26 



A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



vanished; nevertheless there is still an excess of negative nuclei, as shown by the 

 greater leakage of positive charges in the condenser. If negative nuclei had been 

 more rapidly precipitated in the intervening hour in A , the reverse should have 

 been the case; there should have been an excess of positive nuclei, and negative 

 charges in the condenser should vanish more rapidly. 



Tested for coronas, even after about one hour, 50,000 were left, or over 

 ^ of the original io 5 to 2Xio 5 , a result quite out of proportion with the loss 

 of ionization. The electrical and the condensational phenomena are thus 

 distinctly separated. 



1 1 . Results with an Elliott electrometer. For reasons which need not be 

 stated, the electrorreter of modern type in which the charge is imparted to the 

 needle through the suspension, notwithstanding its sensitiveness and low capa- 

 city, was not adapted for further experiments. Accordingly, the data of the 

 following table were obtained with an ordinary electrometer, with the quad- 

 rants permanently charged with a water battery. The core of the tubular 

 condenser communicated with the needle. This adjustment was chosen be- 

 cause the leakage here was relatively smaller, though the high capacity of needle, 

 jar, and condenser is unfavorable to sensitiveness. The table contains results in 

 which the potential of the core of the condenser was altered in steps of one half. 

 Care was taken to determine the insulation immediately before and after each 

 measurement with the nucleated medium. The leakage is seen to be always 

 greater at the beginning than at the end, which is the usual phenomenon of 

 absorption and release of charge in the insulators. If any trace of radioactivity 

 occurred it would be obscured by this phenomenon. 



The results of this table may be summarized. 



TABLE 8. CHARGES OF WATER NUCLEI. dV/dt=2 LIT./MIN. 

 DEFLECTION OF THE ELECTROMETER, 5. 



CAPACITY 409 cm. 



The ionization here is somewhat greater than the preceding, but the differ- 

 ence is at once! referable to the gradually increasing size of the holes in the lead 

 jet as the result of long spraying. Slight changes in V lit./min. are now of 

 importance because of the rapid loss of the charges in the influx tube of the 

 condenser. 



