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is fused with feld-spar; the solvent for ten- books. Titanium was not known at Sévre der porcelain is silex, potash, and lead; it when Brougniart first came to that manuis not volatilized like the preceding, be- factory. He treated this singular metal in cause the fire is much inferior to that of the various ways, and never obtained any hard porcelain.

grounds but a slight obscure yellow, and These colours being previously fused do very uncertain in its quality. not in the least change when applied. The blues for glass are the same as for

Concerning the Blacks. tender porcelain.

Black colours are the most difficult to be

obtained very beautiful. There is no me. Concerning Greens.

tallic oxide which, singly, affords a fine The greens, employed in painting, are black. Manganese gives the best; iron, an made with the green oxide of copper, or opaque, dull

, blistered black, which easily sometimes with a mixture of yellow and turns to red. The makers of colours have bine. They must be previously melted with therefore combined several metallic oxides their flux; without this precaution they which, singly, do not afford blacks, and they would become black; but they do not have obtained a very beantiful colour, but change after the first fusion.

it is subject to scale and become dull. They must not be treated with a violent The oxides are those of manganese, the fire or they would totally disappear, The brown oxides of copper, and a little of that green grounds by strong heat are made with of cobalt. Grey is obtained by suppresthe oxides of cobalt aud nickel, but it is sing the qnantity of copper and increasing only a brownish green.

the quantity of flux. The bluish greens, named sky-blue, for- The Sévres manufactory is the only one · merly a colour very much in esteem, can which has as yet produced beautiful blacks only be used on tender porcelain; they with a strong fire. This is more owing to always scale off from hard porcelain, be- the quality of the biscuit than to any pecucause there is potash in their composition. liarity of process. It is by a mixture of These greens cannot be used on glass be. blue with the oxides of manganese and iron canse they afford a dirty colour : it is ne- that they make this very brilliant black. cessary to put a yellow on one side, and a The blacks for opaque glass are made the more or less pale blue on the other, in same as for painting, by giving different order to produce a green. This colour doses of solvent. may likewise be fabricated by mixing a After the display of the principles of blue with the yellow oxide of iron. Broug. fabricating each principal colour, it is clear niart hoped to obtain a green from the that by mixing these colours all possible oxide of chrome; and the experiments he shades may be obtained: and also that care made promised to be attended with suc- in the preparation, choice of materials, and cess. The pure chromate of lead fixed on just proportions of doses, must exhibit very porcelain by means of a strong fire, afforded sensible differences to the experienced eye him a very deep and very fixed blue, of of a painter. A knowledge of the compoconsiderable beauty.

sition of colours does not give the requisite

care and neatness in making them up. Concerning Bistres and Brown Reds.

On recapitulating the facts 'bere' just These are obtained by mixtures of differ- stated, in order to present them in a geneent proportions, of manganese, brown oxide ral view; we see, first, that amongst the of copper, and the oxide of iron, called colours usually employed for hard porcelain, umber. They are likewise previously fused one only is susceptible of change, namely, in their solvents, so that they do not in the the carmine; and this may be replaced by least change on tender porcelain ; lead the reds of iron, and then no colour not having the same action on the oxide of changes. manganese as it has on that of iron. This

M. Brougniart presented to the Institute colour may be employed very well on an unbaked head made in this manner, and glass.

a painting of two roses, the one baked and The brown red, ground by strong heat, the other in its first state. There was not known by the name of fonds cuille, are any difference between them. made in the same manner: feld-spar is Secondly, That amongst the colours of their Aux. There is no titanium in their soft porcelain and enamel, several change composition, though generally asserted in considerably, particularly the reds of iron VOL. III.

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mons.

and gold, with the yellows, greens, and lines or parts of the figures; then with a browns. None have been substituted in- fine hammer, striking on the metal, sustainstead of them, this species of painting be. ed by the block, the metal yields and the ing almost abandoned.

block makes an indenture or cavity on the Thirdly, That several of these colours inside, corresponding to which there is a change likewise upon the glass by becom- prominence on the outside, which is to stand ing perfectly transparent, particularly the ' for that part of the figure. yellows and violets.

Thus the workman proceeds to chase and Fourthly, That neither an additional cal- finish all the parts by successive applicacination, nor an additional fusion, as has tion of the block and hammer, to the been suspected, will prevent them from several parts of the design. And it is changing: for this method alters the colours wonderful to consider with what beauty that change, and does nothing to the rest. and justness, by this simple piece of meThe change which several colours undergo chanism, the artists in this kind will repreon tender porcelain, and on glass, does not sent foliages, grotesques, animals, histotherefore relate to the nature of their com- ries, &c. position, bat rather to that of the body on ENCHELIS, in natural history, a genus which they are placed. Consequently, by of the Vermes Infusoria. Worm invisible suppressing the carmine of gold from the to the naked eye, very simple, cylindrical. colours of hard porcelain we shall have a There are fifteen species. An account of series of unchangeable colours.

these may be found in Adams “On the ENARGEA, in botany, a genus of the Microscope.” Hexandria Monogynia class and order. ENCROACHMENT, in law, an unlawEssential character : calyx none; petals six, ful gaining upon the rights or possessions of oblong, ovate, concave, acute, three outer, another. It is generally applied to the three inner, green spotted; berry three unlawful occupation of wastes and comcelled, with four or five globular seeds. There is but one species, viz. E. marginata, a na- ENDEAVOUR, where one endeavours tive of Terra del Fuego.

actually to commit felony, &c. he is punishENCALYPTA, in botany, a genus of able as for a misdemeanour; and an assault, the Cryptogamia Musci class and order. with intent to rob, is punished by transporCapsule cylindrical; fringe simple, of six

tation. Stat. 7, Geo. II. c. 21. teen linear erect distinct teeth ; veil com

ENDECAGON, a plane geometrical panulate, inflated lax. There are six spe- figure of eleven sides and eleven angles. If cies.

each side of this figure 1, its area will be ENCAUSTIC, the same with enamel. 9.3656399 = of the tangents of 731 deling and enamel. See ENAMELLING.

grees to the radius one. ENCAUSTic painting, a method of paint- ENDEMIC, or ENDEMICAL discascs, ing made use of by the antients, in which those to which the inhabitants of particular wax was employed to give a gloss to their countries are subject more than others, on colours, and to preserve them from the in- account of the air, water, situation, and juries of the air.

manner of living. ENCHASING, or CHASING, the art of ENDIVE, in botany, &c. broad-leaved enriching and beautifying gold, silver, and succory. See CICHORIUM. other metal work, by some design, or ENDOWMENT, in law, is the widow's figures represented thereon, in low relievo. portion; being a third part of all the freeSee RELIEVO and SCULPTURE.

hold lands and tenements, of which her husEnchasing is practised only on hollow band was seized at any time during the thin works, as watch-cases, cane-heads, coverture. Of lands not freehold, her portweezer-cases, or the like. It is performed tion varies according to the custom in difby punching or driving out the metal, to ferent places. form the figure, from within side, so as to ENEMY, in law, an alien or foreigner, stand out prominent from the plane or sur- who in a public capacity invades any counface of the metal. In order to this they try, and who cannot be punished as provide a number of fine steel blocks, or traitor, but must be subjected to martial puncheons, of divers sizes; and the design law. An alien residing here, wder the probeing drawn on the surface of the metal, tection of the king's peace, may be dealt they apply the inside upon the heads or with as a traitor, because he owes a qualitops of these blocks, directly under the fied allegiance.

a

ENG

ENG ENFRANCHISEMENT, in law, the apply in all the figures, A, A, A, A; fig. 3 incorporating a person into any society or and 4, is a cast-imon cylinder truly bored, it is body politic; such as the enfranchisement ten inches diameter and fifteen long, it has of ope made a citizen of London or other a flanch at each end wherсon to screw two city, or burgess of any town corporate, be- covers, with stuffing boxes,' a, a, in their cause he is made partaker of its liberties, centres, through which the spindle, B, B, or franchises.

of the engine passes, and being tight packENGINE, in mechanics, is a compounded with hemp round the collar, makes a machine, made of one or more mechanical tight joint; the piston, D, is affixed to the powers, as levers, pullies, screws, &c. in spindle within the cylinder, and fits it tight order to raise, cast, or sustain any weight, all round by means of leathers, applied as or produce any effect which could not be described in the beer-engine ; at E, fig. 4, a casily effected otherwise.

partition called a saddle, is fixed in the Engines are extremely numervus; some cylinder, and fits against the back of the used in war, as the battering-ram, ballista, spindle tiglit by a leather. waggons, chariots, &c.; others in trade We have now a cylinder divided by the and manufactures, as cranes, mills, presses, saddle, E, and piston, into two parts, whose &c.; others to measure time, as clocks, capacity can be increased and diminished watches, &c.; and others for the illustration by moving the piston, with proper passages of some branch of science, as the orrery, and valves to bring and convey away the cometarium, and the like.

water: this will form a pump. These pasIn general we may observe, concerning sages are cast in one piece with the cylinengines, that they consist of one, two, or der: one, d, for bringing the water is square, more of the simple powers variously com- and extends about 4d round the cylinder; it bined together; that in most of them the connects at bottoin with a pipe, e; at its axis in peritrochio, the lever, and the screw, two upper ends opens into two large chamare the constitutent parts; that in all a cer- bers, f g, extending near the whole length tain power is applied to produce an effect of the cylinder, and closed by covers, h h, of much greater moment; and that the screwed on : i k, are square openings (shewn greatest effect or perfection is when it is by dotted squares in fig. 3.) in the cylinder, set to work with four-ninths of that charge communicating with the chambers:fg, lin, which is equivalent to the power, or will are two valves, closing their ends of the curvbut just keep the machine in equilibrio. ed passage, d, and preventing any water re

In all machines the power will just sus. turning down the passage, d: no, are two tain the weight, when they are in the in passages from the top of the cylinder to converse ratio of their distances from the cen- vey away the water; they come out in the top tre of motion.

of the cylinder, which, together with the top Engine, fire, by Rowntree. We have of the chambers, f8, form a large flat surface, selected an engine by this maker to give a and are covered by two valves, P,9, to redrawing and description, as it is greatly supe- tain the water which has passed throngh rior to the common engine with two force them. A chamber, K, is screwed over pumps. As that kind of engine has so often these valves; and has the air-vessel, k, fig. 1 been described by various authors, and its and 2, screwed into its top; from each side principle so easily comprehended from the of this chamber a pipe, w w, proceeds, to description of a force-pump; we judged it which a hose is screwed, as shewn in fig. 1. unnecessary to give any drawing of it. Levers, x x, are tixed to the spindle at each

The fire engine, by Rowutree, is a dou- end, as shewn in fig. 1, and carry the lianble force-pump, of a peculiar construction, dles, H H, by which men work the engine. similar in its action to the beer-engine When the piston moves, as shewn by the (described under that article), but as it is arrow in fig. 4, it produced a vacmum in on a much larger scale, its constructions are chamber, f, and that part of the cylinder of course varied. Plate Rowntree's Engine, contiguous to it; the water in the pipe, e, fig. 1 and 2, are two elevations at right then opens the valve, m, and fills the cylinangles to each other, of the external part der. The same motion forces the water of the engine mounted op four wheels. Fig. contained in the other part of the cylinder 3 and 4, are two sections perpendicular to through the valve, q, into chamber, K, and each other, of the body of the engine or thence to the hose through the pipe, w; the pump : fig. 5 and 6, are parts of the engine. piston being turned the other way, reverses The same letters are used as far as they the operation with respect to the valves, though it continues the same in itself. The frames, B B, (fig. 1, Plate Pump- Engine,) pipe, e, is screwed by a flanch to an upright screwed together by means of five wrought pipe, P, fig. 5,connected with another square iron pillars, a a a a; D, is another smaller iron pipe, fastened along the bottom of the frame, to support the axis of the fly-wheel, chest of the engine; a curved brass tube, connected with the other frame by three G, comes from this pipe through the end of short pillars; E, is the fly wheel turned by the chest, and is cut into a screw to fit on winches on the end of its axis; it has a pithe suction hose when it can be used; at nion (13) of 13 leaves upon its axis, turning other times a close cap is screwed on, and a wheel (48) of 48 teeth, on whose axis are another brass cap at H, within the chest is two cranks, bb, opposite to each other, to screwed upwards on its socket, to open se- work the pumps; e e, are the two crank veral small holes made in it, and allow the rods, made each in two branches, and jointwater to enter into the pipe; in this case ed at the lower end into two other rods, ff, the engine chest must be kept full of water which slide through holes made in the fixed by buckets. The valves are made of brass, bars, &, fig. 2; the crank rods receive and turn upon hinges. The principal ad- these bars between their two branches, and vantage of the engine is the facility with by this means, though the rods, ff, are conwhich it is cleaned from any sand, gravel, fined by their guides to move truly vertical, or other obstructions, which a fire-engine the crank rods, e e, can partake of the irreguwill always gather when at work.

lar motion of the crank. The pump rods of The chambers, f, g, being so large, allow the pumps are screwed to the rods, ff, by sufficient room to lodge a greater quantity two nuts, and go down into the pumps, GH, of dirt than is likely to be accumulated in supported from the iron frame by eight iron the use of the engine at any one fire, and if braces, h h. The pumps consist of two barany of it accidentally falls into the cylinder, rels, G H, with valves at the bottom, allowit is gently lifted out again into the cham- ing water to enter them freely, but prebers by the piston, without being any ob- venting its return; the buckets fixed to the struction to its motion : to clear the engine pump rods fit the barrels truly, and have from the dirt, two circular plates, » r, five valves in them shutting downwards; I, is a inches diameter, are unscrewed from the chest bringing water to the valves in the lids, hh, of the chambers, fg, and when bottom of the barrels ; K, is another comcleaned are screwed on again : these screw municating with the top of the barrels by covers fit perfectly tight without leather, two crooked passages to carry away the and can be taken out, the engine cleared, water from them; the barrels are close at and enclosed again in a very short time, top, and the pump rods pass through close even when the engine is in use, if found stuffing boxes, through which no water will necessary.

leak by them. The action of the pump is The two upper valves, p 9, and chamber, the same as the common sucking pump; K, can also be cleared with equal ease, by when the bucket is drawn up, the valve in it screwing out the air-vessel, k k, fig. 1, which closes, and it forms a vacuum in the lower opens an aperture of five inches, and fits air- part of the barrel; this causes the water to tight, without leather, when closed. The ascend into it through the chest, I, to restore valves may be repaired through the same the equilibrium, at the same time it raises openings. The use of the air-vessel, kk, all the water which was above it throngh fig. 1 and 2, is to equalize the jet from the the chest, K; on the descent of the bucket engine during the short intermittance of the valve at the bottom of the barrel shats, motion at the return of the piston stroke; and prevents the escape of the water; the this it does by the elasticity of the compres- valve in the bucket opens, and the water sed air within it, which forces the water out passes through it, ready to be raised at the continnally, though not supplied quite regu- next stroke. The barrels in question are larly from the engine.

34 inches diameter, and 8 inches stroke. The engine from which our drawing was As the two cranks, bb, are opposite each taken was made for the Sun Fire Insurance other, when one bucket is rising, the other Company, in London, and trom some expe. is going down; by this means the power riments made by their agent, Mr. Samnel required to turn the machine by the handles Hubert, appears to answer every purpose. is equalized, and also the quantity of water

Engine for raising water. The frame raised by the engine. of the machine is of cast iron, nearly in the Engines for raising water by the pressure form of the letter A; there are two of these and descent of a column inclosed in a pipe

ENGINE. have been lately erected in different parts this rod would be the communication of the of the country. The principle now advert- first mover. KL, is a tumbler, or tumbling ed to was adopted in some machinery exe- bob, capable of being moved on the gudcuted in France about 1731, and was likewise geons, V, from its present position to ano. adopted in Cornwall more than forty years ther, in which the weight, L, shall haug over ago; but the pressure engine, of which we with the same inclination on the opposite are about to give a particular description, side of the perpendicular, and consequently is the invention of Mr. R. Trevithick, who the end, K, will then be as much depressed probably was not aware that any thing at as it is now elevated. all similar had been attempted before. This The pipe, RS, has its lower end immersed engine, a section of which on a scale of 4d in a cistern, by which means it delivers its of an inch to a foot is shewn in Plate Pressure water without the possibility of the external Engines, one was erected about eight years air introducing itself; so that it constitutes ago at the Druid copper mine, in the parish of a Torricellian column, or water barometer, Illogan, near Truro. A B, represents a pipe and renders the whole column from A to S six inches in diameter, through which water effectual, as we shall see in our view of the descends from the head to the place of its operation. delivery to run off by an adit at S, through The operation. Let us suppose the lower a fall of 3+ fathoms in the whole; that is to bar, KV, of the tumbler to be horizontal, say, in a close pipe down the slope of a hill and the rod, PO, so situated, as that the 200 fathoms long, with 26 fathonis fall; then plugs, or leaden pistons, D and E, shall lie perpendicularly six fathoms, till it arrives at opposite to each other, and stop the water B, and thence through the engine from B to ways, G and F. In this state of the engine, S two fathoms; at the turn, B, the water though each of these pistons is pressed by a euters into a chamber, C, the lower part of force equivalent to more than a thousand which terminates in two brass cylinders, pounds, they will remain motionless, befour inches in diameter; in which two plugs cause these actions being contrary to each or pistons of lead, D and E, are capable of other, they are constantly in equilibrio. The moving np and down by their piston rods, great piston, H, being at the bottom of its which pass through a close packing above, cylinder, the tumbler is to be thrown by and are attached to the extremities of a hand into the position here delineated. Its chain leading over and properly attached to action npon, O P, and consequently upon the wheel, Q, so that it cannot slip. the wheel, Q, draws up the plug E, and de

The leaden pieces, D and E, are cast in presses D, so that the water way, F, becomes their places, and have no packing whatever. open from A B, and that of G to the pipe They move very easily; and if at any time R: the water consequently descends from they should become loose, they may be A to C, thence to F, until it acts above the spread out by a few blows with a proper piston F. This pressure forces down the instrument, without taking them out of their piston, and if there be any water below the place. On the side of the two brass cylin- pistor, it causes it to pass through GGG ders, in which D and E move, there are into R: during the fall of the piston, which square holes communicating towards, G, carries the pit rod, MN, along with it, a with a horizontal trunk, or square pipe, four sliding block of wood, I, (dotted) fixed to inches wide, and three inches deep. All this rod is brought into contact with the tail, the other pipes, G, G, and R, are six inches K, of the tumbler, and lowers it to the horiin diameter, except the principal cylinder zontal position beyond which it oversets by wherein the piston, H, moves; and this cy- the acquired motion of the weight L. linder is ten inches in diameter, and admits The mere rising of the piston, if there a nine foot stroke.

was no additional motion in the tumbler, The piston rod works through a stuffing- would only bring the two plugs, D and E, to box above, and is attached to, M N, which the position of rest, namely, to close G and is the pit rod, or a perpendicular piece di. F, and then the engine would stop; but the vided into two, so as to allow its alternate fall of the tumbler carries the plug, D, upmotion up and down, and leave a space be- wards, quite clear of the hole, F, and the tween, without touching the fixed appara- other plug, E, downwards, quite clear of the tus, or great cylinder. The pit rod is pro- hole, G: these motions require no consumplonged down in the mine, where it is em- tion of power, because the plugs are in ployed to work the pump; or if the engine equilibrio, as was just observed. In this was applied to mill-work, or any other use, new situation the column, A B, no longer

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