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XXXVII. Experimental and Theoretical Researches on the Figures 

 of Equilibrium of a Liquid Mass devoid of Weight. — Fifth 

 Series * By M. J. Plateau f- 



New process for the production of figures in a state of equilibrium. 

 — -Pressure exerted by a liquid spherical film on the air which it 

 contains. — Investigation of the very small limit within which, in 

 a particular liquid, the value of radius of appreciable molecular 

 attraction varies. 



IN the Second and Fourth Series of this investigation 1 have 

 applied my process of the immersion of a mass of oil in a mix- 

 ture of water and alcohol to the production of some of the figures 

 in a state of equilibrium which pertain to a liquid mass, supposed 

 to be devoid of gravity and in a state of repose. This process, so 

 simple in principle, presents in practice certain difficulties, and 

 it required a certain cleverness to arrive at perfectly regular 

 results. In the present series, I shall point out a process 

 wholly different, far more simple and more convenient, and 

 entirely exempt from the inconveniences of the previously 

 described plan; I shall demonstrate afterwards some of the 

 numerous results which the employment of the new method has 

 furnished me, and the theoretical principles on which it rests. 



I may remark in the first place, that oil immersed in the 

 alcoholic mixture is easily converted into thin films; I shall 

 show, for example, that, with a number of precautions which I 

 describe, one can obtain, in the mixture in question, a hollow 

 bubble of oil more than 12 centimetres in diameter, by inflating 

 it with the same alcoholic mixture, just as one obtains in air a 

 soap-bubble filled with air itself. 



It must be remembered, with regard to these films of oil, 

 that in the experiment in my First Series where a ring of oil is 

 formed, this ring remains at first united to the central apparatus 

 by a thin film ; and starting with that fact, I shall show once 

 more the incorrectness of every deduction, derived from this 

 experiment, in favour of a cosmogonic hypothesis. 



After having thus established the facilities for the production 

 of liquid films removed from the action of gravity, I shall 

 demonstrate that the figures in a state of equilibrium which 

 appertain to the liquid films devoid of weight, are identically the 

 same as those of full liquid masses, likewise deprived of weight. 



* For the preceding Series see Taylor's Scientific Memoirs, Parts XIII. 

 and XXI ; and Phil. Mag. (S. 4), vol. xiv. p. 1, and vol. xvi. p. 23. 



f The original memoir will he found in the thirty-third volume of the 

 Memoires de I'Academie de Bruxelles. The abstract, of which a trans- 

 lation is here given, appeared in the Annates de Chimie et de Physique for 

 June 1861. 



