C 527 3 
XXVI. On the Nature of the Salts termed triple Prussiates, and 
on Acids formed by the union of certain Bodies zvith the Elements 
of the Prussic Acid, By Robert Porrett, Esq. Commu- 
nicated by William Hyde Wollaston, M. D. Sec. R. S. 
Read June 30, 181 
Since the admirable experiments of Scheele on the Prussic 
acid, chemists have distinguished between the salts formed by 
the direct combination of this acid with alkaline or other bases, 
and those obtained either by adding to the salts just mentioned 
a certain portion of a metallic oxide, or by decomposing by 
the alkalies a prussiate of a metallic oxide. Thus for instance, 
the salt formed by the union of the Prussic acid with potash 
has been called the simple prussiate of potash, while that ob- 
tained by boiling a solution of potash on Prussian blue has been 
called the triple prussiate of potash and iron, it having been 
proved that the black oxide of iron enters into its composition. 
The differences between these salts are very remarkable, the 
simple prussiate is always alkaline, is soluble in alcohol, is 
incapable of forming Prussian blue when added to the salts of 
per-oxide of iron, gives a yellow precipitate with salts of per- 
oxide of copper, is decomposed at the temperature of boiling 
water, and has its acid displaced by the carbonic acid. On the 
contrary, the triple prussiate is neutral, is insoluble in alcohol, 
forms Prussian blue with the salts of per-oxide of iron, gives 
a reddish brown precipitate with salts of per-oxide of copper, 
3 Y 2 
