From what has been said, it is evident that Dr. Zeeman’s desire to see the results of his discovery applied to the study of astronomical problems has been fully realized. THE STARK EFFECT Lorentz’s prediction regarding the effect of a strong magnetic field on spectral rays, and the movements of electrons in the field having been confirmed so brilliantly by Zeeman, it remained to ascertain what effect, if any, would be exerted by electrical force on light-rays. The answer to this problem was given by Prof. Johannes Stark, at Aix-la-Chapelle, in 1913, by his skillful demonstration of the electrical decomposition of the spectral rays of hydrogen, helium and lithium.[30] Stark’s task was a more difficult one than Zeeman’s, owing to the fact that he had to deal with luminescent gases, which, being conductors, exhaust the electrical field almost before any observations can be made, even hurriedly. This condition gives rise to difficulties in connection with the application of the electric field. But these were very ingeniously met by employment of highly evacuated tubes and the light emitted by the “canal rays”—positively charged particles similar to the alpha rays.[31] Where the rays issue from the perforated electrode (or “canal”), the conduction of electricity is weak, and Stark was able to apply intense electric fields in a small space. It was then found that the diffuse rays of the spectrum produced were strongly influenced, while the “sharp” rays were less so. The attentive reader will note that this result was in marked contrast with the _magnetic_ decomposition produced in the Zeeman experiment, in which the rays did not differ one from another in respect to the degree of their decomposition. In all the details there is a difference between the electric and magnetic decompositions, and analogy existing only in this, namely, that in both cases polarized rays were obtained. In both cases the results produced were due to disturbance of the _motions of electrons_, giving rise to broadening, displacement or other modifications of spectral laws. Both “effects” confirm the theoretical view of Maxwell, namely, that light is an electromagnetic phenomenon. Faraday’s famous question is thus more than answered in the affirmative: not only is the rate of vibration of “atoms” (electrons) changed by a magnetic field, but also under the action of an electrostatic field, producing _decomposition_ of certain spectral lines, which are usually _polarized_, as in the Zeeman effect. As a result of his intensive investigations of the Zeeman effect, Dr. Henri A. Deslandres, Director of the Astrophysical Observatory at Meudon (a southern suburb of Paris), proposed a new general formula which represents the series relationship of the component lines and heads of bands both for emission and absorption spectra. According to his experimentally-derived law, “the origin of these radiations may be found in the transverse and longitudinal vibrations of the atoms.”