in any manner, it may be done, and I shall feel myself obliged by the attention.

"Glue is an inspissated jelly made of the parings of hides or horns of any kind, the pelts obtained from furriers, and the hoofs and ears of horses, oxen, calves, sheep, &c. quantities of all which are imported, in addition to the home supply, by many of the great manufacturers of this article; these are first digested in lime water, to cleanse them as far as it can from the grease or dirt they may have contracted; they are then steeped in clean water, taking care to stir them well from time to time; afterwards they are laid in a heap, and the superabundant water pressed out; then they are boiled in a large brass cauldron, with clean water, skimming off the dirt as it rises, and further cleansed by putting in, after the whole is dissolved, a little melted alum or lime finely powdered, which by their detersive properties still further purge it ; the skimming is continued for some time, when the mass is strained through baskets and suffered to settle, that the remaining impurities, if any, may subside; it is then poured gently into the kettle again, and further evaporated by boiling a second time, and skimming until it becomes of a clear, but darkish brown colour: when it is thought to be strong enough (which is known either by the length of time a certain quantity of water and materials have boiled, or by its appearance during ebullition) it is poured into frames or moulds of about six feet long, one broad, and two deep, where it hardens gradually as the heat decreases: out of these troughs or receivers it is cut, when cold, by a spade, into square pieces or cakes, and each of these is placed within a sort of wooden box, open in three divisions to the back; in this the glue, as yet soft, is taken to a table by women, where they divide it into three pieces,* with an instrument not unlike a

When the women by mistake cut only two, that which is double the size is called a bishop, and thrown into the kettle again to be manufacture

h

bow, having a brass wire for its string; with this they stand behind the box, and cut, by its opening, from front to back; the pieces thus cut are taken out into the open air, and dried on a kind of coarse net work, fastened in moveable sheds of about four feet square, which are placed in rows in the glue-maker's field, every one of which contains four or five, or more rows of net-work; when perfectly dry and hard it is fit for sale.

"That is thought the best glue which swells considerably without melting, by three or four days immersion in cold water, and recovers its former dimensions and properties by drying. Glue that has got frost, or that looks thick and black, may be melted over again and refined, with a sufficient quantity added of fresh, to overcome any injury it may have sustained; but it is generally put into the kettle, after what is in it has been purged in the second boiling. To know good from bad glue, it is necessary for the purchaser to hold it between his eye and the light, and if it appears of a strong dark brown colour, and free from cloudy or black spots, the article is good."-So far Mr. Clennell.

A glue that is colourless, and of superior quality, is obtained of the skins of eels, and known by the name of size. It is also procured from vellum, parchment, and different species of white leather; but for common purposes this is by far too expensive, and is only made use of in those cases of delicate workmanship where glue would be too gross. The skins of the rabbit, hare, and cat are also made use of in the manufacturing of size, by those who are employed in gilding, polishing, and painting in various colours.

Another fine species of glue is known by the name of isinglass, and is the produce of a certain fish very common in the Russian seas. From various foreign writers on the subject of glue, it appears that it was first principally pre

pared from the membranous and cartilaginous parts of animals, and after being dried, they were melted into tablets. It is certain, however, that every animal substance containing jelly may be used in the manufacture of glue; and, according to Duhamel, a strong but blackcoloured glue may be obtained from bones and hartshorn, after they are dissolved in Papin's digester. The English glue, is reckoned far superior to any kind manufactured abroad, and furnishes an article of exportation to the continent; and the Dutch society of arts and manufactures have long offered premiums for a specimen equal to the English, the Flanders glue being considerably inferior to that manufactured in England, and that manufactured in France is still worse.

From the experiments of Parmentier, it appears that six pounds of button-maker's raspings yielded a pound of excellent glue, not inferior to that which is manufactured in England. The glue which he obtained from the filings of ivory was equally good, but more highly coloured. The filings of horn yielded none of this substance. To obtain glue as colourless as possible, a very small quantity of water should be employed for extracting the jelly, by which means it may be concentrated without long evaporation, as exposure to heat has always a greater or less influence on the colour in proportion to the time. The whiteness and transparency of the Flanders' glue are said to originate from an adherence to this plan.

In their consistence, colour, taste, smell, and solubi. lity, glues are found to differ from each other consider. ably, Some glues will dissolve by agitation in cold water, while others are only soluble at the point of ebullition. It is generally admitted that the best of glue is transparent, of a brownish yellow colour, and having neither taste nor smell. It is perfectly soluble in water, forming

a viscous fluid, which, when dry, preserves its tenacity and transparency in every part, and has more solidity, colour, and viscidity, in proportion to the age and strength of the animal from which it is produced.

Glue is of the greatest use in many of our principal manufactories, particularly that of hats.

EBOR.

Remarks by the Editor.-Near Philadelphia the process is this. The cuttings parings, &c. of skins, and other materials that will boil to a jelly, are immersed for 2 or 3 days in lime water, to take off the hair. They are then washed well. They are put in a coarse canvass bag, suspended by a chain from a large iron arm fixed in the brickwork. The bag is immersed in the boiler of water: the materials are gradually dissolved. The feculences, add to the dung heap. The solution is evaporated till on trial being cold, it is gelatinous; in this state, while hot, it is poured into long wooden moulds somewhat broader than the usual breadth of a piece of glue. It is then cut into lengths while in the box, by children, who take out the solid mass of jelly, being a little longer, a little broader than the usual size of glue-cake, and thick enough (the depth of the wooden.trough, box, or mould) to make half a dozen cakes of glue. It is then carried and placed before the man who cuts it. This is done by a square frame with brass wires, set at such distance apart, that each cutting will make a cake of glue. By one motion, pressing the brass wires through the jelly toward his breast against which a board is placed, half a dozen, (or if ne cessary, more) cakes of glue, or rather of jelly, are cut and separted at once. These are carried away, put upon netting under a shed, and dried gradually in the air: by which means, the jelly is hardened into glue.'

This business, cannot be carried on, but between SepVol. II. 3 H

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tember and May, on account of the materials being so liable to putrefaction. For the same reason they omit no Sundays, the necessity of the business requiring it. think about 2lb. of rosin per hundred weight, would make the glue better, and enable the manufacturer to work a month longer.

On the Art of covering Wire Cloth with a transparent Varnish, as a Substitute for Horn; and on other Objects of public Utility. By ALEXIS ROCHON, of the National Institute of France, &c.*

IN the progress of the present war, the marine storehouses of France were totally without the essential article of horns for lanthorns. It was impossible to substitute glass in the place of this article, on account of its brittleness, and the obvious danger which might result from that quality. In this situation of distress, the agents of the French government consulted Citizen Rochon, and directed him to make every experiment he could think of to discover a proper substitute. His attention was first directed to a memoir of the celebrated Poivre on the fabrication of lanthorns of horn by the Chinese. It is known that this industrious nation prefer horn to glass on account of its cheapness and toughness, and that they possess the art of welding this substance together with so

Extracted from a memoir read to the National Institute of France the 21st Ventose, in the year VI. (March 11th, 1798), and inserted in the Journal de Physique for April 1798. The memoir contains various political and economical observations more particularly applicable to France, with general observations, which I have not thought it necessary either to transcribe or abridge; neither have I been solicitous to take the very words of my author in the parts I have abstracted. N.