49_a._ No re-distribution took place unless the outside conductor was connected to earth or to a conductor of large capacity, nor would an outside conductor, which was already charged, serve to exhibit the sensitive state. The re-distribution effect was proved by means of a telephone connected in circuit between the outside conductor and the earth Fig. 5, p. 17. When the state was sensitive, that is, during the use of the air-gap, the telephone produced a sound in unison with the intermissions occurring at the air-gap. § 9 and 9_a_.
50. REITLINGER AND URBANITZKY’S EXPERIMENT. SENSITIVE STATE ILLUSTRATED BY A FLEXIBLE CONDUCTOR WITHIN THE DISCHARGE TUBE. _Proc. Vienna Acad._, 1879. _Nature_, Nov. 20, 1879.—The discharge tube was 20 cm. long. It had the usual platinum electrodes, and it stood upright. From the upper electrode, was suspended a strip of tinfoil in the middle of the tube, which was connected to a pump so that the density of the gas could be varied. At atmospheric pressure, the secondary current of a Ruhmkorff coil connected to the electrodes caused the strip to be attracted to the glass tube. The attraction was less and less as the process of exhaustion was carried on, and when a pressure indicated by 7 mm. was reached, the strip was neither attracted nor repelled, but hung downward the same as without any electricity whatever, but it was _attracted_ by a neighboring shell-lac rod which had been rubbed with cloth, and it was _repelled_ by a glass rod which had been rubbed with amalgam, it being assumed that the strip was connected to the anode. § 36. The opposite action took place when it was connected to the cathode. As the exhaustion continued and became greater and greater, these actions died away also up to a rarefaction of about 4 mm. Independently of the degree of rarefaction, the flexible strip of tinfoil was always deflected by an outside conductor connected to earth. § 49.
51. TESLA’S EXPERIMENT. INCANDESCENT ELECTRODE BY HIGH POTENTIAL AND ENORMOUS FREQUENCY. SYSTEM REFERRED TO BY ROENTGEN FOR GENERATING POWERFUL X-RAYS. _U. S. Letters Pat._, No. 454, 622, June 23, ’91. _Martin’s Researches of Tesla_; _Trans. Amer. Inst. Elec. Engineers_, May 20, ’91; _Elec. Review_, N.Y., June 24, ’93, p. 226; _Lect. Franklin Inst._, Feb. 24, ’93, and _Nat. Elec. Light Asso._, Mar. 1, ’93; also _Lect. in Europe_. Later he again experimented in this direction, see _Elec. Review_, N.Y., May 20, ’96, p. 263.—By the U. S. Patent Office he was granted, among other claims, the following: “The improvement in the art of electric lighting herein described, which consists in generating and producing for the operation of lighting devices, currents of enormous frequency and excessively high potential, substantially as herein described.” A simple combination of circuits together with great skill in the construction of apparatus involving high powers of insulation, resulted in the production, within a vacuum, of an electrode radiating intensely white light. The circuit may be easily traced in the diagram Fig. 17 p. 17. Briefly described, there may be noticed an alternating current generator of comparatively low E. M. F. The current from this generates a secondary current by means of an induction coil. This secondary current generates a tertiary current by a second induction coil. An air-gap for automatic and intermittent disruptive discharges, § 49 near end, is in the circuit of the secondary coil of the first named induction coil, which is directly charged by the alternating current generator. The gap may be noticed between the two balls. In shunt to the air-gap is a condenser (see Fizeau, chapter I.) represented by several parallel lines. The lamp consists merely of an evacuated bulb having an electrode of carbon or other refractory material, which is connected to one pole of the last secondary coil while the other pole may be outside, and may consist, for example, of the walls of a room, which in such a case should be of some electric conducting material. The higher the vacuum the more intense the light; he found no limit to this rule. Fig. 16_a_ p. 17 illustrates his ideal method of lighting a room. He found that with two plates at a distance apart as indicated and connected to the poles of the coil, and with electrodeless vacuum bulbs, the latter became bright in space—no mechanical or electrical connection other than air and the assumed ether.