33(3 l^cp^y io Captain Forman 



are acquainted with hydrostatics, well know that all liquids in 

 open vessels act upon the jirinciple of the syphon inverted. 



The next point to which Ca])tain Fonnan alludes, where he 

 says, " I can prove in hundreds of instances that the tides are 

 rising when his supposed cause has no existence," is decidedly 

 hostile to his (Captain Forman's) hypothesis; for, if my cause 

 has no existence, I would ask Captain Forman where is his 

 cause ? Now I wish to impress Captain Forman's mind with 

 one particular fact, namely, that the instant his cause is re- 

 moved, the effect ceases ; whereas in the old theory, the wa- 

 ters having been I'emoved, and consequently elevated, in en- 

 deavouring to recover their equilibrium, produce those inland 

 flows whicli in many parts of the world do not arrive until the 

 next tide, which is to give birth to the succeeding flow, is even 

 past its highest. Generally speaking, the age ol the tide when 

 it arrives at London Bridge amounts to about twelve hours. 

 The next pomt in question is the Atlantic Ocean ; and here 

 I confess it would be difficult to make 90 degrees out of only 

 60 or 70 ; but as it is well known to every experienced navi- 

 gator that the Atlantic receives its principal supply from the 

 Southern Ocean, I do not perceive that there is any need of 

 conjuration. 



The paragraph of the handful of water which Captain For- 

 man has copied, I am sorry to say has undergone such a 

 change as not only to convince me that he did not understand 

 my meaning, but it has altered the sense materially ; instead 

 of " the moon has no power," it should be " the moon has 

 not power ;" again, " a magnet has no power," should be " a 

 magnet has not power." I say a magnet has not power to 

 lift a scale-beam, and yet it has power to disturb its equili- 

 brium. And this I hesitate not to declare a perfectly analo- 

 gous case with the equilibrium of the ocean, or with the 

 equilibrium of any fluid in any open vessel whatever. If 

 Captain Forman still thinks that it makes any difference 

 whether the balance is su})ported from above or below, w-e 

 may accommodate him with a simple contrivance. 



Let a stick of about an inch in diameter be loaded at each 

 end with a steel ball, taking care that its specific gravity be 

 less than that of water: while swimming on its surface, by ap- 

 plyino- a magnet, the ball to which the influence of the mag- 

 net is directed will be sensibly elevated, although the magnet 

 has not sufficient power to support the ball in the atmosphere. 

 In this experiment the ball under the influence of tlie magnet is 

 elevated by the superior gravity of the other ball, on the same 

 principle that the flood tide is elevated by the superior gravity of 



the 



i 



