44 Mr. William Sutherland on the 



Table XXXIII. (continued). 

 From Table XXIX. 



01. Br. I. S. Se. P. 



M/3 17 22 25-6 15-7 171 135 



(M 2 1-9 2-6 3-6 2-5 3-2 21 



Eatio 9 83 71 6-3 5-3 6-4 



As has already been pointed out, the numbers for CI are 

 rough, so that no importance attaches to the discrepance 

 between the ratio 9 for CI and 14 for Cl 2 , which numbers 

 ought to be identical. All that the table shows is that the 

 relation found to hold between M/3 and (M 2 Z) S in the gaseous 

 non-metals does not extend to the other non-metals. The 

 transition cases from metal to non-metal will have to be 

 worked out before the principle ruling in the values of (M 2 // 

 for the non-metals becomes clear. 



4. General Summary and Analysis of Molecular into 

 Atomic Attractions. 



The chief result of the present inquiry has been the 

 demonstration that M 2 Z, which occurs in the treatment of the 

 attractions of like molecules, and which represents Am' 2 in the 

 expression 3A?n 2 /r 4 for the attraction between two molecules 

 of mass m, can be analysed into two factors (M 2 /) 5 which are 

 the sum of numbers characteristic of the atoms composing 

 the molecule whose mass referred to the atom of hydrogen is 

 M. This is the logical outcome of the proof given in the 

 papers on " The Attraction of Unlike Molecules/' that the 

 attraction of two unlike molecules is expressed by the product 

 of two parameters characteristic of each and equal to the square 

 roots of the corresponding attractions for a pair of each of the 

 molecules. The values of (M 2 fp studied in this paper are there- 

 fore relative values of A?m. But as we have found no evidence 

 of a direct connexion between m and A*m, it is desirable to 

 remove all implication of such a connexion, which was 

 originally adopted for the sake of analogy with the Newtonian 

 law of gravitation. Accordingly A?m would be better denoted 

 by a single symbol a, so that the attraction between two 

 molecules of mass m x at distance r apart is 3ai/r 4 9 and of two 

 molecules of masses m l7 m 2 is 3% a 2 /r 4 , and so on. 



The fact that a for a molecule is the sum of parts due to 

 the atoms in it enables us to analyse molecular into atomic 

 attraction ; for if two molecules of composition B$, C c , D<* . . . 



