at the maximum are obtained by differentiating the expression for

with respect to

, and equating to zero, since the maximum of absorption will occur when

is at a maximum.

The analytical treatment calls for no comment. Its basis has been fully discussed by R. H. Fowler[374] in a series of papers. The weights (

) of the atomic states employed were based on the work of Bohr[375] on the relative values of the a priori probabilities of the different stationary states for hydrogen. On this view,