14 REPORT— 1892. 



those in whicli we still live. They donbtless listened with interest to the 

 speculations of Kant, Laplace, and Herschel, on the probable evolution 

 of nebulte, suns, and planets, but it was with the languid interest attach- 

 ing to ideas that lay outside of their own domain of research. They re- 

 cognised no practical connection between such speculations and the data 

 furnished by the earth itself as to its own history and progress. 



This curious lethargy with respect to theory on the part of men who 

 were popularly regarded as among the most speculative followers of 

 science would probably not have been speedily dispelled by any discovery 

 made within their own field of observation. Even now, after many years 

 of the most diligent research, the first chapters of our planet's history 

 remain undiscovered or undecipherable. On the great terrestrial palimp- 

 sest the earliest inscriptions seem to have been hopelessly effaced by those 

 of later ages. But the question of the primeval condition and subsequent 

 history of the planet might be considered from the side of astronomy and 

 physics. And it was by investigations of this nature that the geological 

 torpor was eventually dissipated. To our illustrious former President, 

 Lord Kelvin, who occupied this chair when the Association last met in 

 Edinburgh, is mainly due the rousing of attention to this subject. By 

 the most convincing arguments he showed how impossible it was to 

 believe in the extreme docti'ine of uniformitarianism. And though, 

 owing to uncertainty in regard to some of the data, wide limits of time 

 were postulated by him, he insisted that within these limits the whole 

 evolution of the earth and its inhabitants must have been comprised. 

 While, therefore, the geological doctrine that the present order of Nature 

 miist be our guide to the interpretation of the past remained as true and 

 fruitful as ever, it had now to be widened by the reception of evidence 

 furnished by a study of the earth as a planetary body. The secular loss 

 of heat, which demonstrably takes place both from the earth and the sun, 

 made it quite certain that the present could not have been the original 

 condition of the system. This diminution of temperature with all its 

 consequences is not a mere matter of speculation, but a physical fact of 

 the present time as much as any of the familiar physical agencies that 

 affect the surface of the globe. It points with unmistakable direct- 

 ness to that beginning of things of which Hutton and his followers could 

 find no sign. 



Another modification or enlargement of the uniformitarian doctrine 

 was brought about by continued investigation of the terrestrial crust and 

 consequent increase of knowledge respecting the history of the earth. 



