ABSTRACT
The fact that glowing bodies discharge positive and negative electricity with unequal facilities, has been shown by many observers. The objective of this chapter was to test the validity of certain results obtained from a theoretical consideration of the conductivity of gases when the ionization was confined mainly to the surface of one electrode. A very simple means of obtaining strong surface ionization is to heat a platinum wire or plate to a red heat by an electric current. In order to settle the amount of agreement between the calculated and actual velocities, a direct method of measuring the velocity of the ions was employed. In experiments on the velocity of the negative ions produced by ultraviolet light, the alternating EMF of the Cambridge town mains was employed. The galvanometer was slightly disturbed by the magnetic field due to the large current circulating in the leads.
