PKOGKESS OF THE INVESTIGATION. 225 



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 regarding the question, and by 

 fresh investigations on the specific heat of gases has contri- 

 buted much to its support. For some important consequences 

 the experimental proof is still wanting, but the number of 

 confirmations is so predominant, that I have not deemed it 

 too early 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 mechanical 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 new law correspond to 

 this more general significance. It is in the first place clear, 

 that the work which, by any natural process whatever, is per- 

 formed under favourable conditions 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 impor- 

 tant question arises, " If the quantity of force cannot be aug- 

 mented except by corresponding consumption, can it be 

 diminished or lost? For the purpose of our machines it cer- 

 tainly can, if we neglect the opportunity to convert natural 

 processes to use, but as investigation has proved, not for a, 

 nature as a whole." 

 10* 



