The Values ofRand ofem, from the Spectra of H, D andHe+

The 1940 data of Drinkwater, Richardson and Williams (DRW) on the ${\mathrm{H}}_{\alpha }$ and ${\mathrm{D}}_{\alpha }$ lines have been completely recalculated, to get values of the Rydberg constant for hydrogen and deuterium, and from these, for helium and for infinite mass. Explicit equations, some of which have not previously been published or used, are derived for all the necessary calculations. The value of $R_{\infty }$ now obtained is appreciably higher than that published by DRW, but it is surprisingly low, compared to the value commonly used for the past decade, which is based on the 1927 work of Houston on H and ${\mathrm{He}}^{+}$. His work, as well as later work by Chu, is also completely recalculated, with the use of the latest values of all auxiliary constants. About one-half of the proposed change in the value of $R_{\infty }$ is due to new values of the index of refraction of air. Recent work on this subject is summarized and put in a form suitable for use by spectroscopists. The data of DRW, as well as that of Houston and Chu, lead also to values of $E$ (atomic weight of the electron) and $\frac{e}{m}$. The explicit equations needed for such calculations are derived. All recent precision work on $\frac{e}{m}$ is also recalculated. Thus one gets finally twelve different precision values of $\frac{e}{m}$, obtained by seven distinctly different experimental methods. Although the data are not as consistent as could be desired, there are no really serious discrepancies. If the adopted value of the Faraday were raised by about 30 coulombs, almost complete consistency of the $\frac{e}{m}$ values would be obtained. There is, however, no direct experimental evidence to justify such a change. The recommended values of $R$, $\frac{e}{m}$ and $E$ are listed at the end of the paper. That for $\frac{e}{m}$ is (1.7592±0.0005) ×${10}^7$ abs. e.m.u., as contrasted with the value 1.7591 ±0.0003 recommended three years ago.