[ 429 ] 



XL. The Distribution of the Active Deposit of Radium in 

 an Electric Field. By IS. Ratner (Petrograd), Research 

 Student, University of Manchester* . 



A 



the question of the distribution in an electric field 

 of the active deposit from the emanations of radium, 

 thorium, and actinium has led to the general conclusion 

 that the carriers of the active matter are positively charged. 

 Great difficulties, however, have arisen from the fact that 

 even with large electric forces a certain fraction of the 

 active deposit appears on the anode. This anode activity 

 varies with the conditions, but when small quantities of 

 emanation are employed it usually does not exceed 10 

 per cent, of the total activity. In case of large quantities 

 of emanation, however, the anode activity becomes very 

 large and may rtach the value of the cathode activity f. In 

 order to account for the origin of the anode activity, it has 

 been suggested either that a certain fraction of the recoil 

 atoms carry a negative charge, or that some of the posi- 

 tively charged atoms lose their charge by recombination with 

 negative ions and reach the anode by the process of diffusion. 

 Considerable disagreement in the results of different observers 

 suggests, however, that the origin of the anode activity is of 

 a more complicated nature. 



Several years ago, using a vessel in which large quantities 

 of radium emanation had been constantly kept previously, 

 the author noticed that the activity concentrated on the 

 electrode introduced into this vessel did not depend upon 

 the direction of the field applied, even when minute quantities 

 of emanation were used. A closer study of this phenomenon 

 led to the supposition that the distribution of the active 

 deposit may be in some way influenced by the electric wind, 

 which is always produced in an ionized gas when in an 

 electric field J. Experiments carried out in this direction 

 have established the predominant role of the electric wind in 

 the process of the distribution of the active deposit of radium 

 in an electric field. In the present paper these experiments 

 are described and the results given. 



* Communicated bv Sir E. Rutherford, F.R.S. 

 t Wellisch, Phil. Mag. [6] xxviii. p. 418 (1915). 



X Zeleny, Proc. Camb. Phil. Soc. x. p. 14 (1898) ; Ratner, C. 21. clviii. 

 p. 565 (1914) ; Phil. Mag. [6] xxxii. p. 455 (1916). 



