Arrhenius, developed a theory of the entire
phenomena of electrolysis, which, in particular, furnishes a striking
explanation of the mechanism of the production of electromotive force
in galvanic batteries.
Extending the analogy, already so happily invoked, between the
phenomena met with in solutions and those produced in gases, Professor
Nernst supposes that metals tend, as it were, to vaporize when in
presence of a liquid. A piece of zinc introduced, for example, into
pure water gives birth to a few metallic ions. These ions become
positively charged, while the metal naturally takes an equal charge,
but of contrary sign. Thus the solution and the metal are both
electrified; but this sort of vaporization is hindered by
electrostatic attraction, and as the charges borne by the ions are
considerable, an equilibrium will be established, although the number
of ions which enter the solution will be very small.
If the liquid, instead of being a solvent like pure water, contains an
electrolyte, it already contains metallic ions, the osmotic pressure
of which will be opposite to that of the solution.
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