the lining and preserve the glasses. The seat is then finished, by fixing boards on the seat rails, from the back pannel one foot eight inches. The hind upper quarter is formed by two compass slats, fixed to a neck-plate in the standing pillar joint, two feet eight inches long, two inches at top, reduced to one inch at bottom and an inch thick; on the top of the hind slat is fixed the back rail, three feet five inches long, by two inches square; sweeped to correspond with the front rail, on the top of the other slat is fixed a hoop-stick of the same, sweep three feet ten inches by one inch thick and two inches wide. On the top of the door case are fixed three more hoop-sticks of the same dimensions, at the distance of two inches from each other. On the back of the elbow and to the corner pillar is fixed a strong iron prop, which projects six inches from the body; secured inside by an iron stay, as also one on the top of the standing pillar projecting an inch and a quarter, in the ends of which props the main joint is fixed; the lower slat and top rail is then fixed up eighteen inches from the back rail; and the upper slat and hoop-stick fixed ten inches from it; on the elbows made to the sweep are fixed two strong iron plates five inches deep. The steps are then fixed in the centre of the door way in the bottom sides with bolts, width eleven inches, depth, if treble, eleven inches, if single, sixteen inches, cased round with deal to conceal them, when the body is tummed; the body loops are fixed on the bottom of the rockers, with bolts and nut headed screws, the hind body loops thirteen inches compressed to fancy; the front body loop to the head eighteen inches, from which proceeds a horn six inches long, joined at top to a split stay, which takes the foot board at eighteen inches distance; the other part extending upwards to the bottom of the barouch seat eighteen inches; there is also an iron stay fixed in a socket at the top part in front of the fore pillar, which fastens to the bottom of the seat at the distance of sixteen inches from the body; the width of the seat fifteen inches, and length thirty-one inches, rounded at the hind corners, made of solid board, on the top of which an iron is fixed twelve inches high, level with the outside; the foot board thirty-one inches long, seventeen inches deep, and from the seat to the centre eighteen inches, which finishes the body from the coach-makers' bench.

The body being completed from the coachmakers, it is usual next to cover the sword case with a piece of fine neat's leather prepared for that purpose, and put on wet with paste or white lead to keep it from rising in the hollow part. A very great improvement has lately taken place in covering the top part of coaches, and chariots, by putting the leather on whole, so as to prevent the possibility of wet penetrating, as was frequently the case when put on in separate pieces, and joined on each other by nails, &c. The pannels of the body are painted three or four times with oil color, and several times after with a composition of ground white lead, spruce or brown ochre, turpentine and varnish, and when ard, rubbed to a smooth surface with pumice stones and water. The color, whatever it may be, is laid a sufficient number of times to be solid,

and varnished twice, previous to arms, if any, being put on, afterwards varnished as often as required, being various according to color, &c. &c. The process of painting the carriage is, by giving it a sufficient number of coats to fill up the grain of the wood, rubbing it between each coat with fine sand paper, till it becomes smooth, then ornament it by picking out, and varnish it as often as the nature of the color requires, which never exceeds four times. The inside of the body is then trimmed, the art of which consists in fitting a lining in it composed of cloth, leather lace, &c. in the most ornamental and comfortable manner. The roof, the doors, front, bottom quarters, seatfall, and the bottom part of the cushions are usually cloth, the upper quarters, top and bottom back, elbows, and top of the cushions morocco. The process is this; first cut out the roof and all the larger parts of the lining; fit the pockets and falls on the front and doors, the pockets and falls are usually bound with broad lace. The morocco part of the lining, with the exception of the cushions and elbows, are made with canvas backs, and bound with narrow lace, stuffed full with curled hair, and tufted with silk or worsted. When the lining is cut out and made up, proceed to line the inside of the sword case with serge, or shalloon of the color of the lining, paste up slips of cloth round the lights, and paste cloth on the recess of the door left to contain the step; nail lace all round the lights, and finish round the same with narrow lace, called parting, fix in the elbows, the bottom, back, bottom quarters, top back, and top quarters, fixing up the roof which is fastened to the hoop-sticks by narrow slips of list nailed to them, and screwed to the roof. The pillars are lined with slips of cloth, bound on each side with lace, through which the hand holders' pass, and are nailed firm to the standing pillars, fix in the front, finishing the sides with the line of lace, which forms part of the front light, fix on the door lining, finishing the edges with a row of parting lace all round. The steps are mostly now very handsomely finished, one side being morocco, and lined with cloth or velvet, welted all round, and the front bound with broad lace. The treads are usually carpet; and, besides a carpet fitted in the bottom, most carriages have spring curtains made of silk, on barrels with silvered ends, the cutting out and fixing up of which, forms a part of the inside trimming. The outside upper part is covered with oiled linen, previous to being covered with very strong-grained neat's leather, which is closed and welted together to fit the roof quarters and back, and, when fixed on, completes the trimmings of the body, the seat; the top iron is usually platted with neats leather, and japaned, round it a squab or cushion is fitted, the back part of strong leather, the front or inside cloth puckered in full, and welted all round, stuffed and tufted, and fixed in the top iron with straps made up with buckles. Inside the iron the the cushion for the seat is fitted, and a fall is fixed along the front part, a deep valance all round the seat of very strong leather, and a leather from the foot hoard to the front of the seat, which is called a heel leather. Bodies are, in a greater or less degree, ornamented with beading, of which there are three sorts, plated, brass, and

COAGULATION, in chemistry, the act of rendering a fluid body, in some degree, solid, by exposure to cold, or by the addition of some agent by which it is decomposed. Thus the white of eggs, the serum of the blood, &c. are coagulated by the addition of alcohol; milk by mixture with acids; the serum of the blood by exposure to heat, &c. Some writers have called crystallisation by the same name. See ALBUMEN.

COAK, a kind of charred fossile coal. For the exciting intense heats, as for the smelting of iron ore, and for operations where the acid and oily particles would be detrimental, as the drying of malt, coals are previously charred, or reduced to coak; that is, they undergo an operation similar to that by which charcoal is made. By this operation coals are deprived of their phlegm, their acid liquor, and part of their fluid oil. Coak, therefore, consists of the two most fixed constituents parts, the heavy oil and the earth, together with the acid concrete salt, which, though volatile, is dissolved by the oil and the earth. It is used in metallurgic works all over Britain, and gives most intense heat. See below.

COAL, n. s. & v. a.) Sax. col; Lat. calor; COAL-BLACK, adj. heat. A peculiar mineCOAL-BOX, N. s. ral fossil fuel; any COAL-MINE, n. s. thing inflamed or igniCOAL-PIT, N. s. ted. Black, of the COAL-STONE, 2. s. darkest species, is the COAL-WORN; n. s. color of the fossil-coal. CoʻALERY, n. s. Writing on a light surCo'ALY, adj. face, with a piece of coal, Camden calls coaling; he coaled out rhimes upon the wall.' To coal, is to burn,or to convert into coal any substance capable of such transformation by fire.

Sered pokettes, sal peter, and vitriole;
And divers fires made of wode and cole.

Chaucer's Canterbury Tales.

Instede of cote-armure,-on his harnais,-
With nayles yelive and bright as any gold,-
He hadde a beres-skin, cole-blake for old.

Id.

As burning Etna, from his boiling stew, Doth belch out flames, and rocks in pieces broke, And ragged ribs of mountains molten new, Enwrapt in coal-black clouds and filthy smoke. Faerie Queene.

You are no surer, no, Than is the coal of fire upon the ice, Or hailstones in the sun. Shakspeare. You have blown this coal betwixt my lord and me. Id. Whatsoever doth so alter a body, as it returneth not again to that it was, may be called alteratio major; as when cheese is made of curds, or coals of wood, or bricks of earth. Bacon. Charcoal of roots, coaled into great pieces, lasts longer than ordinary charcoal. Id.

Or coaly Tyne, or ancient hallowed Dee. Milton,
Coal-black his color, but like jet it shone ;
His legs and flowing tail were white alone.

Dryden. Leave a pail of dirty water, a coal-bor, a bottle, a broom, and such other unsightly things. Swift. Coal-stone flames easily, and burns freely; but nolds and endures the fire much longer than coal.

Woodward.

Henry III. granted a charter to the town of Newcastle, in which he gave the inhabitants a license to dig coal. This is the first mention of coal in England. Hume's History of England.

COAL, among chemists, is synonymous with charcoal, and in the new nomenclature is styled carbon. See CHARCOAL and CHEMISTRY, Index. In the burning of charcoal one part of it exhales without decomposition, and forms a vapor, or an invisible gas, called fixed air or carbonic acid. This vapor is found to be very pernicious, and to affect the animal system in such a manner as to occasion death in a very short time. For this reason it is dangerous to remain in a close place where charcoal, or any other sort of coal, is burnt. Persons struck by this vapor are stunned, faint, and motionless. The best method of recovering suffer a violent head-ache, and fall down senseless them is by exposure to the open air, and by making them swallow or breathe the steam of vinegar.

COAL, in mineralogy, a kind of solid inflammable substance, supposed to be of a bituminous nature, and commonly used for fuel. Of this substance there are various species, viz.

COAL, BOVEY, XYLANTHRAX, of a brown or brownish-black color, and of a yellow laminar texture. According to the German chemists its ashes contain a little fixed alkali; but Mr. Mills disputes this. It is found in almost all the countries of Europe. See XYLANTHRAX.

COAL, CANNEL, AMPELITES, of a dull black color. It breaks easily in all directions; and, if broken transversely, presents a smooth conchoidal surface. It burns with a bright lively flame, but is very apt to fly in pieces in the fire; however, it is said to be entirely deprived of this property by immersion in water for some hours previous to its being used. It contains a considerable quantity of petrol in a less condensed state than other coals. Its specific gravity is about 1270. See AMPELITES.

COAL, CULM, called kolm by the Swedes, has a greater portion of argillaceous earth and vitriolic acid, with a moderate proportion of petrol. It has the same appearance which the lithanthrax, though its texture is more dull: it burns with a flame, without being consumed, but leaves behind it a flag of the same bulk with the original volume of the coal. Kirwan thus describes it in the Memoirs of the Stockholm Academy: its fracture has a rougher section than the cannel coal; its specific gravity is from 1300 to 1370. The best kind affords by distillation, at first, fixed air; then, an acid liquor; afterwards, inflammable air, and light oil of the nature of petrol; then, a volatile alkali, and, lastly, pitch oil. The residuum is nearly three

fourths of the whole; and being slowly burnt, affords thirteen per cent. of ashes, which consists mostly of argillaceous earth; and about 300th parts of them are magnetic. It is found in England and among some alluminous ores in Sweden.'

COAL, KILKENNY, is the lightest of any; its specific gravity being only about 1400. It contains the largest quantity of asphaltum; burns with less smoke and flame, and more intensely, though more slowly, than the cannel coal. The quantity of earth it contains does not exceed one-twentieth part of its weight; but this kind of coal is frequently mixed with pyies. It is found in Kilkenny, Ireland. Its quality of burning without smoke, is proverbially used as an encomium on the country. COAL, PIT. Pit coal is a black, solid, compact, brittle mass, of moderate hardness, lamellated structure, more or less shining, but seldom capable of a good polish; and does not melt when heated. According to Kirwan, it consists of petrol or asphaltum, intimately mixed with a small portion of earth chiefly argillaceous; seldom calcareous; and frequently mixed with pyrites. A red tincture is extracted from it by a spirit of wine, but caustic alkali attacks the bituminous part. The varieties of this coal,' says Mr. Magellan, are very numerous, according to the different substances with which it is mixed.' See COAL-MINE, Sect. VIII. But in regard to their economical uses, only two kinds are taken notice of by the British legislature, viz. culm, and caking coals. The caking coals, in burning, show an incipient fusion, so that their smallest pieces unite in the fire into one mass; by which means the smallest pieces, and even the mere dust of this kind, are almost equally valuable with the largest pieces. The culm does not fuse or unite in the fiercest fire; so that the small coal, being unfit for domestic purposes, can only be used in burning limestone.' See CULM, and LITHANTHRAX.

COAL, SLATE, contains such a quantity of argillaceous earth, that it looks like common slate; however it burns by itself with a flame. M. Magellan is of opinion that this is the bituminous schistus, already described under CLAY. This schistus is of a dark, bluish, rusty color; when thrown on the fire it burns with a lively flame, and almost as readily as the oily wood of dry olive tree, or lignum vitæ ; emitting the very disagreeable smell of petrol. Such large quarries of it are found near Purbeck in Dorsetshire, that the poorer part of the inhabitants are thence supplied with fuel. From the appearance of this slaty coal, Cronstadt had been induced to suppose that the earth of all kinds of coal is argillaceous, though it is not so easy to distinguish it after being burnt. The pit coals, he says, contain more or less of the vitriolic acid; for which reason the smoke arising from them attacks silver in the same manner as sulphur does, let the coals be ever so free from marcasite, which however, is often imbedded or mixed with them. COAL, SULPHUREOUS, consists of the former kinds mixed with a very considerable portion of pyrites; whence it is apt to moulder and break when exposed to the air, after which water will

act upon it. It contains yellow spots that look like metal; burns with a sulphureous smell, leaving behind it either slag or sulphureous ashes, or both. Its specific gravity is 1500 ór more.

The above are the most considerable varieties of coal commonly known; but we must not imagine that each of them is to be met with in a homogeneous state. On the contrary, the different qualities and proportions of their ingredients make a vast number of other varieties, fit for different purposes, according to the quality and quantity of those they contain. Some of the finer sorts generally run like veins between those of a coarser kind. M. Magellan observed in the fine coal employed in a curious button manufactory at Birmingham, that it produced a much clearer flame than he had ever observed from common coal; yet, on enquiry, he found that the former was picked out from the common coal of the country, through which it ran in veins, and was easily distinguished by the manufacturers. Fourcroy remarks, that this fossil bitumen, when heated in contact with a body in combustion, provided it has a free access of air, kindles the more slowly and with the greater difficulty, in proportion as it is more weighty and compact. When once kindled, it emits a strong and durable heat, and burns for a long time before it is consumed. The matter that is burned, and produces the flame appears very dense, and seems united to some other substance which retards its destruction. On burning it emits a peculiar and strong smell, which is not at all sulphureous when the coal contains no pyrites. When the combustible, oily, and other volatile parts of the coal are dissipated, if the combustion be ther stopped, the remainder is reduced to a true charred state, and is called coak. It is well known, says M. Magellan, that the English method of burning pit coal into coak has been a most profitable and happy acquisition for the smelting our ores, and for many other metallurgical and chemical processes in this island. But the ingenious and extensive undertaking of lord Dundonald, by which he turns to very valuable purposes the mines of coal in his and other estates, building ovens of a proper construction for burning pit-coal into coak, and at the same time for collecting, in separate receptacles, the volatile alkali, oil, tar, and pitch, which were generally lost by the usual method, deserves to be noticed, as it affords a very remarkable instance of the great losses to mankind, for want of carefully attending to every result from great processes of art when made on a large scale. These ovens are so contrived, as to admit an under supply of air; and the coals, after being kindled, decompose themselves by a slow but incomplete combustion, which does not destroy the ingredients. The residuum left in the oven proves to be most excellent cinders or coaks, whilst the volatile parts which otherwise would be dissipated in the air, are separated and condensed in reservoirs or receptacles of capacious size, placed at proper distances beyond the reach of fire. M. Faujas de St. Fond, who visited these works in a trip he made to Scotland, undertook to erect a similar kind of oven in France. On subjecting

pit coal of any kind to distillation in close vessels, it first yields a phlegm or watery liquor; then an ethereal or volatile oil; afterwards a volatile alkali; and lastly, a thick and greasy oil; but it is remarkable, that, by rectifying this last oil, a transparent thin and light oil of a straw color is produced, which, being exposed to the air, becomes black like animal oils. From these and similar observations, Messrs. Magellan, Chattal, and others, have inferred, that pit coal is originally a vegetable substance.

COAL, SMALL, is a term sometimes used for a sort of charcoal prepared from the spray and brushwood stripped off from the branches of coppice wood, sometimes bound in barns for that purpose, and sometimes charred without binding, in which case it is called coming together.

Kirwan divides carbonaceous substances into four species, of which the first two contain almost all the varicties of coal. i. Native mineral carbon, the blende kohle of Werner, of which the coal found near Kilkenny and the culm of Wales is a species. The former he thus characterises: Its color is black, and when fresh broken some parts of it generally display a violet color. Its lustre, 4. Metallic. Transparency, 0. Fracture foliated, and the course of the lamellæ variously and confusedly directed. Its fragments, from 2 to 3, often coated with whitish illinitions. Hardness, 7. Specific gravity, 1.526. Will not burn till wholly ignited, and then slowly consumes, without caking, or emitting flame or

smoke.

ii. Mineral carbon, impregnated with bitumen, which he subdivides into three families, and thus describes :

First Family.-Mineral carbon, impregnated with maltha; cannel coal.-First variety.-Compact. This is found chiefly in Lancashire, its proper name is candle-coal, as it burns like a candle; but candles in that shire are called cannels. Its color is black. Lustre, common. Transparency, 0. Cross fracture, conchoidal. Fragments, from 2 to 3. Hardness, from 7 to 8. Specific gravity, 1:273 per Watson, or 1-232 by my trials. Does not stain the fingers; easily kindles, and burns with a large bright flame, but of short duration, and then leaves a sooty residuum that difficultly burns; does not cake; 240 grains of it heated until all the coaly part was consumed, left 7.5 of reddish-brown ashes, mostly argillaceous and siliceous; 100 parts of it contain by my analysis 75 carbon, 217 maltha, and 312 of ashes.

Second Variety. Slaty.-This coal comes to us from Scotland, where it is called splentcoal. Its color is grayish-black. Lustre, 2, common. Transparency, 0. Fracture, partly slaty and partly imperfectly conchoidal. Fragments, 3. Hardness, from 5 to 8. Brittle. Specific gravity, 1:426, by my trials; burns as the former variety, but soon ceases to flame; does not cake, and leaves a stony residuum; 240 grains of it, treated as the former, left 50 grains of reddish-gray ashes; 100 parts of it contain by my analysis 47.6 carbon, 31-6 maltha, and 20,8 of ashes. I even doubt,' says this mineralogist whether it contains so much carbon,

for the best specimens discovered by the smell, when inflamed, a proportion of sulphur.'

Second Family.-Mineral carbon, impregnated with asphalt and maltha, in various proportions. Peckhole, Schiefer, kohle of Werner.-Its color is more or less perfectly black, sometimes presenting bright reddish-yellow illinitions, sometimes variegated. Lustre, from 2 to 4, seldom common, mostly greasy or metallic. Transparency 0. Fracture various, mostly foliated, plain, or curved, large or small granularly foliated, sometimes in layers of contrary directions, sometimes promiscuously directed, sometimes presenting small conchoidal distinct concretions, sometimes striated; often in the gross; slaty. Its fragments, 2, often oblong parallelopipeds. Hardness, from 4 to 6. Specific gravity, from 1.25 to 137, stains the fingers, if moist, or disintegrating, otherwise not. Inflames more slowly, but burns longer than the former family, and cakes more or less, according to the proportion of asphalt. It is often contaminated with lumps, or veins of martial pyrites, sometimes with alum, or intersected with veins of spar. Of this family there are numerous varieties.

First Variety. From Whitehaven. — Black. Lustre 3, greasy. Fracture plane foliated. Fragments 2. Hardness 6, very brittle. Specific gravity 1.257; 240 grains of it exposed to a heat of 27° for five hours, after flaming a considerable time, caked, and at last left fourteen grains of reddish ashes; 100 parts of it contain by my analysis 56-8 carbon, and 43 of a mixture of asphalt and maltha, in which the asphalt predominates.

Second Variety. From Wigan.· Black. Lustre 3, greasy, often with bright yellowish illinitions. Fracture foliated, some laminæ uniformly, some promiscuonsly directed, in_the gross slaty. Fragments 2. Hardness 6. Specific gravity 1268, burns more quickly than the former; 382 grains of it exposed in an open crucible, like the former, to a heat of 27°, for four hours, left a residuum of 5.13 grains of reddish-brown ashes.

Third Variety. - From Swansea. Black. Lustre, 2. Fracture, foliated, but from a contrary direction of the lamellæ seems in part fibrous. Fragments 2. Hardness 5, very brittle. Specific gravity 1.357, burns more slowly than the former varieties; 240 grains of it, treated as above, left eight grains of yellowishred ashes. One hundred parts of it contain 73.53 of carbon, 23:16 of a mixture of asphalt and maltha, in which the former appears to predominate, and 5,21 of gray ashes.

Fourth Variety. From Leitrim.-Black. Lustre 3. Fracture, foliated. Fragments, 2. Hardness, 6, very brittle. Specific gravity, 1,351; 240 grains of it exposed to heat, as before, left in three hours a residuum of 12,5 of reddishgray ashes; one hundred parts of it contain 71,42 of carbon, 23,37 of a mixture of asphalt and maltha, in which the latter appears to. predominate, and 521 of gray ashes.

Fifth Variety.-From Irvine, in Scotland.Black. Presents layers in contrary directions, hence often called ribband-coal. Lustre of the alternate layers 3, 2. Fracture small grained