PART II 

 CHEMICAL STATICS 



Contents and arrangement. As explained in the intro- 

 duction, chemical statics treats a single substance as a case 

 of equilibrium of the simplest kind, occurring on completion 

 of a reaction. It is, in the first instance, defined by its 

 qualitative and quantitative composition. But as, for the 

 same composition, it is possible to have different states 

 of equilibrium, e.g. polymerism and isomerism, a closer 

 characterization is necessary. The external features, apart 

 from hypothesis, whether physical, such as heat of forma- 

 tion, density, optical rotation, crystalline form, and so on, 

 or chemical, as affinity, velocity of reaction, and so on, have 

 not up to the present afforded any means of predicting 

 the conditions of such polymerism or isomerism. The case 

 is different if molecular and atomistic theory be taken as 

 the starting-point. We must therefore treat chemical 

 statics in this sense too, i. e. we must develop the views 

 as to the internal structure of matter, after saying a word 

 on the basis of the molecular and atomistic treatment. 



The atomic hypothesis, it is well known, is an attempt 

 at explaining the peculiar relationships observed in the 

 quantitative composition of compounds. Three funda- 

 mental laws have proved to be strictly true : 



i. The law of constant composition, which amounts to 

 saying that a compound, however prepared, has always 



