To make the Maftic Varnish.

Put two ounces of the clearest gum maftic, finely pow dered, into a bottle, with fix ounces of oil of turpentine : stop the bottle clofe, and shake them well together, in order to incorporate them with each other. Then hang the bottle in a veffel of boiling water for half an hour, taking it out three or four times to shake it. If it be necessary to make the varnish ftronger, it may hang a quarter of an hour longer in the boiling water.

To make Camp Paper, with which a Perfon may write or draw, without Pen, Ink, or Pencil.

Mix fome hard foap with lamp-black and water, into the confiftence of a jelly; with this mixture brush over one fide of the paper, and let it dry. When you use the paper, put it between two sheets of clean paper, with its black fide downwards then with a pin, a stick, or any other substance with a fharp point, draw, or write upon the clean paper; and where the point has touched, there will be the impreffion upon the lowermoft fheet of paper, as if it had been drawn or written with a pen.

This camp paper may be made of any other colour, by mixing the foap with different colours.

By this paper alfo any print or drawing may be exactly copied, by laying it under the fame, and tracing the outines, &c.

The

The Method of taking Impreffions from Moulds, Medals, &c. in Plafter of Paris, and therely counterfeiting the fame.

Oil the furface of the mould, or medal, with a piece of cotton, or camel-hair pencil, dipped in oil of olives; put a hoop of paper, or pafteboard, round the medal, exactly equal to the thickness you would choofe your impreffion to be made: then mix some plaster of Paris with water, to the confiftence of a thick cream, and with a brush lay it on the furface of the mould or medal, and inmediately after lay on more plafter, to make it of a fufficient thicknefs. By rubbing it on the furface of the medal with a brush, it will entirely prevent any air-holes from appearing on the surface of the impreffions. After it has flood about half an hour, it will be fo hard, that it may be fafely taken off without breaking; then pare it fmooth on the back, and round the edges, and it will be done. If the weather be cold or damp, it should be dried before a brifk fire. Alfo, in the operation, when the plafter is laid on to a fufficient thicknefs, it fhould be fprinkled with fome of the dry powder of plafter of Paris, which makes it harder, and dry fooner. If the face of the medal only be covered with the fine plafter, the coarser fort will answer to fill it up, which will be a confiderable faving. And, Note, no more plafter fhould be mixed at one time than is used, otherwise that which is mixed will thicken and fpoil; for, adding water to it to thin it, will totally prevent it from fetting hard a fecond time.

Having taken an impreffion from a medal, &c. according to the foregoing directions, a plafter mould may be prepared from it, according to the following receipt, whereby a metallic or wax impreffion may be again taken from the plaster mould, fo as to exactly refemble the original.

Το

To prepare a Plafter Mould fo as to take an Impreffion

from it.

Having prepared a plafter mould, according to the foregoing receipt, and letting it be quite dry, dip it in the following mixture: half a pint of boiled linfeed oil, and one ounce of spirits of turpentine; these are to be mixed well together in a bottle, and when wanted, the furface of the mould is to be dipped into it, and then fuffered to dry. When the mould has fucked up the oil on its furface, it is to be dipped again in the oil. This operation is to be repeated till the mould will imbibe no more oil, and the oil begins to ftagnate upon it; then, with a little cotton wool, rolled up hard, wipe all the loose oil off the mould, and put it in a dry place for a day or two, to dry, and the mould will acquire a very hard furface from the effect of the oil. When it is to be used, it must be oiled with oil of olives, in the fame manner as before directed. By these two methods, any medal, feal, or impreffion, may be fo exactly imitated, that the new medal can scarcely be diftinguifhed from the original.

The Method of cafting Brimftone, and of giving it a metallic Glofs.

Melt fome ftone brimstone over the fire, in an iron ladle, and let it flame for about five or fix minutes, then take it off the fire, and extinguish the flame, by covering the mouth of the ladle with a piece of board; when it is a little cool, fo as not to feel gluey, or run ropy, it is then fit for use, and may be poured into the mould, in which it should stand five or fix minutes, and then be taken off; part it as before, and rub the furface of the impreffion over with fome cotton and the best black lead in powder, which will give it a very fine metallic glofs.

To make Sulphur red or green, and caft it in Moulds like Marble.

Melt two ounces of the best stone brimstone over a gentle fire, without permitting it to flame; when melted, mix it well with one ounce of vermilion. Pour the compofition over the furface of the mould, and immediately pour it off again, and fill up the mould to a proper thickness, with common brimstone; let it ftand the fame time as before, then pare and rub over the furface with fome clean cotton, which will give it a polish. The more impreffions there are made at once, melting the brimftone, the better it will be, because the brightnefs of the red fades the oftener it is melted. If it be required to be green, it is done in the fame manner, but adding a fmall quantity of fmalt inftead of vermilion; and it requires more stirring to make it mix. It may alfo be made to imitate a beautiful marble, by mixing several colours feparately, and made in small squares of equal fizes, which break into exact lengths, and difpofe them according to your fancy; after which, melt them together, and the colours will unite in a pleasing manner, and each will appear diftinct. And, Note, when the brimstone is melting, be careful not to shake it; and fuffer it to cool by degrees.

FINIS.