354 Mr. Gregor's Experiments on a mineral Substance 
of this mineral without effervescence, but it swims about the 
fused globule, unaltered. Borax dissolves a fragment of a 
crystal, and the globule remains transparent. 
(5.) Some of this mineral, reduced to a fine powder, was 
mixed with about half its weight of pounded quartz, and kneaded 
with water into a ball : but as soon as the mass became dry, 
all cohesion was destroyed, and it fell into powder. 
(6.) Sulphuric acid, poured upon some of it, caused no 
effervescence, nor was there any perceptible vapour extricated. 
( 7. ) Some of the pulverized crystals were put into a crucible 
of platina, and sulphuric acid was poured upon them. The 
crucible was covered with a piece of glass, and placed in warm 
sand. On examination of the crucible and its contents, after 
some time, it appeared that the greater part of the mineral 
had been dissolved, but the surface of the glass cover was not 
in the least affected. 
( 8. ) Some of the crystals were introduced into a small glass 
retort, to which a receiver was adapted. The retort was ex- 
posed to the heat of a charcoal fire. A fluid distilled over into 
the receiver, which had a peculiar empyreumatic smell. It 
changed litmus-paper to a faint red. It produced no change 
in a solution of nitrate of silver ; but it caused a white preci- 
pitate in a solution of nitrate of mercury. I attributed these 
phenomena, at the time, to a small bit of the feather with 
which I had swept the powder into the retort, and which, I 
thought, had fallen into it. A slight whitish crust was also 
produced in the neck of the retort, but the smallness of the 
quantity did not admit of examination. 
(9.) Some of this mineral exposed to a red heat, for about 
ten minutes, lost in weight at the rate of 25^ per cent. Another 
