Moss—On the State in which Helium Exists in Pitchblende. 159 
expiration of that time the mineral was rapidly transferred to the grinding apparatus, 
which was then closed and exhausted. The mineral was now reduced to powder, 
an operation which occupied thirty minutes. The pump was kept going during 
the grinding, and for an hour afterwards. In this way a quantity of gas, measur- 
ing 1-155 ¢.c. at the standard temperature and pressure, was collected. An analysis 
of this gas gave the following results :— 
Per Cent. 
OOne ax bs 0429 37-60 
OMe. ae 0049 4-29 
Ee age: ee 0049 429 
N, oh 600 oe 0:433 30°95 
Hes - oo ONG 15-87 
1:141 100-00 
It will be observed that the total of the gases determined is 0:014 ¢.c. less than 
the original volume. This I cannot account for, unless it is due to incomplete 
combustion of hydrogen. When the carbon dioxide, oxygen, and hydrogen had 
been removed, the excess of oxygen employed for the endiometric determination of 
hydrogen was removed by combustion with phosphorus, and the residual gas was 
found to measure 0°614 c.c. instead of 0°628, the difference between the sum of 
the gases determined and the original volume. This may be accounted for on 
the supposition that the combustion of hydrogen in the endiometer was incom- 
plete. 
On the removal of the gases, as above described, the apparatus was allowed to 
stand over-night. The pumping was then resumed, and at occasional intervals 
for six hours the apparatus was exhausted to the utmost limits with the Tépler 
pump. Gas came over in gradually diminishing quantity, and no doubt a further 
minute quantity of gas might have been collected had the operation been continued 
for some hours longer. 
The gas obtained in this second pumping measured 1°186 ¢.c., and gave the 
following results on analysis :— 
Per Cent. 
COFnEe ie 608 51-53 
ORF Mae te 024 203 
Hie ae og ~ 008 “68 
N, 000 oe ee O07 45°51 
He, ... oe e 003 25 
