112 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



tional nuclei obtained with phosphorus emanation. It is thus necessary 

 to examine in detail the three more obvious causes for the decrease in 

 nuclei, which are as follows: (i) The exhaustions, applied alike in all 

 cases; (2) the subsidence of fog particles during the short time of their 

 suspension, i. e., between the exhaustion and the evaporation by influx of 

 air; (3) the occurrence of electrical charge in the case of ionized nuclei, 

 whereby the charged water nuclei may be brought to coalescence. 



Probably the best method of reaching a numerical result will consist 

 in eliminating the effect of exhaustion and subsidence, as was done above 

 for phosphorus nuclei, thus leaving the new losses of nuclei alone out- 

 standing. If 



where y is the exhaustion ratio and the product n(i S/s 2 z _ 1 ), the 

 correction for subsidence, the data marked n' calculated in the table may 

 be obtained. They are such as apply for solutional nuclei produced by 

 phosphorus, but they are throughout enormously in excess of the values 

 n observed for vapor nuclei and for ions. If we suppose that there is a 

 second cause of dissipation with each exhaustion we may therefore write 

 (abbreviating the products n) 



n' z = n 1 y z - 1 x z ~ l U 



merely to get a numerical statement of the case. The values of the frac- 

 tion or coefficient of survival x so found show a gradual increase of value 

 as the numbers of exhaustions increase or the nucleations decrease, indi- 

 cating that the greatest dissipation of nuclei is during the first exhaustion. 

 If these values of x, as summarized in table 48, be constructed in 

 terms of n, they show that x is considerably in excess for vapor nuclei 

 as compared with ions. Thus, at an average (n l + n 2 )/2, very roughly, 



-ii ?= 100,000 vapor nuclei ions, < 



= 50,000 vapor nuclei ions, { x ~ 



I -45 



= 10,000 vapor nuclei ions, < 



results which are too irregular for further comparison. 



A simple term like (n' n)jn is preferable in other respects, and in 

 order to put the larger and more certain data on the diagram, (' n)/n 

 may be constructed in terms of i/n. If it w r ere a question of time loss 

 merely, some further theoretical progress might be made, but the results 

 are not sufficiently smooth to give much assistance here. Hence in fig. 

 35- ( n ' n)/n is shown in terms of io e /w, both for ions and for vapor 

 nuclei. In both cases the curves rise higher as the parameter n is greater. 

 The initial ascent is not very different for ions and for vapor nuclei. 

 The dissipations up to (or due to) the first exhaustion are similar in 

 amount. But thereafter the curves for ions rise more rapidly than the 



