150 ON THE INTERACTION OF NATURAL FORCES. 



Since that time the interest of the scientific public for this 

 subject has gradually augmented, particularly in England, of 

 which I had an opportunity of convincing myself during a visit 

 last summer. A great number of the essential consequences of 

 the above manner of viewing the subject, the proof of which 

 was wanting when the first theoretic notions were published, 

 have since been confirmed by experiment, particularly by those 

 of Joule ; and during the last year the most eminent physicist, 

 of France, Regnault, has adopted the new mode of regarding the 

 question, and by fresh investigations on the specific heat of gases 

 has contributed much to its support. For some important con- 

 sequences the experimental proof is still wanting, but the number 

 of confirmations is so predominant, that I have not deemed it 

 premature to bring the subject before even a non-scientific 

 audience. 



How the question has been decided you may already infer 

 from what has been stated. In the series of natural processes 

 there is no circuit to be found, by which mechanical force can 

 be gained without a corresponding consumption. The per- 

 petual motion remains impossible. Our reflections, however, 

 gain thereby a higher interest. 



We have thus far regarded the development of force by natural 

 processes, only in its relation to its usefulness to man, as me- 

 chanical force. You now see that we have arrived at a general 

 law, which holds good wholly independent of the application 

 which man makes of natural forces ; we must therefore make the 

 expression of our law correspond to this more general signifi- 

 cance. It is in the first place clear, that the work which, by 

 any natural process whatever, is performed under favourable con- 

 ditions by a machine, and which may be measured in the way 

 already indicated, may be used as a measure of force common to 

 all. Further, the important question arises, If the quantity of 

 force cannot be augmented except by corresponding consump- 

 tion, can it be diminished or lost ? For the purposes of our 

 machines it certainly can, if we neglect the opportunity to 

 convert natural processes to use, but as investigation haa 

 proved, not for nature as a whole. 



