518 
HON. R. J. STRUTT ON THE CONDUCTIVITY 
The measurements are given in the following table :— 
Gas. 
Conductivity (air = 1). 
Separate determinations. 
Mean. 
Hydrogen .... 
•218 -224 _ -212 
•218 
Sulphur dioxide . . 
1-89 2-00 1-92 2-10 
1-98 
Methyl iodide . . . 
3-78 3-72 3-82 36-3 
3-74 
§ 6. Radiation from Polonium. 
This radiation is not deflected by tbe magnet* (Curie, ‘ Comptes Eendus,’vol. 130, 
p. 73), and, so far at least, resembles the “ soft ” radiation from the active barium. 
The first set of experiments was made with the samjile of polonium prepared by 
myself. The following numbers give the rate of leak at various pressures; about 
five observations were made in each case, and the mean taken. 
Pressure, 
millims. 
Time taken to pass 
over 100 divisions. 
Current 
(arbitrary scale). 
740 
19-2 
521 
477 
27-3 
366 
315 
39-3 
255 
180 
76-9 
130 
46 
302-0 
33 
The results are plotted on diagram No. 3. There is not much indication of 
absorption until the pressure is comparable with that of the atmosphere. For the 
various gases, the following results were obtained :—■ 
Gas. 
Relative conductivity (air = 1). 
Separate determinations. 
Mean. 
Hydrogen .... 
215 
•226 
•242 -215 
•226 
Oxygen . 
1 
13 
1-16 
— 1 -18 
1-16 
Carbon dioxide . 
1 
53 
1-55 
— 1-54 
1-54 
Cyanogen .... 
1 
95 
1-93 
— — 
1-94 
Chloroform .... 
4 
42 
4-45 
— — 
4-44 
Sulphur flioxide . 
1 
96 
2-02 
2-14 — 
2-04 
Methyl iodide . . . 
3 
32 
3-88 
3-43 3-42 
3-51 
Carbon tetrachloride. 
5 
30 
5-37 
■ 
5-34 
* This result is not in agreement with that arrived at by Giesel (‘ Wied. Ann.,’ vol. 69, p. 834). But 
my own experience confirms Curie’s conclusion. 
