Quantum Theory of Electric Discharge. 237 



After this stage, the cathode glow spreads up to the 

 positive column and gradually overlaps it, practically the 

 whole tube being illuminated. 



Experiment II. — Voltage in the primary a little above 

 12 volts. (Curve II.) 



(Illumination stronger than in the previous case.) 



35 



14-9 



17 



14-9 



7 



14-9 



5 



14-9 



2 



14*9 



14-65 



•25 cm. 



14-3 



'6 „ 



13-85 



1-05 „ 



13-4 \ 

 13-45 f 



1-5 „ 



As the pressure is further reduced, the cathode glow 

 appears to extend up to the positive column and overlap it. 



40 



6 



5 



20 



10 



\ 







1 



a\ 









. \ \ 

 c\ \ 



<5A\ \ 









4) \ 











~* 



length of the dark space 



