, as it does in the electrolysis of hydrogen.
In 1908, however, Townsend[57] devised a method of measuring directly the ratio
and revised his original conclusions. His method consisted essentially in driving ions by means of an electric field from the region between two plates
and
([Fig. 11]), where they had been produced by the direct action of X-rays, through the gauze in
, and observing what fraction of these ions was driven by a field established between the plates