OF GASES UNDER THE BECQUEREL RAYS. 
523 
Relative conductivity. 
Gas, 
Relative 
density. 
Ronfcgeri 
rays. 
Cathode 
Radium rays. 
Polonium rays. 
Uranium 
J. J. Thomsox. 
Pereix. 
rajs. 
Pencl rat¬ 
ing type. 
Absorbable 
type. 
I. 
11. 
rays. 
Hydrogen . 
• 0693 
•33 
•026 
•069 
•157 
•218 
•226 
•219 
•213 
Air .... 
1-00 
1-00 
1-00 
1-00 
1-00 
1-00 
1-00 
1-00 
1-00 
Oxygen. . . 
Hydrochloric 
1-11 
— 
— 
1-106 
1-21 
■-- 
1-16 
— 
— 
acid . 
Carbonic 
1-27 
8-9 
8 
-- 
1-461 
— 
— 
— 
— 
acid . . . 
1 -53 
1-4 
1-34 
1-53 
1-57 
— 
1-54 
— 
— 
Cyanogen . 
Snljjhur 
1-86 
1-05 
— 
— 
1-86 
— 
1-94 
— 
— 
dioxide . 
2-19 
G-4 
6 ■ 
— 
2-32 
1-92 
2-04 
2-03 
2-08 
Chloroform 
4-32 
— 
— 
— 
4-89 
— 
4-44 
— 
— 
IMethyl iodide 
Carbon 
5-05 
— 
— 
— 
5-18 
3-74 
3-51 
3-47 
3-55 
tetrachloride 
5-3] 
— 
— 
— 
5-83 
— 
5-34 
— 
§ 8. Discussion of Results. 
It remains to be considered what conclusions can l^e drawn from the measure¬ 
ments. 
In the first place, let us consider the penetrating radiation from the radium pre¬ 
paration. It will he seen, that in all cases except hydrogen, the conductivity is neaily 
proportional to the density of the gas. Hydrogen is the only case in which the 
departure from this law is considerable, its conductivity being about double what the 
law would recpiire. But, since the conductivity of hydrogen is small, the ahsolute 
difference between the observed conductivity and that which the law wo\dd require 
is not larger than in the other cases. And it is possible that this is the right way 
of regarding the matter. This aspect of the question is brought out Ijy a graphic 
representation of conductivity as a function of density. (See diagram No. Q.'*) I 
think that it is impossible to doid^t, in view of the results exhibited on this diagram, 
that the conductivity depends mainly on the density of the gas. 
The much greater relative departure fi'om tlie law in the case of hydrogen 
naturally raised the question of wliether tlie experiments were open to criticism. 
They were carefully I'epeated, taking additional precautions against contamination 
by impurities. But the accuracy of the former determinations was completely 
confirmed. There is, I tliink, no reason whatever to doidjt their substantial 
correctness, t 
* The determination for liydrochloric acid is not re23re.sented in the diagram, liecause of its nncertaintj", 
mentioned above. 
t It is worthy of note, in connection with the large deiiarture of hydrogen from the law of density so 
3x2 
