PLATEAU ON THE PII.ENOMEXA OF A FilEE LIQUID MASS. 585 



these devoted friends ? Thanks to their generous help, science 

 is still an open field for me : notwithstanding the infirmity with 

 which I am afflicted, I am able to put in order the materials I 

 have collected, and even to undertake fresh researches. 



Preliminary Considerations and Theoretical Principles. General 

 Condition to be satisfied by the free Surface of a Liquid Mass 

 withdraivn from the Action of Gravity, and in a state of 

 equilibrium. Liquid Sphere. 



1. iHE process described in the previous memoir enabled 

 us to destroy the action of gravity upon a liquid mass of con- 

 siderable volume, leaving the mass completely at liberty to 

 assume the figure assigned to it by the other forces to which 

 it is subject. This process consists essentially in introducing 

 a mass of oil into a mixture of water and alcohol, the density of 

 which is exactly equal to that of the oil employed. The mass 

 then remains suspended in the surrounding liquid, and behaves 

 as if withdrawn from gravity. By this means we have studied 

 a series of phaenomena of configuration, dependent either simply 

 upon the proper molecular attraction of the mass, or upon the 

 combination of this force with the centrifugal force. We shall 

 now abandon the latter force, and introduce another of a dif- 

 ferent kind, the molecular attraction exerted between liquids and 

 solids : in other words, we shall cause the liquid mass to adhere 

 to solid systems, and study the various forms assumed under 

 these circumstances by tliose portions of the surface which re- 

 main free. In this way we shall have the curious spectacle 

 presented by the figures of equilibrium appertaining to a liquid 

 mass, absolutely devoid of gravity and adlierent to a given solid 

 system. 



But the figures which we shall obtain present another kind of 

 interest. 1 he free portions of their surface belong, as we shall 

 show, to more extended figures, which may be conceived by the 

 imagination, and which, in the same condition of total absence 



VOL. V. PART XX. 2 K 



