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 Théorie Mathématique 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 
