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VII

30. Plücker and Hittorf’s Experiments. Action of Magnet on Cathode Column of Light. Pogg. Ann., 1858 and 1869. Plücker found that the magnet acts on the cathode light in a rarefied atmosphere in a different manner from that on the anode light. In the former the light follows the magnetic curves and strike the side of the bulb, according to position of the poles, see Fig. VII. “Where the discharge is perpendicular to the line of the poles, it is separated into two distinct parts, which can be referred to the different action exerted by the electro-magnet on the two extra currents produced in the discharge.” Ganot. § 925.

31. Thomson’s Experiment. A Discharge Retarded Across and Accelerated Along the Lines of Magnetic Force. Nature, Lon., Jan. 31, 1895, p. 333. Lect. Royal Inst.—Prof. J. J. Thomson, F. R. S., performed an experiment which illustrates that the electrical discharge is retarded in flowing across the lines of magnetic force and accelerated in flowing with or parallel to such lines. As illustrated in Fig. 20, p. ssss1, he employed a large electro-magnet adapted to be cut in and out of circuit. He had two air chambers, one a bulb, indicated by a circle, and the other a tube bent into a rectangle, indicated by the dotted square. Between these, was an adjustable coil having its terminals connected to the outside coatings of Leyden jars. When the discharge took place between the poles of the magnet, that is, in the direction of the lines of force, the discharge was helped along by the magnetic field, but when it took place across the bulb, that is, across the lines of force, the discharge was retarded. “The coil can be adjusted so that when the magnet is ‘off’ the discharge passes through the bulb, but not round the square tube; when, however, the magnet is ‘on,’ the discharge passes in the square tube but not in the bulb.”