4,4: Captain Forman's Defence 



lative positions of the rest. Mr. Russell, in his veneration for 

 old theories, will no doubt allow that the power of gravity de- 

 creases as the square of the distance increases ; and, admitting 

 this, he should inform us how the superior gravity of the 

 waters in one part of the world can possibly produce a rising 

 of the v.aters in another part at the distance of nearly 6000 

 miles, when, by the above rule, th.e gravity of the waters in 

 this place is only the 144000d!h part less than it is in the other. 

 In the annexed figure, I have supposed the whole earth to be 

 covered with water, with the 

 moon perpendicular to B, where 

 the watei's, in consequence of her 

 influence, have reached their ut- 

 most height. Now it follows, 

 upon Mr. Russell's principle, that 

 the waters which are rising be- 

 tween C and D must be lifted up 

 by the downward pressure of the 

 waters that are ebbing between 

 B and C ; and consequently that 

 the influence of this downward 

 pressure must extend to the di- 

 stance of 6000 miles, which is 

 about the fourth part of the v.hole circumference of the earth. 

 Tills, however, is not the only difficulty attending Mr. Russell's 

 hypothesis; for if we suppose the waters (which is really the 

 case in the Atlantic Ocean) to be confined within the boun- 

 daries I and //, there will, at this time, be a constant rising in 

 every part, without any downvvard pressure to lift them up. 

 Mr. Russell has endeavoured to explain away tliis objection, 

 by observing that a sufficient quantity of water to produce the 

 flow may be poured in from the Southern Ocean : but this ar- 

 gument completely overturns his own hy);)othesis ; for, to say 

 nothing of the absurdity of supposing that those waters can 

 travel at the rate of three or four thousand miles an hour, which 

 they must do to produce such an effect, the tides would then 

 be raised, not hy the doism'ii.-nrd pi-esstire of those ivaters ivhich 

 constitute the ebb, but by an accumulation of water coming in 

 from the Southern Ocean ; and Mr. Russell has yet to explain 

 in what way this accumulation is produced. Mr. Russell may 

 perhaps be inclined to argue that the waters that constitute the 

 ebb are seldom, if ever, at a greater distance from those that 

 constitute the flood than two or three hundred miles; and I ad- 

 niit that they are not. But then the gravity of all these par- 

 ticles must be very nearly the same, and consequently the one 

 cannot be lifted up by the superior gravity of the other when 



this 



