NUCLEI OF PURE WATER. 



i per cent, showing that almost all nuclei have vanished in the first 

 evaporation of the corresponding fog particles. The curves Nos. 4 and 5, 

 fig. i , give these results on a scale ten times larger than the preceding, to 

 bring out the small values n' /n, which would vanish on the scale adopted 

 for the solutional nuclei. For reasons which do not clearly appear, the 

 data in series 4 are larger than corresponding results in series 5, possibly 



TABLE 3. Persistence of water nuclei when fogs are precipitated on vapor nuclei. 

 Glass fog chamber. <J/> 3 = 32 for vapor nuclei; <J/> S = 22 or 23 for water nuclei. Lower 

 dp = 22 or 23 is above fog limit, but vapor nuclei are inactive. 



*Long waiting (3O m )for2- tNo waiting ( i ra ) for s t . 



because the exhaustion in the former case was above the fog limit of dust- 

 free air and would therefore catch the smaller order of water nuclei than 

 occur in series 5. These water nuclei, in fact, are reduced appreciably in 

 number in the lapse of time, as will be seen by comparing the two experi- 

 ments for w = 320,000 nuclei in series 5. The following exhibit may be 

 regarded as a smoothed curve for about the same period of dissipation. 

 The curves rise for smaller nucleation; the exhaustion loss is 0.23. 



