882 Mr. Wilson Taylor on the Coalescence of 



occupy all the space in the liquid, we have 



it n m 

 p 



where p is taken at a low temperature. This enables hi& 

 relation to be written : 





where Li = mL, which is identical with that we obtained by 

 considering the surface energy given up by the coalescence 

 of liquid spheres. 



Thus the carefully compiled data supplied by Hammick's- 

 tables really account for the whole of the latent heat, and 

 there is no need to employ the hypothesis of molecular 

 attraction and the doubtful principle of equipartition of 

 energy along the three geometrical axes to obtain a relation 

 that fits in his experimental data. 



In this connexion it is interesting to note that Einstein 

 (Ann. d. Phi/sik, iv. 3, p. 513 (1901)) has put forward a 

 view that the surface energy of a liquid is of the nature 

 of potential energy expressible by a certain equation, one of 

 whose terms depends on the atomic weight. This is exactly 

 what our formula does, which may be written 



LJ m /36ttN 



= T / 36ttJN vi 



' \ mp" J 



the expression with the brackets being the whole area of the 

 N free molecules of a gram molecule of the gas, and T the 

 energy per sq. cm. which we have supposed to exist in 

 the surface of the free molecules. This energy is potential,, 

 as Einstein predicted, for it is stored in the surface of the 

 free molecule incapable of being released for doing work 

 until two such molecules by coming into contact coalesce 

 and lessen their total enveloping area. 



Our formula, which was obtained above from the phe- 

 nomena of the coalescence of liquid spheres and not from 

 any hypothesis concerning molecular attraction, would seem r 

 then, to indicate that this view of the connexion between the 

 latent heat and surface energy is the correct one ; and 

 therefore, in addition to the confirmation furnished by 

 Hammick, we shall examine some further experimental 

 evidences in support of this view. 



If n, which we may suspect is Avogadro's number, is con- 

 stant for all substances, we should seek for those values of 



