.

N=1. Hydrogen.

In [Part I.] we have considered the binding of an electron by a positive nucleus of charge

, and have shown that it is possible to account for the Balmer spectrum of hydrogen on the assumption of the existence of a series of stationary states in which the angular momentum of the electron round the nucleus is equal to entire multiples of the value

, where

is Planck’s constant. The formula found for the frequencies of the spectrum was