put some bright copper coins into the solution and set it aside in a warm
place for three or four days, occasionally giving it a circular motion.
The separated laminae are pure silver, which is to be digested with ammonia
until it ceases to be colored blue. The silver, after being washed and dried,
is again dissolved in nitric acid, and the liquid, diluted with water,
is kept as solution, of silver.

Either of the above solutions (the one of oxide of silver and copper,
and the pure silver solution) may be prepared for use by putting them
in a bottle, with a quantity of water, and adding common fine salt,
you obtain a white curdy precipitate of chloride of silver.
No matter how much salt is used, provided enough be added to throw
down all the chloride of silver. This solution should be well agitated
and then allowed to stand for a few minutes; thus the white precipitate
is in the bottom of the bottle. When the water has become clear,
pour it off with care, leaving the sediment behind, then add a fresh
quantity of clean water, shake, let settle, and pour off as before.
Repeat the same for several times, and the excess of salt will disappear,
leaving the white precipitate, which may be drained of the water
and dried in the dark, and kept free from light and air.


CYANIDE OF POTASSIUM.

Cyanide of Potassium.--This important article is worthy
the undivided attention of every Daguerreotypist.
I here give Mr. Smee's process for its preparation.
This is from that author's work entitled, "Electro Metallurgy,"
American edition: