68 NUCLEATION OF THE UNCONTAMINATED ATMOSPHERE. 



which are always blurred and rainy, the probability of a curve doubly 

 inflected near the fog limit is apparent, particularly if mean values be 

 taken (curves 68). 



Radium at D = 200 and at D 100 cm. show data lying very nearly 

 in this curve, but the last observations of the series prove that the fog 

 limit is nevertheless definitely lower, or that the largest groups of 

 nuclei are appreciably larger than the largest nuclei in dust-free non- 

 energized air. 



TABLE 41. Fog limits of fleeting nuclei. Cylindrical fog chamber. s% = o, tested. 



* Radium 15 cm. from line of sight. 



-( Radium 5 cm. from line of sight. 



\ Growth from s = 3.3 to s = 3.8; radium 5 cm. from line of sight. 



Radium at D= 10 and at /} 25 cm. form a similar group with an 

 obviously much lower fog limit, and the case is accentuated for radium 

 at D = o cm. from the end, or 15 cm. and 5 cm. (on top) from the line 

 of sight. At this point the data for the X-rays with the anticathode at 



