283 . 



equal quantities of motioii they produce. But as to tii 

 powers of gravitation and projection, the proportion be- 

 tween them, as ascertained by the ablest mathematicians, 

 is so far from being equal, that the immense disparity 

 between them, can scarce be reduced to a calculation. 

 Therefore it is utterly impossible that these two powers 

 should produce the revolution of the earth. 



If the sun and earth were as near each other as the 

 earth and the moon are, and were left to the power of 

 their mutual attraction, they would move toward each 

 other with the same velocity as it is supposed the earth 

 and rnoon do, which I think is about sixteen feet in a 

 minute : except so far as the proportion of jpatter in the 

 earth to that in the sun, differs from that of the earth to 

 the moon. If then the earth at that distance from the 

 sun, would gravitate toward him with the velocity of 

 sixteen feet in a minute, and if the decrease of gravita- 

 tion, be inversely as the squares of the distances, (that 

 is, at double distances four times less) then the earth 

 being immensely farther from the sun than the moon 

 is from the earth, the velocity with which the earth at 

 her present distance from the sun would move towards 

 him, if left to the power of attraction, must be im- 

 mensely less than sixteen feet in a minute. But what is 

 the force which moves the earth sixteen feet or a thou- 

 sand, to the force of that projection, which is supposed 

 to move it at the rate of near a thousand miles in a 

 minute ? 



In short, if the power of gravitation draws the earth 

 towards its centre of gravity, with the force of sixteen 

 feet, or sixteen hundred in a minute, while the powers 

 o* projection impresses it with the force of almost a 

 thousand miles in the same time, it is impossible for ma- 

 thematics to demonstrate that any orb hurried off by 

 such a projection, can ever be recalled from its eccentric 

 motion, by such an inconceivably small and dispropor- 

 tionate resistance : especially as the power of gravitation, 

 small as it is, must be growing smaller every moment, 

 Nor can the mathematical properties of an 



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