CENTRAL HEAT OF THE EARTH. 419 



authors, have continually added new lustre to the im- 

 perishable glory of Newton. Let us act so that this 

 example may not be lost. While the civil law imposes 

 upon the tribunes the obligation to assign the motives of 

 their judgments, the academies, which are the tribunes of 

 science, cannot have even a pretext to escape from this 

 obligation. Corporate bodies, as well as individuals, act 

 wisely when they reckon in every instance only upon the 

 authority of reason. 



CENTRAL HEAT OF THE TERRESTRIAL GLOBE. 



At any time the Theorie Mathematique de la Chaleur 

 would have excited a lively interest among men of re- 

 flection, since, upon the supposition of its being complete, 

 it threw light upon the most minute processes of the arts. 

 In our time the numerous points of affinity existing be- 

 tween it and the curious discoveries of the geologists, 

 have made it, if I may use the expression, a work for 

 the occasion. To point out the intimate relation which 

 exists between these two kinds of researches would be to 

 present the most important part of the discoveries of 

 Fourier, and to show how happily our colleague, by one 

 of those inspirations reserved for genius, had chosen the 

 subject of his researches. 



The parts of the earth's crust, which the geologists 

 call the sedimentary formations, were not formed all at 

 once. The waters of the ocean, on several former occa- 

 sions, covered regions which are situated in the present 

 day in the centre of the continent. There they deposited, 

 in thin horizontal strata, a series of rocks of different, 

 kinds. These rocks, although superposed like the layers 

 of stones of a wall, must not be confounded together; 

 their dissimilarities are palpable to the least practised 



