NUCLEATION CONSTANTS OF CORONAS. 49 



is available for computing the initial nucleation w , and hence all sub- 

 sequent nucleations, absolutely. Naturally a number of observations 

 n z and s z will be used for computing w and 5. The equation shows very 

 well how the constants n , S, a, m, are involved. 



From n z the diameter d g of the sth fog particle may then be computed 



d z = n- J/ l?/6m/7r (n) 



and similarly the 0th aperture s z will be, since dsa 



to be compared with the observed value of s z . It is clear that d and 5 

 will be independent of m, while n varies directly with it. Examples of 

 all these relations will be found in the following section. 



27. Data for moderate exhaustions. These data are given in tables 

 1 6 and 17. The drop of pressure is 17 cm. and the barometer unusually 

 high at 77.7 cm. Consequently the relative drop is dp 3 /p = o.2ig 

 and v l /v = i . 19, temperature 20 C. The symbols denote dp'=p p', 

 dps = P Ps< [$p2\ = P [Pz]> as explained in sections 25 and 26, where the 

 meaning of y, a, S, D, etc., will also be found. 



The first column shows the number z of the exhaustion, the second 

 and third the selected annuli of the coronas and their apertures s, meas- 

 ured to the outer edge of red or the first annuli. In the fourth column 

 n' = 6ms 3 /xa 3 , while the fifth shows successive values of n and their 

 mean. The sixth column gives the computed absolute nucleation, the 

 seventh the corresponding diameter of the fog particle, and the eighth 

 the computed aperture s. The data have been left as originally com- 

 puted, for their relations are chiefly of interest; but the value of 

 m = 3 . 2 X io~ 6 here used is too small and will be corrected in section 34. 



These data are shown graphically in figs. 12 and 13, the computed 

 values of s being taken as abscissas, the computed n as ordinates. To 

 admit the enormous range of the nucleation n the ordinates are appro- 

 priately changed in the scale of 10. The observed data are given in 

 the same diagram, but with a different designation for the points. 



28. Remarks on the tables and charts. One may observe at the 

 outset that the initial nucleation n is about the same in both cases, 

 being n = 5. 100,000 and 4,010,000 smaller in the second. The same 

 order of values will be found for the nucleations n in very different orders 

 of exhaustions in the succeeding tables. 



The following values of 5 were computed as shown in equation 9 

 from the data of tables 1 6 and 1 7 : 





\ 



lui ^ Y i 



I 



