THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JANUARY 1895. 



I. Further Studies on Molecular Force. 

 By William Sutherland*. 



IN two recent papers on the Attraction of Unlike Mole- 

 cules the result has been established, that if two molecules 

 of mass m 1 attract one another with a force 3 jAj m^/r 4 ", and 

 two of mass ra 2 with a force 3 2 A 2 m 2 2 /^ 4 ? then an m, attracts 

 an m 2 with a force 3( 1 A 12 A 2 )^??i 1 m 2 /^ 4 ; from which it follows 

 that Am 2 is resolvable into two factors A*m each belong- 

 ing to a molecule. Now in the " Laws of Molecular Force " 

 (Phil. Mag. xxxv., March 1893), values of M 2 /, which is 

 proportional to Am 2 , are given for a large number of sub- 

 stances as determined by fiYe methods, so that it is only- 

 necessary to take the square roots of the tabulated values of 

 M 2 / to get relative values of A*ra. Indeed, in originally study- 

 ing the values of M 2 Z, the first step I took was to examine the 

 values of (M 2 iy ; and I noticed the reign of law amongst 

 them, but apparently not over so wide a range of values as 

 was dominated by the empirical law M 2 / = 6S + '66S 2 , where 

 S is the sum of certain constants characteristic of the atoms 

 in the molecule, and called the Dynic Equivalents of the 

 atoms. Accordingly this empirical expression was adopted 

 in the " Laws of Molecular Force." Yet even this expression 

 failed to apply to the simpler typical compounds ; but in 

 connexion with the values of (M 2 /) 5 I have discovered that 

 there are two principles in operation amongst them, one 



* Communicated by the Author. 

 Phil. Mag. S. 5. Vol. 39. No. 236. Jan, 1895. B 



