Oldal 34 [34]
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 con¬
tents precipitated by cauftic volatile alkali; but the earthy precipi¬
tate, after being filtered and wafhed, but not dried, was perfe@ly dif¬
folved 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 preci¬
pitated 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
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