air density did not affect the amount, but only the clearness of the minimum magnetic deflection. The circumstance that affected the amount of the deflection was a variation in the contents of the originating or high-vacuum tube. 114. LODGE’S EXPERIMENT. APPARATUS EMPLOYED. _The Elect._, Lon., April 10, ’96, p. 783.—With his apparatus, he was able to obtain rays sufficiently powerful to illuminate the usual fluorescent screen after passing through one’s skull. It is of interest to note about the details of the electrical apparatus (§ § 106, 109, 131, 137) used by those who experimented. The best results were obtained by a make and break of a direct primary current at a point under alcohol, the primary battery consisting of three storage cells, and the current of the primary acting on a large secondary coil. Leyden jars he considered entirely unnecessary, and he preferred direct currents to alternating currents for the primary. He did not give the exact dimensions of the primary and secondary coils, but, judging from reports of others and the author’s own experience, it is highly preferable to have what is called a very large inductorium, 15 in. spark in open air, or else the Tesla system (§ § 51, 137). There is little satisfaction in trying to perform the experiments with induction coils adapted to give only a 2 or 3 in. spark in open air. [Illustration: STINE’S EXPERIMENT. FIG. 5, § 108, p. 103. ] [Illustration: STINE’S EXPERIMENT. FIG. 6, § 108, p. 103. ] 115. LODGE’S EXPERIMENT. X-RAYS EQUALLY STRONG DURING FATIGUE OF GLASS BY PHOSPHORESCENCE. _The Elect._, Lon., Apr. 10, ’96.—In order to explain in what way the rays were propagated, he says that it is not as if the glass surface were a wave front from every point of which rays proceed normally, but that the glass radiates X-rays just as a red-hot surface radiates light, namely, a cone of rays starts from each point, and all the rays of each cone start in a different direction. Every point of the glass radiates the rays independently of all other points. Crookes’ Experiment (§ 58) may now be called to mind in reference to the fatiguing of the glass after phosphorescing for a while. Lodge tested the fatiguing as to the power to emit X-rays, but found that there was no such property whatever. The glass which became fatigued as to luminous phosphorescence (§ 105) was not fatigued as to the power of X-rays. He noticed that the phosphorescent spot became less and less bright, and yet the X-rays remained of the same power.