Absorption of Gases in Vacuum,' Tubes. 



241 



Eleetrodes. 



Absorption. 



Disintegration. 



Gold 



Platinum 



1-25 Xl0" 4 (0-320) 



0-90 X 10-4(0 -400) 



l-95xl0- 4 (C-495) 

 0-81xlO~ 4 (C-495) 





The absorption was determined for gold and platinum 

 electrodes. In the last column are given the corresponding 

 disintegration values for discharge in air as calculated from 

 results of Holborn and Austin*. The table shows the 

 intimate relation between absorption and disintegration. 



The considerable difference between the absorption with 

 gold and platinum electrodes was used to prove, by alternately 

 changing the metal of the anode and cathode, that the con- 

 servative absorption was connected with the cathode. 



The relation (1) only holds approximately for cathode-falls 

 up to about 1000 volts. When the cathode-fall is increased 

 still more the absorption increases less rapidly and reaches, 

 as already mentioned, a maximum value. 



In helium the absorption was smaller ; but there was a 

 distinct conservative absorption to be observed. 



In hydrogen, however, no conservative absorption was founds 

 but only absorptions of the more conservative type, which 

 very much depended on the state of the bulb and its previous 

 history of running. This want of conservative absorption in 

 hydrogen gave an explanation of the effect of the residual 

 gases of the bulbs to reduce the velocity of absorption. 



Regarding the view taken about the mechanism of the 

 process, I give the following statements from my paper. 



" Whatever may be the view we take about the mechanism of 

 the process, ice cannot escape from the assumption that gas is 

 attached to the metal and carried away with the metallic 

 deposit." And further, " The previous residts suggest that the 

 electric discharge imparts to the gas a new kind of combining 

 poicer, ' electric affinity,' which probably is a function of the 

 cathode-fall and ivhich is a power attached to ions moving with 

 a high velocity." 



The attachment of the gas to the metal was considered as 

 something between an occlusion and a real chemical combi- 

 nation, and was compared with the attachment of helium to 

 the radioactive minerals. 



* Wissenschaftl Abh. d. Phys. Techn. Reichsanst. B. iv. p. 101 (1904). 

 Phil. Mag. S. 6. Vol. 32. No. 188. Aug. 1916. K 



