1 1 8 Analysis, <^^c. of Cordier''s Essay upon the 



the superincumbent column. Would not this account for 

 much of the caloric extricated at great depths ? 



" Oil the conclusions cleducible from the preceding experiments. 



" 1. The earth possesses within itself a source of heat, not de- 

 pendant on the rays of the sun : A heat which increases rapidly 

 as we descend deeper. 



" 2. The law of this increase of heat is not the same every 

 where. It may be double or triple at one place, what it is at 

 another. 



" 3. Nor do these differences depend on latitude or longitude. 



" 4. The increase of temperature is more rapid than was sus- 

 pected. It may rise to one degree at thirteen metres deep in 

 some countries. The average cannot exceed twenty-five metres. 

 " Applications of these facts to the theory of the Earth. 



" 1. All the phenomena agree with the mathematical theory 

 of heat ; and with a high temperature belonging to the earth it- 

 self from its veiy origin. As the mass of solid matter in the 

 earth is ten thousand times greater than the liquids, the original 

 liquidity of our globe must have been owing to caloric, and not 

 to water. 



" 2. Suppose an increase of one degree for each twenty-five 

 metres (eighty-two feet) in depth, the temperature of our globe 

 at its centre would be thirty-five hundred degrees of Wedge- 

 wood's pyrometer, or two hundred and fifty thousand degrees of 

 the centigrade thermometer. 



" 3. The temperature of one hundred degrees Wedgewood, 

 sufficient to melt all the lavas, and most of the known rocks, 

 would be found at fiftj-five leagues or five thousand metres deep 

 at Carmeaux, at thirty leagues at Littry, and at twenty-three 

 leagues at Decise. Numbers, which agree with 1-23, 1-42, 

 1-55 of the mean radius of our planet. 



" 4. It is probable, therefore, that our earth is a star partially 

 cooled, as Des Cartes and Leibnitz thought: and that the centre 

 still preserves its original fluidity. 



" 5. If we consider on one hand the generality which the ob- 

 servations of Dolomieu on the situation of the eruptive fires, 

 (Rapports snr ses voyages Journ. des Mines, tom. 7, p. 385,) and 

 our own (Cordier's) experiments on the composition of lavas, 

 (Recherches sur diflferents produits volcaniques Jour, des Mines 

 tom. 21, p. 249, tom. 23, p. 55. Memoir sur la composition des 

 Lavas de tous les ages Journ. de Phys. tom. 83, p. 135,) have 

 given to volcanic phenomena-- and on the other hand, the great 

 fusibility of the ejected matters of ancient and modern volcanos, 

 we must conclude, that internal fluidity begins in many places at 

 a less depth than where the heat rises to one hundred degrees of 

 Wedgewood. 



