1. Common glue is extracted from hoofs, horns, and cuttings of the hides of various animals. For this process the materials are first steeped in water for 2 or 3 days, well washed, and afterwards boiled to the consistency of a thick jelly, which is passed while hotthrough osier baskets to separate the grosser particles of dirt or bones from it, and allowed to stand some time to purify further. When the rmeaining impurities have settled to the bottom, it is melted and boiled a second time. It is next poured into flat frames or moulds, from which it is taken out hard and solid, and cut into square pieces or cakes, and afterwards dried in the wind in a coarse kind of net. 2. Substances intended for the glue-maker are macerated with milk of lime for 14 days, and dried by exposure to the air; they can then be transported to any distance without undergoing decomposition. The manufacturer generally treats the materials again with dilute milk of lime; afterwards they are carefully washed and exposed to the air for about 20 or 30 hours. they are then placed in acopper boiler having a perforated false bottom, which supports the materials and prevents their being burnt; the boiler is filled about two-thirds with water, and is piled up with the animal substances until they are level with the brim; a gentle but steady boil should be maintained, and the substances should be stirred from time to time. When the liquor on cooling forms a firm gelatinous mass, the clear portion is run off into another vessel, and a small quantity of dissolved alum is added. It is kept warm by means of hot water, and allowed to remain undisturbed for some hours to deposit its impurities; it is next run into the congealing boxes, and left to cool. When cold the masses are turned out upon boards wetted with water, cut into small cakes, and these cakes are placed upon nettings to dry. The dry cakes are then dipped into hot water, and lightly rubbed with a brush to give them a gloss, and lastly stove-dried for sale. This furnishes the best and pales glue. After the first liquor is drawn from the copper, the remnants left in the boiler are treated with fresh water, again and again, until no gelatinous matter can be extracted.