1919. ] The Sixth Indian Science Congress. CXxv 
the influence of its own radiations, to the lowest member of 
the group. If this explanation were correct, it should be pos- 
sible to obtain carbon from thorium, and possibly from other 
curous nitrate were performed at the same time. In these 
obtained varied directly with the atomic weight of the element 
treated, except in the case of lead, which furnished only 
‘013 ¢ 
t will be noticed that the suggestion here is that thorium 
from an ny known natural radioactive process. It is true that the 
adioactiv to the helium group, are 
partially. transformed into helium, the | Aeon member, but this 
of helium. The experiments are, however, to be judged on 
their merits. Whence comes the —. Excluding for the 
possible s sources. The first may be rejected, since the amounts 
of carbon dioxide found seal correspond with a leakage of air 
very many times greater than the capacity of the vessels used. 
The solutions employed were all acid, and so could not absorb 
carbon dioxide selectively ; ep were prepared with extreme 
care, under conditions which sec red the absence or the des- 
shown that small amounts of this gas can be evolved persist- 
ently from carefully cleaned glass vessels under bombardment 
by cathode rays, and presumably also under the action of the 
radiations we are consideri In this connection it is perti- 
nent to call attention to two points: first, that no carbon 
dioxide or monoxide could be found in the gases from mercurous 
