288 SEE— TEMPERATURE, SECULAR COOLING [April 20, 



the mountains and coast have been greatly elevated and the adjacent 

 sea bottom correspondingly sunk down. 



2. The earthquake shocks producing these effects are found to 

 occur at a depth of some 15 miles, where the pressure is so great that 

 no cavities in the earth can possibly exist. Therefore there are 

 neither voids at this depth beneath the mountains nor corresponding 

 increases of density beneath the sea where the bottom has subsided, 

 but vast quantities of matter have been expelled from beneath the 

 ocean and pushed up under the adjacent mountains. These phenom- 

 ena, as observed in South America, are clear and indisputable, and 

 admit of but one interpretation : namely, that the Andes have been 

 formed by successive earthquakes which have expelled the lava from 

 beneath the bed of the adjacent sea, and thus upraised the crust into 

 some of the mightiest mountains of the globe. 



3. The next question then becomes : How is the lava expelled 

 from under the sea? We say lava rather than solid rock, because 

 owing to the increase of underground temperature, at a depth of 

 15 to 20 miles below the surface, where the world-shaking earth- 

 quakes originate, the matter must be essentially molten, in spite of 

 the great pressure to which it is subjected. We therefore answer 

 that since the earth is neither contracting nor experiencing any other 

 sensible changes from secular cooling, the expulsion can be accom- 

 plished only by explosive vapors such as are emitted from the 

 neighboring volcanoes, which often break out into eruption simul- 

 taneously with an earthquake noticed to produce an elevation of the 

 shore and a sinking of the sea bottom. This vapor therefore can be 

 nothing else than common steam. 



4. Now the steam developing beneath the earth's crust and pro- 

 ducing earthquakes and volcanic activity can be traced to but two 

 possible sources : First, the original magma of the globe, which, in 

 default of a better explanation, has been frequently invoked by the 

 geologist ; Second, the secular leakage of the ocean bottoms effected 

 through 15 miles of solid rock like granite, which naturally appeals 

 to the physicist. If the escaping steam, or any sensible part of it, 

 came from the central magma of the globe, volcanoes and earth- 

 quakes necessarily would occur in the interior of continents as well 

 as along the coasts, on islands, and in the depths of the sea. For 



