EFFICIENCY OF FOG CHAMBER. 



2 9 



saturation is about the same. This applies even in the following cases, 

 where dust-free air is energized by radium and by intense X-radiation, 

 as far as the middle regions of the curve are concerned. 



23. The same. Action of radium. The small increment of pressure 

 difference (say op = ig to 21) is here in sharp contrast to the gradual 

 increase observed in the old results (say between dp = 19 and 25). The 

 nucleations which eventually are not quite doubled in the new results, 

 as compared with the older, are therefore at first enormously in excess. 

 In fig. 20 the results of table 10 are given in full, the old results (table 7) 

 in broken lines, and the same method is pursued in the other cases. 



700 



600 



500 



400 



300 



BOO 



100 



18 ZO ZZ Z4 Z6 Z8 30 32 34 36 38 40 4Z 



Fig. 2i. Efficient nucleation (N) in dust-free air corresponding to fig. 19. Table 10. 



24. The same. Action of X=rays. Remarks to the same effect may 

 be made with reference to the old and the new data for X-ray ionization 

 when D = $o (broken and full lines in fig. 20). Initially the old curve 

 is even below the present curve for radium, but it eventually intersects 

 the new data for dust-free air at about dp = 35. The mean nucleations 

 have not been quite doubled. The maxima in cases of D = 50 and D = 1 2 

 lie above the interval of large variation for dust-free air. Finally, the 

 breaks in the curves at dp = 22 are again quite apparent. 



25. Remarks on the A=curves. With regard to the iV-curves, fig. 21, 

 one need merely note that the maxima have in most cases been defi- 

 nitely wiped out, and that the nucleation available for condensation, if 

 it be supposed that removal of nuclei is more rapid than the reproduction, 

 increases continually with the supersaturation up to the highest values. 



