For any given series of spectral lines of atomic hydrogen, let$∆$$\stackrel{—}{v}$= $\stackrel{—}{v}$_max   $—$$\stackrel{—}{v}$_min be the difference in maximum and minimum frequencies in cm^–1. The ratio of $∆{\stackrel{-}{\mathrm{\nu }}}_{\mathrm{lyman}} \mathrm{to} ∆{\stackrel{-}{\mathrm{\nu }}}_{\mathrm{balmer}}$