EBB AND FLOW. 203 



Sea hath a considerable tide ; and the Persian Gulf, with 

 a yet more entire westward direction, a still stronger. 

 But the Mediterranean, the greatest of all gulfs, and its 

 parts the Tuscan, Pontic, and Propontic Seas, and in like 

 manner the Baltic, all which tend eastward, are almost 

 destitute of tide, or have only languid ones. But this 

 difference is most conspicuous in certain parts of the 

 Mediterranean which so long as they tend eastwards or 

 turn towards the north, as in the Tuscan Sea and the 

 others we have mentioned, are pacific and without much 

 tide. But after getting a westerly direction, which takes 

 place in the Adriatic, it acquires a remarkably large tide. 

 To which we may also add this, that in the Mediterranean 

 the slight reflux which is found begins from the ocean, the 

 flow from the opposite direction, so that the water follows 

 rather a course from the east than the natural refluence of 

 the ocean. The three instances only we shall use for the 

 present, in reference to this second inquiry. 



There may be added to these another species of proof 

 agreeing with those already advanced, but of a more diffi 

 cult nature : it is this, that an argument may be sought for 

 proof of this motion from east to west, not only from the 

 consenting motion of the heavens of which we have already 

 spoken, where this motion is, as it were, in full flower 

 and strength, but also from the earth when it seems wholly 

 to cease: so that it is really a direction of the universe, and 

 pervades all things from the zenith to the interior parts of 

 the earth. Now we apprehend that this conversion takes 

 place from east to west (as in reality it is found to do), 

 upon the south and north poles. And Gilbertus has, with 

 great care and accuracy, accomplished for us this discovery, 

 that the whole earth and nature, so far as we call it terres 

 trial, have an inclination or polarity, not softened down, but 

 rigid and, as Gilbertus himself calls it, robust, latent, but 

 betraying itself in many nice experiments towards the north 

 and south. And this observation we thus modify and cor 

 rect, that this ought to be asserted only of the exterior for 

 mation about the surface of the earth, and ought not to be 

 extended to the bowels of the earth, for that the earth is a 

 magnet was at one time conceived, a light imagination, 

 for it cannot be that the inward parts of the earth resemble 

 any substance which the eye of man hath seen ; since all 

 the substances among which we live are loosened, subdued, 

 or broken up by the sun and heavenly bodies, so that they 

 cannot possibly agree with those which have had their seat 



