ABSTRACT
This chapter describes collision of an a particle with the helium nucleus of equal mass, the range of the helium atom which should be the same as the α particle before the collision if it carries two charges, but four times this range if it carries one charge. The chapter explores that on the assumption of unit charge, all the atoms of atomic weight up to oxygen should be detected beyond the range of the α particle. It reveals experiments with air, nitrogen, and oxygen, and carbon dioxide, the screen and source were placed in a rectangular box and a slow current of the dried gas passed through during the experiment. The scintillations in pure oxygen and carbon dioxide were about the same brightness for corresponding ranges, and had nearly the same equivalent ranges in air as those due presumably to Nitrogen atoms from the air.
