(HO Prof. J. S. Townsend on the Genesis of Ions 



has just been described, is more accurate for the determina- 

 tion of the larger values of than the method which was 



P 

 applied to the previous experiments. The values of " 



P 

 which were found in the earlier determinations for the 



larger values of are somewhat too laroe since the 



p » 



positive ions contributed slightly to the increases of con- 

 ductivity which were observed. Thus with air the value of 



- corresponding to =787 was given as 9*3, whereas ihe 



value obtained by the more correct method is 8*9. In the 

 case of hydrogen the errors which were introduced are larger. 



Fio-. -6. 



A 



•t 















■■■■1 

























n 







































































































'/ 











































j 











































1 











































'h> 



■DfH 



G£ 



U 





















































































































, 

































































•66 











































/ 







































u 



/ 







































•6€ 



/ 



A/A 



. 





































/ 









































/ 



























1 















'^x 



























** 



T 











1 



y 



























84 



=•/ 









2|| > 



^ 



























8 



r^ 



/ 









1 



























X 



500 



It may be possible to determine accurately the values of a 

 and /3 corresponding to forces larger than those which were 

 used in the experiments which I have described in this paper, 

 but since the researches have not yet been carried far in this 

 direction a more complete investigation dealing with large 

 forces and small pressures may more conveniently be reserved 

 for future investioation. 



