OF THE EARTH'S AXIAL ROTATION. 7 



beginning of time, and will always go on ; that the Rotation 

 of the Earth is a free motion, in which the slightest quantity 

 that is taken from it is lost without reparation, whereas 

 the diminishing cause remains unceasingly active in the 

 same strength, it would be a prejudice highly unbecoming 

 in a philosopher to declare a slight effect to be insignificant 

 when, by its constant summation, it must yet ultimately 

 exhaust even the largest quantity. 



In order that we may estimate in some measure the 

 greatness of the effect which the constant movement of 

 the ocean from east to west opposes to the axial rotation 

 of the earth, we shall only calculate the onset which the 

 ocean makes upon the eastern coasts of the continent of 

 America ; and we shall prolong its extension to both poles, 

 while we shall more than abundantly compensate for what 

 is wanting in that range by the projecting point of Africa 

 and the eastern coasts of Asia. Let us put the velocity 

 of the said ocean movement at the equator at one foot 

 a second, let it decrease towards the poles proportionally 

 with the parallel movement of the circles of latitude, and 

 finally let the height of the surface which the solid land 

 presents to the onset of the water, estimated in perpen- 

 dicular depth, be taken at 100 fathoms; then we shall 

 find that the force of the violence with which the ocean 

 presses by its motion upon this opposing surface will be 

 equal to the weight of a body of water whose basis is 

 equal to the whole said surface extending from the one 

 pole to the other, and its height ^| T of a foot. This 

 body of water, which comprises eleven times a hundred 

 thousand cubic fathoms, is exceeded by the magnitude of 

 the terrestrial globe 123 bimillion times; and as the weight 

 of this body of water always presses against the motion 



