produced in Gases by Rontgen Bays §c. 



423 



to the presence of the uranium was being observed. For 

 higher voltages the zinc was first brought to the voltage 

 given in the table and then disconnected and left to itself. 



w 



Voltage Leakage per minute 



6 m sc. divs. 



2 92 



4 100 



22 120 



92 129 



132 138 



200 130 



300 137 



415 136 



[Sensibility of electrometer 140 sc. divs. per volt.] 



The appended curves (fig. 4) were drawn by taking the 

 leakage per minute as ordinate, the voltage as abscissa. 

 Curve (a) represents the results of the first series of experi- 





Fig. 4. 





— Y~~~~~~7^-j ' 



; 'j- - ,.'; /.. 





A 





/ 





V/^: 



w\ 



1 





I 





ments (a) reduced to voltages per 2 millim. between the 

 outside coatings of A. Curve (b) gives tbe results of the 

 second series of experiments (6). It will be seen that with 

 uranium, as with Rontgen rays, the leakage through air is 

 not proportional to the E.M.F. We found also that both 

 positive and negative charges leaked away at the same rate. 



