Evolution of tJui Earth. 103 



of infinite time, of wiiich the life of humanity is but an 

 ej>och, Avas then born in the mind of man ; and again the in- 

 tellectual horizon of man was infinitely extended. These 

 two were the grandest ideas, and their introduction the 

 grandest epochs, in the intellectual histoi-y of man " 



When Ave note that all these processes of geological change 

 have tended to diversify the earth's surface, — to produce 

 variety in scenery, in climate, in vegetation, in fauna, — 

 when we see them followed by steadily increasing integra- 

 tion of structure and individuality of feature, in landscape 

 and in organic life, we cannot avoid the conclusion that the 

 entire process of geological change has been one of evolution, 

 obedient to the mandates of constant and invariable natural 

 laws. And if Ave take the simplest integral product of this 

 evolutionary process — a pebble from the sea-shore, or a 

 mote of dust floating in the sun-kissed air — and trace back 

 the causes Avhich operated to bring it into its present condi- 

 tion ; if Ave folloAv it through the action of all the forces^ 

 igneous, aqueous, atmospheric, that formed and disinte- 

 grated the primeval rock, back to the sun, whose heat set in 

 motion all these terrestial agencies ; back again, to the ac- 

 tion of the cosmic forces that formed the worlds and sent 

 them spinning around their central orbs, — -back still, to the 

 distant systems of Avorlds, Avhich, through the action or 

 gravity, balance and sustain each other in their several 

 courses through the infinite regions of space, — then, indeed^ 

 shall Ave realize that it takes the Infinite and Absolute fully 

 to explain the smallest things. We shall see that the Per- 

 sian aphorism but clothes the sober truth of science in poetic 

 form, Avhen it affirms that " God viaketh of every atom of 

 the Universe a mirror, and fronteth each with his perfect 

 fnceP 



