246 THE AGE OF THE EARTH AS AN ABODE FITTED FOR LIFE, 



and the words "meteoroidal aggregate" be substituted in the sentence 

 quoted, it will be a rather too strong statement of the alternative 

 explanation which springs obviously from the meteorological hypoth- 

 esis herein urged. It is not easy to see how such heterogenity as is 

 required to account for the continents and ocean basins could arise 

 from a white-hot liquid-surfaced earth descended from a gaseous earth. 

 To those who do not follow the petrological conceptions of the address, 

 but who conceive the hypothetical lava ocean to have been one great 

 solution, stirred by convectional and other currents and depositing 

 crystals as supersaturation arose from change of temperature or from 

 change in the solution itself, there seems not much more reason to 

 suppose that its deposits would have been localized persistently on the 

 sites of the present continents than to suppose that the present envel- 

 oping solution — the ocean — if duly concentrated, would localize in a 

 similar wa}^ the crystals which it would throw down. But this must 

 be left to the petrologists. I can not, however, express too strongly 

 my appreciation of the value of Lord Kelvin's stalwart opinion respect- 

 ing the incompetency of the thermal theory of crustal deformation, 

 since this carries with itself, more remotely and occultly {jxice Kelvin), 

 an implication of like weakness in the theory of the white-hot earth 

 itself. 

 University of Chicago. 



