Liquid Spheres — Molecular Diameters. 889 



(b) Surface tension extends to molecular masses causing 

 them to coalesce in the same manner as liquid spheres. 



(c) Since N is constant for all substances, if any two of 

 the three quantities T m , p , and L can be found for any sub- 

 stance, the other may be calculated from the relation 



M") 



x "W 



0b7T 



(d) It is assumed that the empirical law T© = T — B# 

 holds down to 0° A, and that T m = T . 



(e) The actual mass diameter of the molecule is 



dc 



WoNJ ' 



and the average diameter of the space it occupies in the solid 

 or liquid is 



, _ / 6 in \ 3 



Note on the Surface Tension of Solid Bodies. 



The idea that solid bodies possess surface tension is 

 believed to be tenable. Van der Mensbrugge (Anal. Soc. 

 Sri. de Bruxelles, B. xxix. (1904-5)), from consideration of 

 the forces in the curved meniscus at the side of a vertical 

 glass plate in water, concludes that a glass surface possesses 

 an effective surface tension. M. Petrova (Jurn. liussk. 

 Fisik. Chimecesk, xxxvi. Phy. pt, pp. 203 (1905)), from the 

 fact that enlarged photographs of mercury drops on glass 

 taken before and after solidification when superimposed 

 showed no appreciable change, inferred that solid mercury 

 possesses surface tension. And, finally, M. Berggren (Ann. 

 d. Physik, xliv. 1, pp. 61-80 (1914)), by measuring the 

 velocity of deformation when amorphous bodies solidify in 

 the case of threads hanging vertically, found that solid 

 amorphous bodies possess surface tension of the same order 

 of magnitude as that of liquids. 



