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ON ELECTROLYSIS. 751 
temporary severances occur throughout the liquid, no individual atom 
need remain in its uncombined state for a thousandth of a second, so far as 
the phenomena of electrolysis are concerned. But in proportion as the 
dissociated atoms are few and far between, the longer must they be sup- 
posed to continue in a free condition. 
Something must here be said concerning the views of Quincke and of 
Wiedemann on the mechanism of electrolytic conduction. 
Theory of Quincke. 
Prof. Quincke, adopting the dissociation view of isolated atoms, sup- 
poses the electrical charges of opposite ions to be not only opposite in 
sign but specifically unequal in quantity. He considers the direct 
action of the electrodes to reach every atom, and to propel the one set 
one way and the other set at a different speed the other way according 
to simple electrostatic laws, and thus explains at one step both decompo- 
sition and ‘ migration.’ Moreover, since the charges of opposite ions are 
not equal they do not neutralise each other; the resulting molecules are 
therefore charged with a balance of one or other electricity, and get pro- 
pelled either with or against the current—thus accounting for electrical 
endosmose. 
Evidently the hypothesis is very elastic, and, if granted, explains the 
facts; but I must confess to an invincible repugnance to the idea of 
numerically unequal charges existing in the dissociated atoms of a mole- 
cule, as well as to the corresponding idea of all the molecules of an electro- 
lyte being similarly charged. 
The laws of Faraday seem to me to point so distinctly to a definite 
charge for every ion, depending solely on its valency in the compound 
from which it has just been liberated, that it would require very strong 
necessity to render palatable any other view. And I find no necessity at 
all. The inequality of charge is postulated only in order to account for 
the facts of migration as provisionally understood by Hittorf, i.e. for the 
assumed inequality in pace of opposite ions. Now without pressing un- 
duly the prejudices I have ventured to suggest against such inequality in 
pace, I may claim to have proved that the facts of migration do not at 
any rate necessitate such inequality; and the facts of migration are all 
that the theory is based upon. 
And as to endosmose: it seems to me very doubtful whether any 
tendency to electric endosmose exists except in the immediate neighbour- 
hood of a surface; one can only observe it in capillary tubes and porous 
partitions, and it seems allied to surface phenomena in general. It has 
indeed been elaborately considered by Helmholtz from this point of view, 
along with the reciprocal phenomenon of the E.M.F. generated by the 
flow of liquids along tubes. 
Theory of Wiedemann. 
Prof. Wiedemann’s theory of electrolysis is not unlike Prof. Quincke’s, 
but it is based on contact electricity. He supposes the atoms charged 
by contact with each other, and the mclecule charged by contact with 
the vessel; and, having thus obtained the needful electrifications, decom- 
position and endosmose naturally follow; moreover endosmose comes 
