ON THE PHYSICAL VIEW OF NATURE. 113 



other forces of nature into his consideration, showing, in 

 the case of the phenomena of heat, electricity, galvanism, 

 and magnetic induction, how the different agencies can 

 be brought into comparison with mechanical ones by 

 measuring the work they perform ; refers to the attempts 

 to fix the mechanical value of heat; concludes in each 

 case that no observed phenomena not even the pro- 

 cesses in living organisms stand in contradiction with 

 the principle announced, and ends with the words : " I 

 think in the foregoing I have proved that the above- 

 mentioned law does not go against any hitherto known 

 facts of natural science, but is supported by a large 

 number of them in a striking manner. I have tried 

 to enumerate as completely as possible what con- 

 sequences result from the combination of other known 

 laws of nature, and how they require to be con- 

 firmed by further experiments. The aim of this 

 investigation, and what must excuse me likewise for 

 its hypothetical sections, was to explain to natural 

 philosophers the theoretical, practical, and heuristic im- 

 portance of the law, the complete verification of which 

 may well be looked upon as one of the main problems 

 of physical science in the near future." 1 The reasons 

 why this valuable document attracted little attention at 

 the time and was set aside, as were the earlier contribu- 

 tions of Mohr and Mayer, by the central organ of ex- 

 perimental physics abroad, are interesting from a 

 historical point of view. The first and main reason 

 seems to have been that none of the three original and 

 independent expressions contained any new experimental 



1 ' Gesammelte Abhandlungen,' vol. i. p. 67. 

 VOL. II. H 



