254 W. Orookes—Radiant Matter. 
sides of the glass bulb. When the pressure is only a few mil- 
lims. of mercury, on passing the induction current a halo o 
velvety violet light forms on the metallic side of the vanes, 
the mica side remaining dark. As the pressure diminishes, a 
dark space is seen to separate the violet halo from the metal. 
At a pressure of half a millimeter this dark space extends to the 
glass, and rotation commences. On continuing the exhaustion 
the dark space further widens out and appears to flatten itself 
against the glass, when the rotation becomes very rapid. 
Here is another piece of apparatus (fig. 10) which illustrates 
the mechanical force of the Radiant Matter from the negative 
a: ‘ : t 
aluminium terminal (e) is sealed in at the top of the tube, and 
vanes on the screen. 
attached, so that the platin 
