240 Mr. D. L. Hammick on Late'nt Heat 



and 



B ; 



B>-d<? 



-i(4l +T )= ' 



The terms written last in five of these six equations are 

 the terms constituting a material difference. 



Terms of a similar character, but less simple, present 

 themselves in the Spherical Polar Coordinate system. 



This communication deals only with a proposed formal 

 solution, and no application to a particular problem is 

 offered. The difficulties which will arise in respect to 

 surface conditions are of a quite different character and are 

 probably always greater than those of obtaining a mere 

 solution. 



XXI. Latent Heat and Surface Energy. — Part I. By D. 

 L. Hammick, Chemical Laboratory, Ihe College, Win- 

 chester *. 



THAT the surface energy of a liquid and its latent heat 

 must be intimately related has long been recognized, 

 and in connexion with the familiar demonstration that 

 variation of the magnitude defined as u molecular surface 

 energy " pV* (where p is the surface energy in ergs per sq. 

 cm. and Y is the gramme molecular volume) with temperature 

 is a constant, a relationship between surface energy and latent 

 heat is often met with (cf. van t'Hoff, ' Lectures/ vol. iii. 

 p. 77, Eng. Translation ; Nernst, 4 Theoretical Chemistry,' 



* Communicated by the Author. 



