dividing it into small fragments, and boiling it gently for an hour in
distilled water acidulated with acetic acid, which must previously be
ascertained not to contain any copper. If the liquid be not viscid,
filter it at once; but if it be too viscid for filtration, pass it
through a muslin sieve, add two volumes of rectified spirit to it when
cool, and then filter it. Transmit through a small portion of it a
stream of hydrosulphuric acid gas; and if a brownish-black precipitate
or cloud form, subject the whole liquid to the gas. A brown precipitate,
which is sulphuret of copper, will separate either immediately, or after
ebullition and repose for an hour. Collect the precipitate, if abundant,
by filtration, if scanty, by repeated subsidence and affusion. Dry it,
subject it to a low red heat, and then heat it with a little strong
nitric acid, which will convert the sulphuret into the sulphate of
copper. This salt, dissolved out by boiling distilled water, may be
subjected to the tests described above, and especially to ammonia.