Molecular Thermodynamics. G35 



constitution, whereby, as indicated in section IV., very 

 great uncertainties are introduced at high concentrations. 

 It seems advisable, therefore, that the study of strong non- 

 conducting solutions and of non-polymerized solvents should 

 precede that of high concentration conducting solutions. 



Summary. 



In section I. it is shown that on the basis of a very broad 

 assumption, a general treatment of the thermodynamics of 

 any system of phases, from the point of view of molecular 

 theory, can be developed. 



This u molecular thermodynamics " which is thus slightly 

 less general than strictly u general thermodynamics" was 

 really initiated by Planck in his classical treatment of a very 

 dilute solution in a non-associated simple solvent. 



In section II. the meaning and value of this "molecular"" 

 treatment is discussed, and also the general aim ;md mode of 

 application. It is shown how this treatment paves the way 

 for the introduction of dynamical theory as an aid to the 

 solution of the general problem. 



In section III. a slightly modified procedure, useful for 

 many practical cases, is introduced, and the significance of 

 the chief types of experimental data is concisely demon- 

 strated. 



Section IV. contains a special treatment of the case of 

 polymerized and mixed solvents, and it is shown how far we 

 can proceed in this case without precise knowledge of the 

 molecular constitution of the solvent. 



Some second-approximation equations are put forward for 

 use at medium concentrations, and in an appendix to this 

 section the importance of a second approximation at such 

 concentrations is illustrated by the non-validity of the 

 ordinary mass-action equation for perfect solutes. 



In section V. the question of electrolytes is considered 

 from the point of view of molecular thermodynamics. It is 

 shown that Milner's calculation of the " virial " of a mixture 

 of ions is of considerable value here, although his application 

 of the Virial theorem is rejected on theoretical grounds. In 

 fact, a striking example of the use of dynamical theory as 

 an aid in the solution of the thermodynamic problem is here 

 forthcoming, and considerable confirmation of the con- 

 clusions reached is found in already (recently) established 

 empirical facts. 



The question of weak and " semi-strong " electrolytes is 



