[RUTHERFORD ] THE NEW GAS FROM RADIUM 28 
ebonite stoppers. Two insulated brass rods a and 6, each half the length 
of the tube, passed througn the ebonite stoppers and were supported 
centrally in the tube. The cylinder was insulated and connected to one 
pole of a battery of 300 volts, the other pole of which was to earth. The 
central rods could be connected to a sensitive quadrant electrometer. 
The cylinder was covered with a thick layer of felt, and placed 
inside a metal box filled with cotton wool, in order to keep temperature 
conditions as steady as possible. 
In order to carry a sufficient quantity of emanation into the half 
cylinder A, it was necessary to slightly heat the radium. The slide S 
was closed and the side tubes opened. A slow current of dry air from a 
gas bag, passed through a platinum tube, in which a small quantity of 
aradium compound was placed. The emanation was carried with the 
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air into the cylinder A. When a sufficient quantity had been introduced, 
as tested by the electrometer, the current of air was stopped. The side 
tubes were closed by fine capillary tubes. These prevented any appreci- 
able loss of gas due to diffusion, but served to keep pressure of gas inside 
A at pressure of outside air. ‘The three entrance tubes into the cylinder, 
shown in the figure, were for the purpose of initially mixing the 
emanation and gas as uniformly as possible. 
After standing for several hours to make temperature conditions 
steady, the slide was opened, and the emanation began to diffuse into the 
tube B. 
The current through the tubes A and B was measured by an electro- 
meter, with suitable capacity in parallel, at regular intervals. Initially 
there is no current in B, but after the opening of the slide, the amount in 
A decreased and the amount in Z steadily increased. After several 
hours the amount in each half is nearly the same, showing that the 
emanation is nearly uniformly diffused throughout the cylinder. 
