. The London, Edinburgh and Dublin philosophical magazine and journal of science. ume effect was very large compared withthat due to the surface. The velocities which have been determined are the sum ofthe velocities of the positive and negative ions, but we haveso far given no direct experimental evidence to show whetherthe velocities of the positive and negative ions are the same. In the case of air, an experiment which will now be de-scribed seems to show that the velocities of the two ions areequal or very approximately so. In previous determinations the calculation of the velocityof the i
. The London, Edinburgh and Dublin philosophical magazine and journal of science. ume effect was very large compared withthat due to the surface. The velocities which have been determined are the sum ofthe velocities of the positive and negative ions, but we haveso far given no direct experimental evidence to show whetherthe velocities of the positive and negative ions are the same. In the case of air, an experiment which will now be de-scribed seems to show that the velocities of the two ions areequal or very approximately so. In previous determinations the calculation of the velocityof the ions has depended on the truth of an equation whichhas been experimentally verified as far as possible, but inthe case of air the velocity may be obtained by a methodnot involving any theory depending on the rate of recom-bination of the ions. Two large plane plates, A and B (fig. 3), were placedparallel to one another, lb cm. apart, on insulating blocks Cand D. The bulb was so arranged, in regard to the platesA and B, that the radiation fell on the plate A and half of Fier. A To Battery ofCells the volume of air between A and B. No radiation reachedthe air to the left of the dotted line E F in the figure, whichwas 8 cm. from either plate. The plate A was connectedto one terminal of a large battery of storage-cells, the other of Recombination of the Ioiis of Gases. 437 pole being connected to earth. The plate B was connectedthrough a contact-lever, LM, mounted on an insulatingblock, to one pair of quadrants of the electrometer, the otherbeing connected to earth. The pendulum interrupter was soarranged as to make the current in the primary of the induction-coil, to break the electrometer-circuit by knocking away thelever LM, and then to break the battery-circuit shortly after-wards. For this two other shunt-levers were required whichare not shown in the figure. A condenser, N, was introducedinto the electrometer-circuit to increase its capacity. Asteady difference of potentia
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Keywords: ., bookcentury1800, bookdecade1840, bookidlondon, booksubjectscience
