Page:Über die Konstitution des Elektrons.djvu/1

On the Constitution of the Electron.

By W. Kaufmann.

Submitted by Mr. Warburg.

In some earlier reports ^[1] I have shown, that the mass of the electron moving in the $\beta$-rays of radium, considerably grows with increased approximation to the speed of light, and that the law of growth is in agreement with the formulas calculated by Abraham^[2]. The presupposition made by Abraham reads:

The electron is to be considered as a rigid sphere, uniformly charged over its surface or its volume.

The good agreement of my previous measurements with the consequences drawn from this assumption by application of the Maxwell-Lorentz equations, at first seem to justify the conclusion that the question after the constitution of the electron is definitely solved.

A recent investigation by H. A. Lorentz^[3], however, led to the surprising result that an agreement with my previous experiments can be achieved using totally different assumptions on the electron. Lorentz namely showed, that the difficulties which prevented the explanation of the negative results of certain experiments aimed to demonstrate an influence (of second and higher order) of Earth's motion upon optical and electric phenomena, can be completely removed when it is assumed that all bodies (including the electrons) are deformed in a very specific way in their motion through the aether.

If $q$ is the velocity of the moving system, $c$ the speed of light, and if $\beta =q/c$, then all

1. Gött. Nachr. 1901, Heft 1; 1902, Heft 5; 1903, Heft 3; Phys. Zeitschr. 4, 55, 1902.
2. Gött. Nachr. 1902, Heft 1; Ann. d. Phys. (4) 10, 105, 1903.
3. Versl. Akad. Amsterdam, 27. Mai 1904.