PEALE.] 



TEMPERATURE SOURCE OF HEAT. 



381 



110° r. The plication and folding in the rocks of the Appalachians not 

 only afford the opportunity for the water to escape, but as the lesult of 

 that motion have imparted to the rocks an increased temperature which 

 is seen in the waters of its thermal springs. 



3d. Internal heat. — The proofs of the internal heat of the earth, given 

 in Dana's Manual of Geology, are briefly as follows : 1st. The spheroidal 

 form of the earth ; 2d. The increase in temperature, as shown in arte- 

 sian wells and shafts in mines; 3d. The wide distribution of volcanoes 

 over the globe. The increase of temperature in the earth was noted, iu 

 1664 by Kircher.* Boerhiive t also, in 1732, mentions the increase of heat 

 toward the center of the earth, and Mairan,| in 1719, advanced the 

 theory of the existence of fire in the interior of the earth. 



Ever since the middle of the eighteenth century observations have 

 been taken in mines and springs § in France, Germany, England, and 

 America, so that the average rate of increase is pretty well known. 



*Mnndu8 Subterraneus, 1664, fol., vol. ii, pp. 184 and 185, cited by Bischof. 



tElemeota ChemisB, Lipsise, 1732, vol. i, p 403, cited by Biscliof 



tM6m. de l'Acad6inie, pour 1719, cited by Biscbof. 



\ The followiDg table gives the results of borings for artesian wells, which Arago 

 long ago declared were peculiarly adapted to the determination of the increase of 

 temperature below the surface of the earth. 



Locality. 



EUROPE. 



Pregny, near Geneva 



Tottenham Conrt road, England 



Eank Herlany, in Hungary 



KLssingen, Germany 



Passy, iu Prance 



Grenelle, near Paris, France 



Neusalzwerk, near Minden, Prussia 



Mondorf. in Luxembourg 



Bada Pesth, in Hungary 



UMTED STATES. 



Charleston, South Carolina 



Louisville, Kentucky 



Belcher well, at Saint Louis, Mo 



Columbus, Ohio 



Insane asylum. Saint Louis, Mo 



Temperature 

 at the bottom. 



63. 

 57. 

 75. 

 66. 

 82. 

 85. 

 01. 

 89. 

 178. 



87. 

 86. J 

 7.3.4 

 91. 

 105. 



The following table presents some of the temperatures that have been observed in 

 mines : 



Mines. . 



Depth. 



Temper- 

 ature. 



Authority. 



Bex 



Feet. 

 677 



1,200 



1,377 

 1,607 

 ],844 

 2,000 



°F. 

 63.05 



77 



75i 

 98.'] 5 

 75.50 

 130 



De Saussnre in Annal. de Ghem. et Phys., vol. liii, 

 p. 245. 



Earth and Sea. By W. H. Davenport; Adams, Lon- 

 don, 1870. 

 Do. 



Humboldt in Gilbert's Annalen, vol. Ixxvi, p. 450. 



Proc. Inst., Civ. Engineer's, vol. lii p. 397. 



J. A. Church, Amer. Jour. Sci. and Arts: April, 

 1879, p. 289-290. 



Killingworth coal mine 



Dolcoifh Coppermine 



Guanaxuato, Mexico 



Maria mine, near Aachen.. 

 Comstock mine 





A comparison of these tables shows a fair agreement between the niiiios and artesian 

 wells, except in the case of the mines at Guanaxuato and the Comstock mine of Ne- 

 vada. The explanation is probably to be found in the presence of igneous rocks at 

 both localities. 



