Earth as an Abode fitted for Life. 89 



Newcomb, and myself * says NO if the consolidation of the 

 earth took place as long ago as 50 million years ; the solid 

 earth mast in that case have waited 20 or 50 million years 

 for the sun to be anything nearly as warm as he is at present. 

 If the consolidation of the earth was finished 20 or 25 million 

 years ago, the sun was probably ready, — though probably 

 not then quite so warm as at present, yet warm enough 

 to support some kind of vegetable and animal life on the 

 earth. 



§ 44. My task has been rigorously confined to what, 

 humanly speaking, we may call the fortuitous concourse of 

 atoms, in the preparation of the earth as an abode fitted for 

 life, except in so far as 1 have referred to vegetation, as 

 possibly having been concerned in the preparation of an 

 atmosphere suitable for animal life as we now have it. 

 Mathematics and dynamics fail us when Ave contemplate 

 the earth, fitted for life but lifeless, and try to imagine the 

 commencement of life upon it. This certainly did not take 

 place by any action of chemistry, or electricity, or crystalline 

 grouping of molecules under the influence of force, or by any 

 possible kind of fortuitous concourse of atoms. We must 

 pause, face to face with the mystery and miracle of the 

 creation of living creatures. 



Addendum. — May 1898. 



Since this lecture was delivered I have received from 

 Professor Roberts-Austen the following results of experiments 

 on the melting-points of rocks which he has kindly made at 

 my request : — 



Melting-point. Error. 



Felspar. . . 1520° C. ±30° 



Hornblende . about 1400° 



Mica . . . 1440° ±30° 



Quartz . . . 1775° +15° 



Basalt . . . about 880° 



These results are in conformity with what I have said in 

 §§ 26-28 on the probable origin of granite and basalt, as 

 they show that basalt melts at a much lower temperature 

 than felspar, hornblende, mica, or quartz, the crystalline in- 

 gredients of granite. In the electrolytic process for pro- 

 ducing aluminium, now practised by the British Aluminium 



* See ' Popular Lectures and Addresses,' vol. i. pp. 376-429, par- 

 ticularly page 397. 



