A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



27 



Whereas the current for positive charges decreases with the potential, the 

 current for negative charges increases ; but this, too, is due to incidental reasons 

 of the kind mentioned. Seen in the light of the results preceding and following 

 it, the general evidence of the table is rather to the effect that the current in 

 the condenser is constant, independent of the electromotive force when the 

 gradient exceeds about 20 volts per radial centimeter. 



7- 



These results are given in the chart. 



figure 



ni6"aMip. 



-\-dhargt. 



^ 



—Cihargt 







volt ~10 20 30 40 50 60 70 80 90 



nw'cmp.. 



-8- 



—Charge^ 



OVOU 10 20 SO 40 50 60 70 BO ^0 



Figures 7, 8. — Curves Showing Radial Currents (Amperes) for Different Charges and 

 Potentials (Volts) in the Condenser. 



12. Further data. — A series of results quite similar to the last, but with a 

 more sensitive electrometer, is given in the next table. As a rule, positive 

 charges were taken in succession, though a number of incidental data accom- 

 pany the table. The insulation of the electrometer was found before and after 

 each measurement with nuclei. Having been taken on different days and not 

 in a single sweep, the results cannot be quite coincident, because of jet differ- 

 ences, water pressures, etc., as already stated. 



These results are summarized. 



The currents are given in the chart marked figure 8. They show that 

 above lo volts the cuiTents are practically constant, remembering that any 

 change in V due to water pressure, etc., will convey the nuclei more rapidly into 

 the condenser, and from their exceedingly rapid decay at the outset the currents 

 will necessarily be variable. Below lo volts the current decreases with the 

 potential, but remains quite appreciable even when the potential is zero with 

 the absence of charge in the condenser. The two observations made for the 

 negative charge indicate similar relations, when taken in connection with the 

 preceding results. 



