centimetres per second.
In the experiments on the thorium emanation, on account of the rapid loss of activity, a slightly different method was necessary. The steady stream of gas was passed over the thorium compound, and the temperature was observed at the instant when an appreciable movement of the electrometer appeared. This gave the temperature at which a small fraction of the thorium emanation escaped condensation, and not the value T1 observed for the radium emanation, which gave the temperature for which a small fraction of the previously condensed emanation was volatilized.
The following table illustrates the results obtained.
| Current of Gas | Temperature | |
|---|---|---|
| Hydrogen | ·71 c.c. per sec. | -155° C. |
| “ | 1·38 „ „ | -159° C. |
| Oxygen | ·58 „ „ | -155° C. |
On comparing these results with the values obtained for the radium emanation, it will be