the sulphuret of copper. This test is one of very great delicacy; but it
is not alone decisive of the presence of copper, since lead, bismuth,
mercury, and silver, are similarly affected by it. A method, however,
will be presently described, by which the precise nature of the
sulphuret may be determined.
The alkaline hydrosulphates, for example the hydrosulphate of ammonia,
answer equally well with sulphuretted-hydrogen. The solution of the
common liver of sulphur throws down, not a black, but a chestnut
precipitate.