ON THE PHYSICAL VIEW (JF NATIKK. 105 



embrace a mechanical or kinetic view of the nature 

 of heat. Joule, as stated above/ was the first who 

 emancipated himself from it. 



But whilst these suggestions that heat may te re- 8. 



1 • 1 • ComrUition 



garded as somehow connected witli motion remained offoreai. 

 mostly vague ami undeveloped, they tended to impress 

 upon the scientiiic mind the interchangeability — or, as 

 it was called, the correlation of the different forces of 

 nature ; and the idea seems to have forced itself in- 

 dependently on many minds, through the study of very 

 different groups of natural phenomena. In Germany 

 we may look upon Liebig as the centre of a great 9. 



Licbig. 



scientific movement which tried l)y means of chemistry 

 to bring the realms of organic and animated exist- 

 ence under the treatment of exact methods. Xot 

 (jiily were the methods of organic analysis perfected 

 l)y him and his school, and many compounds inves- 

 tigated which appeared to be specially the bearera of 

 the living process ; but he was also among the first to 

 study the economy of li\ing organisms, the circulation 

 of matter, and the play of the varied processes by 

 which life is maintained. Among these processes, the 

 phenomenon of animal heat, its origin, and the part it 

 plays in the living organism attracted special attention, 



may be said to rest where it did whiih was shown to have the same 



at the time the.se Lectures were properties of refle.\ion, refraction, 



written. The facts which have and polarisation as Hght possessetl. 



just been mentioned clearly point The analogy of this form of heat 



out its undulatory character" (p. with liglit threw into oblivion 



50(5). Between the years 1835 and the beginnings of a more general 



184.') theoretical ideas on the nature mechanical theory of heat, which 



of heat were entirely dominated i — as we shall see further on — had 



by the remarkable discoveries of | been laid by Sadi Carnot iu 



Melloni, Baden-Powell, Forbes, and 1824. 



others referring to radiant heat, ' ' See vol. i. of this work, ji. 434. 



