WATER NUCLEI. 



8l 



In table 29 the effect of different drops of pressure (dp) is investigated 

 for low exhaustions and smaller coronas and there is scarcely any 

 periodicity. As the exhaustion is higher, periodicity in the size of 

 successive coronas is correspondingly marked. The data give an esti- 

 mate as to the degree in which periods are to be guarded against. 



In table 30 experiments similar to the preceding are made with 

 ionized air. It will be seen that the periodicity is in every case just as 

 marked as before. In the absence of evaporation (closed filter cock) 

 the successive coronas are equal. Precipitation at a low drop (dp) of 

 pressure is followed by a relatively large corona at a higher drop of 

 pressure, as the water nuclei have been removed in the former. 



Table 30. Periodicity of ionized air. X-rays; D=50 cm. Filter cock permanently 

 just open. Exhaust cock 2^"; dp = 23 cm. below fog limit of dust-free air. 



Exp. No. 



1 

 2 

 3 



4 

 5 

 6 



7 



s. 



Cor. I n Xio~ 3 . 



10.5 



6-3 

 9.6 

 5-o 

 10.4 

 5-6 

 9.2 



wrg 

 cor 



wcg 

 cor 



wrg 

 cor 



wcg 



210 



75 

 200 



4i 

 210 



58 

 190 



Filter cock closed during exhaustion 

 and subsidence. 



s 



'9-3 



wcg 



190 



Dust-free air not energized; dp** 31; 

 repetitions without waiting Dec. 13; 

 internal evolution of nuclei has ceased. 



"5 

 "5 



wyg 

 wyg 



335 

 335 



Dust -free air not energized; dp =36 cm. 



13-5 

 13-5 



P 

 P 



480 

 480 



Evap. nuclei precipitated at dp =23.2 

 cm. and then tested at dp =31. 



1 

 2 



3 



8 



o 



410 



1 No difference between 7 and 8. 2 Corona enlarged by the preceding precipitation. 



Some interesting questions present themselves in connection with 

 this work. Are the nuclei holding positive ions different from those 



