498 Prof. Helmholtz on the Interaction of Natural Forces^ 



Starting from each of these different manifestations of natural 

 forces, we can set every other in motion, for the most part not 

 in one way merely, but in many ways. It is here as with the 

 weaver's web, — 



AVTiere a step stirs a thousand threads. 



The shuttles shoot from side to side. 



The fibres tlow uuseen, 



And oue shock strikes a thousand combinations*. 



Now it is clear that if by any means we could succeed, as the 

 above American professed to have done, by mechanical forces, 

 to excite chemical, electrical, or other natural processes, which, 

 by any circuit whatever, and without altering permanently the 

 active masses in the machine, could produce mechanical force in 

 greater quantity than that at first applied, a portion of the work 

 thus gained miglit be made use of to keep the machine in mo- 

 tion, while the rest of the work might be applied to any other 

 purpose whatever. The problem was to find, in the complicated 

 net of reciprocal actions, a track through chemical, electrical, 

 aiagnetical, and thermic processes, back to mechanical actions, 

 which might be followed with a final gain of mechanical work : 

 thus would the perpetual motion be found. 



But, warned by the futility of former experiments, the public 

 had become wiser. On the whole, people did not seek much after 

 combinations which promised to furnish a perpetual motion, but 

 the question was inverted. It was no more asked, How can I 

 make use of the known and unknown relations of natural forces 

 so as to construct a perpetual motion ? but it was asked. If a 

 perpetual motion be impossible, what are the relations which 

 must subsist between natural forces ? Everything was gained by 

 this inversion of the question. The relations of natural forces ren- 

 dered necessary by the above assumption, might be easily and 

 completely stated. It was found that all known relations of 

 forces harmonize with the consequences of that assumption, and 

 a series of unknown relations were discovered at the same time, 

 the correctness of which remained to be proved. If a single one 

 of them could be proved false, then a perpetual motion would be 

 possible. 



The first who endeavoured to travel this way was a French- 

 man named Carnot, in the year 1824. In spite of a too limited 

 conception of his subject, and an incorrect view as to the natm'e 

 of heat, which led him to some erroneous conclusions, his expe- 

 riment was not quite unsuccessful. He discovered a law which 

 now bears his name, and to which I will return further on. 



* " Wo ein Tritt tausend Faden regt, 



Die Schifflein heriiber hiuiiber schiessen, 



Die Faden ungesehen fliessen, 



Ein Schlag tausend Verbindungen schlagt." 



