a New Class of Salts. 28S 



cent. Calculating the mean analysis deprived of this supposed 

 impurity, we have 



Theory of nitroprusside of silver. 

 Iron . . . 12-92 1301 



Silver . . . 49-81 5018 



Carbon . . 13-28 13-38 



Hydrogen . 0-097 0*18 



10000 100-00 



In the previous calculation the cyanide supposed to be pre- 

 sent is Fe Cy^ ; this only denotes the proportion of iron to 

 the cyanogen ; it is possible though less probable that it might 

 be 2(Fe Cy + HCy). In this case we might suppose the ana- 

 lysed silver salts to contain this cyanide somewhat in the fol- 

 lowing proportion : 7 equivs. nitroprusside to 1 equiv. of the 

 supposed cyanide. On this supposition the calculated and 

 actual numbers would be as follows : — 



It is not however to be supposed that this cyanide is present 

 as a chemical compound in the above proportion, as the dif- 

 ferences in the analyses show that it occurs in varying and not 

 very definite proportions. 



It would indeed appear that the barium and sodium nitro- 

 prusside contained a body in which the iron and cyanogen are 

 in the same proportion as in ferrocyanogen (Fe Cy^). But as 

 the silver salt precipitated from them does not contain an 

 excess of carbon, it can scarcely be supposed that this would 

 not be precipitated. But in fact there are no data further 

 than the mere ultimate analyses upon which reasoning can be 

 founded with regard to this dissolved and combined foreign 

 substance in the partially decomposed nitroprussides. As 

 however all their essential characters and their crystalline 

 form remain altogether unaltered, we cannot view the foreign 

 substances as more than accidental. 



[To be continued.] 



U2 



