CULMINATION OF THE ARGUMENT. 247 



those distant cosmical alterations of which we have spoken, 

 and perhaps force us to make way for new and more com- 

 plete living forms, as the lizards and the mammoth have 

 given place to us and our fellow-creatures which now exist. 



Thus the thread which was spun in darkness by those 

 who sought a perpetual motion has conducted us to a univer- 

 sal law of nature, which radiates light into the distant nights 

 of the beginning and of the end of the history of the universe. 

 To our own race it permits a long but not an endless exist- 

 ence ; it threatens it with a day of judgment, the dawn of 

 which is still happily obscured. As each of us singly must 

 endure the thought of his death, the race must endure the 

 same. But above the forms of life gone by, the human race 

 has higher moral problems before it, the bearer of which it is, 

 and in the completion of which it fulfils its destiny. 



