﻿On Opalescence of Gases in the Critical State, 1.65 



(3) Repulsion. 



It Las been noted in figs. 6, 7, 9 c, 10 a, and 10 b that 

 scattering takes place in the stream, in one case (9 c) rather 

 suddenly. This must be due to the repulsion between the 

 drops. Two choices offer themselves. The drops may be 

 during their whole journey at distances for which the force 

 acting between them is repulsive ; but on account of the 

 velocity with which they leave the nozzle they travel a cer- 

 tain distance in the aligned stream before the repulsive forces 

 due to their neighbours are strong enough to cause divergence 



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from the path which they would traverse under gravity. 

 This view seems to be favoured by the phenomena observable 

 in figs. 6 and 7; the scattering becomes apparent much more 

 quickly at high voltages than at low. 



As was pointed out above, it is possible that in the case of 

 higher voltages we have the coalescence of the drops due to 

 attractions, the formation of large drops which are unstable 

 under such large electrical forces and consequently break 

 into smaller drops. This view seems to be favoured by the 

 abundance of small, almost uniformly sized drops (fig. 10 b) 

 at the point of greatest scattering of the stream charged by 

 the inductor at 720 volts (fig. 6). 



We desire to express our thanks to Professor J. C. 

 McLennan whose lectures on Properties of Matter first 

 suggested the problem, and who has cooperated, as always, 

 by placing the resources of the laboratory for our use as 

 necessity arose. 



University of Toronto, 



Department of Physics, 

 August, 19 LI. 



XIII. On Opalescence of Gases in the Critical State. By 

 M. S. Smoluchowski, Ph.D., LL.D. (Glasgow), Professor 

 of Theoretical Physics, University of Lemberg*. 



THE number for November 1910 of this Magazine con- 

 tains an account of F. B. Young's careful experimental 

 investigation " On the Critical Phenomena of Ether," in- 

 cluding some valuable observations on the critical opalescent 

 phenomena, and a discussion of the various theoretical ex- 

 planations hitherto suggested. Its author appears, however, 

 to have overlooked a kinetic theory of opalescence which I 

 expounded in a paper published in 1907 f, and which h;is 



* Communicated by the Author. 



f Bulletin Intern. Acad. Cracociej Doc. 1907; Ann. d. P'r/s. xxv. 

 p. -205 (1908). 



