64 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



Thus, with a correction for the external gamma radiation, the data for 

 e show reasonable values, in spite of the simplicity of the experiment. 

 It follows, therefore, even in the case of such large numbers of ions as 

 occur in these experiments (over 500,000), that the constants of coronas 

 used heretofore are substantially correct. In case of the last value 

 <?Xio 10 =2.5, for the small capacities of 17 cm., the aluminum leaves 

 on the electroscope converge too rapidly for measurement, so that the 

 air resistance may have produced an appreciable discrepancy. Hence 

 both i and e are too small. No refinement has been attempted in these 

 experiments, their chief purpose being to test the standardization of the 

 fog chamber in terms of coronas and the degree to which positive and 

 negative ions may be caught even at very high nucleation. One may note 

 in conclusion that the currents 2=77 electrostatic units or 2.6Xio 10 

 amperes are already quite within the reach of the sensitive galvanometer. 



