218 PROFESSOR DANIELL ON THE ELECTROLYSIS OF SECONDARY COMPOUNDS. 
inches, and abundant crystals of hydrate of baryta were found around the platinode. 
The evolution of gas in the cell had ceased, but the battery was afterwards found to 
be still capable of generating gas in the voltameter at the rate of 2^ cubic inches in 
ten minutes. Upon attempting to remove the cell the membranes had been so much 
acted upon and softened that they burst ; so that it was impossible to ascertain 
whether the zincode cell still contained any baryta. But as it is most probable, from 
the duration of the experiment, that the transfer was complete, as in the case of the 
strontia, we have still the data for a calculation, from which it would appear that 
about one fifth of an equivalent of baryta was transferred for an equivalent of the 
mixed gases : for 
Mixed gases. Mixed gases. Baryta. Baryta. 
139 : 70-8 : : 26'9 : 137 
which is nearly equal to j or 15. 
Without ascribing to these results an accuracy which, with all the pains I could 
bestow, the mode of experimenting did not admit of, we may conclude, quite within 
the limits of possible experimental error, that in the electrolysis of aqueous solutions 
of acids or the fixed alkalies, the evolution of an equivalent of oxygen at the zincode 
is accompanied in the first instance by an accumulation of acid, which cannot ex- 
ceed one fourth of an equivalent, or fall short of one fifth ; and the evolution of hy- 
drogen at the platinode in the second case, by an accumulation of alkali to an amount 
within the same limits. 
Now with regard to the alkaline experiments it is, I conceive, still more impossible 
to believe that the cathion which travelled to the platinode was an association of an 
equivalent of potassium, or other metal, with three equivalents of hydrogen (the 
fourth being due to the reaction of the metal upon the water), than to believe that, 
in the sulphuric acid experiments, the anion which went to the zincode was a com- 
pound of one equivalent of sulphur and seven equivalents of oxygen. What must we 
then conclude ? 
Shall we suppose that the electrodes of the battery are endued with an attractive 
power for different kinds of matter, in virtue of which free acids pass to the zincode 
and free alkalies to the platinode ? Shall we further imagine that the proper electro- 
lytic force of the current, with regard to water, is assisted by this adventitious force, 
so that water which contains either free acid or alkali is a much more efficient con- 
ductor, and is more abundantly decomposed than pure water ? 
I will not dwell upon other objections to this hypothesis, but I must own my utter 
unwillingness to return to a notion which I think your “ Experimental Researches” 
have so completely subverted ; and it would require much stronger considerations 
than the pressure of the present difficulty to make me abandon your definition of the 
electric current as “an axis of power having contrary forces, exactly equal in amount, 
in contrary directions*.” I am, moreover, not without hopes that you will consider 
* Experimental Researches, § 517. 
