MINES OF CREMNITZ. 369 
nearly filled with nitric acid. Here the silver chap 
dissolves; a gentle heat being communicated ^— s — ' 
to the retorts, to accelerate the solution. It 
has been usual to exclude foreigners from 
the great Laboratory where this takes place ; 
but as we had witnessed every other opera- 
tion, we were also permitted to view the 
interior of this chamber. The sight was beau- 
tiful. It was a spacious and lofty hall, filled 
with enormous globes of glass, ranged in even 
rows, whence the nitrous gas was escaping, in 
red fumes, to the roof; the solution of the 
silver being visible in all of them, by the efferves- 
cence it caused ; the gold falling at the same 
time, in the form of a black powder, to the 
bottom of every retort. After the solution of 
the silver is completely effected, the acid so- 
lution containing the silver, by augmenting the 
heat, is made to pass into another retort ; the 
gold being left behind in the former vessel. 
Afterwards, increasing the heat to a very great 
degree on the side of the silver, the whole of the 
acid is driven off, and the silver remains in the 
metallic state, beautifully crystallized within 
the retort. All the glass globes containing the 
crystallized silver are then cast into a common 
furnace, where the glass, by its levity remaining 
on the surface of the melted metal, is removed 
VOL. VIII. B B 
