Another collection of philosophical conferences of the French virtuosi upon questions of all sorts for the improving of natural knowledg made in the assembly of the Beaux Esprits at Paris by the most ingenious persons of that nation / render'd into English by G. Havers, Gent. & J. Davies ..., Gent.

CONFERENCE CLIX. Why there is more Wind at Sea than at Land. (Book 159)

THe experience of less Wind and more Rain on Land than at Sea, makes their Opinion questionable, who hold, Exhalations to be the matter of the former, and Vapours of the latter: unless we will say, that Winds, to whom the Poets rightly attribute the Empire of the Sea, drive the Clouds over the Land, where being less agitated, they resolve into Rain. But to continue my reasoning with the same Poets, I shall say, that having plac'd Aeolus's Palace in the caverns near the sea, they have sufficiently proved, why the Sea is more troubled with them than the Land. For these Winds visibly issue from deep Caverns fre∣quent on the Coasts of the Sea, whose continually agitated waves incessantly stir them up. 'Tis no wonder then if they display their violences on that side which is freest to them: Which is experienc'd in great Lakes adjacent to high Mountains; as in that of Comum, and de la Garde in Italy, whose waves and roarings resemble those of the Sea; and also in that of Geneva, which is troubled extraordinarily. Not but that Winds are generated in other Subterraneous places too, none of which is exempt from them; as appears in Wells and the mouths of Caves. But the openings of such places being commonly strait upwards, the Wind that come out of them is not so perceptible as that which issues out laterally from high Caverns upon the Sea-shore; and they differ, in that the Sea Wind is dryer and less corrupting, possibly by reason of the saltness of the water, upon which it passes.

The Second said. That the difference in Question proceeds from the vast extent of the Sea, which gives the Air once agi∣tated, more liberty to continue its motion; which, on the con∣trary, is straitned and repress'd on Land by the occurse of Moun∣tains, Trees, Houses, and other obstacles: By the same reason that the waves of a Pool or little Lake, are much less than those of the Ocean, besides, that one and the same Wind hath much greater effect in a smooth and liquid plain, which yields to it, than upon a rough solid Body, upon which burdens are not mov'd but with more force than there needs upon the water; as they experience who endeavour to draw a stranded Ship on the Land, which they saw move almost of it self whilst it was upon the water. The Mechanical Reason whereof is, that the water breaking into infinite points, scarce makes any resistance to its Agent; but the Earth press'd with the same load, resists it in infinite points.

The Third said. He that defin'd Wind to be Agitated Air, rather spoke its Effect than Cause, which is some middle thing between a Vapor and an Exhalation, driven violently according to all the differences of place. For an Exhalation, which always mounts upwards, and the Vapor which refrigerated descends downwards, cannot separately be the matter of Wind. Hence as soon as the Vapor of a Cloud is resolv'd into Rain, the Wind ceaseth; the Exhalations not being sufficient to produce it alone, as neither the Vapor is. Otherwise, Winds should be greatest in hot weather, when Exhalations are most plentiful. Wherefore the Sea having in its Four Qualities the materials of these two Meteors, and being otherwise more capable of emitting them through its liquid substance, than the Earth is through its hard and solid surface, though both be equally heated as well by the Sun, as by Subterraneous Fires, Evaporations and Exhalations, are sooner and oftner made at Sea than at Land.

The Fourth said, That the thickest Air being oftimes the calm∣est, and the clearest the most windy, 'tis doubtful whether Vapors and Exhalations produce Winds; which, besides, presupposeth actual heat in the Sea, which yet is never felt there, but onely on Land. It seems therefore that the Element of Air being very symbolical to that of the Air by their agreement and moisture, they follow the motions one of the other. Hence the Air conti∣guous to the Sea, is agitated by it; whence ariseth a Wind, which again agitates the Sea; it being well known, that when there are no Waves there is no Wind. On the contrary, when the Wind is to change, the billows turn first. And ordinarily, the Winds change with the Tides.

The Fifth said. There are two sorts of Winds upon the Sea; Particular, which reign in our Seas, blowing indifferently from all Coasts; and General, which blow continually from the same quarter, without giving place to their Contraries. Such is the Oriental Wind in the Torrid Zone, which was call'd by the Latins, Subsolanus, and by Mariners at this day, South-East. For it conducts Ships so constantly over the whole extent of Mer du Nord, & du Sud, that without discontinuing Day or Night, it exempts the Sea-men from touching their sails, especial∣ly when they are near the Aequinoctial. Indeed in the East Indies, this Rule alters, for this Wind holds there but six moneths, leaving the other six free to its Antagonist. The Cause whereof, is ascrib'd to the repercussion of the capes and coasts of those Seas, as that first Wind is to the motion of the Primum Mobile, which, together with the inferior Spheres, draws the Air along with it in this place, where the circumference of its motion is largest. There is another general Wind, which blows between the Tro∣pick, or twenty fourth Degree on this side the Line, and the thir∣ty fifth becoming Occidental with the like constancy that the abovesaid Oriental doth. This some attribute to a contrary motion, which all things have when those nearest them are hur∣ri'd

violently; as the stream of water running impetuously in the midst, makes that near the shores recoil backwards.

The Sixth said, That as Vapours make Mists and Fogs, and Sulphureous Exhalations make igneous Meteors; so the Nitrous make Wind, which keeps the air from corruption as the Earth is kept from it by Nitre, and the Sea by Salt. Moreover, both the Wind and Nitre dry, and are the causes of fecundity; as is prov'd (on the behalf of Nitre) by the Nitrous sand of Nilus, whose greater or lesser overflow promises to the Egyptians a year proportionably fruitful; which is also said of the Rhosne abounding with Nitre. And as for the Wind, besides that all flatuous Meats provoke lust, 'tis said that the Mares of Andalu∣sia conceive by the West-wind alone which also is styl'd the Fa∣ther of Flowers. In Brief, if Wind be impetuous, the effects of Nitre in Gun-powder and Aurum fulminans, manifest that Ni∣tre is no less. Now Nitre being mix'd with the Air, where it is volatile; with the Earth, where it is fix'd; and with the Sea, where it is barely dissolv'd; no wonder if it exhale more easily from the Sea then from the Land, and consequently if more winds be there. Whence the reason may be drawn not only of the Sea-winds but also of the tempests and commotions of that vast Element; a Tempest being nothing but the rarefaction of the Sea; Nitre, and the inflation of the Waters at Full Moon in March and September, only the fermentation of the same Nitre in the season proper for generation. As for that inflation hap∣ning at the time of the Dog-star, when the Etesian winds reign, it proceeds from the heat of the Air then inflam'd by the rays of the Sun, like the ebullition of Honey and Syrups impregnated with much Salt, as appears by their dissolution and the bitter∣ness they acquire over the Fire.

The Seventh said, That the coldness of Vapors arising from waters giving more body and consistence to winds, makes them strike a more sensible blow then when they are destitute there∣of; whence they are greater in Winter then in Summer, and in the Morning then at Noon. Thus the same quantity of water will cause more alteration in the body being drunk cold then warm, because the impression of the latter is much less upon our bodies. And the Providence of the Author of Winds is remarkable too, in that they are mischievous at Land but useful at Sea; hurtful things being by a secret of his power as much diminish'd, as profitable are augmented.

The Eighth said, That not only Wind-mills but also the Wind-wagons invented lately in Holland, shew that wind well manag'd is no less profitable at Land then at Sea. Therefore I should refer the cause to the porosities, overtures, and caverns of the Earth, into which the wind entring is by that means less at Land; whereas the surface of the Sea giving it no such ad∣mission, 'tis left to its freer course upon the same; whence when those pores of the Earth are shut up by frost, the wind

becomes more impetuous then it is in Summer when they are open.