GLUE, among artificers, a tenacious viscid matter, which serves as a cement to bind or connect things together. Glues are of different kinds, according to the various uses they are designed for, as the common glue, glove glue,parchment glue, isinglass glue, &c.
The common or strong glue is chiefly used by carpenters, joiners, cabinet-ma kers, &c. and the best kind is that made in England, in square pieces, of a ruddy brown colour, and next to this the Flan ders glue. It is made of the skins of ani mals, as oxen, cows, calves, sheep, &c. and the older the creature is, the better is the glue made of its hide. Indeed, whole skins are but rarely used for this purpose, but only the shavings, parings, or scraps of them ; or the feet, sinews, &c. That made of whole skins, however, is undoubt edly the best ; as that made of sinews is the very worst.
In making glue of parings, they first steep them two or three days in water ; then washing them well out, they boil them to the consistence of a thick jelly, which they pass, while hot, through ozier baskets, to separate the impurities from it, and then let stand some time, to purify it further : when all the filth and ordures are settled to the bottom of the vessel, they melt and boil it a second time. They next pour it into
flat frames or moulds, whence it is taken out pretty hard and solid, and cut into square pieces or cakes. They afterwards dry it in the wind, in a sort of coarse net ; and at last string it, to finish its drying. The glue made of sinews, feet, &c. is managed after the same manner ; only with this difference, that they hone and scour the feet, and do not lay them to steep. The best glue is that which is oldest ; and the surest way to try its goodness is, to lay a piece to steep three or four days, and if it swell considerably without melting, and when taken out resumes its former it is excellent. A glue that will 1-old against fire or water may be made thus : mix a handful of quick lime with four ounces of linseed oil, boil them to a good thickness, then spread it on tin plates in the shade, and it will become exceedingly hard, but may be dissolved over a fire, as glue, and will effect the business to admiration.