The electron, its isolation and measurement and the determination of some of its properties

by Robert Andrews Millikan

-particles (helium atoms) obtained from Rutherford and Geiger’s count, they obtain the mass of one atom of helium from which the number in a given weight, or volume since the gas density is known, is at once obtained. They published for the number

of molecules in a gas per cubic centimeter at 0°76 cm.,

, which corresponds to

This last method, like that of the Brownian movements, is actually a determination of

, rather than of