120 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



70. Conclusion. When fog particles are precipitated upon solutional 

 nuclei, like those of phosphorus, the losses in successive identical ex- 

 haustions are due to the magnitude of this exhaustion, to subsidence, 

 and (in a small measure) to time losses or decay. 



On the other hand, when fog particles are precipitated on ions or 

 vapor nuclei, there is an additional and usually very large loss, accom- 

 panying the evaporation of the fog particles to water nuclei. Fully 50 

 to 80 per cent of the nuclei may be lost after the first evaporation. The 

 time between the evaporations is of little consequence. More nuclei are 

 lost for the cases of ions than for the cases of vapor nuclei, other things 

 being equal. All this is very well brought out by the figures. 



The loss decreases as the number of the exhaustion increases, or as 

 the number of nuclei present is smaller, or better, as their size is larger. 

 If, apart from subsidence, the nucleation n z of the zih identical ex- 

 haustion of ratio y be put 



x' x" 



the fractions x, x' ', x", etc., make an increasing series and may be called 

 the successive coefficients of survival characteristic of the sizes of fog 

 particles in each of the successive evaporations. The values of x increase 

 from about o . 2 for large and o . 5 for small ionization in the initial 

 evaporation to about o . 8 in the latter evaporations. For particles of like 

 size x is larger for vapor nuclei than for ions. The x values of the initial 

 evaporation distinctly increase with the respective size of particles in all 

 cases. 



