STANDARDIZATION OF FOG CHAMBER. 



The last observation being made without an auxiliary condenser. The 

 current i was quite constant throughout the voltage interval (near 250 

 volts) of observation. Hence the effect of gamma-ray penetration has 

 seriously increased the leakage, and e therefore appears too large, except 

 in the last observation, where i is probably no longer measureable. 



53. Further data. In the following experiments the effect of the 

 external gamma rays was eliminated as specified in section 49. The con- 

 duction current was usually quite negligible. The nucleations observed 

 in the exhausted fog chamber were n = 82,000 and N' = 506,000, when 

 the core was charged and uncharged, respectively. The exhaustion was 

 again equivalent to a volume increase of v 1 /v=i.2g. Hence in the fog 

 chamber full of air the respective nucleations are ./V = 653,000 and n = 

 106,000, whence A r2 n 2 = 4i$X io 9 . The drop of pressure dp/p = o.$o 

 was about the same as before. 



TABLE 22. Fall of potential and currents. V in the presence of radium; V" due to 

 f rays; V leakage due to conduction; 4-sec. intervals. Wires in earthed pipes. 



The electrical measurements, if all data are given in electrostatic units, 

 may be summarized from the data in table 22, as follows: 



