92 On a New Theoty of the Tides. 



of expansion in the particles below to push them upwards ; 

 and therefore, however it jnay appear to contradict our experi- 

 ments and preconceived opinions, the fact is indisputable. 



Tlie same argument applies with equal force to the rising of 

 the tides on the side opposite the moon ; for, if the waters on 

 this side were left behind, as Newton supposed, by the other 

 parts of the earth being more strongly attracted by the moon in 

 consequence of being so much nearer, or were carried upwards 

 by a centrifugal force, they could have no tendency to press 

 downwards ; and yet we find that, at the very moment they 

 are rising uj)wards, it is nothing but the resistance of the water 

 below that prevents them from falling down towards the earth's 

 centre. On this side then, as well as on the other, there must 

 be an expansion of the particles of water to produce a rising 

 of the tides; and, as the direction of the moon's attraction is 

 here the same as the earth's, we can only account for this di- 

 minution of the weight or gravity of the particles of water on 

 this side the earth, by supposing that the power of the moon's 

 attraction takes off some portion of the power of the earth's 

 attraction, in the same manner as I have shown the attraction 

 of one magnet will diminish the attraction of anothei', when 

 tlieir two ends are of the same denomination. 



You see then, gentlemen, that this is not a question of mere 

 opinion : it is a question of facts, and is to be proved, not by 

 supposing wliat the known degree of the compressibility of 

 water vuiy be capable of producing, but what it actually does 

 produce. In short, we have only to take a handful of water 

 out of the ocean, at the tune of the rising of tlie tides, to be 

 convinced that the expansion of water is the immediate cause 

 of the phtenomenon ; because, if tlie waters were pulled up- 

 ward by the power of the moon's attraction and not pushed 

 upwards by the expansion of the particles below, this water 

 would not tall back to the earth, until tlie influence of the 

 moon's attraction had gone off. 



Here then, gentlemen, upon these grounds I rest my case ; 

 and I call upon you, and, as I intend that this letter shall go 

 forth into the world, I call upon every astronomer and every 

 philosopher, to answer the following questions : Do the waters 

 at tlie time of their rising, press downwards, or do they not? 

 If they do, how ai"e we to account for their rising, except by 

 supposing that they are pushed upwards by the expansion of 

 the particles below? If you can account for this in any other 

 way, I am ready to confess that, as my hypothesis, in that case, 

 will not bo wanted, you will effectually deprive me of the only 

 grounds upon wliich 1 can make good its claim to supersede 

 tlie old one. But- if you cannot, vou must acknowledge that 



the 



