586 HISTORY OF THERMOTICS. 



made up of differential weights. And therefore, 

 even if we were to adopt the emission theory of 

 heat, we are by no means bound to take along with 

 it the hypothesis of discrete molecules. 



But the recent discovery of the refraction, polar- 

 ization, and depolarization of heat, has quite altered 

 the theoretical aspect of the subject, and, almost at 

 a single blow, ruined the emission theory. Since 

 heat is reflected and refracted like light, analogy 

 would lead us to conclude that the mechanism of 

 the processes is the same in the two cases. And 

 when we add to these the property of polarization, 

 it is scarcely possible to believe otherwise than that 

 heat consists in transverse vibrations ; for no wise 

 philosopher would attempt an explanation by as- 

 cribing poles to the emitted particles, after the 

 experience which optics affords, of the utter failure 

 of such machinery. 



But here the question occurs, If heat consist in 

 vibrations, whence arises the extraordinary identity 

 of the laws of its propagation with the laws of the 

 flow of matter ? How is it that, in conducted heat, 

 this vibration creeps slowly from one part of the 

 body to another, the part first heated remaining 

 hottest; instead of leaving its first place and travel- 

 ling rapidly to another, as the vibrations of sound 

 and light do? The answer to these questions has 

 been put in a very distinct and plausible form by 

 that distinguished philosopher, M. Ampere, who 

 published a Note on Pleat and Light considered 



