82 Barus — Nuclei produced by Shaking Different Liquids. 



The curious result thus appears that the number of nuclei 

 produced by a definite amount of shaking is least for water, 

 about 5 times greater for dilute organic solutions in water, 

 about 10 times greater for dilute inorganic solutions in water, 

 and about 30 to 40 times greater for dilute solutions of non- 

 conductors like naphthalene and paraffine in benzol. It is diffi- 

 cult to even conjecture a reason for this behavior. 



2. Coronas in general. — The coronas in benzol for the same 

 pressure differences as above are all normal even if nucleation 

 from sulphur, phosphorus, etc., is introduced. From the slow 

 diffusion of the vapor they soon become distorted during suc- 

 cessive exhaustions unless the vessel is shaken between each. 

 It is interesting to show, however, that in spite of the normal 

 coronas, the high initial nucleation is fully accounted for. To 

 do this I shall select a series of observations for coronas in 

 benzol vapor at random (I. c, p. 56). Sulphur nuclei were 

 used and the vessel shaken between observations. The table 

 gives the results. 



Table II. — Coronas in benzol vapor, shaken between observations, dp = 

 18 cm ; n = ftm/ird* ; m = 33 x 10- 6 g per cm 3 ; d = -00144/s. 



Exhaustion ' 





dxlO 3 





dxlO 3 



n x 10~~ 3 



No. 





observed. 



cm. 





computed. 

 cm. 



computed. 







Fog 



without coronas 



•2 



6,800 



1 



a 



u 



u 



•3 



3,200 



2 . 



« 



it 



a 



•4 



1,400 



3 



(C 



a 



a 



•5 



610 



4 



u 



t( 



a 



•6 



270 



5 





•8 





•8 



120 



6 





1-0 





1-1 



52 



1 





1-3 





1-4 



23 



8 





1-8 





1-8 



10 



9 





2-6 





2-4 



4-4 



10 





3-7 





3-2 



1-9 



11 





4-2 





4*2 



•85 



. Computed exponentially the initial nucleation would run up 

 into the millions. The observations are not, however, in keep- 

 ing with such a locus and conform more closely to 1 = d(l/d Q — 

 2d /a) or s = s — az and ds = a. For present purposes this is 

 near enough. I shall, therefore, lay off the aperture s asa 

 linear function of the number of the exhaustion 2, for which 

 the observations show per unit of 2, in case of sulphur nuclei, 

 8s = '28 and in case of punk nuclei 8s = *19. The initial aper- 

 ture computed herefrom as the mean of six series in each of 

 which the nucleation was introduced independently, are for 

 sulphur, s — 3*4 and for punk s Q = 22. Hence n = 840,000 in 

 the former case and n — 230,000 in the latter. 



