THE DIVISION OF THE WORK AND 

 THE TREATMENT CHOSEN 



IN the inevitably arbitrary division of any subject it is 

 well to choose so that it may easily be seen where each part 

 belongs. For this reason the treatment adopted by Lothar 

 Meyer in the later editions of his Modern Theories of Chemistry 

 seemed to me appropriate for my lectures: in it the whole 

 is divided into Statics and Dynamics. Statics then deals with 

 single substances, i. e.. with views on the structure of matter, 

 the conception of atoms and molecules, and on constitution so 

 far as the determining of molecular configuration. Dynamics 

 is devoted to the mutual actions of several substances, i. e. to 

 chemical changes, affinity, velocity of reaction, and chemical 

 equilibrium. 



To these I have added a third section, in which the chief 

 object is the comparison of one substance with another, and 

 consequently the relations between properties both chemical 

 and physical and composition. 



In preparing for the press I have preserved this arrange- 

 ment, only making a change in the order in accordance with 

 the development of chemical science in the last ten years. 

 Until then Dynamics, that is the study of reactions and of 

 equilibrium, took a secondary place. But lately, and espe- 

 cially since the study of chemical equilibrium has been related 

 to thermo-dynamics, and so has steadily gained a broader and 

 safer foundation, it has come into the foreground of the 

 chemical system, and seems more and more to belong there. 



