99_O_. WORTHINGTON’S EXPERIMENT. DISCHARGE OF ELECTRIFICATION BY FLAMES. _Brit. Asso. Rep._, ’90, p. 225. 99_P_. FLEMING’S EXPERIMENT. DISCHARGE BETWEEN ELECTRODES AT DIFFERENT TEMPERATURES IN AIR AND IN HIGH VACUA. § 99_M_, near end. _Proc. Ro. So._, LXVII., p. 118. 99_Q_. BRANLY’S EXPERIMENT. HALLWACH AND STOLSTOW’S EXPERIMENT. LOSS OF ELECTRIC CHARGE. _Lum. Elect._, LXI., pp. 143 to 144, ’91.—Branly obtained quantitative results. Hallwach found with the use of the arc light, a very small loss of positive electricity at high potentials; Stolstow, no such loss at potentials under 200 volts. Branly, with a 50 element battery and an arc light as the source of illumination, caused a discharge and thereby a constant deflection of 124 degrees of the galvanometer needle. The action of the light upon a positive disk caused a deflection of only three degrees by the same battery. With aluminum in the electrodes, the deflections were about 1400 and 24 respectively. Is it not sufficiently fully established that ultra-violet light will discharge not only negative but positive electricity? He experimented with substances heated to glowing or incandescence. Glass lamp chimneys at a dull, red heat, when covered with aluminum, oxide of bismuth, or lead oxides, withdraw positive charges. In the same way, for example, behaves a nickel tube in place of the lamp chimney. 99_R_. WANKA’S EXPERIMENT. A NEW DISCHARGE EXPERIMENT. _Abk. d. Deuts. Math. Ges. in Rrag._, ’92, pp. 57 to 63.—He confirms the principle that the ultra-violet rays are the most powerful. A glass plate, which, as well known, cuts off most of the ultra-violet rays, was properly interposed and then removed and the difference noted. 99_S_. BRANLY’S EXPERIMENT. DISCHARGE OF BOTH POSITIVE AND NEGATIVE ELECTRICITY BY ULTRA-VIOLET RAYS. _C. R._, CXIV., pp. 68 to 70, ’92.—He further proves that ultra-violet rays of light will dissipate a positive charge. The experiments in this connection seem to prove more and more that the discharging power is only a matter of sufficiently high refrangibility of the rays of light.