284 SEE— TEMPERATURE, SECULAR COOLING [April 20, 



though he no doubt associated them with earthquakes and the sea, 

 which seems to be the view also of Plato, so far as one can judge 

 from his description of the sinking of Atlantis. 



11. The theory here developed was therefore roughly outlined 

 and more or less anticipated by the leading Greek philosophers, 

 especially by Aristotle ; and as formulated by them it continued to 

 be held till modern times, though of late years it has been quite 

 abandoned, owing to the unfortunate development of the theory of 

 tectonic earthquakes. 



12. In the present paper we have examined carefully the ques- 

 tion of the temperature of the earth, and have given what appears 

 to be the most probable law of its internal distribution.^ No external 

 effects traceable to deep-seated movements of heat are discoverable, 

 and we have therefore concluded that the nucleus of the globe is 

 now and always has been quiescent. 



13. The deformations of the earth's surface are found to be due 

 to earthquake processes working just beneath the crust, and to 

 original inequalities of the surface dating from the genesis of the 

 moon, which gave rise to the principal ocean basins. 



14. The two methods for estimating the period since the consoli- 

 dation of the globe agree in indicating that it was of the order of ten 

 million years, and thus by no means so long as many geologists have 

 been inclined to believe. Moreover, appreciable cooling has not 

 extended below the depth of some forty miles, or one one-hundredth 

 of the radius, so that it is confined almost wholly to the crust. 



15. It is estimated that the Andes might be formed in something 

 like three million years, and the plateaus west of the Rocky Mountains 

 in not more than five million years. 



16. When the tension of the imprisoned steam under the oceans 

 becomes very great, it finally causes the crust to yield along the 

 margins, and mountains are pushed up where the crust breaks 

 parallel to the coast. When an avenue of escape is thus once opened 

 for the lava, it continues active, and the mountains grow higher and 

 higher, unless meanwhile the sea recedes to too great a distance. 



^A comparison of the small figure in the right hand upper corner of the 

 diagram with the larger figure F shows how one of the distributions of 

 temperature passes into the other by continuous flow of the heat outward 

 while the planet is consolidating. The monatomic curve thus becomes an 

 ellipse. 



