112 Mr. R. Phillips m the Triple Prussiate of Potash. 



The only question which appears to me to remain unde- 

 cided, is that of the mode in which the elements that consti- 

 tute the salt are combined : the simplest view of the subject is 

 undoubtedly that taken by Berzelius, of its being a double 

 cyanide of iron and potassium containing water of crystalliza- 

 tion ; but he has justly remarked, that the proportions of hy- 

 drogen and oxygen are precisely such as would convert the cy- 

 anogen into hydrocyanic acid, and the metals into oxides; and 

 according to this view, supposing the water to be formed, and 

 not merely expelled, when the salt is dried, it is a double hy- 

 drocyanate, containing no water of crystaUization, and com- 

 posed of 



3 atoms of hydrocyanic acid 81 



1 atom of protoxide of iron 3G 



2 atoms of potash 96 



213 



Or, 1 atom of hydrocyanate of iron ... 63 



2 atoms of hydrocyanate of potash . 1 50 



213 



It may still further be regarded, according to Mr. Porrett's 

 idea, as consisting of potash combined with a peculiar acid con- 

 stituted of iron, carbon, azote, and hydrogen. But even ad- 

 mitting these to be the elements of the acid, the proportions 

 must, I think, differ very considerably from those stated by 

 Mr. Porrett. 



M. Gay Lussac * considers this acid, as Mr. Porrett does, to 

 consist of metallic iron and hydrogen ; but the carbon and 

 azote are in such proportions as form cyanogen, to which Mr. 

 Porrett's analysis is not reducible. According to the former, 

 ferrocyanic acid is composed of 



3 atoms cyanogen 78 



2 hydrogen 2 



1 atom iron 28 



Tos 



Or, 6 atoms carbon 36 



3 azote 42 



2 hydrogen 2 



1 atom iron 28 



108 



* Arm. de Chimie et de Physique, torn. xxii. p. 322. 



According 



