PRODUCED IN GASES BY RONTGEN RAYS. 
221 
The correction mentioned in § 4 (15), which is to be applied to the values indicated 
at T = 0 has in this case been reduced to 1 per cent., 1 per cent, being allowed for 
an increase in the velocity due to a diminution of density caused by the impurities in 
the gas. The corrected value thus obtained for the velocity in moist oxygen is for 
the negative ions = 1’52 centims. per second, and for the positive ions = 1*29 
centims. per second, at a pressure of 76 centims. and at a temperature of about 
16 ° C. 
The following is a summary of the results obtained for the positive and negative 
ions in dry oxygen :— 
Table XII.—Dry Oxygen. Summary of Results. 
Reference 
X. 
U. 
A. 
T. 
Tempera- 
Gas 
Ionic velocity. 
number. 
ture. 
pressure. 
Negative. 
Positive. 
1 
2-73 
13-9 
+ 20-2 
•20 
°C. 
20-3 
77-3 
1-31 
2 
2-73 
13-8 
- 15-37 
•20 
20-3 
77-3 
1-71 
— 
3 
2-73 
133 
+ 19-5 
•21 
19-4 
77-4 
— 
1-31 
4 
2-73 
13-3 
-14-7 
■21 
19-4 
77-4 
1-72 
— 
5 
2-73 
13-3 
+ 19-5 
•21 
19-4 
77-4 
— 
1-30 
6 
3-89 
16-65 
- 13-6 
•23 
15 
78 
1-66 
— 
7 
3-89 
17-7 
+ 17-7 
•22 
15-6 
78 
— 
1-35 
8 
3-89 
16-9 
- 13-4 
•23 
15-6 
78 
1-71 
— 
9 
3-89 
7-97 
- 6-82 
•49 
16 
76-8 
1-56 
— 
10 
3-89 
8-46 
+ 9-45 
•46 
16 
76-8 
— 
M9 
11 
6-89 
8-92 
+ 5-64 
•77 
15-2 
77-1 
— 
1-19 
12 
6-89 
9-07 
- 4-53 
•76 
15-2 
77-1 
1-51 
— 
13 
6-89 
17-35 
- 8-05 
•40 
15-8 
774 
1-63 
— 
14 
6-89 
17-4 
+ 10-33 
•40 
15-8 
774 
— 
D27 
The results are represented graphically in fig. 12. 
When, as in the case of moist oxygen, a 1 per cent, additive correction is applied 
to the values indicated in the figure by T = 0, the final result for the velocity in dry 
oxygen is for the negative ions = 1'80 centims. per second, and for the positive ions 
= 1*36 centims. per second for a pressure of 76 centims. and a temperature of about 
17° C. 
