1821.] Trof, Berzelimon the ComposiHon of Prussiates. 210 



Article XIII. 



Researches on the Composition of the Prusnafes, or Jermginous 

 IJj/drocj^anates. 13y J. Berzelius. (From the Annales de 

 Chimie, vol. xv. p. 144, New Senes.)=* 



The discovery of cyanogen and of the composition of hydro- 

 cyanic acid, which we owe to the genius of M. Gay-Lussac, is 

 certainly one of the most interesting that has been made in our 

 time, particularly since this acid is found on the confines 

 between those combinations which have an organic origin, and 

 those whose origin is purely inorganic. The comparison of cya- 

 nogen with those bodies, which become acids by their combina- 

 tion with hydrogen, has simplified the theory of hydrocyanic acid, 

 and of the phenomena produced by its decomposition ; but never- 

 theless, the researches subsequent to those of M. Gay-Lussac, 

 whose object was to throw more light on the subject, have by 

 no means been made with sufficient care, fully to explain the 

 nature of the salts called ferruginous hydrocyanates, the most 

 important of the combmations of hydrocyanic acid. 



We owe a multitude of important observations on the nature 

 of these salts to Mr. Porrett. He found that the hydrocyanates 

 can combine with sulphur, forming a particular acid, whose 

 existence, and some of its properties, were known before ; but 

 in what the difference between this and hydrocyanic acid con- 

 sists was far from being suspected. Mr. Porret was led, more- 

 over, to conclude from his experiment, that the iron which enters 

 into the composition of the ferruginous hydrocyanates, does not 

 exist in them in the state of oxide, but in its metallic form com- 

 bined with the carbon, hydrogen, and azote ; and that it is, con- 

 sequently, one of the elements of the acid in which the iron 

 plays an analogous part to that of the sulphur in the preceding 

 compounds ; and, therefore, an idea of the hydrocyanates being 

 salts with two bases, of which oxide of iron is always one, is 

 incorrect. Several memoirs have been published on this subject 

 by Mr. Porrett, in Thomson's Annals, the principal results of 

 which I shall detail. 



He at first found ferruginous hydrocyanate of potash com- 

 posed of 



Ferruginous hydrocyanic acid (ferru- 



retted chyazic acid)-. .,c. ». . 47*66 



Potash ..... «,,;t^^ ^^,.mAii^JmJ^^iiii*'-' '39*34 



Water. ...;..... ;^.^..;i...;. .^.:.... . 13-00 ^ 



The same salt, analyzed by M. Ittner, gave 



It 



• Translated from the Memoir* of the Academy of Sciences of Stockhohn, for the 

 7«ar 1819, p. 342. 



