PART III 



RELATIONS BETWEEN PROPERTIES AND 

 COMPOSITION 



Contents and arrangement. Since in Part II of this 

 work we have traced how the constitutional and configura- 

 tional formula has been developed into an expression of the 

 material structure, we have now, in the present part, to 

 discuss the relations which hold between that structure 

 and the properties of bodies. Fundamentally Part II is 

 concerned with the same problem, for the configurational 

 formula is a more or less successful symbolic representation 

 of those properties from which it is derived. Here, how- 

 ever, a distinction may be made. There are properties, 

 such as the quantitative composition of a compound, the 

 density of a gas, and so on, whose connexion with the 

 chemical formula is so far certain, that they may be 

 regarded as directly deducible from the formula in ques- 

 tion, as a necessary consequence of the assumed atomistic 

 and molecular concepts. On the other hand there are 

 relations holding between composition and properties that 

 so far have only an empirical value, or with more or less 

 theoretical support carry in them the germs of relations 

 that might serve for the determination of chemical formula, 



