1907.] AND CONTRACTION OF THE EARTH. 287 



In conclusion it remains^ to notice one difficulty which has oc- 

 curred to some readers, and thus should perhaps be given further 

 elucidation. By those who have not made a careful study of the 

 porosity of matter under great fluid pressure, it seems to be felt that 

 notwithstanding the apparently conclusive character of Daubree's 

 experiments, they form a rather slender experimental basis upon 

 which to build a satisfactory explanation of the sinking of sea water 

 through the earth's crust, which is composed of from ten to twenty 

 miles of solid rock like granite. That this supposed difficulty is 

 devoid of real foundation will appear from the following considera- 

 tions, which enable us to show that the oceans do experience such a 

 secular leakage, and to prove this fact quite independently of 

 Daubree's experiments. 



I. In the paper on the cause of earthquakes, § 15, it is shown that 

 the chances are at least (100 billion)® or a decillion decillions to one, 

 that the mountains are formed parallel to the shore by a true physi- 

 cal cause depending on the oceans. This is of course an absolute 

 certainty. The mountains therefore depend in some way upon the 

 sea. To perceive most clearly what this dependence is, we may 

 notice, as in the former paper, that the elevation of the Andes has 

 been accompanied by the sinking of the adjacent sea bottom into a 

 parallel trough of about the same volume. That lava has been ex- 

 pelled from beneath the sea and pushed up under the land is indicated 

 by the depression in the sea bottom parallel to the Andean Cordillera ; 

 and this inference drawn from the geometrical evidence of the sur- 

 face of the lithosphere is confirmed by direct observations, made 

 within the historical period, on those earthquakes which produce 

 sensible uplifts of the coast and simultaneous subsidences of the sea 

 bottom, as shown by the accompanying seismic sea waves. More- 

 over unbroken continuity between the small uplifts and subsidences 

 observed within the historical period and the vastly greater move- 

 ments gradually accumulated during past geological ages is estab- 

 lished by the deposits of shells and fossil beds found at great heights 

 in the Andes, and by the deep depressions in the adjacent oceanic 

 trough. It is therefore undeniable that in the course of long ages 



^This closing discussion, with the exception of the last sentence, was 

 added April 18, 1907. 



PROC. AMER. PHIL. SOC, XLVI. i86r, PRINTED SEPTEMBER 7, I907. 



