226 FLINT GENUS. Brittle. Eafily frangible. Not particularly heavy. Specific gravit7—2,771, Blumenhach.—2,767 to 2,945, Hauy,—2,896, Kir wan. Chemical Characters, Before the blow pipe it Iofes its colour, and melts into a whitilh enamel. When previoufly calcined and powdered, it forms a gelly with acids. Constituent Parts. Silica 46,0 Alumina 14,50 Carbonate of Lime CO \* p Sulphat of lime 6,50 Oxyd of iron 3>° Water 2,0 100 Klaproth, b. 1. f. r 96. Geognostic Situation. Its geognoftic fituation has not been fatisfa&orily' afcertained. It is faid to have been found near to the