imary or Secondary Decomposition 141

/-gen may be viewed as a secondary result; but I incline
ve that it is not so: for, if it were^ it might be expected
5t proportion from the stronger acid, whereas the reverse
act. This consideration^ with others, also leads me to
e that muriatic acid is more easily decomposed by the
current than water; since, even when diluted with eight
times its quantity of the latter fluid, it alone gives way,
er remaining unaffected.

Chlorides.—On using solutions of chlorides in water—
ance, the chlorides of sodium or calcium—there was
»n of chlorine only at the positive electrode, and of
;n, with the oxide of the base, as soda or lime, at the
2 electrode. The process of decomposition may be viewed
ceding in two or three ways^ all terminating in the same
Perhaps the simplest is to consider the chloride as the
ce electrolysed, its chlorine being determined to and
at the anode, and its metal passing to the cathode,
Ending no more chlorine, it acts upon the water, pro-
hydrogen and an oxide as secondary results. As the
Dn would detain me from more important matter, and
f immediate consequence, I shall defer it for the present.
>wever, of great consequence to state, that, on using the
2Ctrometer, the hydrogen in both cases was definite;
;he results do not prove the definite decomposition of
:s (which shall be proved elsewhere—524, 529, 549),
- not in the slightest degree opposed to such a conclusion,
support the general law.

Fiydnodic acid.—A solution of hydriodic acid was

exactly in the same manner as muriatic acid. When

hydrogen was evolved at the negative electrode, in

proportion to the quantity of electricity which had

i.e. in the same proportion as was evolved by the same

from water; and iodine without any oxygen was evolved

>ositivc electrode. But when diluted, small quantities

jn appeared with the iodine at the anode, the proportion

)gen at the cathode remaining undisturbed.

I "believe the decomposition of the hydriodic acid in this

be direct, for the reasons already given respecting

i acid (498, 490).

Iodides.—h. solution of iodide of potassium being
xl to the voltaic current, iodine appeared at the positive
e (without any oxygen), and hydrogen with free alkali
negative electrode. The same observations as to^thed the results are therefore sufficient