124 LECTURES 



gone still further, and vindicated her claim to be considered the chief 

 handmaid of religion among the sciences. But this would have led 

 me much too far. Thirty years later, and all I have thus far said 

 would have been unnecessary. One generation more and geology 

 will need no defender ; both her dignity and her religious tendency 

 will be universally acknowledged. But for this purpose one more 

 generation must first pass away. 



Perhaps it may seem to some of you as a startling paradox, but it 

 is nevertheless a fact, that the shortness of human life is one of the 

 most powerful elements of human progress. It would seem as if the 

 human mind grows and develops, the philosophy and opinions which 

 govern the conduct of life continue to be modified and moulded, until 

 about the age of twenty-five or thirty, when the character becomes 

 unchangeable, opinions become prejudices, and the whole mind, as it 

 were, petrified. Further progress would be impossible, but that 

 another generation, with minds still plastic, comes forward, takes up 

 and carries on the work a few steps, and becomes petrified in its turn. 

 There are certainly some noble exceptions to this rule — instances of 

 minds which with their maturity retain the plasticity of youth — but 

 the very rarity of the exception only proves the rule. 



You doubtless recollect that tlie children of Israel wandered forty 

 years in the wilderness before they were fit to enter the promised 

 land. The marks of Egyptian bondage were upon their souls as well 

 as upon their necks. One generation must fall in the wilderness, and 

 a new generation, free from Egyptian prejudices, must arise. We 

 are apt to look upon this as an isolated fact in history, and entirely 

 characteristic of this peculiar people. On the contrary, it is a fact 

 of deepest significance in the philosophy of human progress, and 

 intended for the instruction of us all. To this day it seems to be im- 

 possible that any great step should be made in the intellectual progress 

 of our race, except by the sacrifice of at least one generation. We 

 are even now in the midst of such a great change, brought about by 

 the revelations of geology. One more generation dropped in the 

 wilderness and we are fairly in the promised land. Do not misunder- 

 stand me, however, as quai rolling with this conservative spirit; on 

 i\\e contrary, this brake upon the wheels of the car of progress seems 

 absolutely necessary for its steady motion. 



But I find I am again digressing, and therefore hasten to return to 

 my subject. 



I have said that the field of geology is the universe of time. It is 

 one of these time-worlds of which I wish to draw a true, though 

 necessarily an outline, picture in the next two or three lectures. I 

 shall not attempt more than an outline, for this would only tire you 

 with a multitucle of details, but shall seize, if possible, the most strik- 

 ing features, make a comparison between this and other subsequent 

 time-worlds, particularly our own, and endeavor to find the law which 

 binds the whole into one system. 



Among the many time-worlds of which geology tells us I select but 

 one, viz : the Coal Period. Its position is far back in the pah\3ozoic 

 times. Measuring time by space it is in the region of the fixed stars, 

 although one of the brightest in the firmament of time. If I could 



