On the Reflection of Cathode Rays. 



377 



crystalline, and is adherent to the sand grains in such a way as to 

 show that it has been deposited in situ subsequently to the sand grains. 

 Mr. Lomas states that the occurrence of barytes in the trias is fairly 

 common, and mentions the following localities, in which its presence is 

 well known : Beeston, Alderley Edge, Oxton, Storeton, and Peak- 

 stones Eock, Alton. The sulphate is also stated to occur at West 

 Kirby, in Cheshire, and elsewhere as a joint filling, the joints often 

 standing out from the surface of the rock, owing to the resistance of 

 the sulphate to weathering.] 



"On the Keflection of Cathode Rays." By A. A. CAMPBELL 

 SWINTON. Communicated by LORD KELVIN, F.RS. Eeceived 

 January 25, Read February 9, 1899. 



There being apparently some doubt as to the exact nature of the 

 rays, named by Professor S. P. Thompson paracathodic rays,* which 

 in a Crookes tube of the focus type proceed from the front surface of 

 the anti-cathode, and cause the green fluorescence of the glass, the 

 writer has made the following investigations : 



Firstly, in order to determine the magnetic deflectibility of the para- 

 cathodic rays, a tube was constructed as shown in fig. 1, in which C is 

 the cathode, A the anti-cathode and anode, and B an aluminium wire 



Fia. l. 



* ' Phil. Trans.,' vol. 190, pp. 480483. 



