Doublet Separation and Fine Structure of the Balmer Lines of Hydrogen

Abstract

Using two optical trains, (1) two crossed Lummer plates, the larger of resolving power of about 670,000, and (2) an echelon of resolving power of about 660,000, the writers have determined the wave-length difference between the two well known components ${\lambda }^{\prime }$ and ${\lambda }^{\prime \prime }$ (${\lambda }^{\prime }>{\lambda }^{\prime \prime }$) of $\mathrm{H}\alpha$, $\mathrm{H}\beta$ and $\mathrm{H}\gamma$ as 0.1370, 0.0791 and 0.0666A respectively. These values are in good agreement with those obtained by Houston with an interferometer, which latter are in our estimation the most reliable thus far obtained.