96 VAPOR NUCLEI AND IONS. 



value is quite ignored; but the constant probably reproduces the true 

 conditions better than the observation, remembering that the initial 

 corona (t o) is not quite invariable. 



A very important consequence may be deduced from these results. 

 The equations specified may be written 



Hence if the ratio of nucleations or of ions is known (for instance by the 

 method of geometric sequences), n /n is given, and the absolute value 

 of n may be computed if 6 is known. Now, if 6, for the case of ions, 

 may be taken as identical with the value found in electrical experiments, 

 where 6 = 0.0014, roughly and relative to ionization in thousands, bn = 

 0.0014 n\ where n\ is the true nucleation. Thus in table 39,6 = 0.0024, 

 ^,, = 67, 500; therefore n' = (0.0024/0.0014) n or 115,000 nuclei per cubic 

 centimeter. Quite generally, if n /n and 6 are determined from purely 

 coronal measurements 6/0.0014 is the reduction factor for all the rela- 

 tive nucleations to absolute values. 



Another very important consequence may be drawn. If the coeffi- 

 cient is known from direct experiments, it will then be possible to 

 standardize the residual curve (depressed asymptote) leading to the 

 terminal corona. Thus if 6 = 0.0024 is roughly assumed, as an example 

 derived from the data at dp = 24 cm. (table 37 and fig. 47), the value 

 of the ordinates of the curve for dp ^i would then be given by table 

 39 and fig. 49. 



Moreover, in any such curve, while the ordinates denote the computed 

 number of ions, the abscissas denote the observed number of efficient 

 colloidal nuclei and ions in the course of time, largely the former. Hence 

 the curve gives an indication of the distribution of the precipitated 

 water on the two groups of nuclei, different in size and present in different 

 proportions, for the given supersaturation. Experiments of this kind are 

 of the highest importance and the present cursory treatment is admitted 

 provisionally, in view of a projected restandardization of the coronas of 

 cloudy condensation, which the variety of results since obtained has 

 made necessary. The curve for 6 = 0.0024 is shown in fig, 48; the two 

 curves* i and n + i, i and n, in fig. 50. The initial descent of the graph 

 for i and n is clearly steeper than would correspond to any exponential 

 or hyperbola, and an equation of the form 



i {n + A) B = C 

 is at least needed to express the data. The computation of the constants 



Where i denotes the number of ions, n the number of nuclei per cubic centimeter. 



