i. TESOLOGI 



NATURAL TllfilO:l;iOv^|S^ 



CHAPTER I. 



STATE OF THE ARGUMENT.* 



I\ crossing a heath, suppose I pitched my foot 

 against a stone, and were asked how the stone came 

 to be there, I might possibly answer, that, for any- 

 thing I knew to the contrary, it had lain there for 

 ever; nor would it, perhaps, be very easy to show 

 the absurdity of this answer.f But suppose I had 



* The last note of the Appendix describes the mechaniem of a 

 watch, and iUustrates the elementary principles of mechanics. 

 Contrasted with the mere mechanism, there is another essay on 

 the mechanism of the animal body. These may be perused either 

 before or after reading the present chapter. 



t The argument is here put very naturally. But a considerable 

 change has taken place of late years in the knowledge attained 

 even by common readers, and there are few who would be with- 

 out reflection " how the stone came to be there." The changes 

 which the earth's surface has undergone, and the preparation for 

 its present condition, have become a subject of high interest; and 

 there is hardly any one who now would, for an instant, believe 

 that the stone was formed where it lay. On lifting it, he would 

 find it rounded like gravel in a river : he would see that its aspe- 

 rities had been worn off, by being rolled from a distance in water : 

 he would perhaps break it, look to its fracture, and survey the 



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