OF THE COHESION OF FLUIDS. 337 



sive force would be obtained from the supposition that c 



is incomparably smaller than r, and this force would be 



1 ;r 1 



-r -TT r^R, or -^ of the repulsive force of a stratum of the 



interior part of the fluid of the thickness r; but in every 

 case that can actually occur, the superficial force must 

 probably be much less than this. 



Scholium. On the whole, we are fully justified in con- 

 cluding that, since the phenomena of capillary action neces- 

 sarily lead us to infer the existence of a superficial tension, 

 and since, without this supposition, we should be obliged 

 to admit the possibility of a perpetual source of motion, 

 from an unequal hydrostatic pressure, upon any floating 

 body not homogeneous ; the existence of such a cohesive 

 tension proves that the mean sphere of action of the re- 

 pulsive force is more extended than that of the cohesive : 

 a conclusion, which, though contrary to the tendency of 

 some other modes of viewing the subject, shows the abso- 

 lute insufficiency of all theories built upon the examination 

 of one kind of corpuscular force alone. It must also b© 

 recollected that, as far as our experiments enable us to 

 observe, the repulsive force of solids does actually extend 

 further than the cohesive, though, with respect to its 

 mean intensity, we have no direct method of ascertaining 

 the comparative extent of the spheres of action of the two 

 forces. 



