344 AGE OF THE EARTH AS AN ABODE FITTED FOR LIFE. 



face rock equal in bulk to the whole earth. No hypothesis as to chemi- 

 cal action, internal fluidity, eft'ects of pressure at great depth, or possible 

 character of substances in the interior of the earth, possessing the 

 smallest vestige of probability, can justify the supi)Osition that the 

 earth's upper crust has remained nearly as it is, while from the whole 

 or from any part of-the earth so great a quantity of heat has been lost." 



14. The sixteen words which I have emphasized in reading this state- 

 ment to you (italics in the reprint) indicate the matter-of-fact founda- 

 tion for the conclusion asserted. This conclusion suffices to sweep 

 away the whole system of geological and biological speculation demand- 

 ing an "inconceivably" great vista of past time, or even a few thousand 

 million years, for the history of life on the earth and approximate 

 uniformity of i^lutonic action thi-oughout that time, which, as we have 

 seen, was very generally i^revalent thirty years ago among British 

 geologists and biologists, and which, I must say, some of our chiefs of 

 the present day have not yet abandoned. Witness the presidents of 

 the geological and zoological sections of the British Association at its 

 meetings of 1893 (ISTottingham) and of 1896 (Liverpool). 



Mr. Teall: Presidential Address to the Geological Section, 1893. 

 "The good old British ship ' Uniformity,' built by Hutton and refitted 

 by Lyell, has won so many glorious victories in the past, and apjDears 

 still to be in such excellent tightiug trim, that I see no reason why she 

 should haul down her colors either to 'Catastrophe' or 'Evolution.' 

 Instead, therefore, of acceding to the request to 'hurry up,' we make 

 a demand for more time." 



President Poulton : Presidential Address to the Zoological Section, 

 1896, "Our argument does not deal with the time required for the 

 origin of life, or for the development of the lowest beings with which 

 we are acquainted from the first formed beings, of which we know 

 nothing. Both these jirocesses may have required an immensity of 

 time; but as we know nothing whatever about them, and have as yet 

 no prospect of acquiring any information, we are compelled to confine 

 ourselves as to much of the process of evolution as we can infer from 

 the structure of living and fossil forms — that is, as regards animals, 

 to the development of the simplest into the most comj)lex Protozoa, 

 the evolution of the Metazoa from the Protozoa, and the branching of the 

 former into its numerous Phyla, with all their classes, orders, families, 

 genera, and sj^ecies. But we shall find that this is quite enough to 

 necessitate a very large increase in the time estimated by the geologist.'''' 



15. In my own short jDaper, from which I have read you a sentence, 

 the rate at which heat is at the present time lost from the earth by 

 conduction outward through the upper crust, as proved by observa- 

 tions of underground temperature in different parts of the world and 

 by measurement of the thermal conductivity of surface rocks and 

 strata, sufficed to utterly refute the doctrine of uniformity as taught 

 by Hutton, Lyell, and their followers, which was the sole object of that 

 paper. 



16. In an earlier communication to the Eoyal Society of Edinburgh^ 



1 Ou the Secular Cooling of the Earth, Trans. Roy. Soc, Edinburgh, Vol. XXIII, 

 April 28, 1862, reprinted in Thomson and Tait, Vol. Ill, pages 468-485, and Math, and 

 Phys. Papers, Art. XCIV, pages 295-311. 



