263 



the suggested measurement in case of photographs 2 and 3 of series A and 



2 and 3 of series I, we have 



2.8 X 17600 X 10^ 



V = = 4.7 X 10'' cm. per. sec. 



3.2x5.1 x6400 



Values for other photographs calculated by the same method appear in 

 Table 5. 



The above values for the speed of the positive ions approximate those 

 given for positive ions iu rarefied gases. The highest value obtained by 

 other investigators for the gaseous ion at atmospheric pressure, found 

 recorded by the author, is by Helen E. Schaefer of 5x10^ cm. per second. 

 Her value, obtained by use of a rotating mirror, is given as the average 

 speed along the spark path, and not the initial speed obtained by the method 

 used in this investigation. 



The curved path of the stream in series D can not be considered in con- 

 nection with the ordinary formula for centripetal force in solving for a 

 value for the ratio of the charge to the mass, because here the ion is under 

 the influence of the charge on the opposite point. If, however, the value 

 obtained by the above method can be regarded as the initial speed of the 

 positive ion the equation ^m v-=Ve can be used to calculate the value 



e 

 for — . In the above equation ni is the mass of the ion, v its speed, V the 



m 



potential between the points and e the charge on the ion. Since v is the 



initial speed the two expressions for the euergj' are independent of the 



course taken by the ion between the points, and also independent of any 



subsequent speed. Some values of calculated by means of this expres- 



m 

 sion are as follows : 



e 1 v' 



Series A No3. 2 and 31 — = 



m 2 V 



1 (4.7 X 10^)2 



2 23000 X 10« 

 Table 5. 



4.6 X 10^ cm. per. see. 



