286 Dr. Murray on Muriatie Acid, [Aprit, 
agency of no other substance that can afford it, is introduced, 
the conclusion seems necessarily to follow, which forms the 
basis of one of the two systems under which the relations of 
oxymuriatic and muriatic acids have of late years been explained, 
that oxymuriatic acid is a compound of muriatic acid with 
oxygen ; and that muriatic acid in its gaseous state contains 
combined water. This doctrine, accordingly, may be main- 
tained, and may even perhaps be just. It is not, therefore, 
from the consideration of any deficiency im its support that I 
depart from it in the following observations; but that I consider 
the view I have to propose as perhaps more probable, or at 
least as, on the whole, according better with the present state 
of chemical theory. Ina science such as chemistry, the prin- 
ciples of which rest rather on probable evidence than on demon- 
stration, it is of importance to present a subject in every pot 
‘of view under which it may be surveyed; and this must serve 
as an apology for the speculations I have now to offer. 
There are, I believe, only two arguments to which any weight 
is due in support of the opiion that chlorine is a simple sub- 
stance, which, by combination with hydrogen, forms muriatic 
acid. One is drawn from the analogy resting on the general 
fact, sufficiently established, that acidity is, in different cases, 
the result of the agency of hydrogen; the other, from the ana~ 
logy in the chemical relations of chlorine and iodine, 
Sulphur forms with hydrogen a compound unequivocally acid, 
The compound radical of prussic acid cyanogen, discovered by 
the able researches of Gay-Lussac, likewise acquires acidity 
when it receives hydrogen. Acidity, therefore, is a property 
not exclusively connected with oxygen ; it is also communicated 
by hydrogen; and when chlorme with hydrogen gas forms 
muriatic acid gas, the agency exerted may be considered as 
similar to that arising in other cases of the production of an acid 
from the action of hydrogen. 
This is confirmed by the relations of iodine. It too forms 
an acid by combination with hydrogen; and the chemical 
agencies of iodine are in several other respects. similar to those 
of chlorine. When the one, therefore, is considered as a 
simple body (and there is no absolute proof that iodine is a 
compound), the other is, with probability, placed in the same 
class: and certain analogies existing between sulphur and 
iodine serve to connect and confirm these views. Each of them 
forms an acid with hydrogen ; each of them also forms an acid 
with oxygen; but chlorine exhibits precisely the same points of 
resemblance: with hydrogen, it forms muriatic acid ; with 
oxygen, it forms chloric acid. Its chemical relations, with 
regard to acidity, being thus similar, seem to require the same 
explanation to account for them, 
These facts lead undoubtedly to views of chemical theory 
different from those which had before been established; and on 
