36 WASTE AND RECONSTRUCTION. 



of beautiful economy in the works of nature." Such are 

 the words of Dr Hutton in his celebrated ' Theory of the 

 Earth/ towards the end of last century; and such the 

 conclusion at which every one must arrive who gives the 

 matter sufficient and enlightened consideration. But this 

 incessant transmutation of the solid framework of the globe 

 is a conception not readily realised by ordinary minds, partly 

 from the restricted range of observation during a single life- 

 time, and partly from our limited notions of time, which is 

 in itself illimitable and altogether independent of the events 

 that mark the course of its continuity. This difficulty was 

 not unforeseen by the Scotch philosopher, and so he goes 

 on to remark : " It is not to common observation that it 

 belongs to see the effects of time, and the operation of 

 physical causes, in what is to be perceived upon the surface 

 of the earth. The shepherd thinks the mountain on which 

 he feeds his flock to have always been there, or since the 

 beginning of things ; the inhabitant of the valley cultivates 

 the soil as his father had done, and thinks that this soil is 

 coeval with the valley or the mountain. But the man of 

 scientific observation, who looks into the chain of physical 

 events connected with the present state of things, sees great 

 changes that have been made, and foresees a different state 

 that must follow in time, from the continued operation of 

 that which actually is in nature." It is the object of the 

 present Sketch to place this system of waste and reconstruc- 

 tion of destruction and renovation in a clear and obvious 

 light, that the " common" as well as " scientific" mind may 

 perceive the means employed by the Creator to keep this world 

 of ours ever young notwithstanding its vast antiquity, and 

 to maintain its stability in the midst of incessant vicissitude. 



To the casual observer the hills and valleys that surround 

 him appear unchanged and unchangeable. The plains and 



