THE CONQUEST OF NATURE 



the fundamental facts as to the relations of electricity 

 and magnetism, invent mechanisms which, though they 

 seem but laboratory toys, are the direct forerunners 

 of the modern dynamos that take so large a share in the 

 world's work. 



In a word, all along the line there is the closest as- 

 sociation between what are commonly called the 

 theoretical sciences and what with only partial pro- 

 priety are termed the applied sciences. The linkage 

 of one with the other must never be forgotten by 

 anyone who would truly apprehend the status of 

 those practical sciences which have revolutionized 

 the civilization of the nineteenth and twentieth cen- 

 turies in its most manifest aspects. 



Nevertheless there is, to casual inspection, a some- 

 what radical distinction between theoretical and prac- 

 tical aspects of science just as there are obvious 

 differences between two sides of a shield. And as 

 the theoretical aspects of science have largely claimed 

 our attention hitherto, so its practical aspects will be 

 explicitly put forward in the pages that follow. In 

 the present volume we are concerned with those prim- 

 itive applications of force through which man early 

 learned to add to his working efficiency, and with the 

 elaborate mechanisms turbine wheels, steam engines, 

 dynamos through which he has been enabled to 

 multiply his powers until it is scarcely exaggeration 

 to say that he has made all Nature subservient to his 

 will. It is this view which justifies the title of the vol- 

 ume, which might with equal propriety have been 

 termed the Story of the World's Work. 



