•±24 Dr. Tyndall and Mr. Hughes on Cathode 



Influence of the Nature of the Residual Gas. 



It has been shown that the rate of disintegration depends 

 on the nature of residual gas in the tube, certain gases such 

 •as argon apparently favouring disintegration, others such as 

 hydrogen retarding it. Kohlschutter is of the opinion 

 that the rate of disintegration increases with the density of 

 the gas. 



Now the values of normal cathode-fall in different gases 

 are not in the order of their densities ; thus in some recent 

 experiments Rottgardt * obtained the following values : — 

 Argon, 131 volts ; Air, 277 volts ; Nitrogen, 216 volts ; 

 Hydrogen, 276 volts. But it has been shown above that the 

 disintegration tends to vanish at the normal fall ; and if this 

 be so, the statement that the rate of disintegration increases 

 with the density of the gas must break down at low values 

 of cathode-fall. An investigation of rates of disintegration 

 in this region seemed, therefore, desirable. 



Only a few preliminary results have so far been obtained, 

 and these in the two gases, air and hydrogen. The hydrogen 

 was prepared by electrolysis and purified by absorption in 



Curves 4. 



6. 







if- 





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■Z 

 d 







4*" 



V. 



3 

 Q 



A> ^* 



^jt^^ Hytl »-£><je>\ 









\ m 







*w 



^•oo 



Leo Soo Icoo 



of fsob^y.hla.1. 



(6o* 



wits 



spongy palladium. The results are shown in Curves 4, in 



which rate of disintegration (ordinates) is plotted with 



* Rottgardt, Ann. d. Phys. xxxiii. p. 1161 (1910). 



