106 REFUTATION OF THE SALT RADICAL THEORY, 
be oxysulphionide, oxynitrionides, &c. Also, in any salts 
in which any other of the amphigen class of Berzelius is 
the electro-negative ingredient, whether sulphur, selenium, 
or tellurium, all the ingredients excepting the electro-posi- 
tive radical, would be considered as constituting a compound 
electro-negative radical.* 
4. It may be expedient to take this opportunity of men- 
tioning, that the advocates of this new view, disadvanta- 
geous^ as I think, employ the word radical, to designate 
the electro-negative, as well as the electro-positive ingre- 
* The conception of the existence of salt radicals seems to have ori- 
ginated with Davy. It was suggested by Berzelius, in his letter in 
reply to some strictures which I published on his Nomenclature, in the 
following language : — 
" 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-f-SO 4 , 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 N, imitates simple halogen bodies, and gives 
a salt with potassium and other metals. The hydrated oxacids, agree- 
ably 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, an- 
hydrous sulphuric acid, is a body, whose properties, as respects acidity, 
differ from those which we should expect in the active principle of hy- 
drous sulphuric acid. 
"The difference between the oxysalts and the halosalts is very easily 
illustrated by formulae. In KFF (fluoride of potassium,) there is but 
one single line of substitution, that is to say, that of K|FF; whilst in 
KOOOOS (sulphate of potash) there are two, KlOOOOS and 
KOIOOOS, 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 development of 
the constitution of the oxysalts (which applies equally to the sulpho- 
salts and others;) but as to myself, I have a thorough conviction that 
there is therein something more than a vague speculation, since it un- 
folds to us an internal analogy in phenomena, which, agreeably to the 
perception of our senses, are extremely analogous." 
