Page:Über die Konstitution des Elektrons.djvu/4

 The strength of the magnetic field was measured along the whole ray-path by means of a small induction coil, and was compared (for one point) with the field of a precisely measured wire-coil traversed by a current. The current within it, was measured by a precise ammeter whose indications were tested by means of a Weston cell, the electrical resistance, and a compensating apparatus.

For the dimensions of the curves, a small Abbe comparator was used, upon whose slide a second slide was installed at right angles to its direction of motion, which carried the photographic plate and the glass-micrometer (divided in $1/10$mm) that was laid within. As setting-mark, a six-times magnifying microscope located at the focal plane was used, i.e. a sphere scratched upon a glass-plate of 0.2mm diameter. The magnetic deflection was read from the glass-micrometer, and the electric ones from the measuring rod of the main-slide; the screws only served for interpolation.

5 plates were measured altogether, where every single point represents the average from 10 measurements each. All curves were reduced upon the same ordinate measuring-rod (corresponding to a voltage of 2500 volt at the condenser plates) and consequently unified to a single curve. Even though the average error of any point (when calculated from the setting errors) only amounted 2 to 4 microns, the deviations of the curve points (stemming from the different plates) from a steady curve going through all of them, were considerably greater up to 30 microns. The reason for this deviation appears to be on the one hand as stemming from the strong blurring of the plates by diffused radiation that displaced the main line of the curve in an irregular way when it is of spatially variable intensity, and on the other hand from a distortion of the photographic layer which (as special experiments have shown) irregularly varies from plate to plate, and which can amount up to ca. ½ percent in the vicinity of the boundary, however, which is surely small in the parts relevant for this measurement, and which always let the observed deflections to appear as too great.

Therefore – which seems to be admissible regarding the weak curvature of the curve –, by unification of (on average) ca. 5 points (belonging to the different plates) to a center of gravity under consideration of the weights of the single points, a balanced curve consisting of 9 points was generated, which was (as far as possible) free from the individual deviations of the single curves. The curve obtained in this way, was the basis for the comparison of the different theories.