

ELECTRICAL UNITS OF MEASUREMENT. 79 



force, we have scarcely emerged one year from 

 those middle ages when a volt and a Daniell's 

 cell were considered practically identical, to 

 the higher aspiration of measurement within one 

 per cent. It seems, indeed, as if the commercial 

 requirements of the application of electricity 

 to lighting, and other uses of every-day life, were 

 destined to cause an advance of the practical 

 science of electric measurement, not less important 

 and valuable in the higher region of scientific 

 investigation than that which, from twenty to 

 thirty years ago, was brought about by the 

 practical requirements of submarine telegraphy. 



There cannot be a greater mistake than that 

 of looking superciliously upon practical applica- 

 tions of science. The life and soul of science is 

 its practical application, and just as the great 

 advances in mathematics have been made through 

 the desire of discovering the solution of problems 

 which were of a highly practical kind in 

 mathematical science, so in physical science 

 many of the greatest advances that have been 

 made from the beginning of the world to the 



