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in small scales, which appear like the fragments of small hollow spheres. Enamel painters mix this flux with a little nitre and borax. This matter, which produces a very good effect, was employed without attempting to decompose it. It may be a very fusible common white enamel which has been blown into that form. It is to be remarked, that purple will not bear a strong heat; and the color is always more beautiful if the precipitate is ground with the flux before it has become dry.

RED. We have no metallic oxide capable of giving directly a fused red; that is to say, we have no metallic calces which, entering into fusion and combining, under the form of transparent glass, with fluxes or glass, give directly a red color. To obtain this color, it must be compounded different ways, as follows:-Take two parts, or two parts and a half (you may, however, take only one part) of sulphate of iron and of sulphate of alumine, fuse them together in their water of crystallisation, and take care to mix them well together. Continue to heat them to complete dryness, then increase the fire so as to bring the mixture to a red heat. The last operation must be performed in a reverberating furnace. Keep the mixture red until it has every where assumed a beautiful red color, which you may ascertain by taking out a little of it from time to time, and suffering it to cool in the air. You may then see whether the matter is sufficiently red to judge of this it must be left to cool, because while hot it appears black. The red oxides of iron give a red color; but this color is exceedingly fugitive; for, as soon as the oxide of iron enters into fusion, the portion of oxygen, which gives it its red color, leaves it, and it becomes black, yellow, or greenish. To preserve, therefore, the red color of this oxide in the fire, it must be prevented from vitrifying and abandoning its oxygen. I have tried (says M. Clouet) a variety of different substances to give it this fixity, but none of them succeeded except alum. The doses of alum and sulphate of iron may be varied. The more alum you add the paler will be the color. Three parts of alum to one of sulphate of iron give a color which approaches a flesh-color. It is alum also which gives this color the property of becoming fixed at a very strong heat. This color may be employed on raw enamel; it has much more fixity than the purple, but not so much as the blue of cobalt. It may be washed to carry off the superfluous saline matter, but it may be employed also without edulcoration; in that state it is even more fixed and more beautiful. It does not require much flux; the flux which appeared to me to be best suited to it is composed of alum, minium, marine salt, and enamel sand. This flux must be compounded in such a manner as to render it sufficiently fusible for its objects: from two or three parts of it are mixed with the color. In general three parts of flux are used for one of color; but this dose may, and ought to be varied according to the nature of the color and the shade of it required. Red calx of iron alone, when it enters into fusion with glass, gives a color which seems to be black; but if the color be diluted with a sufficient quantity of glass, it

at last becomes of a transparent yellow. Thus the color really produced by calx of iron combined with glass is a yellow color, but which being accumulated becomes so dark, that it appears black. In the process above given for making the red color, oxide of iron does not fuse; and this is the essential point; for, if this color is carried in the fire to vitrification, it becomes black or yellowish, and disappears if the coat be thin, and the oxide of iron present be only in a small quantity.

YELLOW.-Though yellow may be obtained in a direct manner, compound yellows are preferred because they are more certain in effect, and more easily applied, than the yellow which may be directly obtained from silver. The compound yellows are obtained in consequence of the same principles as the red color of iron. For this purpose we employ metallic oxides, the vitrification of which must be prevented by mixing with them other substances, such as refractory earths or metallic oxides difficult to be. fused. The metallic calces which form the basis of the yellow colors are generally those of lead; as minium, the white calx of lead, or litharge, the white calx of antimony, called diaphoretic antimony; that called crocus metallorum is also employed. This regulus pulverised, and mixed with white oxide, gives likewise a yellow. The following are the different compositions used: one part of the white oxide of antimony, one part of the white oxide of lead, or two or three; these doses are exceedingly variable; one part of alum and one of sal-ammoniac. When these matters have been all pulverised and mixed well together they are put in a vessel over a fire sufficient to sublimate and decompose the sal-ammoniac; and when the matter has assumed a yellow color the operation is finished. The calces of lead mixed in a small quantity either with silex or alumine, also with the pure calx of tin, exceedingly white, gives likewise yellows. One part of the oxide of lead is added to two, three, or four of the other substances above mentioned. In these different compositions for yellow you may use also oxide of iron, either pure or that kind which has been prepared with alum and vitriol of iron; you will then obtain different shades of yellow. From what has been said, you may vary these compositions of yellow as much as you please. Yellows require so little flux that one or two parts, in general, to one of the color are sufficient. Saline fluxes are improper for them, and especially those which contain nitre. They must be used with fluxes composed of enamel-sand, oxide of lead, and borax, without marine salt. A yellow may be obtained also directly from silver. All these mixtures may be varied, and you may try others. For this purpose you may use sulphate of silver, or any oxide of that metal mixed with alumine or silex, or even with both in equal quantities. The whole must be gently heated until the yellow color appears, and the matter is to be employed with the fluxes pointed out for yellow. Yellow of silver, like purple, cannot endure a strong heat; a nitric solution of silver may be precipitated by the ammoniacal phosphate of soda, and you will obtain a yellow precipitate which may be used to paint in that

color with fluxes, which ought then to be a little harder. Besides the methods above mentioned, the best manner of employing the oxide of silver is, in my opinion, to employ it pure: in that case you do not paint but stain. It will be sufficient then to lay a light coating on the place which you wish to stain yellow, and to heat the article gently to give it the color. You must not employ too strong a heat: the degree will easily be found by practice. When the article has been sufficiently heated, you take it from the fire and separate the coating of oxide, which will be found reduced to a regulus. You will then observe the place which it occupied tinged of a beautiful yellow color without thickness. It is chiefly on transparent glass that this process suc ceeds best. Very fine silver filings produce the same effect: but what seemed to succeed best in this case was sulphate of silver well ground up with a little water, that it may be extended very smooth. From what has been said, it may readily be seen that this yellow must not be employed like other colors; that it must not be applied till the rest have been fused; for, as it is exceedingly fusible and ready to change, it would be injured by the other colors; and as the coating of silver, which is reduced, must be removed, the fluxes would fix it, and prevent the possibility of its being afterwards separated. Working on glass is not attended with this inconvenience, because the silver yellow is applied on the opposite side to that on which the other colors are laid.

GREEN.-Green is obtained directly from the oxide of copper. All the oxides of copper are good; they require little flux, which even must not be too fusible: one part or two of the flux will be sufficient for one oxide. This color agrees with all the fluxes, the saline as well as the metallic, which tends to vary a little the shades. A mixture of yellow and blue is also used to produce greens. Those who paint figures or portraits employ glass composed in this manner; but those who paint glazed vessels, either earthenware or porcelain, employ, in general, copper green. Independently of the beautiful green color produced by oxidated copper, it produces also a very beautiful red color. This beautiful red color produced by copper, is exceeding fugitive. The oxide of copper gives red only when it contains very little oxygen, and approaches near to the state of a regulus. Notwithstanding the difficulty of employing this oxide for a red color, a method has been found to stain transparent glass with different shades of a very beautiful red color by means of calx of copper. The process is as follows: you do not employ the calx of copper pure, but add to it calx of iron, which, for that purpose, must not be too much calcined; you add also a very small quantity of calx of copper to the mass of glass which you are desirous of tinging. The glass at first must have only a very slight tinge of green, inclining to yellow. When the glass has that color you make it pass to red, and even a very dark red, by mixing with it red tartar in powder, or even tallow. You must mix this matter well in the glass, and it will assume a very dark red color. The glass swells up very much by this addition. Before it is worked it must be suffered to settle, and become compact; but as soon as it has fully assumed the color it

must be immediately worked, for the color does not remain long, and even often disappears while working; but it may be restored by heating the glass at the flame of a lamp. It is difficult to make this color well, but when it succeeds it is very beautiful, and has a great deal of splendor. By employing the calx of copper alone, for the processes above mentioned, you will obtain, when you succeed well, a red similar to the most beautiful carmine. The calx of iron changes the red into vermilion, according to the quantity added. If we had certain processes for the making of this color, we should obtain all the shades of red from pure red to orange, by using, in different proportions, the oxide of copper and that of iron. The calx of copper fuses argil more easily than silex: the case is the same with calx of iron. If you fuse two or three parts of argil with one of the oxide of copper, and if the heat be sufficient, you will obtain a very opaque enamel, and of vermilion red color. The oxide of copper passes from red to green, through yellow, so that the enamel of copper, which becomes red at a strong heat, may be yellow with a weaker heat. The same effect may be produced by deoxidating copper in different degrees: this will be effected according as the heat is more or less violent. The above composition might, I think, be employed to give a vermilion red color to porcelain. The heat of the porcelain furnace ought to be of sufficient strength to produce the proper effect. The calx of iron fused also with argil, in the same proportions as the calx of copper, gives a very beautiful black. These porportions may, however, be

varied.

BLUE. Blue is obtained from the oxide of cobalt. It is the most fixed of all colors, and becomes equally beautiful with a weak as with a strong heat. The blue produced by cobalt is more beautiful the purer it is, and the more it is oxidated. Arsenic does not hurt it. The saline fluxes which contain nitre are those best suited to it: you add a little also when you employ that flux which contains a little calcined borax, or glass of borax, though you may employ it also with that flux alone. But the flux which, according to my experiments, gives to cobaltblue the greatest splendor and beauty is that composed of white glass, which contains no metallic calx, of borax, nitre, and diaphoretic antimony well washed. When this glass is made for the purpose of being employed as a flux for blue, you may add less of the white oxide of antimony: a sixth of the whole will be sufficient.

VIOLET. Black calx of manganese, employed with white fluxes, gives a very beautiful violet. By varying the fluxes the shade of the color may also be varied. It is very fixed as long as it retains its oxygen. The oxide of manganese may produce different colors; but for that purpose it will be necessary that we should be able to fix its oxygen in it in different proportions. How to effect this has, perhaps, never yet been discovered. These are all the colors obtained from metals. From this it is evident that something still remains to be discovered. We do not know what might be produced from the oxides of platina, tungsten, molybdena, and nickel : all these oxides are still to be tried; each of them must produce a color, and perhaps red, which is obtained

neither directly nor with facility from any of the metallic substances formerly known and hitherto employed.

Having laid before the English artists the result of M. Clouet's Researches, as they were presented to the French National Institute, of, which he was an associate, we add a few general observations taken from those of our own countrymen, who have made the subject of enamelling their study and employment. The most beautiful and expensive color known in this branch of the art is an exquisitely fine, rich, and purplish tinge, given by the salts and oxides of gold, especially the purple precipitate formed by tin in one form or other, and the nitromuriate of gold, and also by fulminating gold. This fine color, however, requires much skill in the artist to be fully brought out. Other and commoner reds are given by the oxides of iron, but this requires the mixture of alumine, or some other substance refractory in the fire; otherwise what would, under proper circumstances, be a full red will degenerate into a black.

Yellow is either given by the oxide of silver alone, or by the oxides of lead and antimony, with similar mixtures to those required with iron. The silver is as tender a color as gold, and as readily injured or lost in a high heat. Green is given by the oxide of copper, or it may also be produced by a mixture of yellow colors. Blue is given by cobalt, and this seems the most certain of all enamel colors, and as easy to be managed. Black is produced by a mixture of cobalt and manganese. 'The reader,' says Mr. Aikin in his Chemical Dictionary, 'may conceive how much the difficulties of this nice art are increased, when the object is not merely to lay a uniform colored glazing on a metallic surface, but also to paint that surface with figures and other designs that require extreme delicacy of outline, accuracy of shading, and selection of coloring. The enamel painter has to work, not with actual colors, but with mixtures which he knows from experience, will produce certain colors after the operation of the fire; and to the common skill of the painter in the arrangement of his pallet, and the choice of his colors, the, enameller has to add an infinite quantity of practical knowledge of the chemical operation of one metallic oxide on another, the fusibility of his materials, and the utmost degree of heat at which they will attain not only the accuracy of the figures which he has given, but the precise shade of color which he intends to lay on. Painting in enamel requires a succession of firings; first, of the ground which is to receive the design, and which itself requires two firings, and then of the different parts of the design itself. The ground is laid on in the same general way as the common watch-face enamelling already described. The colors are the different metallic oxides melted with some or other vitrescent mixture, and ground to extreme fineness. These are worked up with an essential oil, that of spike is preferred, and next to it the oil of lavender, to the proper consistence of oil colors, and are laid on with a very fine hair brush. The essential oil should be very pure, and by the use of this, rather than any fixed oil, it is proba

ble that the whole may evaporate completely in a moderate heat, and leave no carbonaceous matter in contact with the color when red-hot, which might affect its degree of oxidation, and thence the shade of color which it is intended to produce. As the color of some of the vitrified metallic oxides, such as that of gold, will stand only at a moderate heat, while others will bear and even require a higher temperature to be properly fixed, it forms a great part of the technical skill of the artist to apply different colors in their proper order; fixing first those shades which are produced by the colors that will endure the highest degree of heat. The outline of the design is first traced on the enamel ground, and burnt in; after which the parts are filled up gradually with repeated burnings to the last and finest touches of the tenderest enamel.'

Those who paint on enamel, on earthenware, porcelain, &c., must regulate the fusibility of the colors by the most tender of those employed, as, for example, the purple. When the degree which is best suited to purple has been found, the other less fusible colors may be so regulated (by additions of flux), when it is necessary to fuse all the colors at the same time, and at the same degree of heat. You may paint also in enamel without flux; but all the colors do not equally stand the heat which must be employed. If the enamel, however, on which you paint be very fusible, they may all penetrate it. This manner of painting gives no thickness of color; on the contrary, the colors sink into the enamel at the places where the tints are strongest. To make them penetrate, and give them lustre, a pretty strong fire will be necessary to soften the enamel, and bring it to a state of fusion. This method cannot be practised but on enamel composed with sand, which is called enamel-sand, as already mentioned. It may be readily seen, also, that the colors and enamel capable of enduring the greatest heat will be the most solid, and the least liable to be changed by the air.

The following method of filling up engraving on silver with a durable black enamel, is practised in Persia and India :

They take half an ounce of silver, two ounces and a half of copper, three ounces and a half of lead, twelve ounces of sulphur, two ounces and a half of sal-ammoniac. The metals are melted together, and poured into a crucible, which has been before filled with pulverised sulphur, made into a paste by means of water; the crucible is then immediately covered, that the sulphur may not take fire, and this regulus is calcined over a smelting-fire, until the superfluous sulphur be burned away. This regulus is then coarsely pounded, and, with a solution of sal-ammoniac, formed into a paste, which is rubbed into the engraving on silver plate. The silver is then wiped clean, and suffered to become so hot under the muffle, that the substance rubbed into the strokes of the engraving melts and adheres to the metal. The silver is afterwards wetted with the solution of sal-ammoniac, and again placed under the muffle till it becomes red-hot. The engraved surface may then be smoothed and polished without any danger of the black substance, which is an artificial kind of silver ore,

either dropping out, or decaying. In this manner is all the silver-plate brought from Russia ornamented with black engraved figures.

The town of Limoges was very celebrated in the twelfth and thirteenth centuries for the excelence of its enamels on various metals. In 1197, tables, vases, basins, tabernacles, candelabra, crosiers, &c., enriched with enamels, were called opus de Limogia, labor Limogiæ, opus Lemoviticum, and are still known to dealers in curiosities of this nature as enamels of Limoges.

The principal artists who have excelled in this beautiful department of the fine arts are Primaticcio and Maitre Roux, who introduced a pure taste in arabesques, and other pictorial ornaments, which were beautifully executed in enamel. Raffaelle and Michel Angiolo also gave designs for enamels on porcelain and earthenware, many of which are still called Raffaelle's ware, or china. Enamelling on metal is of later invention, and is attributed to the French, particularly the smaller and more elegant subjects of history, poetry, and fancy. The first artist who distinguished himself in this latter department, and, in fact, as its inventor, was Jean Toutin, a goldsmith at Chateaudun. He was succeeded by his disciple Gribelin, who was also an excellent artist and workman. Dubie, a goldsmith, made excellent enamels in the galleries of the Louvre. Morliere, a native of Orleans, but who practised at Blois, followed soon after; and was much admired for his miniature enamels for rings and watch-cases. He had for a disciple Robert Vauquer of Blois, who surpassed all his predecessors, particularly in his coloring; he died in 1670. Pierre Chartier, also of Blois, was a celebrated enamellist, particularly in flowers. Jean Petitot, who died in 1691, succeeded as an enamelist of high repute, and practised in England, where his works are well known, and deservedly admired. Bordier followed in the same line, and also practised in this country; as did Louis Hance and Louis de Guernier. Zinck, a Swede, has also obtained a high reputation for the excellence of his works; as did an artist of the name of Boit, whose character as an artist is given in Walpole's Anecdotes of Painters. One of his enamels is there mentioned as being of the extraordinary dimensions of twenty-two inches by sixteen; which have, however, been exceeded by our native artists Bone and Muss. We have also to notice, as eminent practitioners in this art, Schnell, who died in 1704; Sophia Cheron, in 1711; Chatillon, in 1732; Ism. Mengs, in 1764; Nelson, in 1770; Meytens, a Swede, in 1770; Rouquet, who practised in England, and wrote upon the arts; Liotard, Duran, Paguier.

ENAM'OUR, v. a.) Span. and Port. enaENAM'ORADO. morar; Ital. inamorare, from en and AMOUR, which see. To inspire or inflame with love; taking of before the object. But Milton and Shakspeare use it without; an enamorado is one desperately in love.

An enamorado neglects all other things to accom-
plish his delight.
Sir T. Herbert.

Affliction is enamoured of thy parts,
And thou art wedded to calamity. Shakspeare.

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nation; exposition.

ENARRATION, n. s.

Beattie. Lat. enarro. Expla

I might further yet confirm this truth by an anato mical enarration of the several compounding parts of these limbs. Smith on Old Age. ENARTHRO'SIS, n. s. *Εν and αρθρον. The insertion of one bone into another to form a joint.

Enarthrosis is where a good round head enters into as that of os coxæ, receiving the head of the os fea cavity, whether it be a cotyla, or profound cavity; moris; or glene, which is more shallow, as in the scapula, where it receives the humerus.

Wiseman.

ENARTHROSIS, in anatomy, is a species of Diarthrosis. See ANATOMY.

ENA'UNTER, adv. An obsolete word, explained by Spenser himself, to mean lest that. Anger would not let him speak to the tree, Enaunter his rage might cooled be, But to the root bent his sturdy stroke. Spenser. ENASCENT, adj. From e, and nascent; ENATE'. Lat. nascor, rising; springing or rising forth.

nascens,

at a distance from their bodies, are either the adnate The parts appertaining to the bones, which arise out Smith on Old Age.

or enate parts.

Thus when in holy triumph Aaron trod, And offered on the shrine his mystic rod; First 2 new bark its silken tissue weaves, New buds emerging widen into leaves; Fair fruits protrude, enascent flowers expand, And blush and tremble round the living wand.

Darwin.

ENCA'GE, v. a. From en and cage.
shut up in a cage; to coop up; to confine.
He suffered his kinsman March,
Who is, if every owner were right placed,
Indeed his king, to be encaged in Wales,
There, without ransom, to lie forfeited.

To

Shakspeare. Like Bajazet encaged, the shepherd's scoff, Or like slack-sinewed Sampson, his hair off.

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ENCAMP', v. n. ENCAMP'MENT. n. s. Sen and CAMP, which To pitch tents, or form a camp: hence, to settle or dwell for a time.

see.

He encamped at the mount of God. Exod. xiii. 5.

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Among the regulations concerning encampment, published in Britain by authority, the following are particularly to be attended to. 'On the arrival of a brigade, or a battalion, on the ground destined for its camp, the quarter and rear guards of the respective regiments will immediately mount; and, when circumstances require them, the advanced picquets will be posted. The grand guards of cavalry will be formed, and the horses picketed. The men's tents will then be pitched, and, till this duty is completed, the officers are on no account to quit their troops or companies, or to employ any soldier for their own accommodation. Necessaries are to be made in the most convenient situations, and the utmost attention is required in this, and every other particular, to the cleanliness of the camp. If circumstances will allow the ground on which a regiment is to encamp to be previously ascertained, the pioneers should make these, and other essential conveniences, before the corps arrives at its encampment. Whenever a regiment remains more than one night in a camp, regular kitchens are to be constructed. No tents, or huts, are to be allowed in front, or between the intervals of the battalions. A spot of ground for this purpose should be marked out by the quarter-master, with the approbation of the commanding officer. On arriving in a camp which is intersected by hedges, ditches, unequal or borgy ground, regiments will immediately make openings of communication, of sixty feet in width. The ground in front of the encampment is to be cleared, and every obstacle to the movement of the artillery and troops is to be removed. Commanding officers of regiments must take care that their communication with the nearest grand route is open and free from impediments.' The arrangement of tents in a camp is nearly the same all over Europe; which is, to dispose them in such a manner, that the troops may form with safety and expedition. To answer this end, the troops are encamped in the same order as that in which they are to engage the enemy, which is by battalions and squadrons; hence, the post of each battalion and squadron must necessarily be at the head of its own encampment. Gustavus Adolphus, king of Sweden, was the first who formed encampments according to the order of battle. By this disposition the extent of the camp, from right to left of each battalion and squadron, will be equal to the front of each in line of battle; and consequently, the extent from right to left, of the whole camp, should be equal to the front of the whole army when drawn up in line of battle, with the same intervals between the several encampments of the battalions and squadrons, as are in the line. Each regiment posts a subaltern's guard at eighty yards from

the colors to the officer's tent, called the quarterguard; besides a corporal's guard in the rear, called the rear-guard. Each regiment of horse or dragoons has also a small guard on foot, called the standard-guard, at the same distance. The grand guard of the army consists of horse, and is posted about a mile or a mile and a half distance towards the enemy. In a siege, the camp is placed all along the line of circumvallation, or rather in the rear of the approaches, out of cannon-shot. The army faces the circumvallation, if any, that is, the soldiers have the town in their rear. It is of great consequence, that a camp have a commodious spot of ground at its head, where the army, in case of surprise, may in a moment be under arms, and in a condition to repulse the enemy; as also, that there be a convenient field at a small distance, and of a sufficient extent to form in advantageously, and move with facility.

ENCANTHIS, in surgery, a tubercle arising either from the caruncula lachrymalis, or from the adjacent red skin; sometimes so large, as to obstruct not only the puncta lachrymalia, but also part of the sight or pupil itself. See SUR

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ENCAUSTIC PAINTING, Lat. encausticus; Gr. 'Evkavsin. The art of painting in encaustic is a manner of painting which is executed with the operation of fire. Ancient authors often make mention of this species of painting, and which, if it had been described simply by the word encaustic, which signifies executed by fire, might be supposed to have been a species of enamel painting. But the expressions encausto pingere, pictura encaustica, ceris pingere, picturam inurere, by Pliny and other ancient writers, make it clear another species of painting is thereby meant. We have no ancient pictures of this description, and therefore the precise manner adopted by the ancients is not completely developed, though many moderns have closely investigated the subject, and described their processes. At what time, and by whom, this species of painting was first invented, is not determined by antiquaries, although it appears to have been practised in the fourth and fifth centuries. Count Caylus and M. Bachelier, a painter, were the first of modern times who made experiments in this branch of art, about the year 1749. Some years after this, Count Caylus presented to the Academy of Painting at Paris his ideas and experiments on the subject of the ancient manner of painting in encaustic. 1754 the count had a head of Minerva painted by M. Vien, after the process described by himseif, and presented it to the Academy of Sciences in 1755. This success induced M. Bachelier to recommence his experiments, in which he suc

In

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