m 
on certain sto?iy and metalline Subst,ances } &c„ 
again capable of being taken up by the same acid. The solution 
so made, was slowly evaporated; and, as very nearly every 
thing was deposited during the evaporation, I conclude all was 
silica. The proportions resulting from this single analysis, 
without the weight of sulphur contained in the pyrites irregu- 
larly disseminated through the whole, were, 
Silica 
- 
- 
70 
Magnesia 
- 
- 
- 34} 
Oxide of iron 
- 
' - 
52 
Oxide of nickel 
cai 
<3® 
3 
159 - 
EXAMINATION OF THE STONE FROM YORKSHIRE. 
The mechanical separation of the substances in this stone 
being as difficult as in the preceding case, I was necessarily 
satisfied with submitting it to the same treatment. I collected, 
however, 34 grains of malleable particles ; which, by the process 
already more than once mentioned, left 4 grains of earthy 
matter ; and, by yielding 37X of oxide of iron, indicated about 
4 grains of nickel. 
150 grains of the earthy part of the stone were, by analysis, 
resolved into. 
Silica - 75 
Magnesia - - -37 
Oxide of iron - - 48 
Oxide of nickel 2 
162. 
EXAMINATION OF THE STONE FROM BOHEMIA. 
. The probability of never being able to obtain another spe- 
cimen of the very remarkable fragment of this substance, did 
