70 Prof. W. M. Thornton on the 



That chemical affinity in its simplest form is proportional 

 to the product of combining masses does not necessarily 

 identify cohesion and gravitation, though it makes such a 

 relation possible. The difficulty in establishing it in liquids 

 or solids would be to find an expression for, or an experi- 

 mental means of observing, the action of surrounding mass. 

 By analogy with its known influence in electro-optical 

 phenomena*, it might be expected that this effect would 

 be to dilute affinity without changing the ultimate law; but 

 the coefficient of dilution would certainly not be constant. 



Y. The Curves of the Periodic Law. By Prof. W. M. 

 Thornton, D.Sc, D.Eng., Professor of Electrical Engi- 

 neering in Armstrong College, Newcastle-on-Tyne\ . 



1. /~\N the disintegration theory of matter atomic structure 

 \ f is modified by the loss of electrons in a regular 

 sequence, from positions of maximum atomic volume to those 

 of maximum density. The periodic curves of density and 

 atomic volume both have the inflexion characteristic of 

 hysteresis. They can be built up on the assumption that the 

 internal force by which atoms are held together passes 

 through a simple periodic change, and that in the resultant 

 change of atomic volume there is structural hysteresis. 



2. If all aggregates of electrons forming atoms had the 

 same mean density of concentration, atomic volumes would 

 increase indefinitely in a straight line. The density p of the 

 elements oscillates, however, between two limits, a lower 

 line, III. fig. 1, of nearly constant density, and a straight 

 line I. through the maxima which cuts the density axis at the 

 same point m as the lower line. 



If these lines passed through zero so that p = kw = k Yp, the 

 corresponding atomic volumes V would be constant, and the 

 maxima of the curve of atomic volumes (fig. 2) would have 

 equal values. The minima would lie on a lower horizontal 

 line. As it is, p = p -\-kw for the limiting densities, and 

 Y = w/(p + kw). Here V = when w = 0, and the curve is 

 asymptotic to 1/k. 



* a The Dependence of Optical Phenomena on Physical Conditions," 

 by Prof. T. H. Havelock, Roy. Soc. Proc. lxxxiv. pp. 492-523 

 (1911). 



t Communicated by the Author. J 



