198 NOVUM ORGANUM 



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 necessarily 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. 59 



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 a 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 force can be admitted; if otherwise, it must be 

 entirely rejected. It is not difficult to make the experi 

 ment (by sounding in straits), whether the sea be deeper 

 toward the middle in ebbs, than in floods. But it must be 

 observed, if this be the case, that (contrary to common 

 opinion) the waters rise in ebbs, and only return to their 

 former position in floods, so as to bathe and inundate the 

 coast. 



Again, let the required nature be the spontaneous motion 

 of revolution, and particularly, whether the diurnal motion, 

 by which the sun and stars appear to us to rise and set, be 



69 Bacon s sagacity here foreshadows Newton s theory of the tides. 



