NATURAL FHILOSOl'HY. 125 



the flame, the chalk will be raised to a white heat, and give us the sun-like 

 Drummond's light. At the same time, the flame develops a considerable 

 quantity of heat. Our American proposed to utilize in this way the gases 

 obtained from electrolytic decomposition, arid asserted that by the combus"- 

 tion a sufficient amount of heat was generated to keep a small steam engine 

 in action, which ag.iin drove his magneto-electric machine, decomposed the 

 water, and thus continually prepared its own fuel. This would certainly 

 have been the most splendid of all discoveries ; a perpetual motion which, 

 besides the force that kept it going, generated light like the sun, and wanned 

 all around it. The matter was by no means badly cogitated. Each practi- 

 cal step in the affair was known to be possible; but those which at that time 

 were acquainted with the physical investigations which bear upon this sub- 

 ject could have affirmed, on first hearing the report, that the matter was to 

 be numbered among the numerous stories of the fable-rich America ; and, 

 indeed, a fable it remained. 



It is not necessary to multiply examples further. You will infer from 

 those given, in what immediate connection heat, electricity, magnetism, light, 

 and chemical affinity, stand with mechanical 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, 



Wher3 a step stirs a thousand threads. 



The shuttles shoot from side to side, 



The fibres flow unseen, 



Aud one 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 pro- 

 duce mechanical force in greater quantity than that at first applied, a por- 

 tion of the work thus gained might be made use of to keep the machine in 

 motion, 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 ac- 

 tions, a track through chemical, electrical, magnetical, 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 rela- 

 tions 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 1 Everything was gained by this inver- 

 sion of the question. The relations of natural forces rendered 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 



11* 



