Sir A. GeiJcie — Age of the Earth. 453 



themselves. About thirty years ago, however, they were startled 

 by a bold irruption into their camp from the side of physics. They 

 were then called oa to reform their ways, which were declared to be 

 flatly opposed to the teachings of natural philosophy. Since that 

 period the discussion then started regarding the age of the Earth 

 and the value of geological time has continued with varying 

 animation. Evidence of the most multifarious kind has been 

 brought forward, and arguments of widely different degrees of 

 validity have been pressed into service both by geologists and 

 palfieontologists on one side and by physicists on the other. For 

 the last year or two there has been a pause in the controversy, 

 though no general agreement has been arrived at in regard to the 

 matters in dispute. The present interval of comparative quietude 

 seems favourable for a dispassionate review of the debate. I 

 propose, therefore, to take, as perhaps a not inappropriate subject on 

 which to address geologists upon a somewhat international occasion 

 like this present meeting of the British Association at Dover, the 

 question of Geological Time. In offering a brief history of the 

 discussion, I gladly avail myself of the opportunity of enforcing one 

 of the lessons which the discussion has impressed upon my own 

 mind, and to point a moral which, as it seems to me, we geologists 

 may take home to ourselves from a consideration of the whole 

 question. There is, I think, a practical outcome which may be 

 made to issue from the controversy in a combination of sympathy 

 and co-operation among geologists all over the world. A lasting 

 service will be rendered to our science if by well-concerted effort 

 we can place geological dynamics and geological chronology on 

 a broader and firmer basis of actual experiment and measurement 

 than has yet been laid. 



To understand aright the origin and progress of the dispute 

 regarding the value of time in geological speculation, we must take 

 note of the attitude maintained towards this subject by some of the 

 early fathers of the science. Among these pioneers none has left 

 his mark more deeply graven on the foundations of modern geology 

 than James Hutton. To him, more than to any other writer of 

 his day, do we owe the doctrine of the high antiquity of our globe. 

 No one before him had ever seen so clearly the abundant and 

 impressive proofs of this remote antiquity recorded in the rocks of 

 the earth's crust. In these rocks he traced the operation of the same 

 slow and quiet processes which he observed to be at work at present 

 in gradually transforming the face of the existing continents. When 

 he stood face to face with the proofs of decay among the mountains, 

 there seems to have arisen uppermost in his mind the thought of the 

 immense succession of ages which these proofs revealed to him. 

 His observant eye enabled him to see " the operations of the surface 

 wasting the solid body of the globe, and to read the unmeasurable 

 course of time that must have flowed during those amazing 

 operations, which the vulgar do not see, and which the learned seem 

 to see without wonder." ^ In contemplating the stupendous results 



1 " Theory of the Earth," toL i, p. 108. 



