464 Dr. Hare’s Observations on the Electrolysis of Salts, 
can it be correctly alleged by Professor Daniell, the transfer of the 
copper being arrested at the membrane, that as this metal ‘ can find 
nothing to combine with,’ it gives up its electrical charge to the hy- 
drogen, which proceeds to the cathode? As hydrogen cannot be 
present, excepting as an ingredient in water, how can it be said 
that the copper can discharge itself upon the hydrogen, without com- 
bining with the oxygen necessarily liberated at the same time by 
the electrolytic process? How could the copper, in discharging itself 
to a cathion, escape a simultaneous seizure by an anion? Would not 
the oxidizement of this metal be a step indispensable to the propa- 
gation of that electrolytic process, by which alone the hydrogen 
could, as alleged, ‘pass to the platinode,’ i. e. cathode? 
“« 80. In these strictures I am fully justified by the following al- 
legations of Faraday, which I quote from his Researches, 826, 828 :— 
«« * A single ion, i.e. one not in combination with another, will 
have no tendency to pass to either of the electrodes, and will be 
perfectly indifferent to the passing current, unless it be itself a com- 
pound of more elementary ions, and so subject to actual decomposi- 
tion. 
««« Tf, therefore, an ion pass towards one of the electrodes, another 
ion must also be passing simultaneously to the other electrode, al- 
though, from secondary action, it may not make its appearance.’ 
* 81. In explanation of the mixed precipitates produced upon the 
membrane, I suggest that the hydrated oxide resulted from chemical 
reaction between the alkali and acid, the oxide from the oxygen of 
the water or potassa acting as a cathion in place of that of the oxide 
of copper; also that the metallic copper is to be attributed to the 
solutions acting both as conductors and as electrolytes ; so that, at 
the membrane, two feeble electrodes were formed, which enabled a 
portion of the copper to be discharged without combining with an 
anion, and a portion of oxygen to be discharged without uniting 
with a cathion. In this explanation] am supported by the author’s 
account of a well-known experiment by Faraday, in which a solution 
of magnesia and water was made to act as electrodes at their sur- 
faces respectively. 
« 82. There can, I think, be no better proof that no reliance 
should be placed on the experiments with membranes, in this and 
other cases where the existence of compound radicals in acids is to be 
tested, than the error into which an investigator, so sagacious as my 
friend Professor Daniell, has been led, in explaining the complicated 
results. 
“ 83. The association of two electrolytes, and the chemical reac- 
tion between the potassa and acid, which is admitted to have evolved 
the hydrated oxide, seem rather to have created difficulties than to 
have removed them. 
“ 84, In this view of the subject I am supported by the opinion 
of Faraday, as expressed in the following language :— 
«« « When other metallic solutions are used, containing, for in- 
stance, peroxides, as that of copper combined with this or any decom- 
posable acid, still more complicated results will be obtained, which, 
