12 Wellisch — Motion of Ions and Electrons through Gases. 



The values of K for freshly prepared CO^ are scarcely in 

 sufficient agreement to justify the assignment of an average 

 value. It is evident from the table that the electron velocities 

 are very sensitive to the presence of impurities ; the highest 

 value of K obtained was 255^""' per sec, but even this cannot 

 be regarded as a maximum as a greater degree of purification 

 would probably result in still higher values. 



There is some evidence of an indirect character that the elec- 

 tron does not move with a velocity Tvhich is strictly propor- 

 tional to the applied field but traverses with an accelerated 



Fig. 6. 







j "I 



























1 j 

















A 



\ 





— 



Freshly prepared COi 













-^ 



*^ 



J 





> 









^ 



X 









' 





^ 



^ 





















M M M M 











/^ 

























^= /Z7 mm. 









^ 



y 

























> 









y 











































A 





// 













































d 



// 













































^/ 



'h 













































V 



^ 





























































































r 



^ 

























^ 



Y 







A . /7 =^4/06 f= '500 

















7^' 























^ 











B . n =^7968 f^ -530 













^ 



r 























?^ 













































^ 



a^ 



^ 













































16 



24 



32 



40 



Volts. 



motion distances comparable with the distance between the 

 electrodes. The close approach for small potentials of the E 

 curves in fig. 6 which refer to CO, at the same pressure 

 (137"") but with different alternation frequencies suggests very 

 large values for the velocities of the electrons ; this is more 



cl^n\ 

 readily understood if we apply the formula ^' = ^ (/— jyj 



where i' is the current for potential Y when the alternating 

 field is employed and i is the current for potential Y directly 

 applied. If we take the velocity calculated from Y^ at the 

 higher frequency, viz. k=lZZQ at 137"", the above formula 

 (with <:Z=2) gives i'Ji\^=4:-l for Y = 5*78 volts where the suf- 

 fixes 1 and 2 refer to the low and high frequency respectively ; 

 the value obtained from the experimental curves is only 1-3. 

 Similarly for Y=6-96 volts we obtain a calculated ratio of 2*6 

 wliereas that obtained experimentally is 1*2. These considera- 

 tions would seem to imply that the value A;=1336 is too small 



