150 NOVUM ORGANUM. 



quiry must be made into this. Even with this hypothesis, 

 however, it remains equally true, that there must be an ebb 

 somewhere, at the same time that there is a flood in another 

 quarter. 



Again, let the required nature be the latter of the two 

 motions we have supposed : namely, that of a rising and 

 subsiding motion, if it should happen that upon diligent 

 examination the progressive motion be rejected. We have 

 then three ways before us, with regard to this nature. The 

 motion, by which the waters raise themselves, and again 

 fall back, in the floods and ebbs, without the addition of 

 any other water rolled towards them, must take place in 

 one of the three following ways. Either the supply of 

 water emanates from the interior of the earth, and returns 

 back again ; or there is really no greater quantity of water, 

 but the same water (without any augmentation of its quan 

 tity) is extended or rarified, so as to occupy a greater space 

 and dimension, and again contracts itself; or there is 

 neither an additional supply nor any extension, but the same 

 waters (with regard to quantity, density, or rarity) raise 

 themselves and fall from sympathy, by some magnetic power 

 attracting and calling them up as it were from above. Let 

 us then (passing over the two first motions) reduce the in 

 vestigation to the last ; and inquire, if there be any such 

 elevation of the water, by sympathy or a magnetic force. 

 And it is evident, in the first place, that the whole mass of 

 water being placed in the trench or cavity of the sea cannot 

 be raised at once, because there would not be enough to 

 cover the bottom, so that if there be any tendency of this 

 kind, in the water to raise itself, yet it would be interrupted 

 and checked by the cohesion of things, or (as the common 

 expression is) that there may be no vacuum. The water, 

 therefore, must rise on one side, and for that reason be 

 diminished, and ebb on another. But it will again neces 

 sarily follow, that the magnetic power, not being able to 

 operate on the whole, operates most intensely on the centre, 

 so as to raise the waters there, which, when thus raised 

 successively, desert and abandon the sides. 



We at length arrive then at an instance of the cross, which 

 is this : if it be found, that during the ebb the surface of 

 the waters at sea is more curved and round, from the waters 

 rising in the middle, and sinking at the sides or coast, and 

 if, during the flood, it be more even and level, from the 

 waters returning to their former position, then assuredly, 

 by this decisive instance, the raising of them by a magnetic 



