The Evolution of the Sciences 



First of all, one thing is certain, the earth has 

 been fluid at some period of its evolution. Of 

 this we have two proofs, each sufficient to carry 

 conviction. The first, known already to New- 

 ton, is based on the flattening of the earth, but 

 some explanation is necessary to enable us to 

 appreciate its value. The oceans cover three- 

 quarters of the globe, and their surface of equili- 

 brium is placed upon an ellipsoid of revolution, 

 which differs very little from a sphere, as its 

 equatorial radius is only 13^ miles longer than 

 its polar radius. This proves only that the 

 earth rotates. This rotation gives rise to a 

 centrifugal force, which increases from pole to 

 equator with the radius of rotation. Conse- 

 quently the mass of equatorial waters, being 

 relieved of part of its weight by this contrary 

 force, rises higher than the mass of polar 

 waters, and the ascertained difference of level 

 is precisely what results by calculation from 

 the velocity of rotation. 



But let us suppose all this liquid absent, or 

 pumped on to some other planet, leaving the 

 earth's crust quite dry. It would appear to us 

 ridged and irregular, hollowed into profound 



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