78. DE KOWALSKIE’S EXPERIMENT. SOURCE, PROPAGATION AND DIRECTION OF CATHODE RAYS. _Acad. Sci._, Paris, Jan. 14, ’95; _So. Fran. Phys._ Jan. ’95; _Nature_, Lon. Jan. 24, ’95; Feb. 21, ’95.—The conclusions he arrived at are, 1. The production of the cathode rays does not depend on the discharge from metallic electrodes across a rarefied gas, nor is their production connected with the disintegration of metallic electrodes. 2. They are produced chiefly where the primary illumination attains suitable intensity, that is, where the density of the current lines is very considerable. 3. Their direction of propagation is that of the current lines at the place where the rays are produced, from the negative to the positive poles. They are propagated in the opposite direction to that in which the positive luminosity is supposed to flow. § 43. He employed a Goldstein tube reduced at the centre. § 41. It was found that the cathode rays are formed not only at the negative electrode, but also at the constriction, directly opposite the cathode. De Kowalskie carried on further experiments in this line in order to be satisfied with the principles named above, which he formulated. In one tube, he was able to produce cathode rays at either end of the capillary tube forming the constricted part of a long vacuum tube. No electrodes were employed. The tube was merely placed near a discharger through which “Tesla currents” were passed? He seems to have been working with X-rays without knowing it; for his results agree with those of Roentgen and later experimenters that the source of X-rays is the surface of a substance where it is struck by cathode rays. The statements were about as definite as could be expected at that date. [Illustration: HAND, BY OLIVER B. SHALLENBERGER, TAKEN WITH FOCUS TUBE. § 137, p. 136. ] ------------------------------------------------------------------------ CHAPTER VII ------- 79. ROENTGEN’S EXPERIMENTS. X-RAYS, AND A NEW ART. _Wurz. Physik. Med. Gesell._ Jan. ’95; _Nature_, Lon., Jan. ’96; _The Elect._, Lon. April 24, 96; _Sitz. Wurz. Physik. Inst._ D. _Uni._ Mar. 9, 96.—UNINFLUENCED BY A MAGNET IN OPEN AIR.—Although Lenard recognized several kinds of cathode rays, which differed as to penetrating and phosphorescing power, yet he always held, or inferred at least that they were deflected by a magnet, outside, as well as inside, (proved § 72_a_.) of the discharge tube. § 59. Prof. Wilhelm Konrad Roentgen subjected his newly discovered rays to the action of very strong magnetic fields in the open air, but no deviation was detected. This is the characteristic which more than anything else has served to distinguish X-rays from cathode rays. This property has been confirmed by others. He employed the principle of magnetic attraction of internal cathode § 59, rays to shift the phosphorescent spot, for then he noticed that the source of X-rays fluctuated also.