on Nuclei produced hy Shaking Solutions. 269- 



solutions may be considered as subject to this condition, in 

 which all sizes o£ particles are represented. I£ r*==co y 

 p / oo =p ao , the vapour-pressure at the flat surface. 



Neglecting the factor for electrolytes, if 8p is expressed in 

 terms of Raoult's law, n/N and n/N 1 being the original and 

 final ratios respectively, of the numbers of molecules in 

 solute and solvent, and p the vapour-pressure at the flat 

 surface of the reservoir of solution, 



8p=p(n/N'~n/N)'/(l + n/N') . 



Furthermore, if the law discovered empirically by Quincke* 

 (T = 83 + 187 n/N dynes) be adduced, 



T'=tT + 187(k/N'-72/N) 



where T is the initial and T' the final surface-tension in 

 dynes per centim. 



' Thus, finally, if (n/N' -n/N) = k, for brevity, 



n r =2*{T+lSlk)(l + n/N f )/p.(l+(p-l)c)k. 



Supposing the electrolytic factor supplied, this equation ex- 

 presses the relation of the radius of the droplets in terms of 

 the original and final ratios of the numbers of molecules of 

 solute and solvent in solution. It implies that if the nuclei 

 produced by shaking are originally of different sizes this 

 difference will be accentuated. There is thus a curious dis- 

 crepancy between equation and observation; coronas pro- 

 duced from nuclei due to shaking are always annular on first 

 exhaustion, whatever be the vapour or however long the 

 lapse of time. They eventually vanish annularly, in case of 

 the most volatile hydrocarbon liquid. This can only occur if 

 the shaken nuclei are of about the same size originally, which, 

 in fact, is approximately seen on trial. A reason for it r 

 however, seems difficult to discern. The fact that mere 

 agitation f of the liquid should leave nuclei in its wake so 

 nearly of a size as to produce coronas at all is the essential 

 question. 



Brown University, Providence, R.I., U.S.A 



* Winkelmann's Handhtch, vol. i. p. 466 (Breslau, 1891). An ex- 

 cellent account of the capillary coefficients of solutions will here be found, 

 due to Prof. F. Braun. 



f Lenard's experiments (Wied. Ann. xlvi. p. 584, 1892) on the 

 electricity of waterfalls might be recalled. 



