58 



Proceedings of the Royal Irish Academy. 



described later on it was found that, with a short time-interval and a small 

 pressure, ions of mobilities 1 - 10, - 50, "31, "22 em./see. were present. The ion 

 of mobility '-2 cm. sec. was the slowest ion that could be detected. Thus 

 it is quite conceivable that with a very high pressure and a comparatively 

 short time-interval, ions of mobilities 00084 cm./sec. and 00015 em./see. 

 could lie obtained in considerable quantity. 



No attempt was made to try what the effect of a longer time-interval 

 would be. It is possible thai slower i- >ns than thai of mobility -0001 5 cm./sec. 

 would be formed. 



Tic Mon Mobil* Ions. 



To obtain obsei vations of tin- more mobile ions two points were attended 

 to. A small pressure wis use. 1. ami the time between formation and measure- 

 ment was made as short as possible. A measuring tube suitable for high 

 mobilities wa> used, and it was fixed vertically ovei the bubbling vessel. The 

 space between the surface of the alcohol and the end of the insulated 

 terminal was about 300 ccs. in volume, and the time between formation and 

 observation of the ion- was about 1 \ to 2 -■•■ 9. The pressure varied between 

 3 and 5cm. The following table shows the mobilities observed.— 



Tablr I V. 



1-10 - 







•21 



1 10 



•49 





•21 



- • 



17 



•30 



•20 



— 



•66 





■22 



— 









— 



■42 







— 









M, 110? 



•60 



■31 



•21 



The ion of mobility "_'l em. lowest we could detect- It is 



ible that if the mobilities could be observed soonei iftei formation, and 

 ii the pressure was Bmaller, ions of highei mobility would be obtained. It 

 would be difficult with the present apparatus to measure accurately higher 

 mobilities. The three value- given in the first column may represent the 

 -aine ion, but it is difficult to be certain. 



The next -te|. was to link up these observations with the previous 

 results. This was done by increasing the time-interval and slightly 

 increasing the pressure. The time was uow about 5 sees., and a pressure of 



