The Use of the Refraction of X-Rays for the Determination of the Specific charge of the Electron

The discrepancies in the determination of the value of the fundamental constant $\frac{e}{m}$ by the two different methods developed so far make desirable the development of new methods for its evaluation. The index of refraction of x-rays offers one method. According to the theories developed so far, in the case of a dispersive medium with no critical frequencies near the frequency of the incident radiation, the value of $\frac{e}{m}$ may be expressed in terms of well-known constants, the wave-length of the incident radiation, and $\delta$ (one minus the index of refraction).