THE CENTURY'S PROGRESS IN PHYSICS 



By this time, however, the battle was brewing. The 

 rising generation saw the importance of a law which 

 their elders could not appreciate, and soon it was noised 

 abroad that there were more than one claimant to the 

 honor of discovery. Chiefly through the efforts of Pro- 

 fessor Tyndall, the work of Mayer became known to the 

 British public, and a most regrettable controversy ensued 

 between the partisans of Mayer and those of Joule a 

 bitter controversy, in which Davy's contention that 

 science knows no country was not always regarded, and 

 which left its scars upon the hearts and minds of the 

 great men whose personal interests were involved. 



And so to this day the question who is the chief dis- 

 coverer of the law of conservation of energy is not sus- 

 ceptible of a categorical answer that would satisfy all 

 philosophers. It is generally held that the first choice 

 lies between Joule and Mayer. Professor Tyndall has 

 expressed the belief that in future each of these men 

 will be equally remembered in connection with this 

 work. But history gives us no warrant for such a hope. 

 Posterity in the long-run demands always that its heroes 

 shall stand alone. Who remembers now that Robert 

 Hooke contested with Newton the discovery of the doc- 

 trine of universal gravitation? The judgment of pos- 

 terity is unjust, but it is inexorable. And so we can 

 little doubt that a century from now one name will be 

 mentioned as that of the originator of the great doctrine 

 of conservation of energy. The man whose name is thus 

 remembered will perhaps be spoken of as the Galileo, 

 the Newton, of the nineteenth century; but whether 

 the name thus dignified by the final verdict of history 

 will be that of Colding, Mohr, Mayer, Helmholtz, or 

 Joule, it is not for our century to decide. 



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