254 



Solution of 

 prussic acid 

 and sulphate 

 of iron. 



Solution dis- 

 tilled. 



Solution of the 

 acid in alcohol 

 keeps very 

 well. 

 Inference. 



General de- 

 ductions. 



HISTORY OF PttUSSTATES. 



But while the carbon in separating retains azote, the 

 greater part of the latter, combining with hidrogen, forms 

 ammonia. Thus ammonia is found in the yellow liquor, 

 with the remainder of the acid that has escaped decomposi- 

 tion; 



Prussic acid dissolved in water does not render the solu- 

 tion of green sulphate of iron turbid, till it has undergone 

 the changes just mentioned ; it then affords blue with it, from 

 the concurrence of the ammonia recently formed. 



Finally, this solution being distilled affords prussiate of 

 ammonia, and nothing more is found in it but some parti- 

 cles of carbonaceous matter, which fall down. It would 

 have been of importance to ascertain, whether there were 

 any carbonic acid with the ammonia, but I forgot it at the 

 time. I intend, however, to examine it again. 



The alcoholic solution keeps perfectly well. Hence we 

 may even infer with some reason, that, as alcohol is better 

 adapted than water both to dissolve and retain it, the prus- 

 sic gas, considered too with respect to its qualities of being 

 aromatic and inflammable, perceptibly approaches nearer to 

 oily, combustible, and complex products, than to saline sub- 

 stances. 



From these facts it follows, first, that there is but one 

 prussiate of mercury, the base of which is at a maximum : 

 secondly, that the augmentation of attractive power, 

 which the prussic acid borrows from the black oxide, when 

 it has to combine with potash, or the red oxide of iron, and 

 on which Berthollet has so justly insisted, ceases to be ne- 

 cessary, when it has to unite with the oxides of gold, silver, 

 copper, cobalt, nickel, uranium, mercury, &c. We see, in 

 fact, with regard to the latter, this acid, the affinities of 

 which are so sluggish, ep little adapted to entitle it to the 

 name, has notwithstanding no need of black oxide, to fur- 

 nish with mercury a saline compound, very eoluble, very 

 crystalli/able, and, in short, possessed of all the characters, 

 that distinguish the most perfect compounds. To these 

 anomalies let us add those it has of preferring mercury to 

 all the alkalis ; not yielding its oxide either to the nitric 

 or sulphuric acid, each of which is so far beyond it in 

 Strength ; and lastly, to yield it only to the muriatic acid, 



which 



