ON THK PHYSICAL VIEW OF NATURE. 113 



other forces of nature into his consideration, showing, in 

 the case of the phenomena of heat, electricity, i^alvanism, 

 and magnetic induction, how the dillerent agencies can 

 be brought into comparison with mechanical ones by 

 measuring the work they perform ; refers to tlie attempts 

 to hx the mechanical value of heat ; concludes in each 

 case that no observed phenomena — not even the pro- 

 cesses in h\ing 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 liave 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 liypothetical sections, was to ex[)lain 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." ^ 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 ]\Iayer, 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 



^ 'Gesammelte Abhandlungen,' vol. i. j). (57. 

 VOL. J J. " 



