66 NUCLEATION OF THE UNCONTAMINATED ATMOSPHERE. 



TABLE 39. Fog limits of fleeting nuclei. Cylindrical fog chamber, without casket. 



52 = o, but tested. 



TABLE 40. Fog limits of persistent nuclei. Bulb above. 



* Oblong corona. 



t Spindle or gourd-shaped corona. 



t After this, bulb (?) ceases to be efficient. 



Radium, 



X-rays, 



cm. 



25 

 o 



200 

 50 



IO 



5 



Foglimit=2o.4 

 (20.3) 

 20. i 

 20.3 



(20.1) 



(19-7) 

 19.6 



= 9AIO 



(14) 

 20 



16 



(24) 

 (33) 

 (36) 



~ 3 



A r (at S/= 



21 



IO 



18 

 10 



22 



44 



52 



55. Gradation of size of fleeting nuclei Fog limits. The preceding 

 observations, as well as the work of Chapter II, section 34, figure 34, 

 make it probable that the fog limit varies slowly but definitely with 

 the density of the iouization, while the rate, 8NJ8 (S/>), or slope of the 



