Nolan — Ionic Mohilities in Air and Hydrogen. 



89 



we may note the following relationships, which can hardly be accidental. 

 The two already given are included : — 



Mobilities : Hydrogen. 



Air. 



Ratio. 





(1) 



(2) 



Mean 



/Mob. ill HsN 

 \Mob. in air/ 



0-23 



1-37 



1-42 



1'38 



3-79 



5-68 1 

 6-15 ) 



1-52 



1-54 



1-53 



( 3-71 

 ] or 

 f 4-02 



6-77 



1-79 



1-73 



1-76 



3 8.5 



7-93 



2-04 



2-04 



2-04 



3-89 



9-63 



— 



2-5 



2-5 



3 8.3 



11-0 



3-00 



3-04 



3-02 



3-64 



15-0 



4-23 



4-39 



4-31 



3-48 



18-8 



— 



5-1 



5-1 



3-69 



In this table the air mobilities (1) are those found by the air-stream 

 method, and (2) are those found by the alternating-field method. For the 

 second last ion the value 4"31 is probably too high, for reasons mentioned 

 earlier in this paper (page 81). For ttie same reasons the value 5-1 for the 

 last ion is taken. 



Extreme Drying. 



Experiments are now being conducted on the effects of extreme drying. 

 It is hoped to present the results of these experiments shortly. 



The results on hydrogen so far obtained go generally to confirm the 

 observations of Haines. All his ions have been found except his fastest, and 

 that was hardly to be expected, since no special measures for purity or drying 

 were adopted. The principal difference is that Haines did not find the 

 positive ionization to be of a complex character. The results of the author 

 on air and hydrogen involve, first, the composite character of the ordinary 

 ionization, and, second, the existence of small numbers of ions of high 

 mobility. We will consider the evidence now a\ailable under these 

 heads. 



R.I. A. PROC, VOL. XXXVI, SF.CT. A. 



[9] 



