70 UNIVERSITY OF MISSOURI BULLETIN 



compute molecular weights the chemist must study the laws of 

 gases, laws which may have nothing to do with these so called 

 chemical changes. And in a great variety of ways he must 

 depart from a limitation such as is given in some of the older 

 texts. In the same way and from similar causes the physicist 

 breaks down these barriers. To understand why we get the 

 spectrum when light passes through a prism, we must study 

 molecular and atomic structure. 



So in many different lines, both chemists and physicists 

 have worked at the same problem and where this work is 

 essential in the presentation of both subjects, we find our 

 text-books overlapping. The division of these border sub- 

 jects, especially those which are not clearly classified by their 

 nature, is to some extent an historical accident. 



But of far greater efi^ect has been the difference of atti- 

 tude. The chemist has in the past been concerned chiefly 

 with the constitution of matter and those properties of matter 

 which change as the constitution changes. On the other 

 hand, the physicist has been concerned not only with matter, 

 but with the establishment of fundamental laws connecting 

 matter, force, and energy, and in the application of these laws 

 to all phenomena. However, there has recently developed 

 what is almost a new subject. Physical Chemistry. This 

 according to Van't HoflF, one of the most prominent of modern 

 chemists, is the application of these methods of physics to 

 the problems of chemistry. Chemistry is an aggregation of 

 facts and laws relating to the composition of substances. 

 Beyond doubt the facts of chemistry are complex. But such 

 things as chemical affinity and such laws as the law of com- 

 bination in definite proportions are facts and laws of matter 

 and force, and must ultimately be explained in terms of the 

 fundamental laws of matter and force — laws which we call 

 the laws of mechanics. 



This convergence of the two sciences is now well known, 

 recent work in radio-activity having brought this out con- 



