...When this glue is to be prepared, take clippings of sheep's skin, goat's skin, and of parchment, and boil them for three or four hours in sufficient quantity of water (seven or eight parts in weight for one of matter). When the decoction is reduced to a third, strain it through a hair sieve or piece of linen: on cooling it assumes the consistence of a strong jelly, which maybe weakened according to circumstances. In consequence of the consistence here mentioned this glue is distinguished by the name of strong glue, a technical term often employed in the formulae of different compositions, and which cannot be applied to the strong dry glue sold in the shops. The addition of two pounds of water will form a mean kind of glue; and eight pounds of water to the same quantity will give simply glue: it may still be rendered weaker should circumstances require it.,