438 OF CAPILLARY ATTRACTION AND THE COHESION OF FLUIDS. 



causes them to approximate in a horizontal direction, the mass of fluid 

 having always the same effect as a heavy chain attached to the 

 plates. 



The same thing is true of two floating bodies, when they come 

 within such a distance that the fluid is elevated between them ; for 

 it is obvious that the bodies A and 

 B, being placed at a capillary 

 distance asunder, have the fluid 

 elevated between them, and are 

 therefore brought together by the 

 attractive influence of the fluid 

 upon the sides of the globules. 



558. (2.) If two bodies are not susceptible of being wetted by the 

 fluid, they will still approach each other when brought nearly into 

 contact, as if they were mutually attracted. 



For if the two floating bodies A and B, are not capable of being 

 wetted by the liquid, it will be 



depressed between them as at H, A. B 



below its natural level, when they 

 are placed at a capillary distance ; 

 hence it appears, that the two 

 bodies are more pressed inwards 



by the fluid which surrounds them, than they are pressed outwards 

 by the fluid between them, and in virtue of the difference between 

 these pressures, they mutually approach each other. 



559. (3.) If one of the two bodies is susceptible of being wetted by 

 the fluid, and the other not, they will recede from each other as if 

 they were mutually repelled. 



For if one of the bodies as A, is capable of being wetted, while the 

 other as B is not, the fluid will rise 

 round A and be depressed round B; 

 hence, the depression round B will 

 not be uniform, and therefore, the 

 body B, being placed as it were upon 

 an inclined plane, its equilibrium is destroyed, and it will move 

 towards that side where the pressure is least. 



These laws, deduced from experiment by M. Monge, have been 

 completely verified by the theory of capillary attraction as developed 

 by La Place ; from his theory it follows, that whatever be the nature 

 of the substances of which the floating bodies are made, the tendency 

 of each of them to a coincidence, is equal to the weight of a prism of 



