Alfred Bucherer

“ Since the directions of the rays are namely forming all possible angles with the direction of the magnetic force, then the force (occurring according to Maxwell's theory) can assume all possible values. If the electrodynamic force and the electric one is compensated, it is
By means of this arrangement, rays of a certain velocity find quite automatically the angle, at which the compensation occurs at a given field strength, and which allows them to leave the condenser. ”

“ Measurements of Becquerel rays. The Experimental Confirmation of the Lorentz-Einstein Theory.
By A. H. Bucherer (Bonn)
To the extent by which the theory of electricity occupies other areas of the phenomenal world, and in this way is becoming the foundation of the whole of physics, the desire for a consistent theory of the actual electrodynamic phenomena increases. It appeared for a long time, as if the Faraday-Maxwell-concept of the aether as the mediator of the electromagnetic processes, would serve as a sufficient and definite foundational hypothesis. ”

“ The method chosen, allowed for testing my relativity principle, i.e. an investigation of the deflection of electrons flying obliquely towards the field direction, as well as testing the Lorentz-Einstein relativity principle and the initial theory of Maxwell, thus the same question which formed the subject of Kaufmann's investigation. Becquerel rays shall fly through a condenser field, and the electric force acting upon the electrons shall be compensated by superposition of a uniform magnetic field, which is parallel to the plates of the condenser. ”

“ Thus electrons of all velocities and corresponding masses will hit upon the film, and thus produce a curve which allows to determine the mass as a function of velocity. Consequently, a single exposition suffices to test the various theories of the electron. The equations of motion of the electrons assume the following form: Here, mean the specific charge and mass of the electron. The direction of increasing is the direction of the magnetic field . While the - and -axes coincide with the plane of the condenser plates, is perpendicular to this plane. ”

“ It was recognized soon, that the hypothesis of the stationary aether is the simpler one, and Lorentz made it to the foundation of his older theory of electrons. In this theory, the aether occurs as "quasi-matter". Thus the aether must be included in a dynamic system, in order to maintain the validity of the third axiom of Newton. A uniformly moving charge per se exerts another force upon a resting , as upon . ”

“ When one considers the smaller dimensions of the apparatus, then the curves approximately show the same sharpness, as in my experiments. For the faster rays, the velocity function according to Lorentz's theory, is ca. 1,24, according to Abraham it is 1,19. The larger velocities correspond the smaller values of deflection. The smaller velocities correspond to the larger deflections. Even at great velocities, the difference between the theory of Lorentz and that of Abraham only amounts to a few tenths of a millimeter at the measurement ”

“ In the area, which come into question for Kaufmann, the curve is already very small as well. I precisely looked at the curve and discovered an asymmetry of 5 perc. at one portion, which is as much as the difference of the theories in this range of velocity. I alerted Kaufmann to this fact, so he has measured again and has actually found the deviation of 5 perc. Another point is as follows: I have measured the resistance of the condenser; Kaufmann assumes it to be infinitely great. ”

“ This tin can be airtightly sealed by sanded glass covers, so that it can be evacuated. The air pump employed was a Gaede pump, which worked excellently. By suitable drilling, the cables (being isolated from an accumulator battery) were inserted into the brass tube. The photographic plate is pressed by two springs against the interior wall of the tin. The latter can be inserted into the interior of the solenoid, whose rectangular cross-section is adapted to the dimensions of the tin. ”

“ On the arm balance, a vertically located mirror was mounted, in which a fine platinum wire was mirrored. A fine cathetometer of Wolz was adjusted to the image, and if one moved the quartz plate (which was to be measured) between lever and optical plate, then the mirror image was displaced. The cathetometer was again adjusted and read. A simple calculation then gave the thickness of the plate of 0,25075 mm. ”