26 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



Turning specifically to parts I and II, in which the goniometer is in 

 front of the fog chamber, it will be noticed that in series I a two-minute 

 interval between exhaustions has been (exceptionally) introduced. The 

 result is not good ; for, as fig. 4 shows, there is a sudden break of the curve 

 after the seventh exhaustion, probably due to time losses in the extra 

 minutes. The reason, however, is by no means obvious. In series II, 

 for i -minute intervals, there is no break and the locus passing through 

 the points for green disks (the others, not marked g, are to be disregarded) 

 is persistently straight throughout. The curves show for series I, ds/dz = 

 i. oo, green points only, and for series II, ds/dz = 0.80, suggesting a time 

 loss in the first case. Compared with table 9, the values of ds/dz should 

 be in the ratio of red and green minima, or 



dSfjdz : ds g /dz = o.g$ : 0.80 correspond to ^1^ = 63. 0/54. 6 

 The last ratio, 1.15, is somewhat short of the former, 1.19. 

 In series III and IV the pins of the goniometer are behind the fog 

 chamber, the eye being at the front wall. In series III the relation 



5' = 2 . 30+1. 15(19-2) 

 is remarkably well sustained throughout, and in series IV 



S'=2. 50+1. 13(18-2) 



gives a good account of the green coronas, if the dull cases are ignored. 

 The most interesting results are given in parts V and VI of table 1 1 

 and fig. 6, and the computations have been fully carried out. In these 

 cases the chords on a radius of 30 cm. of the edge of the green disk s', 

 and the inner edge of the first green ring s", were successively observed. 

 Fig. 6 contains both pairs of curves and their linear character is again 

 astonishing. We may write 



PartV: s' -= 2.0+ 1.10(19 2) $" = 3. 4+ 1.21(19 2) 



5 = 0.59+1.065'== 0.56 + 0. 965" 



Part VI: 5'= 2.0+ 1.13(18-2) $" = 3.3+1.30(18-2) 



5 = 0.50+1.075'= -0.44 + 0.935" 



where the minimum is located midway between 5' and 5", both of which 

 are fairly well demarcated. 



From both series the mean value 



5 = 0.55+1.06 5'= 0.50 + 0.93 5" 



may be derived for the general reductions in this and other cases where 

 5' is observed. 



With the given value for 5, the optical data for the diameters of the 

 particles, d' 0.004/5, and for the nucleation, w'= 120 5 3 were computed. 



The subsidence constant 



was obtained from the observations between 2=13 and 2=19 and a mean 

 datum, 5=i2, accepted as most satisfactory. It is, then, possible to 

 compute n , the original nucleation, as 



