62 On Figures of Equilibrium of a Liquid Mass. 



(Taylor's Scientific Memoirs, part xiii. p, 16) M. Plateau 

 described a simple process, by means of which he succeeded 

 in completely neutralizing the action of gravity upon a liquid 

 mass of considerable volume, at the same time leaving this 

 mass perfectly free to obey the molecular forces. If, therefore, 

 as in the case of ordinary capillary phBenomena, the attrac- 

 tion of a solid system is interposed, the form which the free 

 surface of the mass will assume will be identically the same as 

 if the liquiil had been in reality deprived of all gravity. But 

 then the equation relative to the surfaces of equilibrium is 

 reduced to a very simple form, which allows, in several cases, 

 of omitting the integration, and, on the other hand, nothing 

 any longer limits the extent which may be given to surfaces, 

 so that the results of experiment are susceptible of exact 

 admeasurements. We are thus able to submit the theory 

 to numerous and perfect verifications. This is one of the 

 objects which M. Plateau proposed to himself in his re- 

 searches, starting from the second series now laid before the 

 Academy. 



But his ingenious experiments, besides the support they 

 give to the theory of capillary action, have another kind of 

 interest, in so far as they exhibit the curious spectacle of 

 figures of equilibrium suitable to a liquid deprived of gravity ; 

 the theoretical and experimental study of these figures forms 

 a second object of research. The equation representing 

 these figures shows at once that the sphere, the plane, and 

 the cylinder must be found among them ; now, the author 

 has shown, in his preceding memoir, that when the liquid 

 mass of his experiments is not adherent to any solid system, 

 it always assumes precisely the spherical form. With respect 

 to plane and cylindrical surfaces, as they are from their na- 

 ture indefinitely extended, the first in all directions, and the 

 second in the direction of its axis, it is evident that they can- 

 not be assumed by a finite and entirely free mass; but the 

 author obtains portions of them by causing the liquid mass to 

 adhere to suitable solid systems. 



The results at which he arrives on this subject lead him to 

 realize polyhedrons entirely liquid, with the exception of their 

 angles, which are formed of thin iron wires. He produces 

 the cylinder by attaching the liquid mass to two rings of iron 

 wire placed parallel one to the other. 



The observation of certain peculiar facts relative to these 

 liquid figures leads the author to several important conse- 

 quences, among which we may mention the indication of a 

 mode of experiment which would perhaps allow of arriving at 

 the determination of a limit above which must be found the 



