324 OBSERVATIONS ON MURIATIC ACID, 
lations of sulphur, iodine, and cyanogen; and from the indue- 
tion that hydrogen, as well as oxygen, communicates acidity. 
It avoids, at the same time, the improbability which attends 
that doctrine, in its leading principle, that muriatic acid con- 
tains no combined water, though other powerful acids are held 
to contain it, and though it affords water by the very same pro- 
cesses by which they yield it; and in the still greater violation 
of analogy, (the most extraordinary perhaps ever admitted in 
chemical reasoning), involved in the conclusion, that the com- 
pounds which this acid forms with salifiable bases, though the 
same in all generic properties with those formed by other acids, 
are not of similar constitution, and are not even ofa saline nature. 
It unites the advantages, therefore, of both doctrines, and con- 
nects under one system facts which are otherwise insulated, 
and partial generalisations, which, instead of having any rela- 
tion, seem opposed to each other. 
The same general view, I have still to add, may be farther 
extended. Alkalinity, as well as acidity, is the result appa- 
rently of the action of oxygen; the fixed alkalis, the earths, 
and the metallic oxides, which all contain it as a common ele- 
ment, forming a series in which it is difficult to draw any well 
defined line of distinction. Ammonia alone remains an excep- 
tion: it contains no-oxygen, and yet possesses in a very mark- 
ed degree all the alkaline properties,—an anomaly so great, as 
to have led almost every chemist to infer that oxygen must ex- 
ist as an element in one or other of its constituent principles ; 
and as nitrogen is the one apparently least elementary, it has 
been supposed to be a compound containing oxygen. ‘The re- 
sult may be accounted for, however, on a very different prin- 
ciple. As hydrogen, in some cases, give rise, as well as oxy- 
gen does, to acidity, so it may in other cases give rise to alka- 
linity. Under this point of view, ammonia is a compound of 
which 
