ABSTRACT
This chapter gives an account of the chequered history of the many investigations to throw light on some questions, and incidentally also of attempts made to detect the presence of the helium isotope of mass 3, which is believed to be produced in certain transmutations. During the first part of the electrolysis nickel cells provided with iron cathodes were used, but during the last part of the process glass cells with c made of platinum were employed. At first, evidence of small traces of these gases was found, but we understand that later work has failed to confirm these conclusions. This, however, is not surprising when we consider that terrestrial helium is probably derived from the α-particles of mass 4 expelled from the radioactive substances present on our earth. In the Cambridge experiments, the treated gas mixed with an excess of helium was passed through the discharge tube, which produced a beam of fast ions.
