the Faraday Dark Space of Vacuum- Tubes. 567 



Table III. — Potential Gradient in Volts per Centimetre for 

 Various Currents. Gas-pressure 1*5 mm. 

 Position of Anode 17. Position of Cathode 162. 



Position 



- 5 m.a. 



•8 m.a. 



10 m.a. 



15 m.a. 



6 m.a. 



in mm. 













19 











60-5 



25 



535 



55-0 



55-0 



55-0 



350 



40 



515 



53-0 



54 



54-5 



310 



60 



55 



55-0 



560 





295 



80 



540 



560 



57-0 



51-5 



220 



100 



49-5 



55 



47-5 



295 



16 5 



120 



530 



44 



25-5 



130 



9-0 



140 



58-5 



275 



100 



2-5 



20 



150 



22-0 









1-0 



154 





11-0 









These values of the gradient are represented graphically in 

 fig. 2 (for '6 mm.), 3 (for 1 mm.) 3 and 4 (for 1*5 mm.). It 



Fier. 2. 

































































•> 

















































P 



= 



rf. 















30 











V 



r\ 





































































t 

















' 







\ 







\\ 































£ 





10 

























s 











\ 































a , 

























X 



v 





\*. 



V 



. 

































\ 





_ 











-- 



«, 



<S" 



*» . 











sX s 



J& 





























J„ 





























~- 



. _ 



































1 







































^ 



;-~- 























« 

















3 







* 





i 







i 





7 



e* 



i 







1 



9 



/ 



JO 



/ 



/«? 



/ 



to 



/j 







' 



fa 



/. 



ro 



A 







Millimetres. 































Fig. 



3 



























































































7 







• 



r 



-^ 



























































it 





-„ 



































"*V 



> 











<* 







30 





4- 







"• 



-■m 



s^ 



6 



"■s. 



W- 













4 



r 













\ 









ft 



O 





( 























- "«I 



r^-_ 















Q- 













v 







^ 



v 





7 































""^ c 









\ 







V^ 







\ 



s 





\ 



\ 



■Jj 















T> 





1.0 































^ 

















/ 







































- v 

































































"■-> 





N 































































■"■ 



-^ 



■*a. 

















/a 



1 



a 



i 







< 



■0 



J 



a 



i 







7 



» 



J 







■) 



» 



ft 







// 







7. 



10 



/ 



Jo 



f 



fe 



/i 





/A J 



Millimetres. 



was observed that the negative extremity of the luminous 

 column could be indicated in the figures by the intersection 

 of the corresponding gradient with the horizontal line 11. 



