Royal LxsTnrTiox of (jtuilvt 



WEEKLY EVENING MEETING, 

 Friday, January 17, 1913. 



His Grace The Duke 

 F.R.S. 



OF Northumberland, K.G 

 President, in the Chair. 



Professor Sir J. J. Thomson, O.M. LL.D. D.Sc. F.R.S. M.R.I. , 



Professor of Natural Philosophy, Royal Institution. 



Some Further Applications of the Method of 

 Positive Rays. 



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. 

 The positively electrified particles move with great velocity to- 

 wards the cathode ; some of them pass through a small hole in the 



Fig. 1. 



centre, and emerge on the other side as a fine pencil of positively 

 electrified particles. This pencil is acted on by electric forces when 

 it passes between the plates L and M, which are connected with the 

 Vol. XX. (No. 107) 2 R 



