GAY-LUSSITE

is a white mineral of a vitreous fracture, which crystallizes in oblique rhomboidal prisms; specific gravity from 1·93 to 1·95; scratches gypsum, but is scratched by calcspar; affords water by calcination; it consists of carbonic acid 28·66; soda, 20·44; lime, 17·70; water, 32·20; clay, 1·00. It is in fact, by my analysis, a hydrated soda-carbonate of lime in atomic proportions. This mineral occurs abundantly in insulated crystals, di eminated through the bed of clay which covers the urao , or native sesquicarbonate of soda, at Lagunilla in Colombia. GELATINE; (Eng. and Fr.; Gallert , Leim , Germ.) is an animal product which is never found in the humours, but it may be obtained by boiling with water the soft and solid parts; as the muscles, the skin, the cartilages, bones, ligaments, tendons, and membranes. Isingla consists almost entirely of gelatine. This substance is very soluble in boiling water; the solution forms a tremulous ma of jelly when it cools. Cold water has little action upon gelatine. Alcohol and tannin (tannic acid, see Gall-nuts ) precipitate gelatine from its solution; the former by abstracting the water, the latter by combining with the substance itself into an insoluble compound; of the nature of leather. No other acid, except the tannic, and no alkali po e es the property of precipitating gelatine. But chlorine and certain salts render its solution more or le turbid; as the nitrate and bi-chloride of mercury, the proto-chloride of tin, and a few others. Sulphuric acid converts a solution of gelatine at a boiling heat into sugar. See Ligneous Fibre . Gelatine consists of carbon, 47·88; hydrogen, 7·91; oxygen, 27·21. See Glue and Isingla .