of the Terrestrial Globe, 217 



by BufFon, and in Bailly's Letters to Voltaire upon the origin of 

 Science, and upon the Atlantis ; but the ingenious romance, to 

 which it served as a basis, has been dissipated as a phantom be- 

 fore the severity of mathematical calculations. Fourier having 

 discovered that the excess of the total temperature of the surface 

 of the earth, over that which resulted from the sole action of 

 the solar rays, has a necessary and determinate relation to the 

 increase of temperatures at different depths, has been able to 

 deduce from the experimental value of their increments, a nu- 

 merical determination of the excess in dispute ; that is to say, 

 of the thermometrical effect which the central heat produces 

 on the surface ; but, instead of the large numbers given by Ma- 

 rian, Bailly, and Buffon, what, will it be supposed, is that given 

 by the learned Secretary of the Academy ? why, the thirtieth 

 part of a degree ! 



The surface of the globe then, which, at the origin of things, 

 was probably incandescent, has, in the course of ages, cooled 

 down to such an extent, as scarcely to preserve a sensible trace 

 of its primitive temperature. It is nevertheless true, that, at 

 certain depths, the original heat is still prodigious. The lapse 

 of time will probably lead to great changes in the interior tem- 

 peratures ; but, at the surface (and the phenomena here are the 

 only ones which can affect or compromise the existence of living 

 beings), all the changes are reduced to almost the one-thirtieth 

 of a degree. The frightful congelation of the globe, then, the 

 date of which was fixed by BuflPon, to the time when the inte- 

 rior heat should be wholly dissipated, is nothing more than an 

 idle dream. 



V I. Is the temperature of celestial space variable 9 And can this tern- 

 perature become the cause of changes in terrestrial climates ? 



Fourier has, within these few years, introduced into the theory 

 of climates a consideration which had hitherto been entirely ne- 

 glected, and of which naturalists, at least, have made no explicit 

 mention. He has given a prominency to the part which the 

 temperature of these celestial spaces, in which the planetary 

 movements are effected, ought to play ; in which, in particular, 

 -the earth annually describes its vast orbit around the sun. 



In regarding mountains, even under the equator, covered 



