194 THE REALITIES OF MODERN SCIENCE 



This relation, which we have reached by considering 

 the energy of the falling electrons, is known as Ohm's 

 Law. It was announced in 1829, years before the 

 more general aspects of electrical conduction were 

 recognized. Covering as it does the special case of 

 conduction through metals and through electrolytes, 

 it has proved of great value to physicists and engineers 

 in the development of the practical utilization of 

 energy in the form of electricity in motion. To-day, 

 however, the place of importance which it holds in 

 most elementary presentations exposes students to 

 the danger of considering the general phenomenon of 

 conduction as an exception, instead of recognizing that 

 those cases for which the law holds are special and 

 simple cases of the general phenomenon. 



