48 Captain Fornian's Defence of 



about the matter, they would immediately perceive that this 

 objection affects their own theories with tenfold greater force. 

 It is impossible to account for the rismg of the tides, in the old 

 way, without supposing the power of the moon's attraction to 

 be even greater than the earth's ; for, if the power of the earth's 

 attraction was not sufficient to prevent the moon from lifting 

 the particles of water off* its surface, it would never afterwards 

 be able to bring them back again, when its own power must 

 necessarily have diminished by the increased distance, while 

 that of the moon would be proportionably increased. 



If, as the Newtonian philosophers suppose, the power of 

 gravity decreased as the square of the distance increased, the 

 power of the moon's attraction, at the earth's surface, could only 

 be equal to the 144000dth part of the earth's; and in that case 

 I readily admit that it would not be sufficient to produce the 

 quantum of expansion that my theory requires. But this doc- 

 trine, after all, notwithstanding it is so generally entertained, is 

 nothmg more than a mere guess : it is grounded upon no ana- 

 logy, is inconsistent with other opinions that are entertained by 

 the same philosophers, and is evidently not true, because it is 

 in direct opposition to indisputable facts. The Newtonian phi- 

 losophers allow that the velocity of accelerated motion m- 

 creases in arithmetical proportion with the distance, and not 

 as the square of the distance increases ; and, by the same rule, 

 unless it can be shown that the diminution of the power of gra- 

 vity is not constant and gradual, it must decrease inversely in 

 the same proportion ; that is, it must increase, from the point 

 where it ceases, in arithmetical proportion with its distance 

 from it : and consequently, before we can determuie m what 

 proportion the power of gravity in any body decreases, we must 

 first of all ascertain to what extent it reaches. If the diminu- 

 tion of the power of gravity be constant and gradual, as has 

 heretofore been supposed, it must accord with the above rule; 

 and if it be not, it must be mdependent of every rule ; so that, 

 in either case, philosophers are evidently mistaken in supposing 

 that the power of gravity "decreases as the square of the di- 

 stance increases." 



So much for the arguments upon which this famous law is 

 grounded ; let us now see how far it is borne out by facts. Ac- 

 cording to the most approved astronomical calculations, the 

 sun is supposed to be about 96 millions of miles distant from 

 the earth*, and his power of attraction is supposed to be 



* I have said 96 millions in order to avoid a tedious calculation, but 95 

 millions will make the argument still stronger in my favour. 



200,000 



