162 SEE— FURTHER RESEARCHES ON [April 24, 



crevices thus formed would not extend over five or six miles deep 

 before they would be closed by the eft'ects of pressure, which nat- 

 urally increases rapidly as we descend into the earth. The belief 

 has therefore prevailed that although the bed of the sea might be 

 rent by an earthquake, it would immediately close up again, and 

 water would thus be prevented from entering the bowels of the globe. 



It scarcely seems to have occurred to investigators to consider 

 the effects of the constant hydrostatic pressure resulting from the 

 depth of the sea, in forcing the water slowly through the fifteen 

 miles of granite composing the earth's crust. A crevice is small, 

 and would let in but little water when closed up quickly; but the 

 whole sea bottom is large, and unless it is really water-tight, even 

 a slow leakage over a large area would at length develop stresses 

 beneath which would necessitate a readjustment of the overlying 

 blocks of the crust. This readjustment is ordinarily called an 

 earthquake. 



Moreover the great abundance of submarine earthquakes has been 

 largely overlooked by previous investigators. It is the secular 

 effect of the constant pressure of the oceans and of capillary forces 

 in promoting the downward movement of the water which has been 

 generally lost sight of. 



But if we admit on the basis of experimental evidence that 

 water can penetrate thin layers of granite, the question naturally 

 arises : Can it also penetrate a layer of granite fifteen or twenty 

 miles thick? It seems obvious that it can, because for small or 

 moderate pressures water is nearly incompressible and would not 

 sensibly increase in density as it went down into the globe. The 

 fluid which passed through the upper layer of granite would there- 

 fore keep on descending, under the increasing fluid pressure from 

 above, and at length the whole layer would be saturated, and per- 

 spiring below with a steady leakage which would give rise to tre- 

 mendous steam power in the underlying molten rock. Thus great 

 stresses due to slow accumulation of steam would develop in the 

 layer just beneath the crust, and this would give rise to earthquakes 

 and mountain formation. 



Among the practical men of science to whom the problem of 

 ocean leakage was submitted, we might name some of the most 



