158 SEE— FURTHER RESEARCHES ON [April 24, 



tain formation and kindred phenomena connected with the 

 physics of the earth. In the course of these three memoirs many 

 important questions are considered, and it seems to be rendered 

 highly probable that six great classes of phenomena, not heretofore 

 closely associated, depend on a single physical cause, namely, the 

 secular leakage of the ocean bottoms, and the resulting movement of 

 molten rock beneath the earth's crust. The six classes of phenomena 

 traced to a single physical cause are : ( i ) world-shaking earth- 

 quakes; (2) the activity of volcanoes; (3) mountain formation; 

 (4) the formation of islands and plateaus; (5) seismic sea waves; 

 (6) the feeble attraction of mountains and plateaus long noticed 

 in geodesy. 



The first of the memoirs printed by the American Philosophical 

 Society deals with the problem of earthquakes in its general aspects, 

 and sets forth grounds for the theory that these six classes of phe- 

 nomena are directly connected and dependent on a single physical 

 cause ; the second examines the question of the earth's temperature, 

 secular cooling and contraction, and endeavors to show that the 

 traditional theory of the changes noticed on the earth's surface is 

 not well founded ; while the third seeks to demonstrate the more 

 important conclusions reached in the first memoir, by an appeal to 

 processes now at work in the depths of the sea, the meaning of which 

 apparently is so plain as to admit of no possible doubt. 



The change in the point of view necessitated by the considera- 

 tions brought forth in these papers is so remarkable as to be worthy 

 of the attention of all who are interested in the grand science of 

 natural philosophy. And we therefore propose to consider in this 

 paper the physical basis of the theory of ocean leakage, the folding 

 of mountain ranges and the uplift of plateaus and continents pro- 

 duced by movements of lava beneath the crust, together with the 

 historical aspects of the problems of the physics of the earth. 

 Heretofore the nature of the forces which have folded mountain 

 ranges and their relationship to those slow movements which have 

 raised whole continents have been equally mysterious and bewilder- 

 ing to the investigator. Accordingly any light which may be shed 

 on this difficult subject will no doubt be exceedinglv welcome to 

 those who are interested in the progress of the physical sciences. 



