of Chemical Philosophy and Nomenclature. 181 



sulphate, susceptible of combination with the sulphate of 

 potash. The analogy is then complete, it exists not only in the 

 perfect neutrality of the two potassic salts, in their saline 

 taste, but also in their manner of forming combinations with 

 other bodies; notwithstanding one of them, the sulphate, con- 

 tains one element more than the other. If, instead of potash, 

 potassium were employed to saturate our two acids, the ana- 

 logy of the operation in both cases, would be still more com- 

 plete. The same quantity of metal would displace equal 

 volumes of hydrogen. When the visible results of our ex- 

 periments are so perfectly analogous, it is to be presumed that 

 the invisible process which we do not see, may also be per- 

 fectly analogous, and that if facts exactly alike are explained 

 differently, there must be a defect in the explanation. If, for 

 instance, the true electro-chemical composition of the sulphate 

 of potash should not be KO-f SO 3 , as is generally supposed, 

 but K + SO**, and it appears very natural that atoms, so 

 eminently electro-negative as sulphur and oxygen, should 

 be associated, we have, in the salt in question, potassium 

 combined with a compound body, which, like cyanogen in 

 K + C 2 Nf, imitates simple halogen- bodies, and gives a salt 

 with potassium and other metals. The hydrated oxacids, 

 agreeably to this view, would be then hydracids of a compound 

 halogen body, from which metals may displace hydrogen, as 

 in the hydracids of simple halogen bodies. Thus we know that 

 SO 3 , that is to say, anhydrous sulphuric acid, is a body whose 

 properties, as respects acidity, differ from those which we 

 should expect in the active principle of hydrous sulphuric 

 acid. 



The difference between the oxisalts and the halosalts is 

 very easily illustrated by formulae. In K|FF — fluoride of 

 potassium, there is but one single line of substitution, that is 

 to say, that of K|FF, whilst in KOOOOS (sulphate of po- 

 tash) there are two, K|OOOOS and KO|OOOS of which we 

 use the first in replacing one metal by another, for instance, 

 copper by iron ; and the second in replacing one oxide by 

 another. 



I do not know what value you may attach to this develop- 



* In the Berzelian symbols, K stands for kalium, or potassium, S for 

 sulphur, O for oxygen, and O 3 for three atoms of oxygen, O 4 for four atoms 

 of oxygen. 



f That is to say, if the salt called sulphate of potash, be considered as a 

 compound of potassium, and a quadroxide of sulphur, instead of being 

 viewed as a protoxide of potassium, or potash, and tritoxide of sulphur, or 

 sulphuric acid. 



This is the formula for cyanide of potassium, consisting of potassium, 

 K, and cyanogen, or two atoms carbon and one of nitrogen, C 8 N. 



