ON THE PRUSSIC AND PRUSSOUS ACIDS. 35 [ 



tube, and as soon as a violent action commenced, the heat 

 was withdrawn. By this process the prussic acid was re- 

 produced, as was proved beyond the possibility of a doubt 

 by the formation of blue prussiate of iron, when poured 

 into a mixture of green and red sulphate of this metal. Blue 

 prussiate may also be produced at once, by substituting for 

 the diluted sulphuric acid a solution of green sulphate of 

 iron with excess' of acid. 



It is essential to the success of this experiment, in which Necessary pre. 

 the prussic acid is regenerated from the liquid B by the*^^"^'""" 

 nascent hyperoxigenised muriatic acid, that the excess of 

 acid remaining in the liquid, after the oxigenising process, 

 should be neutralized by an alcali previous to pouring it into 

 the solution of iron, which should likewise be perfectly 

 neutral. 



Having thus succeeded in proving, that the tingeing prin-xhe new prin- 

 ciple of the liquid B was suboxidised prussic acid, my nextc'ple hitherto 



, . ^ , , , . ^. • . . , . e i^ ^ r combined with 



object was to obtain this principle in a free state- for we potash. 



must recollect, that we have hitherto considered it only in 

 combination with potash, with which it formed a neutral 

 salt. This circumstance gave me reason for supposing it an 

 acid, and I therefore determined to attempt its separation 

 by abstracting its base by a stronger acid. The following 

 was the process I employed for the purpose. 



The liquid B was evaporated nearly to dryness, and put Obtained as a 

 into a retort with diluted sulphuric acid ; a receiver was then 

 adapted to it, and about two thirds of the liquid distilled 

 over by a gentle heat; what remained in the retort was sul- 

 phate of potash. The receiver contained a colourless li- 

 quid, with a faint, sour, disagreeable smell, and a decided The prussous 

 acid taste. This liquor I have named, in conformity with 

 the principles of the new nomenclature, prussous add, and 

 its salts prussites, of which the liquid B contained one in 

 solution, namely the prussite of potash. 



The effects of the prussous acid on the earthy and metal- 

 lic solutions, as far as I have tried them, are noted in the 

 following table. 



TABLE 



