508 NOVUM ORGANUM. [BOOR IL 



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

 towards 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 a real 

 motion of revolution in the heavenly bodies, or only apparent in 

 them, and real in tho earth. There may be an instance of the 

 cross of the following nature. If there be discovered any 

 motion in the ocean from east to west, though very languid and 

 weak, and if the same motion be discovered rather more swift 

 in the air (particularly within the tropics, where it is more per 

 ceptible from the circles being greater). If it be discovered also 

 in the low comets, and be already quick and powerful in them ; 

 if it be found also in the planets, but so tempered and regulated 

 as to be slower in those nearest the earth, and quicker in those 

 at the greatest distance, being quickest of all in the heavens, 

 then the diurnal motion should certainly be considered as real 

 in the heavens, and that of the earth must be rejected ; for 

 it will be evident that the motion from east to west is part 

 of the system of the world and universal ; since it is most rapid 

 in the height of the heavens, and gradually grows weaker, till 

 it stops and is extinguished in rest at the earth. 



Again, let the required nature be that other motion of revolu 

 tion, so celebrated amongst astronomers, which is contrary to 

 the diurnal, namely, from west to east, and which the ancient 

 astronomers assign to the planets, and even to the starry sphere, 

 but Copernicus and his followers to the earth also, and let it be 

 examined whether any such motion be found in nature, or it be 

 rather a fiction and hypothesis for abridging and facilitating cal 

 culation, and for promoting that fine notion of effecting the 

 heavenly motions by perfect circles ; for there is nothing which 

 proves such a motion in heavenly objects to be true and real, 

 either in a planet s not returning in its diurnal motion to the 

 same point of the starry sphere, or in the pole of the zodiac 

 being different from that of the world, which two circumstances 

 have occasioned this notion. For the first phenomenon is well 

 accounted for by the spheres overtaking or falling behind each 

 other, and the second by spiral lines; so that the inaccuracy of 

 the return and declination to the tropics may be rather modifica 

 tions of the one diurnal motion than contrary motion*, or about 



