198 EBB AND FLOW. 



found to follow any affections of the moon. For whether 

 the moon be crescent or waning, whether she be under the 

 earth or above the earth, whether her elevation above the 

 horizon be higher or lower, whether her position be in the 

 zenith or elsewhere, in none of these relations do the ebb 

 and flow of the tide correspond with her. 



Therefore, leaving the moon, let us inquire concerning 

 other correspondencies; and from ;tll the motions of the 

 heavenly bodies, it is certain that the diurnal motion is the 

 shortest, and is accomplished in the least period of time, 

 that is, in the space of twenty-four hours. It is therefore 

 in harmony with this, that the motion of which we inquire, 

 which is yet three times shorter than the diurnal one, 

 should be referred immediately to that motion which is the 

 shortest of the heavenly ones. But this notion has no 

 great weight with us in this matter. Another hypothesis 

 has more influence with us, that this motion is so distri 

 buted that though the motion of the waters is slower by 

 innumerable degrees, still it is referable to a common 

 measure. For the space of six hours is a quarter of the 

 diurnal motion, which space (as we said) is found in that 

 motion of the sea with a difference coinciding with the 

 measure of the moon s motion. Whereupon this belief 

 sinks deep into our mind, and looks as it were an oracular 

 truth, that this motion is of the same kind with the diurnal 

 motion. With this, therefore, as a basis, we shall proceed 

 to a thorough inquiry : and we think that the whole sub 

 ject is exhausted in three points of investigation. 



The first is, whether that diurnal motion is confined 

 within the regions of heaven, or descends, and penetrates 

 to the lower parts ? The second is, whether the seas move 

 regularly from east to west as the heaven does ? The third, 

 whence and how that six hours motion of the tides takes 

 place which coincides with a quarter of the diurnal motion, 

 with a difference falling in with the measure of the moon s 

 motion. Now, as relates to the first inquiry, we think that 

 the motion of rotation, or of turning from east to west, is 

 not properly a motion merely of the heavenly bodies, but 

 manifestly of the universe, and a primary motion in all the 



freat fluids, found to prevail from the highest part of 

 eaven to the lowest part of the waters, in direction the 

 same in all, in impulse, that is, in rapidity and slowness, 

 widely different; in such wise, however, that in an order 

 not in the least confused, the rapidity is diminished in pro 

 portion as the bodies approach the globe of the earth. 



