Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/430

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Dialogue. IV.
401

even, to wit, the surfaces of very vast Seas, which being also far remote from the continuate ledges of Mountains which environ it, seem to have no faculty of carrying the super-ambient Air along therewith: and not carrying it about, we may perceive what will of consequence ensue in those places.

Simpl.I was about to propose the very same difficulty, which I think is of great validity.

Salv.You say very well Simplicius, for from the not finding in the Air that which of consequence would follow, did this our Globe move round; you argue its immoveablenesse. But in case that this which you think ought of necessary consequence to be found, be indeed by experience proved to be so; will you accept it for a sufficient testimony and an argument for the mobility of the said Globe?

Simpl.In this case it is not requisite to argue with me alone, for if it should so fall out, and that I could not comprehend the cause thereof, yet haply it might be known by others.

Salv.So that by playing with you, a man shall never get, but be alwayes on the losing hand; and therefore it would be better to give over: Nevertheless, that we may not cheat our third man we will play on. We said even now, and with some addition we reitterate it, that the Ayr as if it were a thin and fluid body, and not solidly conjoyned with the Earth, seem'd not to be necessitated to obey its motion; unlesse so far as the cragginess of the terrestrial superficies, transports and carries with it a part thereof contigious thereunto; which doth not by any great space exceed the greatest altitude of Mountains: the which portion of Air ought to be so much less repugnant to the terrestrial conversion, by how much it is repleat with vapours,The vaporous parts of the earth, partake of its motions. fumes, and exhalations, matters all participating of terrene qualities, and consequently apt of their own nature to the same motions. But where there are wanting the causes of motion, that is, where the surface of the Globe hath great levels, and where there is less mixture of the terrene vapours, there the cause whereby the ambient Air is constrained to give entire obedience to the terrestrial conversion will cease in part; so that in such places, whilst the Earth revolveth towards the East, there will be continually a wind perceived which will beat upon us, blowing from the East towards the West: and such gales will be the more sensible, where the revolution of the Globe is most swift; which will be in places more remote from the Poles, and approaching to the greatest Circle of the diurnal conversion. But now de facto experience much confirmeth this Phylosophical argumentation; for in the spatious Seas, and in their parts most remote from Land, and situate under the Torrid Zone, that is bounded by the Tropicks, where there are none of those

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