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same origins and fellow causes. Nevertheless (how. ever it be) what I have said remains true, that nature delights in correspondences, and scarce admits anything unique or solitary. We must see therefore with respect to the six hours' motion of the ebb and flow of the sea, with what other motions it is found to agree and correspond. And first, we must inquire respecting the moon, how this motion sorts and combines with the moon. Now we do not find that there is any resemblance, except in the case of the monthly restoration; for the six-hourly course (whereof I am now inquiring) has no agreement with the monthly; nor again is the flow of the sea found to follow any of the conditions of the moon. For whether the moon be in her increase or wane, whether under the earth or above it, whether elevated high or low above the horizon, or whether situated in the meridian or elsewhere, in none of these instances has the ebb and flow of the sea any correspondence.

Therefore dismissing the moon let us inquire of other correspondences. Now of all celestial motions the diurnal is plainly the shortest, and accomplished in the least time (namely, in the space of twenty-four hours). It is natural therefore to refer this motion whereof we are inquiring (which is still shorter than the diurnal motion by three fourths) to that motion among the celestial bodies which is shortest; but this does not press the matter. What weighs more with me, is that this motion is so distributed as to correspond to the divisions of the diurnal motion; so that although the motion of the waters is almost infinitely slower than the dłurnal motion, it is yet commensurable with it. For six hours is a quarter of the diurnal

motion, and six hours is (as I have said) the time of this motion of the sea, with a difference coinciding with the measure of the moon's motion. Of this therefore I am fully persuaded, and take it almost for an oracle, that this motion is of the same kind as the diurnal motion. Taking therefore this as a foundation, I shall proceed to inquire of the rest; and I judge that the whole matter may be resolved by three inquiries. First, does this diurnal motion confine itself to the limits of the heaven, or does it descend and reach lower bodies? Secondly, do the seas move regularly from east to west as the heavens do? Thirdly, whence and in what manner proceeds the reciprocation of the tides every six hours, coinciding with a fourth part of the diurnal motion, though with a difference coinciding with the motion of the moon? With regard to the first inquiry, I judge that the motion of rotation or conversion from east to west is not properly a celestial but quite a cosmical motion; a motion primarily belonging to the great fluids, and found from the summits of heaven to the depths of the water; the inclination being always the same, though the degrees of velocity vary greatly; varying, however, in a regular order, so that the swiftness of the motion diminishes the nearer the bodies approach the earth. Now in the first place that this motion is not terminated with the heaven, may be probably inferred from the fact that it prevails in full vigour through such an immense depth of heaven as that which lies between the starry heaven and the moon (a space much larger than that between the moon and the earth), decreasing regularly all the way; whence it is not likely that nature should throw off suddenly and at once a correspondence of this kind,

which has been continued with a gradual abatement for such an immense distance. That this is the case in celestial bodies is proved by two inconveniences which would otherwise follow. For as it is manifest to the sense that the planets perform a diurnal motion, we must necessarily, unless this motion be set down as natural and proper to all planets, take refuge either in the violence of the primum mobile, which is directly contrary to nature, or in the rotation of the earth, -a supposition arbitrary enough, as far as physical reasons are concerned. In the heavens therefore the thing is So. And leaving the heavens, this motion is further seen most plainly in the lower comets, which, though they are lower than the moon, yet evidently revolve from east to west. For though they have their own solitary and irregular motions, yet in the performance thereof they still participate in the motion of the ether, and move in the same direction. They do not commonly keep within the tropics, and have no regular spirals, but run out sometimes towards the poles; but nevertheless they revolve in order from east to west. And this motion of theirs, though greatly diminished (since the nearer they approach to the earth the smaller are the circles in which they revolve, and the slower is the motion), still remains vigorous, so that it can overcome great distances in a short time. For these comets move round the whole circumference both of the earth and the lower air in the space of about four and twenty hours, with one or two hours over. But when descending gradually we come to those regions on which the earth acts not only by a communication of its nature and virtue (which checks and quiets the circular motion), but likewise by a

material infusion of the particles of its substance in thick vapours and exhalations, this motion is immensely deadened and almost collapses; and yet it is not thereby completely exhausted and stopped, but remains in a languid and as it were latent state. For it is now acknowledged that in sailing within the tropics, where from the openness of the sea the motion of the air is best perceived, and where the air itself (like the heaven) revolves in larger circles and therefore with greater velocity, there is found a constant and perpetual breeze blowing from east to west; so that they who want a west wind often seek for it and find it without the tropics. It appears therefore that this motion is not extinguished even in the lowest air; only it now becomes sluggish and feeble; so that it is scarce felt without the tropics. And yet even outside the tropics here in Europe, when the sky is calm and clear, there is observed at sea a certain breeze following the sun, which is of the same kind. And we may also suspect that what we experience here in Europe, where the east wind is keen and drying, whereas on the other hand the west is genial and moist, does not only depend on this that with us the former blows from the land, the latter from the sea; but likewise on this, that the east wind, being in the same direction as the proper motion of the air, stimulates and irritates that motion, and thereby dissipates and rarefies the air. The west wind, on the other hand, blowing contrary to the motion of the air, turns the air back upon itself, and thereby thickens it. Neither is that common observation to be despised, that the higher clouds generally move from east to west when contrary winds

1 Acosta, Hist. des Indes, iii. 4.

are at the same time blowing on the earth. And if this is not always the case, the reason is that there are sometimes contrary winds blowing, some above and others below; and those that blow above (if they be opposite) disturb the proper motion of the air. And therefore that this motion is not confined within the limits of the heaven is sufficiently clear.

Next in order is the second inquiry; namely, whether the waters move regularly and naturally from east to west? meaning by waters those collections or masses of water, which form portions of nature large enough to have a correspondence with the fabric and structure of the universe. And I am clearly of opinion that the same motion belongs to this mass of waters and exists in it, but that it is slower than in the air, though by reason of the grossness of the body it is more visible and apparent. Out of many experiments therefore which might be brought to prove this, I shall for the present content myself with three, but those ample and eminent, which demonstrate that this is the fact. The first is that there is found a manifest motion and flow of waters from the Indian Ocean to the Atlantic, and that swifter and stronger towards the Straits of Magellan, where there is an outlet to the west; and also a great motion in the opposite part of the world from the German Ocean into the British Channel. And these courses of water manifestly revolve from east to west. Wherein it is to be especially observed, that in these two places only the seas are open and can perform a complete circle; whereas on the contrary in the middle regions of the world they are cut off by the two obstacles of the Old and New World, and

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