EQUATION AND THE NATURE OE COHESION. 73 



Cohesive mass and gravitational mass ave thns of the same nature; 

 each is magnetic in nature; but the cohesive mass is far greater 

 than the gravitational, for the gravitational, which* is the effect of 

 the atomic nucleus, is reinforced bv the action of the valence elec- 

 trons. These relatively great cohesional masses of the molecules 

 cannot be perceived at more than molecular distances, perhaps 

 because the effect added by the valences is absorbed either by the 

 ether or by the surrounding molecules. Possibly we shall have in 

 the future a table of cohesional weights of the elements comparable 

 with the gravitational weights. These cohesional weights will give 

 us perhaps a periodic table of the elements which will be no less, 

 interesting than the usual periodic table. Van der Waals' equation 

 is the scales of molecular dimensions by which we may weigh the 

 molecules and determine their real or cohesive mass and not simply 

 that part of the mass which is able to penetrate matter and space. 



I have sought to find in the laws of attraction of magnets some- 

 thing which would be similar to the law of attraction of molecules. 

 The only relationship of this kind which I have been able thus far 

 to find is the law correlating the weight which a horse-shoe magnet 

 will support and the mass of the magnet. The relationship exists 

 in this case that W, the weight supported, is proportional to the 

 two-thirds power of the mass of the magnet, or TV = aM~ lz . From 

 this it would appear, since they act also proportionaly to the two- 

 thirds power of their masses, that the molecules behave like little 

 magnets, as has been suggested by Sutherland. Here we have the 

 two-thirds power of the mass just as in the molecules we have 

 the two-thirds power of the molecular weight. The valence in the 

 different horse-shoe magnets of iron will, I suppose, remain constant. 



VII. THE RELATION OF COHESION TO CHEMICAL 



AFFINITY. 



The cohesion of molecules is thus shown to be electro-magnetic 

 and magnetism is probably cohesion. If we now go within the 

 molecule, do these same forces exist? Is what we call chemical 

 affinity simply the cohesion of the atoms, and has it in it the 

 same factors as those of molecular cohesion? Is chemical affinity 

 electro-magnetic also, and not electrostatic as it has so long been 

 supposed to be? Is the suggestion of Sutherland correct that what 

 we call cohesion is simply the chemical attraction extending a short 

 distance from the molecule? Or if we turn it about, is the cohe- 



