286 SEE— TEMPERATURE, SECULAR COOLING [April 20, 



21. The calculated fall of temperature for the whole earth of 

 10° C. (Tait) and of 45° C. (Daniell) in 100 million years, with 

 the cubical coefficient of expansion of 0.00002, found by experiment 

 for average rock of the earth's crust, would produce a shrinkage of 

 only 0.26 and 1.16 miles respectively. But if the period since the 

 earth's consolidation be only about one tenth that here assumed, ac- 

 cording to the usage of geologists, the corresponding contraction 

 would certainly not much exceed one tenth of these values, or say 137 

 and 612 feet. These values are so very small that the uplifts due to 

 earthquakes might easily cause the globe to expand rather than con- 

 tract. Accordingly if our present data do not enable us to conclude 

 that the earth is undergoing secular expansion, we may at least 

 conclude that it certainly is not sensibly contracting. Its dimensions 

 seem to have been nearly stationary since the consolidation began. 



22. The principal phenomenon heretofore requiring the theory of 

 contraction is the formation of mountains ; but Rev. O. Fisher has 

 shown that this cause is quite inadequate, and in the paper on the 

 cause of earthquakes we have developed the theory of mountain 

 formation depending on the sea. The doctrine of the secular con- 

 traction of the globe must therefore be entirely abandoned, and the 

 explanation of the phenomena sought in other causes. 



23. By the existence of unstable pinnacles of rock formed by 

 the gradual processes of geological time it seems to be proved that 

 no deep and very powerful convulsions of our globe, except the 

 ordinary shocks noticed in earthquakes, have taken place in many 

 millions of years. We must therefore ascribe to ordinary world- 

 shaking earthquakes the highest geological significance. These 

 forces depending on the sea produce both elevations and depressions 

 of the land, and explain all the phenomena of movement witnessed 

 upon the earth. 



24. In the development of these views Aristotle and Strabo 



occupy the foremost places among the ancients ; Humboldt, Lyell 



and Darwin among the moderns; while Fourier and Lord Kelvin 



naturally claim the leading places among the illustrious physicists 



who have occupied themselves with these great problems of the heat 



of our planet. 



Blue Ridge on Loutre, 



Montgomery City, Missouri, March 22, 1907. 



