PRODUCED IN GASES BY RONTGEN RAYS. 
233 
These values are nearly the same as those obtained above for the ions produced by 
Rontgen rays. 
J. S. Townsend* has shown that from the ionic velocity in a gas and the coeffi¬ 
cient of diffusion of the ions in the gas, the value of Ne can be obtained, N being 
the number of molecules in a cubic centim. of the gas, and e the charge carried by 
an ion. By comparing this value with that obtained from the electrolysis of liquids, 
the relation between the charges on the ions in the two cases can be determined. 
Using the values of the ionic velocities ( v ) given in Table XXII., and the corre¬ 
sponding coefficients of diffusion (K) from the tables given by J. S. Townsend, the 
3 x 10 8 'v 
values of Ne are obtained from the equation Ne = -—-for the positive and the 
negative ions in both dry and moist gases. 
The results are given in the following table :— 
Table XXIII. — Values of Ne X 10 10 . 
Gas. 
Moist gas. 
Dry gas. 
Positive 
ions. 
Negative 
ions. 
Positive 
ions. 
Negative 
ions. 
Air. 
1-28 
U29 
1-46 
1-31 
Oxygen . 
1-34 
1-27 
1-63 
1-36 
Hydrogen. 
1-24 
1T8 
1-63 
1-25 
Carbonic acid . 
1-01 
•87 
•99 
•93 
The corresponding value of Ne obtained for hydrogen from the electrolysis of 
liquids is 1‘23 X 10 10 at a pressure of 76 centims. of mercury, and a temperature 
of 15° C. 
The values of Ne in the table for the positive and the negative ions in moist air, 
oxygen and hydrogen are perhaps in sufficient agreement to justify the statement 
that the charges carried by the positive and negative ions are the same, and that the 
value is also the same for the three gases, and corresponds to the charge carried by 
the hydrogen ion in the electrolysis of liquids. 
The values of Ne for the negative ions in the same three gases when dry are not 
far from those in the moist gases, but the results for the positive ions are consider¬ 
ably larger. It seems very improbable, however, that the charges carried by the ions 
are different in the moist and dry gases, since most likely the moisture does not in¬ 
fluence the act of the ionization itself, but either affects the ions after they are formed 
during the production of clusters of molecules around them, or changes the resistance 
* J. S'. Townsend, ‘Phil. Trans.,’ A, vol. 193, p. 152, 
2 H 
VOL. CXCY,—A, 
