_Cyanide of Potassium._--It may be interesting to our photographic friends
to know that cyanide of potassium is capable of replacing hyposulphite of
soda in all collodion processes. If used of the strength of five grains to
one ounce of water, no danger need be apprehended from it. Its merits are
cleanliness, quickness of operation, and the minute quantity of water
required for washing the picture fixed therewith.