68 UNIVERSITY OF MISSOURI BULLETIN 



The physicist uses as a part of his foundation the concepts 

 of the mathematician. Moreover, as he is deaHng in the 

 main with things which he measures, he must use quantitative 

 definitions and quantitative statements of the relations between 

 his concepts. Since they are quantitative, he can express 

 them in the form of equations. For these reasons, mathe- 

 matical processes are of great service to the physicist. The 

 mathematician and the physicist are usually readily distin- 

 guished by the difference in their attitude, the physicist using 

 the mathematics only as a tool. 



Much of the time the work of the experimentalist runs 

 ahead of the theoretical physicist. On the other hand, there 

 are many famous cases where the result was first pointed 

 out by theory. For example, Clerk Maxwell in an endeavor 

 to unify the two subjects, light and electricity, proposed what 

 is now called the electromagnetic theory of light. According 

 to this, light waves are only a special case of electrical waves. 

 Up to this time electrical waves had never been detected, — 

 they were absolutely unknown. Later they were by direct 

 experiment discovered by the now famous Hertz. This 

 work was a great step in the unification of physics and at 

 the same time opened a new field for practical work — that 

 of wireless telegraphy and telephony. It may be of more 

 than passing interest to point out more of the details of 

 this work. The explanation lies in the principle that when 

 we reject complicated concepts and go back to the simpler 

 ones of mechanics we usually find that a decided advance 

 has been made. In the case we have just cited, the work 

 began with Faraday. In explaining electrical phenomena 

 Faraday rejected a lot of preconceived notions and the 

 existence of substances which could not be perceived. He 

 discarded the notion of a fluid called electricity acting across 

 space. But he left the subject still in a vague condition. 

 Maxwell gathered up Faraday's ideas, simplified them, put 

 them in a more concrete form, and, assuming that he could 



