130 Prof. E. Rutherford on Uranium Radiation and 



investigated the subject, and came to the conclusion that in 

 some cases the rate of leak varied as the pressure, and in 

 others as the square root of the pressure, according to the 

 voltage employed. Their tabulated results, however, do not 

 show any close agreement with either law, and in fact, as I 

 hope to show later, the relation between the rate of leak and 

 the pressure is a very variable one, depending to a large 

 extent on the distances between the uranium and the sur- 



Fig. 5. 



rounding conductors, as well as on the gas employed. The 

 subject is greatly complicated by the rapid absorption of the 

 radiation by gases, but all the results obtained may be inter- 

 preted on the assumption that the rate of production of ions 

 at any point varies directly as the intensity of the radiation 

 and the pressure of the gas. 



To determine the effects of pressure, an apparatus similar 

 to fig. 3 was used, with the difference that the plate _ A was 

 removed. The uranium compound was spread uniformly 

 over the central part of the lower plate. The movable 

 plate ? which was connected with the electrometer, was 10 cm, 



