154 



ELEMENTS OF STATIC ELECTRICITY. 



the lines of force to a focus on a piece of iridio-platinum, 

 >, placed in the center of the globe. This, being a 

 metal of high resistance, becomes white hot under the 

 electric action ; glowing with intense brilliancy, and 

 finally melting. 



The walls of the globe, being remote from the line 



between the electrodes, 

 which is comparatively 

 short, the glass is less af- 

 fected than in the long 

 narrow tubes: so that elec- 

 tric action is chiefly con- 

 centrated on the object at 

 the center. 



Crookes attributes all 

 these phenomena to the 

 impact of the residual air 

 molecules, which he desig- 

 nates as "radiant matter"; 

 and claims that the mole- 

 cules move independently 

 of each other, and are 

 driven with such force 

 against the glass and other 

 objects, as to produce the 

 various phenomena de- 

 scribed. 



Gordon considers this theory reasonable, and elabo- 

 rates it at considerable length : but it is not generally 

 accepted ; and it is believed that the explanations here 

 given will be found more in accordance with well estab- 

 lished electric principles. 



Fig. 49-Heat Produced in High 

 vacua. 



