414 JOSEPH FOURIER. 



pletely verified, they have become laws of nature ; they 

 point out latent properties of caloric which could only be 

 discerned by the eye of the intellect. 



In the second question treated by Fourier, heat pre- 

 sents itself under a new form. There is more difficulty in 

 following its movements ; but the conclusions deducible 

 from the theory are also more general and more impor- 

 tant. 



Heat excited, concentrated into a certain point of a 

 solid body, communicates itself by way of conduction, 

 first to the particles nearest the heated point, then grad- 

 ually to all the regions of the body. "Whence the problem 

 of which the following is the enunciation. 



By what routes, and with what velocities, is the prop- 

 agation of heat effected in bodies of different forms and 

 different natures subjected to certain initial conditions ?. 



Fundamentally, the Academy of Sciences had already 

 proposed this problem as the subject of a prize as early 

 as the year 1736. Then the terms heat and caloric were 

 not in use ; it demanded the study of nature, and the 

 propagation OF FIRE ! The word jfire, thrown thus into 

 the programme without any other explanation, gave rise 

 to a mistake of the most singular kind. The majority of 

 philosophers imagined that the question was to explain 

 in what way burning communicates itself, and increases 

 in a mass of combustible matter. Fifteen competitors 

 presented themselves ; three were crowned. 



This competition was productive of very meagre re- 

 sults. However, a singular combination of circumstances 

 and of proper names will render the recollection of it 

 lasting. 



Has not the public a right to be surprised upon read- 

 ing this Academic declaration : " the question affords no 



