JULIUS ROBERT MAYER [1814-1878) 

 JAMES PRESCOTT JOULE {1818-1889) 

 HERMANN HELMHOLTZ (1821-1894) 



Julius Robert Mayer, a modest practising physician in the 

 town, at that time very small, of Heilbronn on the Neckar, 

 was the discoverer of, and first to announce, the principle 

 of the conservation of energy. He perceived that, beside 

 the laws of motion of Newton and Galileo, another general 

 law holds throughout nature, the grasp of which meant 

 throwing light on just those parts of science which had 

 hitherto remained dark in spite of investigation, and indeed 

 meant the linking together of several separate branches of 

 knowledge which had hitherto appeared disconnected and 

 indeed contradictory. At the present day, the energy prin- 

 ciple may even be described as the highest of all natural laws, 

 inasmuch as it holds for all phenomena of matter as well as of 

 ether, and further, no limits of any kind to its validity have 

 showed the slightest signs of appearing in all the eighty years 

 during which it has been known and applied. 



Mayer announced his new discovery in very few words in 

 the year 1842, in Liebig's Annalen, a widely read scientific 

 periodical, in which words the essential point, the calcula- 

 tion of the mechanical equivalent of heat, is already stated ; 

 it was later discussed in detail in a separate paper which ap- 

 peared in 1845. He had a heavy penalty to pay for all this. 

 It is necessary to go back to Galileo to find an adequate anal- 

 ogy to his suff'ering on account of a new and profound idea. 

 But since no two individual cases ever show exactly the same 

 course, here also a difference is present: Galileo was opposed 

 by dark powers hostile to natural science; Mayer's fate lay 

 within science itself. The great majority who were the official 

 representatives of science did not understand him, the few 

 who did, who immediately grasped the idea, did not like him. 



Matters went so far that when the new ideas finally began 



271 



