82 . • Mr. A. A. C. Swinton. 



It may further be remarked that the diameter of the luminescent 

 ring may be increased or diminished, or finally reduced to a point, 

 without altering the degree of vacuum, by moving the anti-cathode 

 away from or towards or finally into the focus of the cathode stream, 

 the appearance of the ring in each of these cases being practically 

 similar to those shown in the figures for a uniform distance with 

 varying vacuum. When the anti-cathode surface is not at right- 

 angles to the line of the discharge, the ring, in place of being cir- 

 cular, takes the px^oper form of a conic section. The holding of a 

 magnet near the tube distorts the ring from a circular shape and 

 moves its position on the carbon. 



From these experiments it appears that the diverging cone of 

 cathode rays acts as though it were not of uniform density through- 

 out its section, but, at any rate in some instances, as if it were com- 

 pletely hollow. This fact does not appear to have previously been 

 noted. 



Apparent Hollowness of the Convergent Cone of Bays. 



The apparent hollowness of the divergent cathode ray being thus 

 established, it was thought desirable to ascertain whether the same 



