NATURAL HISTORY. 17 



The ocean, since the creation of the solar system, 

 has been subject to a regular flux and reflux. This 

 motion, which uniformly takes place twice in twenty- 

 four hours, is principally owing to the moon, and is 

 greater in the equatorial regions than in ether climates. 

 The earth too performs a rapid motion on its axis, and 

 consequently has a centrifugal force, which is also 

 the greatest at the equator ; which last circumstance 

 proves that the earth must be more elevated under the 

 equator than at the poles. From the tides, therefore, 

 and the motion of the earth combined, we may fairly 

 conclude, that, though this globe had originally been a 

 perfect sphere, its diurnal motion, and the ebbing and 

 flowing of the tides, must, in a succession of time, have 

 elevated the equatorial part-;, bv gradually carrying 

 mud, shells, &c. from other climates, and depositing 

 them at the equator. On this hypothesis, the great- 

 est inequalities on the earth's surface ought to be found 

 and indeed are found near the equator. But farther, 

 as the alternate motion of the tides has been regular 

 since the existence of the world, may we not naturally 

 imagine, that, at each tide, the water carries from one 

 place to another a small quantity of matter, which 

 falls to the bottom as a sediment, and forms those ho- 

 rizontal and parallel strata that every where appear. 



It may, however, be objected, that as the flux is 

 equal to, and regularly succeeded by the reflux, the 

 two motions will balance one another, and, of conse- 

 quence, that thi; cause of the formation of strata must 

 be chimerical, as the bottom of the ocean can never be 

 affected by a uniform alternate motion of the waters. 



But, in the first place, the alternate motion of the 

 waters is far from being equal, as the sea has a con- 

 tinual motion from east to west, and also as the agi' 



Vol. I. P, 



