ABSTRACT
The experiments in this chapter on the scattering of simple gases indicate that the hydrogen atom has the simplest possible structure of a nucleus with one unit charge, and helium comes next with a nucleus of two unit charges. The observations on the scattering of α particles by matter in general afford strong experimental evidence for the theory that the atom consists of a positively charged nucleus of minute dimensions surrounded by a compensating distribution of negative electrons. The reduction in velocity of the α particle in passing through a sufficient pressure of gas to scatter half the α particles was deduced from the loss of range of the α particle in the gas, using the relation between velocity and range found by Geiger. If the reduction in the number of α particles in passing between the glass plates is due mainly to 'single' scattering.
