. Discord and harmony. Musical instruments. Vocal organs. The ear 166-205
CHAPTER VI.
Etber Dynamics. Radiant Energry.
The ether. Radiation. Light. Intensity of illumination. Mirrors. Refraction. ' Prisms and lenses. Prismatic analysis of light. Spectroscopy. Color. Optical instruments. The eye. Thermal effects of radiation . 206-267
CHAPTER VII.
Ether Dynamics. Electrostatics.
Electrification. Conduction. Induction. Potential. Atmospheric
electricity 268-278
CHAPTER VIII.
Mectrokinetics.
Voltaic cells. Effects producible by electric current. Electrical quantities. Ohm's law. Instruments for measurement of electric current. Resistance and its measurement. Divided circuits. Methods of combining cells. Magnets and magnetism. Magnetic relations of the current. Mutual action of currents. Electromagnetic induction. Dynamos. Electric motors. Storage batteries. Thermo-electric currents. Electric light. Electroplating and electrotyping. Telegraph. Telephone and microphone. Electro-magnetic theory of light. Radiography. Tesla's investigations 279-366
Appendix 367-375
Index 377-381
LIST OF PLATES AND PORTRAITS.
Spectbums, Plate I . . . . Frontispiece.
Sir Isaac Newton 28
Galileo 38
Archimedes 118
Benjamin Franklin 278
Lord Kelvin 306
Michael Faraday 330
Telboraph, Plate II 355
Radiooraph, Plate III 362
Digiti;
Digiti;
Bead Nature ^Nk^Ag
if Experiment,
ELEMENTS OF PHYSICS.
oJOio
CHAPTER I. INTRODUCTION.
SECTION I.
DOMAIN OF PHYSICS.
1. The perception of changes constantly taking place in the external world is a universal human experience. The manifestations of these changes to the senses are called phenomena; that which undergoes change is called matter. Since most of the changes which come within the scope of our present studyare due to the motions ^ of portions of matter, we may adopt the following provisional definition : ^
Physics is the science which treats of the phenomena of Tnatter and motion.
2. Some Properties of Matter or of Material Bodies:
(1) Extension. Every portion of matter, however small, ^ occupies space, i.e. it has length, breadth, and thickness. The property thus manifested is called extension,
^ Sound, heat, and light, considered as distinct from the sensations to which they giye rise, are nothing but motions.
"1 do not belieye that there exists in external bodies anything for exciting tastes, smells, and' sounds, but motion, swift or slow ; and if tongues, noses, and ears were removed, I am of the opinion that motion would remain, but there would be an end of tastes, smells, and sounds." -- Galtleo.
> A proyieional definition is one that answers present needs.
INTRODUCTION.
Fig. 1. |
The quadrupeds are elephants, rhinocerofes, camels, dromedaries, horfes, affes, mules, oxen and buffaloes; tigers, lions, leopards, wolves, jackalls, mufk cats, very large bats, apes and monkies; red deer, fallow deer, elks, antelopes, fheep, goats, kids, hogs, hares, &c. birds of the moft beautiful. plumage embellifh the forett. The rivers abound in fifh, but many of them are greatly infefted by crocodiles, Serpents and fcorpions abound in every part of India, and Mufketoes, locufts, and other infeéts of a fimilar nature, are very troublefome to the inhabitants. ‘The mines yield gold, diamonds, rubies, topazes, amethifts, beryls, afterias or cats eyes, and other precious ftones or gems. ‘Travellers inform us that mines of lead, iron, copper, and even filver are found in Indoftan; and quarries of ftone are in great plenty.
4. Mountains, Rivers.] The moft remarkable mountains of India are thofe of Caucafus which divide it from Ufbec ‘Tartary, and thofe of Naugracut which feparate it from Tibet ; befides thefe there are chain: of mountains on both peninfulas running ha
nort
ee ee ee ee ee ee, ee. ee. ae ee
INDIA.
S. V. (117)
of north to fouth almoft the whole length of the country. On the ‘et- hither or Weftern Peninfula it is fummer on one fide of thefe ms mountains when it is winter on the other. Thus a fouth weft eS, wind prevails for months on the coaft of Malabar, attended by prodigious and conftant rains, while the weather is ferene on the is coaft of Coromandel on the eaft ; and when on the change of the in monfoon no veffel dare venture to ftay on the coaft of Coromandel, nd they periodically return to Bombay on the weit. on ‘The principal rivers are in the Farther India, the Domea, the on, Mecon, the Menan and the Ava; inthe Hither Inciia are the Indus by and the Ganges. ‘The Indians are perfuaded that tue Garges does en not take its rife from the bofom of the earth, but defcends from ym Heaven into the paradife of Devendre, and from thence into er Indoftan : they therefore hold its waters in the greatefl reverence, ly crowding in multitudes from the remotett parts of the country to ch wath in chem ; they think themfelves favoured by Heaven if they are m permitted to expire on its banks ; and he who accidentally meets death ft. by its waters, is not only fuppofed to have been ‘himwfelf purified re from fin, but that even his furviving family participate in the ve bleffing, and they are ever after treated with peculiar marks of refpect and regard. Such are the miftaken notions of that poor ts harmlefs race the Hindoos or Gentoos ; their priefts are the Bramins re the followers of the celebrated Brumma. ‘To be a ftranger among 2 thefe people is a fufficient fecurity, provifions are furnifhed by ‘ hofpitality, and when a peafant is afked for water he runs with r, alacrity and fetches milk, s, 5. Manufa@ures, Commerce.] The different kingdoms and pro- - vinces of India traffic with each other, and with the neighbouring Sy iflands, the nations of China, Tartary, Perfia and Arabia, but their ir principal trade is with European nations. ‘The exports are gold, diamonds, ivory, filks, muflins, chintzes, dimities, calicoes, lacquered s, wares, and various toys, different kinds of gums, drugs, &c. From 5, Europe are imported broad cloth, lead, flints and cutlery wares, d wrought plate, watches and looking glafles, with other poods of % 5, inferior value for the ufe of the natives. as The empire of Indoftan, particularly the kingdom or ptovince of Bb Bengal, from the mildnefs of its climate, the fertility of its foil, and |
H. F. slight vibrations and shocks. H. F. slight vibrations and shocks, . F. slight vibrations and shocks. . F. slight vibrations,
|. F. alight vibrations and shocks, . F. alight vibrations and shocks. . F. slight vibration.
Declin. and H. F. slight vibrations. H., F. slight vibrations.
H. F. slight vibrations.
H. PF. slight vibrations.
H. F. slight shocks.
H. F. slight vibration.
H. F. slight vibration.
H. F. much vibration and shocks.
H. F. very much vibration and shocks, H. F. slight vibration and shocks.
H. F. slight vibration.
H. F, slight vibration,
H. F, slight vibration and shocks,
H, F. much vibration.
Hl. F. much vibration,
H. F. very much vibration (30 divisions). H. F. much vibration and shocks,
H. F. very much vibration and shocks. H, F. much vibration.
H. F. very much vibration.
H. F. much vibration and shocks. H. F, slight vibration and shocks. H. FP. much vibration and shocks.
AUGUST,
SEPT.
OCTOBER.
NOVEMBER,
DECEMBER.
Mol
JANUARY,
V7 ll 3 25 He
F. much vibration,
F. much vibration and shocks. « Fy alight vibration.
F. slight vibration,
+ F, moderate vibration,
+ F, moderate vibration. . F, slight vibration.
H. F. much vibration.
H. F. slight vibration. H.F, slight vibration. H. F. and V. F. slight vibration.
Declin, and H. F. slight vibration.
H. F. much vibration.
H. F. slight vibration.
H. F, much vibration and shocks.
H. F. slight vibration and much shocks.
H. F. much vibration. H. F. slight shocks,
H. F. slight vibration.
H., F. moderate vibration.
H. F. slight vibration. .
Declin. and H. F. slight vibration. Declin, and H. F. slight vibration. Declin, slight vibration.
H. F, slight vibration.
H. F, moderate vibration.
Declin, slight, H. F, moderate vibration, H. F. slight vibration,
H. F. slight vibration.
Declin, and H. F, slight vibration.
H. F. slight vibration and moderate shocks, 1;
H. F. moderate vibration. H, F, slight vibration.
H. F. moderate vibration. | H. F. slight vibration. \ a H. F. slight vibration and shocks. || H, F. moderate vibration,
H, F. slight vibration,
H, F. moderate shocks,
H. F, slight vibration.
H. F. slight vibration and shocks. H. F, slight vibration,
H. F, moderate vibrations.
H. F. much vibration, H. F. moderate vibration, H, F. much vibration. H. F. elight vibration, H. F, much vibraticn,
oe
TORONTO, 1844-45. MAGNETICAL OBSERVATIONS.
Times oF Onservation at which the MaGNeToMerers were disturbed, but the mean readings were not materially changed--continued,
FEBRUARY,
H.
MARCH.
APRIL,
H. F. slight vibration, Declin, and H. F, moderate shocks,
| Declin, slight vibration, | Declin, slight vibration and shocks; H. F. slight vibration. | Declin. slight shocks; H. F. slight vibration,
H. F, slight vibration, H. F. and V. F. much vibration. H. F. and V. F. much vibration, V. F. slight vibration,
) Declin, and H. F. much vibration and shocks ; V. F. slight vibration, | H. F. and V, F. very much vibration,
H. F. moderate vibration,
Declin, and H, F, slight vibration,
H. F. and V, F, slight vibration,
V. F. moderate vibration,
H. F. and V, F, modevate vibration.
H. F. moderate vibration ; V. F. very much vibration, H. F, and V. F. moderate vibration,
| H. F. and V. F, moderate vibration,
H. F. much vibration, and V, F. slight vibration, V. F. moderate vibration.
| H. F. slight vibration, | V. F. alight vibration.
. F, moderate vibration.
’, F. slight vibration,
’, F, moderate vibration,
. F, alight vibration,
. F. and V. F. moderate vibration. . F. and V. F, much vibration,
. F, moderate vibration, . F, slight vibration, . F. moderate vibration.
H. F. slight vibration.
H. F. slight vibration,
H, F, slight vibrations and shocks.
H. PF. slight vibration.
Decliv, and H. F. slight vibration,
| H. F, slight vibration and shocks.
H. F, slight shocks,
. slight vibration,
. slight vibration, *, moderate vibration, . slight vibration,
Declin. slight vibration, H. F. slight vibration, |
The chief difficulty in using the available energy of destructors for power purposes is this. The refuse must be burned at a nearly regular rate. But demands for power are fluctuating and intermittent. Presently, a method of heat storage is to be described which overcomes this difficulty. The adoption of such a method would render the utilisation of the waste heat of destructors much more practicable, and \vould give to this source of energy a much greater importance in connection with the problem of distributing power in towns.1 Of course, refuse is a very poor fuel, and there is considerable expense in labour in burning it. It would not, therefore, be chosen as a fuel for raising steam. But it has to be burned for sanitary reasons. If any profit can be made by utilising the heat, that is a gain. The cost of the power obtained is merely the interest on the cost of the boilers and appliances which have to be added to the destructor, in order to utilise the heat which would otherwise be wasted.
1 It may be mentioned here that Prof. G. Forbes has proposed to use the heat from destructors to work steam pumps lifting water to a reservoir on a hill. A store of water power would thus be continuously accumulated, \vhich could be used to drive hydraulic motors at times when motive power was required. It will be seen later that a constant water power due to the flow of a river is thus utilised, by pumping to a reservoir, for intermittent work, in the systems at Zurich and Geneva. Prof. Forbes's proposal is the adaptation of the same method to a new case.
CHAPTER II
POWER GENERATED BY STEAM ENGINES. CONDITIONS OF ECONOMY AND WASTE
SIR FREDERICK BRAMWELL, in an address to the Institution of Civil Engineers in 1885, indicated in a convenient phrase those •conditions involving waste of fuel in the production of steam power, which are unavoidable when separate engines are used, but which can be diminished by central-station working. He said that we were ' every day becoming more alive to the benefit, where little power is required, or where considerable power is required intermittently, of deriving that power from a single source.' Small steam-engines are nearly always costly, uneconomical, and inconvenient. Large steam-engines and boilers working with a varying and intermittent load are in conditions unfavourable to economy. It is necessary to examine these cases in detail, and to trace the causes of waste. That is one step towards understanding in what circumstances central-station working is desirable.
Evaporative Power of Boilers at Full Load. -- The following Table contains a selection of the results of the most carefully made tests of boilers. The boilers may be assumed to have been worked at nearly the full load, except where trials were made with a varying rate of evaporation. For comparison of different boilers, working with different feed and steam temperatures, the evaporation per pound of fuel is reduced to the equivalent evaporation from and at 212° F. Where possible, the influence of different qualities of ccal in different trials has been eliminated by reducing the evaporation to the equivalent evaporation by a pound of pure carbon.
The first thing to notice in this Table is that the evaporation per pound of coal does not vary in different boilers so greatly as might perhaps be expected, from the great variation of construction and of the conditions of working in different experiments. Thus taking the column which gives the evaporation
c 2
DISTRIBUTION OF POWER
TABLE I.-- EVAPORATIVE EFFICIENCY
Water
Steam
Coal
evaporated
No.
Description of boiler
Authority
Indicated horses power
pressure pounds per sq. in. by gauge
burned per sq. ft. of grate per hour
! per sq. ft. of total boiler heating surface per
hour
Ibs.
Ibs.
Portable (loco, type)
i Kennedy &
Donkin
Cornish .
Unwin
Lancashire
Ellington .
Donkin .
)f • •
Longridge .
Donkin &
Kennedy
H •
Babcock .
Longridge .
i>
JT
Percy Still |
shall underwrite any policy or policies of insurance thereon, or of any merchant or merchants that siiall load goods thereon, or of any owner «+ owners of such ship or vessel, every person so offend. ine being thereof lawfully convicted before the Supreme Judicial Court of this Commonwealth, shail be deemed and adjudged a felon, and shall be sentenced to muprisonment for life, or fore term not less than five years, at the diseretion of the court: Provided nevertheless, that nothing berem contuned shall be consirued to bar or prevent the party injured from having and maintaining his acuom for (he damages sustamed thereby,
ft any owner of any ship or vessel shall equip or fit out such ship or vessel within this Commonwealth, with mient that the game shall be wilfully cast away, burnt, or otherwise destroyed, to the prejudice of any owner ot any goods laden on board svid ship or vessel, or of any underwriter upon muy policy or policies of insurance Apo ‘vch ship or vessel, or upon any goods laden thereon; aud
shall be thereof convicted beiure the Supreme Judicial Court of this Commonwealth, such offenders shall be semenced to pay a fine not exceeding 5000 dollars, to be set in the pillory one hour, and be haprsoned fora term wotless than 2 years, nor more than 10 years, at the discretion of the said court,
Ji any owner of apy ship or vessel, or of any gouds laden’on board such ship or vessel shall make Gut and echibit, or cause to be made out and exhibited, any false or fraudulent billy of parcels, ins viives or esiitaates of any such goods laden or pretended to be laden on board such ship or vessel, with initeat to defwad any underwriter upon any policy or policies of insurance upon such ship or vessel, or upon any goods Jaden Uereon, every persou so offending, and being thereof lawtully convicted, shall be sentenced to pay a fue not exceeding 5000 coat to be set in the pilory one beur;
wt acd iore tem not excceding 1) wears, at Ure dereten of the cogrt,
aud tu bu it
"OY na tice seal hig met ship time doll rhe
con ne
‘ou boa der dnen
§ Fdit.
th the master's report or Klurs But this penal y ere uve such, or the col- Ho partot the woods has in such cuses the masier
ver necessity, shall putin with the mate shoil withia rsou Gary authors d, of of such distress OF CCR one ) and a copy left wth bin rthe cofiector, of the veer he wardens of the port or jon oft such vessels, any y named by the collector rye any) shall grant a pete Mid ali goods, so unladen, le marthoror owners, shall, of a perishable nature, er ed, hat the entry shal be secured lo be paid; und tihe master, and the + isao such penalues as iu like len on board the same vesother proper person, und ye than for the storing and of CASES, connive atany false entry,
ing away ships and cargoes, ithe high seas, wilfully and nto which he belongeth, bee the same to be done, aud
y, burn or otherwise destroy y wise direct or procure the sthat hath underwritten, oc ierchant or merchants that vessel, the person or perned and adjudged guilty of
ruction of masters of vessels, tructivn and casting away o:
nging to any ship or vessel, away, burn, sink, or othermvgeth, or in any wise direct erson er persons that hath or merchant or merchants that ssel, every person so offend. of this Commonwealth, shail ent for life, or for & term not rss, Uhat nothing beremn conand maintaining his action
- vessel within this Common-
otherwise destroyed, to the j,or of any underwriter upou hy goods laden thereon ; aud mminonwealth, such offender: the pillory one hour, and be ie discretion of the said court, uch ship or vessel shall make audulent bills of parcels, inlon board such ship or vessel, Insurance upon such ship or ld being thereof lawtully conbe set inthe pilory one bour; on or the court.
8 [dir Appendis. 17 |
the poles and about an inch from the poles,) with sealing-wax dissolved in spirits of wine. As the spirit evaporates,^ perl manent and uniforni coating of resin remains upL the surface of the magnet. When the magnets are not in use, the parts not covered wth resin may be preserved from rust by a paste prepaied 111 the following manner: -- In a Florence flask with the
N 2
THE COMPASS.
neck cut off, heat about two fluid ounces of oliye-oil to about 400°. This will expel any water which may be mechanically combined with the oil. Then stir up with the oil, a quantity of newly made dry lime, suflicient to form a soft paste. If the exposed parts of magnets be anointed with a thin surface of this paste, they will be effectually preserved from rust. When the magnets are to be used, this paste can be wiped off easily. In this way the writer preserves his magnets, and can speak from experience of the success and advantage of the plan.
Boiling water has been found to he very injurious to a magnet; hut, as the magnet cools, its power returns. At 200° of heat, two-fifths of the magnetism is dissipated; and at 500° it is all lost. These effects are likewise accelerated, when the magnet lies ’ oblique to the meridian, or with its poles reversed.
45. The application of a force to a magnet -which has the effect, as we have said, of magnetising a bar of steel, and of destroying such magnetism when already formed, operates some¬ times in reversing the poles of a magnet. Thus, an electric discharge may convert a steel needle into a magnet; -- may destroy a magnet already formed; -- or may reverse its poles. The latter effect has been the cause of many a shipwreck. We read some time ago of a Genoese ship sailing for Marseilles, which was struck by lightning at a short distance from Algiers, when the electric discharge reversed the poles of the compassneedle; so that the ship dashed on the African coast, when it was thought on hoard that they were sailing to the north.
46. We should observe, before quitting this part of our subject, that Professor Robison, who, in the middle of the last century, made many and varied experiments on this occult branch of science, suspended by a thread a very fine artificial magnet, with its south pole pointing downwards. A person was employed to tap it incessantly with a smooth pebble, in such a manner as to make it ring very clearly. Its magnetism was examined from time to time, with a very small compass-needle. In three quarters of an hour its original magnetism was de¬ stroyed ; and the lower end showed signs of a north pole. The same magnet was re-magnetised, and made as strongly magnetic as before ; it was then tightly bound over with wetted whipcord, leaving a small part bare in the middle. It was again tapped wdth the pebble, but could no longer ring. At the end of three quarters of an hour, its magnetism was still vigorous, and was not gone after two hours and a quarter. Professor Robison sup¬ poses that sonorous percussion produces a reoession of the particles of a magnet; and that at every such recession a certain
THE MAGNET.
portion of the magnetic fluid escapes and is lost. Percussion and friction, in the required position, would seem, therefore, from all that has been said before, to he the chief means of magnetising iron and steel. These means do, as it were, waken up the inert particles of the metal to admit new magnetism, or to develope that which already resides in it, originally derived from the earth. |
roaring sound being audible, in coosetiuence of the diffused vapout being supplied with more osygen, and bummg more rapidlj than it would do if aimply oonsuined from a stick or glass rod wetted with the fluid. A still greater rapiditj of combustion is ensured by dropping some bisul' phide of carbon into a long stout cylindncal jar, fifteen inches long and three inches in diameter, containing iiitric oxide gas (NO,) ; when flame is applied the mixture buma with a bright flash and some noise, and if bunvt in a tmrrow mouthed bottle would most likely blow it to
The greatest rapidity of combustion, and of course the budest noise, is obtained by shaking some bisulphide of carbon ia a similar stout and strong cylindrical jar filled with ojygen gas, but in ttia case the jat must be protected with a double cylinder of stout wire gauze i it does not always break, but if it is blown to fragments each particle becomes a lancet-shaped piece of glass, which is capable of producbg the most dangerous wounds. (Fig. 152.)
Selenium {at^rli, the Moon*) ; symbol, Se ; combining proportion, 39 '5. This new metallic element is allied to sulphur, and ia a species of chemical curiositv, being fonndiuminatequantitiesin various minerals; it may be meltea and cast into anyfonn. Medallions of the discoreier (Berzelius) of seleniom, ia little cases, are imported from Gennanj, for the cabinets of the curioua.
' • dUed Hkailnm cm lommit of il< itroiiK uulogj \o the mettd t«lliiriiun {IMu, th*
166 bot's playbook of science.
FHOSFHOBTJS.
Phosphorus (<^«ff, light ; (^epwv, to bear ; symbol, P ; combining
proportion, 32.)
Monsieur Salverte, in his work on the Occult Sciences of the Ancients, quotes a remarkable story respecting the probable discovery of the nature of phosphorus in 1761 : -- " A Prince San Severe, at Naples, cultivated chemistry with some success ; he had, for example^ the secret of penetrating marble with colour, so that each slab sawed from the blocK presented a repetition of the figure imprinted on its external surface. In 1761, he exposed some human skulLs to the action of different reagents, and then to the heat of a glass furnace, but paying so little attention to his manner of proceeding, that he acknowledgea he did not expect to arrive a second time at the same result. Prom the product he obtained a vapour, or rather a gas was evolved, which, kindling at the approach of a light, burned for several months without the matter appearing to £e or diminish iu weight. San Severo thought he had found the impossible secret of the inextinguishable lamp, but he would not divulge his process, for fear that the vault in which were interred the princes of his family should lose the unique privilege with which he expected to enrich it, of beinfi^ illuminated with a perpetual lamp.^* Had he acted like a philosopher of the present day, San Severo would have attached his name to the important discovery of the existence o^ phosphortts in the bones, and made public the process by which it might be obtained.
This element, formerly sold at four or five shillings the ounce, has now faUen so much in price, from the ^eater demand and larger production, that it may be bought for a few shillings the pound, and is imported in tin cases m large quantities from Germany. It was discovered about two hundred years ago by Brandt, a merchant of Hamburg, and may be prepared on a small scale by distilling at a red heat phosphoric acid previously fused with one-fourth of its weight of powdered charcoal.
First Experiment. |
. (28.) If we know the mass of the central body, and if we suppose the revolving body to be projected at a certain place in a known direction with a given velocity, the length of the axis major, the excentricity, the position of the line of apses, and the periodic time, may all be calculated. We cannot point out the methods and formulae used for these, but we may mention one very remarkable result. The length of the axis major depends only upon the velocity of projection, and upon the place of projection, and not at all upon the direction of projection.
(29.) We shall proceed to notice the principle on which the motion of a planet, or satellite, in its orbit is calculated.
It is plain that this is not a very easy business. We have already explained, that the velocity of the planet in its orbit is not uniform, (being greatest when the planet's distance from the sun is least, or when the planet is at perihelion ;) and it is obvious, that the longitude of the planet increases very irregularly ; since, when the planet is near to
Di
24 GRAVITATION,
the sun, its actual motion is very rapid, and, therefore, the increase of longitude is extremely rapid ; and when the planet is far from the sun, its actual motion is slow, and, therefore, the increase of longitude is extremely slow. The rule which is demonstrated by theory, and which is found to apply precisely in observation, is this : -- The areas described by the radius vector are equal in equal times. This is true, whether the force be inversely as the square of the distance from the central body, or be in any other proportion, provided that it is directed to the central body.
(30.) Thus, if in one day a planet, or a satellite, moves from A to a, fig. 5 ; in the next day it will
Fig. 5.
move from a to b, making the area a S b equal to A S a ; in the third day it will move from 6 to c, making the area b S c equal to A S a or a S 6, and so on.
(31.) Upon this principle mathematicians have invented methods of calculating the place of a planet, or satellite, at any time for which it may be
EQUATION OF THE CENTRE. 25
required. These methods are too troublesome for us to explain here ; but we may point out the meaning of two terms which are frequently used in these computations. Suppose, for instance, as in the figure, that the planet, or satellite, occupies ten days in describing the half of its orbit, AabcdefghiB, or twenty days in describing the whole orbit ; and suppose that we wished to find its place at the end of three days after leaving the perihelion. If the orbit were a circle, the planet would in three days have moved through an angle of 54 degrees. If the excentricity of the orbit were small, (that is, if the orbit did not differ much from a circle,) the angle through which the planet would have moved would not differ much from fifty-four degrees. The excentricitics of all the orbits of the planets are small ; and it is convenient, therefore, to begin with the angle 54° as one which is not very erroneous, but which will require some correction. This angle (as 54°), which is proportional to the time, is called the mean anomaly ; and the correction which it requires, in order to produce the true anomaly, is called the equation of the centre. If we examine the nature of the motion, while the planet moves from A to B, it will readily be seen, that, during the whole of that time, the angle really
GRAVITATION.
described by the planet is greater than the angle which is proportional to the time, or the equation of the centre is to be added to the mean anomaly, in order to produce the true anomaly ; but while the planet moves in the other half of the orbit, from B to A, the angle really described by the planet is less than the angle which is proportional to the time, or the equation of the centre is to be subtracted from the mean anomaly, in order to pro* duce the true anomaly. |
Shaft, (shaft) m. an arrow i straight jmrt of a column : passage into a mine : |)ole of a carriage ; hnndle of a weapon ; spire of achurch; an axis, cs connected with steam power: tfflr. thesharp thrusts of misfortune, malice, etc. : a. thqft'ed, as a pit
Shaggy, (shag'gi) n. hairy ; rough I-- n. sliagg'iness.
6hagveen,(sha-gretr) u.leather prepared from the skins of horses, asses, sharks, &c.
Shah.(sha) n.ft Persian king.
Shake,(sl)ftk) v. t. or t. to agitate ; disturb : to cause to move backwards or forwards, or to waver in opinion : to shiver :-- a. fhak'n, insecure, asa cte<litor; full of cracks, as timber; unsteady; feeble; w*. Shak'er, one of a sect of celibates ; iJiak^hifj, vibratory motion : concussion : punibhment : thnktdnwn, bed on the floor
Shale, (sh&r> n. slate-stone.
Shall, ishal) r.i. an auxiliary verb used in future tense \ tc be under obligation ; in the^-s< person, thaU foretell or declares ; in the tecond and thinl, it promises, commands, asserts, etc., or it is used in anting peiTnission or direction.
Shallow, (shal'd) a. silly; not deep ;-- H. shoal water :-- ». tJiaflotc'nes.^, silliness; lack of depth ; aJhallow-hrained
Sham,(8ham) ». anything deceitful ; a humbug ; -- a. false; pretended: fictitious; V. t. to feign; imiwse upon.
Digitized
Optimum obsonram labor. -- La- bor is the best sauce.
On a beau mener le boeuf ^ Teau s'a n*a soif.-In vain do you
lead tbe ok to tbe water if he is not thirsty. Omne principium pmre. -- ^AQ beginnings are difficult.
SHAHBLES
28T
SHIYEB
Sbamhle«. (nhainrMx) ». pK a
pluct! witere meat in snld.
ShambUiiz, (Khttm'bfinK> n »
a. ^ufffiug, awkward gait.
Shame, (akiua) n. acBke or caoseof dwt;mc«: reproach ; emotion, exprened souwtiiiien by MuslieK ; %non»> kiy ;-- 't*. t. to make okkanv cd : --- nJj$. fhame'fneetl, banhf ul ; eacOy cnnf UMd ; $kamc'lem, atHlaetutu ; ii>»- ■nodest^-- n. Kkn nie1e«n»e«M 7 -- <t. thnmt'/Mif ii>faKM)U»: full of imlKnity: indecent; an/. Khaiue'fnlty. Inmc^ ;-- M. thamef alncM, enormity
SlininpoA, (t>IiaTn-poo>') i'. t. tu wa»h and rub the nend.
Shrink, (i>haB|rk) m. btme nt tbe \9g t lonK part of a too^
Shnnty, (Khnnlt) «. a hut.
Shape, (tfh&p) V. f. to motiM; embody ; adap* t rejnrtate t eoiicri>'e ^-- •. external 1\g' «res-- <k/>». »Aap€'k>v.yranth\g resubr fomis !'/iap€:'fjf, «cltimde: ayminetricnl:-- N. fhtlpf'tiuef.*, comeiiiiesii.
Snnre, (Khir) u. a part ; a plow-iron :-- r. t. to divide f -- n#. More' Aolr/er, one who ownkaakareef ItR. atock, ete. ; shaf^tT, pnrticlpnnt t iihaftuif, parttt'ipaticii).
Shark, (akark) ». a voraciooa fUh or person « a dieat.
Sharp, (ahirp) a. havbi; a thin cage > acid x neute :-- r. f. iharp'tm, to pohit ; to rrind:-- Arf. $Atirp'fifi, keen> ly: severely :--ii. ffiarf>'t»*»t acutcncM: shrewdncea: mp> eoiini ; eajtemeH t ahri^l- neftt r emnclntiwn of feature*;--o<//«. ttknrp'-4>pt,nkr' rnoiiBskcen mkarp'-gts^ied, gkarp'-tritted. ahrewd : aagariouH ;-- ». fharyt'tihooter, a aotdicr: Mor/Zcr, a ehent.
Shatter, (nhwt'er) v. t. break.
Sliavc.(KhAv) i'. t. to pnreoff; to hwi nuM in paiM»in>; ; to defraud : -- wat rff/r'er, a ^harper: barber; tndr ehnps Mor'Afff, act of taking off the beard ; a thin ^\^c^>.
Shawl. (»hawl>». a ninntlo.
She, (»h6) prow, a female.
Slieaf. (Khef) n. a bundle of ntnlka, *c. t--pl. aheavea.
Slienr. (nherj v. t. clip wool from iiheep:-- n. nhenfer;'- n.theurt, bladca on a pivot.
Sheath, <aheth>«. a ctuo :-- r. t. tfieuthe, to put in a kcabbard : -- n. sheot/i'Htpji metal pn)tecti(>n, efp. of a »hip.
Slieave, Cali^v) n. a wheel.
Shed. (»kcd> n. as^bt building :-- 1-. t. to cast oif ; Fpill; --uf. rhed'drng. ahed'der.
Siieen, (»hen) ». br%iitneii» ; a xiecMiMpIeudid: shiniM
Sheep, (tliep) >*• mm^i. or fit an dDimal raliiabie for ita wool and ffe«h ; a dunce ; diorcb iteopk ; God's floefc; m. thtep'M, diffident : ahy. |
From the cap descends a stout cylindrical metallic bar, which I was told is either of copper or bronze (gun metal), but which more probably is iron. The spire, with the exception of a few feet at the top, is hollow, and the bar proceeds downwards nearly forty feet, and rests in the intersection of two stout flat iron bars, crossing one another at right angles ; hence from the shank of the cross, where the lightning first struck, to the bottom of the central rod, no damage was done to the spire. But, as the lightning no longer found a continuous conductor, it commenced its destructive effects on the masonry at the extremities of the cross iron bars on which the central bar rested. I cannot say that the effects produced were different from what might have been expected from a heavy flash of lightning striking an edifice whose materials were similar, and similarly distributed, to those which constituted this steeple. The stones are held together by copper clamps, and the spare lead which had been left in the ladles, after soldering the clamps into the stone, seems, whilst yet in fusion, to have been carelessly poured into the crevices between the stones ; forming, when cooled, solid bars of lead of considerable dimensions, both in length and breadth. Several of these masses of lead were completely dislodged by the electric force, and many scores of pounds might have been easily removed by the hand only from the rents made in the spire. I brought a few pieces with me, which are now lying on one of the tables of the gallery of this Institution.
The effect, generally below the iron rod, would seem to have been accomplished by a formidable expansive force in the interior of the spire, which has operated in two diametrically opposite sides to the greatest extent ; or, at least, the effects produced are greatest diametrically opposite each other in all those places where absolute rents are made in the masonry ; and the rents themselves are such as to indicate an expansive force from within. In several places, however, large masses of masonry are split off the inside of the spire, but by far the greatest quantity of shattered stone is carried outwards. There are some vertical rents at the octagonal angles more than twenty feet long ; and in all cases where there is a rent on one side, there is another on the opposite side of the steeple.
The axle of the clock bell is broken, and the bell itself leaning on the loft floor, probably in consequence of a large mass of displaced masonry falling upon it ; but there can be no doubt whatever of the lightning making a stepping-stone of this bell to facilitate its transit from the last place of damage above it to the metallic works of
ELECTRICAL STORMS, ETC. 631
the clock below. From the works of the clock the lightning has darted through the wall close to the lower edge of that face of the clock, which is over the body of the church, and has peeled a considerable slice off the outer side of the stone work. This appears to have been the last point of destruction, from which it no doubt darted to the lead work of the roof of the body of the church, and thence to the ground by the conduction of the metallic water pi])es.
In conclusion I may add, that had the architect been disposed to build an edifice for the precise purpose of being destroyed by lightning, he could scarcely have improved upon the plan exhibited by this spire, either as to the choice or the distribution of the materials. |
5. With what velocity must a stone be thrown vertically upwards at a place where gis 981 that it may rise to a height of 3000 centims. ? and to what height would it ascend if projected vertically with this velocity at the surface of the moon, where g is 150 1
Ans. 2426 centims. per second ; 19620 centims.
32 UNITS AND PHYSICAL CONSTANTS. [CHAP.
Centrifugal Force.
33. A body moving in a curve must be regarded as continually falling away from a tangent. The acceleration with which it falls away is-- , v denoting its velocity
and r the radius of curvature. The acceleration of a body in any direction is always due to force urging it in that direction, this force being equal to the product of mass and acceleration. Hence the normal force on a body of in grammes moving in a curve of radius r centimetres,
with velocity v centimetres per second, is -- -- dynes. This
force is directed towards the centre of curvature. The equal and opposite force with which the body reacts is called centrifugal force.
If the body moves uniformly in a circle, the time
of revolution being T seconds, we have v = --^ ',
hence ;==(^p~)r> and *ne force acting on the body is
nes.
If n revolutions are made per minute, the value of T is
60 (mr\- ,
-- , and the force is mr\ ^1 dynes.
Examples.
1. A body of m grammes moves uniformly in a circle of radius 80 centims., the time of revolution being J of a
in.] MECHANICAL UNITS. 33
second. Find the centrifugal force, and compare it with the weight of the body.
Ans. The centrifugal force ismx/-^j x80 = mx 647r2
x 80 = 50532 m dynes.
The weight of the body (at a place where g is 981) is 981 m- dynes. Hence the centrifugal force is about 52| times the weight of the body.
.2. At a bend in a river, the velocity in a certain part of the surface is 170 centims. per second, and the radius of curvature of the lines of flow is 9100 centims. Find the slope of the surface in a section transverse to the lines of flow.
Ans. Here the centrifugal force for a gramme of the water is (17^8 = 3-176 dynes. If g be 98 1 the slope will
o .1 fr f* 1
be = -- -- ; that is, the surface will slope upwards
i/ol oUJ
from the concave side at a gradient of 1 in 309. The general rule applicable to questions of this kind is that the resultant of centrifugal force and gravity must be normal to the surface.
3. An open vessel of liquid is made to rotate rapidly round a vertical axis. Find the number of revolutions that must be made per minute in order to obtain a slope of 30° at a part of the surface distant 10 centims. from the axis, the value of g being 981.
Ans. We must have tan 30°= /, where /denotes the
intensity of centrifugal force -- that is, the centrifugal force
per unit mass. We have therefore
34 UNITS AND PHYSICAL CONSTANTS. [CHAP.
981 tan 30° = lof-- Y' n denotin« the number of \30/ revolutions per minute,
w V
Hence rc = 71'9.
4. For the intensity of centrifugal force at the equator due to the earth's rotation, we have r = earth's radius = 6-38 x 108, T = 86164, being the number of seconds in a sidereal day.
This is about -- -- of the value of g.
If the earth were at rest, the value of g at the equator would be greater than at present by this amount. If the earth were revolving about 17 times as fast as at present, the value of g at the equator would be nil.
SUPPLEMENTAL SECTION.
On the help to be derived from Dimensions in investigating Physical Formulae.
When one physical quantity is known to vary as some
power of another physical quantity, it is often possible to find the exponent of this power by reasoning based on dimensions, and thus to anticipate the results -- or some of the results -- of a dynamical investigation.
Examples.
1. The time of vibration of a simple pendulum in a small arc depends on the length of the pendulum and the intensity of gravity. If we assume it to vary as the mth
in.] MECHANICAL UNITS. 35 |
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