190 LIGHT SCIENCE FOR LEISURE HOURS. 



Lyell that, c the general tendency of subterranean 

 movements, when their effects are considered for a 

 sufficient lapse of ages, is eminently beneficial, and 

 that they constitute an essential part of that mechanism 

 by which the integrity of the habitable surface is pre- 

 served. Why the working of this same machinery 

 should be attended with so much evil, is a mystery far 

 beyond the reach of our philosophy, and must probably 

 remain so until we are permitted to investigate, not 

 our planet alone and its inhabitants, but other parts of 

 the moral and material universe with which they may 

 be connected. Could our survey embrace other worlds, 

 and the events, not of a few centuries only, but of 

 periods as indefinite as those with which geology 

 renders us familiar, some apparent contradictions might 

 be reconciled, and some difficulties would doubtless be 

 cleared up. But even then, as our capacities are 

 finite, while the scheme of the universe may be in- 

 finite, both in time and space, it is presumptuous to 

 suppose that all source of doubt and perplexity would 

 ever be removed. On the contrary, they might, 

 perhaps, go on augmenting in number, although our 

 confidence in the wisdom of the plan of nature should 

 increase at the same time ; for it has been justly said ' 

 (by Sir Humphry Davy) e that the greater the circle 

 of light, the greater the boundary of darkness by 

 which it is surrounded.' 



(From the ComMl Magazine, March, 1868.) 



