W. Crookes— Radiant Matter. 251 
If, instead of a flat disk, a hemi-cylinder is used for the neg- 
ative pole, the Matter still radiates normal to its surface. The 
(tube before you fig. 6) illustrates this property. It contains, 
as a negative pole, a hemi-cylinder 
(a) of polished aluminium. is is 
connected with a fine copper wire, 
b, ending at the platinum terminal, 
c. At the upper end of the tube is 
another terminal, d. e induction- 
pole positive, and when exhausted 
to a sufficient extent the projection 
hemi-cylinder in a direction normal 
to its surface, come to a focus and 
then diverge, tracing their path in 
brilliant green phosphorescence on 
