But as the very slightest expenditure of energy is sufficient to produce the commencement of electrolysis, it is necessary to suppose that these two ions are not united by any force.

Thus the two ions are, in a way, dissociated.

Clausius, who was the first to represent the phenomena by this symbol, supposed, in order not to shock the feelings of chemists too much, that this dissociation only affected an infinitesimal fraction of the total number of the molecules of the salt, and thereby escaped all check.
This concession was unfortunate, and the hypothesis thus lost the greater part of its usefulness.

M.Arrhenius was bolder, and frankly recognized that dissociation occurs at once in the case of a great number of molecules, and tends to increase more and more as the solution becomes more dilute.

It follows the comparison with a gas which, while partially dissociated in an enclosed space, becomes wholly so in an infinite one.
M.Arrhenius was led to adopt this hypothesis by the examination of experimental results relating to the conductivity of electrolytes.