Materials J or a History of the Prussiates. 47 



important to have ascertained if the carbonic acid existed 

 there with ammonia, but I neglected it at the time. I shall, 

 however, return to that subject. 



Prussic alcohol is preserved extremely well : we might 

 even conclude from this, with some foundation, that if al- 

 cohol is more proper than water for its solution and preser- 

 vation, the prussic gas, considered besides in its qualities of 

 being aromatic and inflammable, is perhaps more visibly 

 allied to oily combustible products, and of a complex na- 

 ture, than to saline substances. 



It results from these facts, in the first piace, that there is 

 only one prussiate of mercury, being that of which the base 

 is at the maximum. Secondly, that all this exaltation of affi- 

 nities which the prussic acid borrows from the black oxide, 

 when it is requisite to use potash, or the red oxide. of iron, 

 and upon which Berthollet has insisted with so much jus- 

 tice, ceases to be necessary to it, if it is in contact with 

 oxides of gold, silver, copper, cobalt, nickel, uranium, 

 mercury, &c. We see, in fact, that with regard to the lat- 

 ter, this acid, the affinities of which are so indolent, and 

 so little deserve the title of affinities, has however no oc- 

 • casion for black oxide, in order to furnish with mercury a 

 saline combination, very soluble, very crystallizable, en- 

 dowed, in a word, with all the characters which distinguish 

 the most perfect compounds. Add to these mysterious cir- 

 cumstances, its preference to mercury over all the alkalis, 

 and its not yielding its oxide either to the nitric acid or to 

 the sulphuric acid, which their power raises so much above 

 it; and lastly, its only yielding 4o the muriatic acid, which 

 we know to be in so many respects inferior to the sulphuric 

 and nitric acids. 



Lixivium of Animal Charcoal. -^Equal parts of charcoal 

 of blood, and of carbonate of potash, made red-hot in a 

 covered crucible, have always furnished me with the richest 

 lixivium. 



Thinking that the carbonic acid might be an obstacle, to 

 the saturation of the potash, I added lime to the mixture, 

 but the lixivium was not improved by it. 



I kept red-hot for half an hour, a mixture of 144 grains 



cf 



