594 E. M. Wellisch — Mobilities of Ions in Air. 



v 9 



X 



Eate 



V 2 



X 



Rate 



volts 



volts 





volts 



volts 





— 120 



104-0 



6-10 



— 120 



17-5 



2-80 





92-5 



6-02 





16-7 



2-73 





80-0 



5-95 





15-9 



2-65 





63-2 



5*26 





14-3 



2-49 





55-0 



5*08 





13*6 



2-42 





50*1 



4-90 





12-9 



2-35 





46-3 



4-76 





12*2 



2-25 





40'0 



4-47 





11-5 



2'17 





34*4 



4-13 





10-2 



2-07 





29*5 



3*88 





9'0 



1-96 





25-0 



3'50 





7'91 



1-84 





24-0 



3-40 





6-9 



1-77 





23*0 



3-31 





5-0 



1-59 





22-0 



3-23 





3-4 



1-49 





21*0 



3*20 





2-14 



1*33 





20-1 



3-09 





1-13 



1-07 





19*2 



3*00 





•73 



•82 





18-4 



2-91 





•42 



•47 



The small circles drawn in the diagram refer to the points 

 from which the mobilities of the negative ions were obtained 

 in the manner previously described. The experimental data 

 relating to these curves are as follows : 



Curve 



Pressure 

 mm. 



Critical 



Potential 



Vo 



Volts 



f 



Time for 



100 r 000 



alternations 



sec. 



k 2 



cm/sec 



K 



cm/sec 



A 



•39 



1-75 



•592 



117-1 



3300 



1-695 



B 



•87 



4-0 



•559 



118-3 



1512 



1-73 



C 



1-69 



7-5 



•553 



117'5 



821-2 



1-83 



D 



2-80 



11-5 



•545 



114-6 



557-0 



2*05 



E 



5-92 



25-0 



•500 



114-4 



279-8 



2-18 



F 



8-09 



35-0 



•539 



116-3 



182-3 



1-94 



G 



12*12 



52-5 



•543 



116-4 



120-5 



1-92 



H 



22-6 



90-0 



•564 



118-4 



66-5 



1-98 



K 



62-0 





•565 



121-3 







The lowest pressure employed for the case of the negative 

 current was -15 mm ; the curve was of the general type and gave 

 a normal mobility value for the ion. 



In none of the curves is there evidence of an intermediate 

 or transition stage in the nature of the negative carrier ; it is 



