ADDRESS. 1 9 



has unconcernedly believed to be ample has somehow taken to itself 

 wings and disappeared. When the geologist was suddenly awakened 

 by the energetic warning of the physicist, who assured him that he had 

 enormously overdrawn his account with past time, it was but natural 

 under the circumstances that he should think the accountant to be mis- 

 taken, who thus returned to him dishonoured the large drafts he had 

 made on eternity. He saw how wide were the limits of time deducible 

 from physical considerations, how vague the data from which they had 

 been calculated. And though he could not help admitting that a limit 

 must be fixed beyond which his chronology could not be extended, he 

 consoled himself with the reflection that after all a hundred millions of 

 years was a tolerably ample period of time, and might possibly have been 

 quite sufficient for the transaction of all the prolonged sequence of events 

 recorded in the crust of the earth. He was therefore disposed to acquiesce 

 in the limitation thus imposed upon geological history. 



But physical inquiry continued to be pushed forward with regard to 

 the early history and the antiquity of the earth. Further consideration 

 of the influence of tidal friction in retarding the earth's rotation, and of 

 the sun's rate of cooling, led to sweeping reductions of the time allowable 

 for the evolution of the planet. The geologist found himself in the 

 plight of Lear when his bodyguard of one hundred knights was cut down. 

 ' What need vou five-and-twenty, ten or five ? ' demands the inexorable 

 physicist, as he remorselessly strikes slice after slice from his allowance 

 of geological time. Lord Kelvin is willing, I believe, to grant us some 

 twenty millions of years, but Professor Tait would have us content with 

 less than ten millions. 



In scientific as in other mundane questions there may often be two 

 sides, and the truth may ultimately be found not to lie wholly with either. 

 I frankly confess that the demands of the early geologists for an unlimited 

 series of ages were extravagant, and even, for their own purposes, unneces- 

 sary, and that the physicist did good service in reducing them. It may 

 also be freely admitted that the latest conclusions from physical con- 

 siderations of the extent of geological time require that the interpretation 

 given to the record of the rocks should be rigorously revised, with the view 

 of ascertaining how far that interpretation may be capable of modification 

 or amendment. But we must also remember that the geological record 

 constitutes a voluminous body of evidence regarding the earth's history 

 which cannot be ignored, and must be explained in accordance with as- 

 certained natural laws. If the conclusions derived from the most careful 

 study of this record cannot be reconciled with those drawn from physical 



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