616 HISTORY OF GEOLOGY. 



from Paradise ; and Buriiet, in his Sacred Theory 

 of the Earth, (1690,) adopted this notion of the 

 paradisiacal condition of the globe : 



The spring 



Perpetual smiled on earth with verdant flowers, 

 Equal in days and nights. 



In modern times, too, some persons have been 

 disposed to adopt this hypothesis, because they 

 have conceived that the present polar distribution 

 of light is inconsistent with the production of the 

 fossil plants which are found in those regions 11 , 

 even if we could, in some other way, account for 

 the change of temperature. But this alteration in 

 the axis of revolution could not take place without 

 a subversion of the equilibrium of the surface, such 

 as does not appear to have occurred; and the 

 change has of late been generally declared impos- 

 sible by physical astronomers. 



The effects of other astronomical changes have 

 been calculated by Sir John Herschel. He has ex- 

 amined, for instance, the thermotical consequences 

 of the diminution of the eccentricity of the earth's 

 orbit, which has been going on for ages beyond the 

 records of history. He finds 18 that, on this account, 

 the annual effect of solar radiation would increase 

 as we go back to remoter periods of the past ; but 

 (probably at least) not in a degree sufficient to 

 account for the apparent past changes of climate. 



11 Lyell, i. 155. Lindley, Fossil Flora. 



12 Geol. Trans, vol. iii. p. 295. 



