VII. On the discharge of electricity from hot platinum

Abstract

The following paper contains an account of the results obtained in a series of experiments on the loss of electricity from hot platinum in several gases at various pressures. I shall begin by giving a brief account of some of the results obtained by previous workers on this subject, confining myself to those results which appear to bear more or less directly on the present investigation. Further information on the results of the earlier investigations may be found in Wiedemann’s ‘Elektrizität,’ vol. 4, in J. J. Thomson’s ‘Recent Researches,’ in Stark’s ‘Die Elektrizitat in Gasen,’ and in the papers referred to. Elster and Geitel (‘Wied. Ann.,’ vol 37, p. 315, 1889) found that hot platinum, in air and oxygen, produces positive electrification of the surrounding gas and bodies immersed in it, except at low pressures, when negative electrification is obtained. In hydrogen they found the electrification is always negative.