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OCR
284. MINERALOGICAL REMARKS. well wathed, dried, and at laft, together with the paper, burnt and calcined in the crucible ; which, deduting for the afhes of the paper, and for the refiduum of the iron from the phlogifticated alkaline falt, gave half a grain of iron. sthly, Upon dropping a few drops of vitriolic acid into this folu‚tion, now free from metal, there was not the fmalleft indication of ponderous earth. 6thly, The folution was evaporated to a few ounces, ‘and its contents precipitated by cauftic volatile alkali; but the earthy precipitate, after being filtered and wafhed, but not dried, was perfe@ly diffolved in a fuperfluous quantity of vitriolic acid, 7thly, This folution had the tafte of alum; its contents I: precipi-tated: by boiling it ftrongly with dry earth of magnefa:.1' then boiled it with depurated mineral alkali, placed it on. the filtrum, wathed, dried, and at laft heated it in a crucible, by which means I obtained fix grains of argil. 8thly, The folution, containing the earth of magnefia, was precipitated by a folution of mirieral alkali: this precipitate, after being edulcorated and dried, weighed three grains more than the magnefia that had been ufed to precipitate the argil. Thefethree grains, after being heated red.hot, produced one and a half grain of cauftic earth of magnefia. gthly, Now the fluid which had remained after the precipitation of the argil and magnefia by the volatile alkali (No, 6) remained to be examined, This was likewife evaporated to a few ounces, which, 6 by 32
