C 35 3 cold, it turned into a kind of gelatinous fubftance. d. It was not afted upon by fire, when eXpofed to its a&ion by itfelf. e. Upon the addition of an alkali, it melted into glafs. / This glafs, with three parts of a common fixed alkali, melted into a blue mafs. p-. The fame being pounded, and put into a ' cellar, very foon ran per deliquium, and turned into a gelatinous fubftance. h. An acid precipitated a powder from it. i. It was difiolved in borax, without the leaft effervefcence. All thefe circumftances prove it to be a real /ilex, or flinty fubftance. 12. In a metallic cylinder a quantity of pounded Spar was put, and then infufedwith oil of vitriol. A wetted charcoal, or piece of iron, was fufpended in the middle of the cylinder, and all being covered and properly fecured, was placed near the fire. In four hours, a white cruft, fimilar to the abovementioned (6), was formed round the coal and the iron. This experiment proves, that tire abovementioned incruftation was not formed from the corrofion of the glafs, which is mentioned above (6), but rather from the aqueous particles uniting with the acid of Spar. What is more corro borating than all this is, that the artificial or regenerated Spar (io), upon being decom pounded in the fame manner with oil of vitriol, formed the very lame kind of cruft on the furface of the water in the recipient; but re peating the operation, with the fame identical Spar, for feveral times, no cruft was farther formed -, becaufe the acid of Spar had been all expelled in the former operations. Nor can it D 2 be