CAPILLAR Y A TTRACTION. 



portance in the molecular theory : The tension 

 of the film, which is sensibly constant when the 

 thickness exceeds fifty micro-millimetres, diminishes 

 to a minimum, and begins to increase again when 

 the thickness is diminished to ten micro-millimetres. 

 It seems not possible to explain this fact by 

 any imaginable law of force between the different 

 portions of the film supposed homogeneous, and we 

 are forced to the conclusion that it depends upon 

 molecular heterogeneousness. When the homo- 

 geneous molar theory is thus disproved by ob- 

 servation, and its assumption of a law of attraction 

 augmenting more rapidly than according to the 

 Newtonian law when the distance becomes less 

 than fifty micro-millimetres is proved to be in- 

 sufficient, may we not go farther and say that it 

 is unnecessary to assume any deviation from the 

 Newtonian law of force varying inversely as the 

 square of the distance, continuously from the 

 millionth of a micro-millimetre to the distance of 

 the remotest star or remotest piece of matter in 

 the universe ; and, until we see how gravity itself 

 is to be explained, as Newton and Faraday thought 



