10 POPULAR LECTURES AND ADDRESSES. 



it must be explained, by some continuous action 

 of intervening or surrounding matter, may we not 

 be temporarily satisfied to explain capillary attrac- 

 tion merely as Newtonian attraction intensified 

 in virtue of intensely dense molecules movable 

 among one another, of which the aggregate con- 

 stitutes a mass of liquid or solid. 



But now for the present, and for the rest of 

 this evening, let us dismiss all idea of molecular 

 theory, and think of the molar theory pure and 

 simple, of Laplace and Gauss ; returning to our 

 two pieces of rigidified water left at a distance 

 of 250 micro-millimetres from one another. Hold- 

 ing them in my two hands, I let them come 

 nearer and nearer until they touch all along the 

 surfaces A and B. They begin to attract one 

 another with a force which may be scarcely 

 sensible to my hands when their distance apart 

 is fifty micro-millimetres, or even as little as ten 

 micro-millimetres ; but which certainly becomes 

 sensible when the distance becomes one micro- 

 millimetre, or the fraction of a micro-millimetre ; 

 and enormous, hundreds or thousands of kilo- 



