138 Prof. E. Rutherford on Uranium Radiation and 



emitted by the uranium was not completely absorbed at 

 atmospheric pressure, so that the total ionization is pro- 

 bably larger than the value given in the table. 



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Assuming that there is the same energy of radiation 

 emitted whatever the gas surrounding the uranium and that 

 the radiation is almost completely absorbed in the gas, we 

 see that there is approximately the same amount of ionization 

 in all the gases for the same absorption of energy. This is a 

 very interesting result, as it affords us some information on 

 the subject of the relative amounts of energy required to 

 produce ionization in different gases. In whatever process 

 ionization may consist there is energy absorbed, and the 

 energy required to produce a separation of the same quantity 

 of electricity (which is carried by the ions of the gas) is 

 approximately the same in all the gases tried. 



From the results we have just given, it will be seen how 

 indefinite it is to speak of the conductivity of a gas produced 

 by uranium radiation. The ratio of the conductivities for 

 different gases will depend very largely on the distance 

 apart of the electrodes between which the rate of leak is 

 observed. When the distance between the electrodes (<?. g. 

 two parallel plates) is small, the rate of leak is greater in 



