XI. On the electrical conductivity of flames containing salt vapours

Abstract

In a recent paper on the electrical conductivity and luminosity of flames containing salt vapours, by Professor A. Smithells, Mr. H. M. Dawson, and the writer, the similarity between the conductivity of flames and that of gases exposed to Röntgen rays was pointed out, and it was shown that the relation of the current between two electrodes in the flame to the potential difference between them could be represented by the formulæ I - i = k 2 i 2 /E 2 , C = i + k 1 E, where C = the current, E = the P. D. between the electrodes. I, k 1 , k 2 are constants, and i is defined by the second equation. When E is large, these equations become C = I + k 1 E, and if k 1 = 0, then they reduce to I - C = k 2 C 2 /E 2 , which represents the relation between the current and P. D. for the conductivity of Röntgenised gases. (See a paper by J. J. Thomson and E. Rutherford, 'Phil. Mag.,' Nov., 1896.) The experiments described in the present paper were undertaken with the object of following up the analogy between the conductivity of salt vapours and that of Röntgenised gases, and especially of getting some information about the velocities of the ions in the flame itself.