 Dr..Hare on the Salt Radical Theory. 85 
gen, is as much entitled to be considered as an hydracid, as mu- 
riatie acid, (the chloride of hydrogen.) ‘The oxide, no less than 
the chloride, consists of a “radical in combination with hydro- 
gen in which the hydrogen may be replaced by a metal.” Hence, 
as no rational line of demarcation can be drawn about oxygen, 
so as to separate it from its congener chlorine, it follows either that 
all the compounds consisting of two chlorides, and hitherto called 
double chloro-salts by Brrzexius, are consistently simple chloro- 
salts; or, that all compounds consisting of two oxides and called 
simple, should be considered as double oxysalts. 
12. The supposed hydracids, consisting of oxacids containing 
only basic water, being liquid, while the hydracids proper, when 
equally devoid of water, are aériform ; had the comparison been 
made between them, neither being associated with water as a sol- 
vent, the idea of any similitude could hardly have arisen. Be- 
sides unless so associated, they’ are generally insusceptible of 
change by reaction with metals without heat, and when subject- 
ed to decomposition, there is no analogy in the result. In the 
case of hydracids proper, the halogen body uniting with any met- 
al presented to it, hydrogen is evolved; but in that of the hy- 
drated oxacids, the alleged compound radical is decomposed with 
an evolution of some combination of the non-metallic ingredient 
with oxygen. Thus instead of hydrogén, sulphuric acid yields 
sulphurous acid, nitric acid yields nitric oxide. It follows that 
the presence of basic water alone, does not fulfill the conditions 
of Luepre’s definition, since per se the hydrogen entering into 
combination with the alleged compound. radical, cannot be re- 
placed by a metal. 
13. It may be expedient here to advert to the fact that in the case 
of magnesium and aluminium, oxygen plays the same part in ta- 
king place of chlorine and causing the chloride of hydrogen to be 
evolved, that chlorine performs in the cases of various oxides in 
which oxygen is replaced by chlorine and the oride of hydrogen 
is evolved. Again, the reaction of muriatie acid with any bro- 
mide or iodide of which the metallic ingredient prefers chlorine 
to bromine or iodine, is analogous to the reaction of the same 
hydracid with certain oxides which prefer chlorine to oxygen. 
"44. It is therefore clear that in the reaction of haloid compounds 
with each other and with oxides, there is a perfect analogy, and 
that the erection of a special genus for oxygen is unjustifiable, — 
