32 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



The astonishing feature of these data is the occurrence of linear loci 

 for 5 and z nearly throughout the extent of the curves. It is as difficult 

 to even conjecture a reason for this as it is easy to find reasons against 

 it. The presumptive equation for 5 is 



and for n z if r. denotes the product 



"z = u 



Hence _^ 



s = 0.004 O" /6w) 1/3 (/ 77) 1/3 



If we disregard the subsidence correction / / for large coronas 



ds/dz OC/ /3 



in which there is no suggestion of a sustained constancy of the coefficient 

 ds/dz such as the experiments show. 



To come to some conclusion as to the cause of the discrepancy between 

 the optic value of the nucleation n' and the presumable value n (geo- 

 metric progression), we may, as in table 12, compare the successive value 

 n 'z+i/ n 'z = s z+i 3 / s z 3 m their relation 10^ = 0.771, the exhaustion applied. 

 The table shows that for very large coronas n' z+l /n'g>y, whereas for 

 VITV small coronas n' z+l jn' z <y. For the intermediate coronas (g 3 ), 

 i. e., from the seventh to the tenth exhaustion among twenty, the ratio 

 is nearly equal to y. Ratios smaller than y may be reasonably inter- 

 preted as due to subsidence and the subsidence constant S is actually of 

 the order of values to be computed from the viscosity of the medium 

 and the size of the vessels and fog particles. Within this range (coronas 

 smaller than g a ) the optic and the presumptive nucleation may in fact 

 be brought into agreement. 



In case of the large coronas, however, subsidence is virtually absent 

 and the occurrence of n' z+l /n' z >y calls for some apparent production of 

 nuclei at each exhaustion, which is naturally altogether improbable. In 

 table 12 I have therefore additionally inserted n' and n n' , the latter 

 showing the number of nuclei not registered by condensation. 



For, no matter whether condensation on a given group of nuclei occurs 

 or not, no matter how many nuclei have failed of catching a charge of 

 water, the removal of nuclei by partial exhaustion must take place in the 

 same way. Such removal is independent of condensation and would 

 occur in a dry atmosphere under similar treatment. Consequently y can 

 not be too large. It may be too small not only from subsidence, but from 

 time losses (decay) or as the result of the purification of air due to turbu- 

 lent motion across a solid or liquid surface. Consequently n may be 

 regarded as an inferior limit of the nucleation with a probably close 



