Chap. 45-] [ 2 *7 1 



CHAP. XLV. 



THE STRUCTURE OF THE EARTH. 



*The Curioflty of Man on this Topic limited by the Weaknrfs of his 

 Powers. The Body of the Earth difpofed in Strata. Declivities of 

 Mountains. Dijfojition and Order of the Strata. Caldy IJland.~ 

 Where Metals are ufually foiled. Probable State of the Earth at its 

 Creation. Lanus by 'which Alterations 'would be produced. Fojfil 

 Shells, &c. accounted for. Formation of IJlands, ffr. Other Irre- 

 gularities of the Earth's Surface explained. 



AFTER the preceding furvey of the natural 

 contents of this globe of earth, and of their com- 

 ponent principles, the next object of attention is the 

 earth itfelf, and the general arrangement of thofe fub- 

 flances of which it is compofed. Thefe are neither 

 difpofed in a regular feries, according to their fpecific 

 gravities, nor yet thrown together in total diforder, as 

 if by accident or chance. Human industry has hitherto 

 been able to penetrate but a very little way into the 

 bowels of the earth, and we can but know little of its 

 interior parts. The depth of the earth, from the fur- 

 face to the center, is more -than four thoufand miles, 

 and yet the deepeft mine in Europe, that at Cotteberg, 

 in Hungary, is not more than one thouland yards 

 deep ; " the greateft depth, therefore," fays an excel- 

 lent writer, "to which avarice has ever yet penetrated, 

 may be compared to the pun&ure made in the body of 

 an elephant by the probofcis of a gnat." 



From what has been difcqvered, however, of thofe 

 parts which lie moft contiguous to our obfervation, 

 naturalifts have compared the ftructure of the earth to 

 the leaves of a book, or the coats of an or.ion. Ex- 

 cept, 



