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 108 
Vv = —- = 4.7 x 10’ em. per. sec. 
3.2 x 5.1 x 6400 
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 in 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* em. 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 4my*—Ve can be used to calculate the value 
e 
for __, In the above equation m is the mass of the ion, v its speed, V the 
m 
potential between the points and e the charge on the ion. Since y is the 
initial speed the two expressions for the energy are independent of the 
course taken by the ion between the points, and also independent of any 
subsequent speed. Some values of at) calculated by means of this expres- 
m 
sion are as follows: 
e eve 1 (4.7 x 107)? 
Series A Nos. 2 and 3) — = = - = 4,6 x 10? em, per, sec, 
m 2 Vi 2 23000 x 10° 
TABLE 5. 
| | | 
Series. } Nos. in Series. | Speed v in cm. per. sec. =, 
A and I 2 and 3 4.7 x 10" 46 x10? 
Aa Bag | 1 x 108 2.17 x 10° 
Bas id Qe 8 | 2.6 x 10! 1.3 x10 
(OMS << DRS: | 6 x10 6.7 x10? 
(Ch era 5 a6 2.7x 10! iS) exsl0? 
5.12 x 10° 
D 1.6 x 108 
