OF GEOLOGICAL DYNAMICS. 83 



" ' that the sun has not illuminated the earth for 

 " ' 100,000,000 years, and almost certain that he 

 " ' has not done so for 500,000,000 years. As for 

 " ' the future, we may say with equal certainty that 

 " ' the inhabitants of the earth cannot continue 

 " ' to enjoy the light and heat essential to their 

 " ' life for many million years longer, unless new 

 " ' sources now unknown to us, are prepared in the 

 " ' great storehouse of creation.' " 



" This result of Professor Thomson's, although 

 " very liberal in the allowance of time, Jias offended 

 " geologists , because, having been accustomed to deal 

 ' with time as an infinite quantity at tJieir disposal, 

 "they feel naturally embarrassment and alarm at 

 " any attempt of the science of PJiysics to place a 

 "limit upon tJieir speculations. It is quite possible 

 " that even a hundred million of years may be 

 " greatly in excess of the actual time during which 

 " the sun's heat has remained constant" 



" Although * I have spoken somewhat disrespect- 

 fully of the geological calculus in my lecture, yet 



1 Manual of Otology. By the Rev. S. Haughton, F.R.S. Edition 

 1865, p. 99. 



G 2 



