THE 



POPULAR SCIENCE 



MONTHLY. 



JUNE, 1913 



» 



SOME FUETHEE APPLICATION'S OF THE METHOD OF 



POSITIVE EAYS 1 



Professor SIR J. J. THOMSON, O.M., LL.D. D.Sc, F.R.S. 



CAVENDISH PROFESSOR OF EXPERIMENTAL PHYSICS, CAMBRIDGE, AND PROFESSOR OF 

 NATURAL PHILOSOPHY, ROYAL INSTITUTION 



THE method to which I shall refer this evening is the one I described 

 in a lecture I gave here two years ago. The nature of the method 

 may be understood from the diagram given in Fig. 1. A is a vessel 

 containing the gases at a very low pressure; an electric discharge is 

 sent through these gases, passing from the anode to the cathode C. 



Fig. 1. 



The positively electrified particles move with great velocity towards the 

 cathode; some of them pass through a small hole in the center, and 

 emerge on the other side as a fine pencil of positively electrified par- 



1 Address before the Eoyal Institution of Great Britain, Friday, January 

 17, 1913. 



VOL. L.XXXII.— 36. 



