THE PROBABLE AGE OF THE WORLD. 653 



alike with reasoning from probability or the investigation of facts. 

 In all the operations of Nature as they unfolded themselves before 

 our eyes God worked by law by the process of slow development 

 by means beautifully simple, and involving no viole'nce and no haste, 

 yet irresistible. There was abundant evidence that these causes had 

 been at work for thousands perhaps millions of years before the 

 date of the supposed miracle. Beginning from the present age, the 

 time was calculated that each development would require, till the 

 united aares of all amounted to the enormous sum of three hundred 

 millions of years. 



Modern English geology holds that all geological changes have 

 been effected by agents now in operation, and that those agents have 

 been working silently at the same rate in all past time ; that the great 

 changes of the earth's crust were produced, not by great convulsions 

 and cataclysms of Nature, but by the ordinary agencies of rain, snow, 

 frost, ice, and chemical action. It teaches that the rocky face of our 

 globe has been carved into hill and dale, and ultimately worn down 

 to the sea-level, not only once or twice, but many times over during 

 past ages ; that the principal strata of the rocks hundreds, and even 

 thousands, of feet thick have been formed on ocean-fioor-beds by 

 the slow decay of marine creatures and matter held in solution by 

 the waves ; that every part of the earth has been many times sub- 

 merged, and has again been lifted into the air. This slow rising and 

 sinking of the ground is an axiom of the geological creed. We are told 

 that it is now going on, and that there are large areas of subsidence 

 and of elevation on the surface of the globe. But when we consider 

 the slow rate at which that oscillation is now proceeding, and argue 

 back from the known to the unknown, we are landed in conclusions 

 as to the length of time required for geological changes which the 

 opponents of the theory declare to be absolutely inadmissible. 



Sir William Thomson, Prof. Tait, and Mr. Croll, argue the ques- 

 tion as one of geological dynamics. They find reason, in recent dis- 

 coveries of science, to assert that the sun and the earth, from their 

 physical condition, cannot possibly have existed for the enormous 

 length of time supposed. Playfair, the founder of what is called the 

 Uniformitarian school of geology, declares, on the other hand, that in 

 the existing order of things there is no evidence either of a beginning 

 or of an end. " In the planetary motions," he says, " where geometry 

 has carried the eye so far both into the future and the past, we discover 

 no mark either of the commencement or the termination of the pres- 

 ent order. The author of Nature has not given laws to the universe, 

 which, like the institutions of men, carry in themselves the elements 

 of their own destruction." This was a bold assertion : it was adopted 

 with very little limitation by Sir Charles Lyell and the later geolo- 

 gists his disciples and contemporaries. Indeed, if they admitted 

 any limitations at all, they placed the origin of the world so many 



