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



the heat is available within the life era of the earth, instead of being 

 brought to the surface and dissipated in the prezoic hot stage, when 

 it was a barrier to the existence of life instead of an aid. 



Ao-ain, in the liquid earth there were the best imaginable conditions 

 for the intermixture of the earth constituents and for the formation 

 of such chemical and mineral combinations as best accorded with the 

 high pressures of the interior. In the heterogeneous solid earth, on 

 the other hand, such combinations were restrained and delayed and 

 have been able to take place only slowly throughout the secular inter- 

 mingling of the internal material. It, therefore, hypothetically follows 

 that throughout geological ages, as the internal material was able slowly 

 to readjust itself, new chemical and mineral combinations become 

 possible. These combinations would be controlled by the high pres- 

 sure in the interest of maximum density, and of hypothetically possi- 

 ble mineral combinations, only those would form which gave the 

 higher density.^ Thus a slow process of recrystallization in the inter- 

 est of greater density would be in progress throughout the ages. This 

 denser crystallization would set free heat. It would furthermore per- 

 mit the shrinkage of the whole mass and consequent intensihcation of 

 its self -gravitation, and this would in turn result in further develop- 

 ment of heat. This large possible shrinkage meets the demands of 

 geological phenomena at a point where the liquid earth has been felt 

 to conspicuously fail. The losses of heat from the earth, as computed 

 by Lord Kelvin and other authorities, and the skrinkage resulting 

 therefrom have long been held to be quite incompetent to produce the 

 observed inequalities. Their incompetence is now very generally 

 admitted by careful students. Lord Kelvin also admits this by impli- 

 cation when he says (sec. 31, p. 706): 



"If the shoaling of the lava ocean up to the surface had taken place 

 everywhere at the same time, the whole surface of the consistent solid 

 would be the dead level of the liquid lava all around, just before its 

 depth became zero. On this supposition there seems no possibility 

 that our presenc-day continents could have risen to their present 

 heights, and that the surface of the solid in its other parts could have 

 sunk down to their present ocean depths, during the twenty or twenty- 

 five million years which may have passed since the consistentior status 

 began, or during any time however long." 



In addition to this recognized quantitative -deficiency, the present 

 writer has been led to question its qualitative adaptability. The phe- 

 nomena of mountain wrinkling and of plateau formation, as well as 

 the still greater phenomena of continental platforms and abysmal 

 basins, seem to demand a more deep-seated agency than that which is 

 supplied by superficial loss of heat. This proposition demands a 

 more explicit statement than is appropriate to this place, but it must 



1 Prof. C. R. ^^an Hise has worked this out elaborately in manuscript not yet pub- 



