264 SEE— FURTHER RESEARCHES ON [April 24, 



of the phenomena, both of the animate and inanimate world. The 

 physicist must content himself with showing the mechanical causes 

 at work and their mode of operation, while the geologist and paleon- 

 tologist may deal with the evidences of life under these known 

 conditions. 



§ 56. TIic Eqiiilibriuiii of the EartJi bctzi'ccii tlic Land and Water 

 Hemispheres Explained by the Intnincseencc of the Land Arising 

 from the Expulsion of Porous Lava from under the Bed of the Sea. 

 — The remarkable equilibrium preserved by the earth between the 

 land and water hemispheres has long been a matter of speculation 

 among philosophers. Sir John Herschel j,ustly remarked that the 

 high altitude of the continents in the land hemisphere would be 

 most easily accounted for by an intumescence of the land. Pratt 

 has since treated the question in a convincing manner, and shown 

 that the solid parts of the earth's crust beneath the water hemisphere, 

 with pole in New Zealand, must be denser than in the correspond- 

 ing parts on the opposite side, otherwise the water would flow away 

 towards the land hemisphere and tend to submerge it more com- 

 pletely. (Cf. " Figure of the Earth,"' 3d edition, pp. 159-160.) 

 Hence he concludes that 



" There must therefore be some excess'of matter in the solid parts of the 

 earth between the Pacific ocean, and the earth's center which retains the 

 water in its place." 



When Pratt wrote this forty years ago there was no suspicion of 

 an intumescent layer beneath the land due to the expulsion of porous 

 lava from beneath the bed of the sea, and accordingly he added 

 that 



"This effect may be produced in an infinite variety of ways; and therefore, 

 without data, it is useless to speculate regarding the arrangement of matter 

 which actually exists in the solid parts below." 



Now, however, it is proved that the plateaus and continents have 

 been uplifted by intumescent matter expelled from under the sea ; 

 and consequently we have data for speculating on how the observed 

 effect is produced. 



It is clear that all the great plateaus of the globe and even the 

 continents themselves are underlaid by material lighter than the 

 average of the earth's crust. Naturallv the eft"ects are greatest 



