the Intenor of the Earth. 275 



The results have Ijcen compared witli one anotlier, and with the 

 mean temperatures of the surface, and the important conchision 

 has been drawn, that, proceeding from the level at which the 

 fixed temperature commences in the soil of each country, the 

 heat increases rapidly as the depth advances, and this in a quan- 

 tity which has been valued at 1° centig. for every thirty or forty 

 metres *. 



These remarkable facts, considered partially by some, and 

 grouped in various ways by others, have carried with them all 

 who had a predilection for the hypothesis of central heat. The 

 common conclusion is, that the earth possesses in its interior a 

 temperature, incomparably more elevated than the compound 

 temperature which is observed at the surface ; and even accord- 

 ing to some, that beyond a certain depth, there probably exist 

 an incandescence and a fluidity, whose origin has been coeval 

 with the commencement of things. 



La Grange and Dolomieu were the first who revived the 

 hypothesis of central heat. Hutton and his able commentator 

 riayfaii', must also be mentioned, notwithstanding the obscurity 

 in which they involved their opinion, and the errors into which 

 they fell when employing this principle in the support of geolo- 

 gy. More lately, this great question has been investigated by 

 the illustrious geometrician whose loss the sciences have to de- 

 plore, M. de La Place, and before him, by Mr. Fourier, who 

 was naturally led into the subject by his memorable researches 

 regarding the general theory of heat. Other autliorities would 

 not be wanting, were it possible to make mention here of the 

 many learned men, especially in England, who, during the last 

 twenty years, have successively adopted the same opinion. 



Thus the hypothesis of subterranean heat now presents itself, 

 supported by a mass of authorities and facts which no longer 

 permits us to view it as a creature of the imagination. In the 

 state in which the subject now stands, this hypothesis seems 

 to merit the particular attention of the learned world. If the 

 proofs adduced in its favour are insufficient, recourse must be 

 had to new observations ; if they suffice, we must hasten to a- 

 dopt the principle, determine its characters, deveiope its conse* 

 quences, and if it be possible elicit its applications. 



• Metre is 3 feet and 3.371 inches English, «r 39.371 inches. 



