ON THE PRUSSIC AND PRUSSOUS ACIDS. 349 



cd carbonate of ammonia, it must have done the same, and 

 likewise have given out ammoniacal gas when potash and 

 lime were added; it must also have turned blue the solution 

 of copper ; and had it contained prussiate of potash, it must 

 have produced prussiate of iron, when added to the green 

 sulphate of this metal : but it will be seen by referring to 

 Table I, that none of these effects were produced. Were 

 farther evidence necessary of the dissimilarity of the two 

 liquids, it might be mentioned, that Professor Proust poured 

 alcohol on the saline residuum of his distillation of the 

 prussiate, which took up a part that he found to be prussiate 

 of potash ; had any of the tingeing salt B been present, the 

 alcohol must have dissolved this likewise, and it could not 

 have escaped his observation. We have therefore ample 

 grounds for negativing the first question. 



In order to answer the second question, I passed sulphu- Question 3 

 rous acid gas for a long time through a solution of triple 

 prussiate of potash; the prussic acid was expelled, and sul- 

 phite of potash formed; but this sulphite was not mixed 

 with any tingeing salt. On the supposition, that the disap- 

 pearance of the prussic acid, in the liquid A, might have 

 been owing to its having been expelled entirely by the sul- 

 phurous acid ; and that the tingeing liquid resulted from the 

 mutual action of the other principles, namely, the oxide of 

 iron and hidroguretted sulphuret of potash ; I subjected a 

 mixture of these materials to long boiling, but could not 

 by this means produce a liquid, that tinted oxisulphate of 

 iron red. Sulphurous acid gas, passed through water in 

 which Prussian blue was diffused, did not in the least affect 

 this compound. These experiments completely refute the 

 opinion, on which the second question was grounded. 



To enable me to reply to the third /juestion, I passed sul- Question J 

 .... /. • < ii t 1 i- answered. 



phurettcd hidrogen gas for several hours through a solution 



of triple prussiate of potash, on which it was found to have 

 no effect. 



Wc shall be little disposed to allow, that there is any Question -1 

 foundation for the fourth question, when we consider the 

 circumstances of the last-mentioned experiment, in which 

 sulphur in the state of the most minute division was offered 

 to the triple prussiate, without any combination ensuing; 



4 and 



