222 Barns — Ionization of Water and Phosphorus Nuclei. 



the first few centimeters of the condenser, or very near the 

 influx tube. A condenser was, therefore, constructed the 

 length of which could be varied by placing earthed tubes, 

 2r 9 =2'10 cm in diameter and of different lengths, I = 60,30, and 

 15 cm9 , around a fixed charged insulated core, 2/ , 1 = , 6i cm , con- 

 centrically with the usual precautions. 



Table II shows the results in which the insulation of the 

 condenser was determined before and after each measurement 

 with the nucleated medium. The condenser lengths 60 and 

 15 cm9 are inserted as a sufficient contrast. 



Table II. 



Effect of length of tubular condenser. dV/dt = l - 91iters/min. 



Leakage ds/dt 



Length 



Charge at 



Before 



During 

 nucleation. 



After 



Current 

 ixl0 n 



amperes. 



60 cm 



+ 80 volts 



•02 



•42 



•00 



1-07 



15 cm 



+ 80 volts 



•05 



•45 



•00 



1-12 



15 cm 



+ 80 volts 



•00 



•47 



•02 



1-20 



15 cm 



— 80 volts 



•03 



•26 



•00 



•62 



It is seen that the current is certainly quite as large, caeL 

 par., when the length of the tube condenser is 15 as when it is 

 60 cm . It is actually larger at 15 cms due to the gradual enlarge- 

 ment of the needle holes in the lead jet* whereby fresher nuclei 

 are" conveyed into the condenser. The current for positive and 

 for negative charges have the usual relation to each other. 



The experiments showed another interesting fact already 

 pointed out elsewhere, that the current, ds/dt, increases as the 

 water level in the receiver rises or as the discharge into the 

 condenser is fresher. One naturally inquires what the maxi- 

 mum charge of each nucleus would be if there were no con- 

 veyance tube. In the present installation this jet was unable 

 to charge the condenser, the charging current being less than 

 10~ 12 amperes, about of the same order as the leakage. 



One may conclude, therefore, that the loss of charge per 

 minute, i. e., the current radially traversing the condenser, is 

 practically independent of its length if the latter exceeds a few 

 centimeters, for the air current and width given. All but a 

 few per cent of the charge are lost in the first few centimeters 

 ahead of the influx tube of the condenser. The experiments 

 are thus in keeping with the surmize of Table I. 



7. /Summary. — In case of water nuclei it was found from 

 coincident electrical current graphs, TJl = *73, and if the con- 



* The fine holes clog with lead hydrate when the jet is left standing in a 

 damp atmosphere, and the obstruction is gradually removed by the friction 

 of the water. Old jets long unused, therefore, show small electrical currents 

 as compared with new jets. 



