Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/434

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G. Galilæus, his Systeme.

the Aire which partaketh of that motion to distend so low as to the Tops of the highest Hills,It is demonstrated inverting the argument, that the perpetual motion of the Air from East to West, cometh from the motion of Heaven. and that likewise they would reach to the Earth, if those Mountains did not impede them, which agreeth with what you say: For as you affirm, the Air, which is invironed by ledges of Mountains, to be carried about by the asperity of the moveable Earth; we on the contrary say, That the whole Element of Air is carried about by the motion of Heaven, that part only excepted which lyeth below those bodies, which is hindred by the asperity of the immoveable Earth. And whereas you said, That in case that asperity should be removed, the Air would also cease to be whirld about; we may say, That the said asperity being removed, the whole Aire would continue its motion. Whereupon, because the surfaces of spacious Seas are smooth, and even; the Airs motion shall continue upon those, alwaies blowing from the East: And this is more sensibly perceived in Climates lying under the Line, and within the Tropicks, where the motion of Heaven is swifter; and like as that Celestial motion is able to bear before it all the Air that is at liberty, so we may very rationally affirm that it contributeth the same motion to the Water moveable, as being fluid and not connected to the immobility of the Earth:The motion of the Water dependeth on the motion of Heaven. And with so much the more confidence may we affirm the same, in that by your confession, that motion ought to be very small in resect of the efficient Cause; which begirting in a natural day the whole Terrestrial Globe, passeth many hundreds of miles an hour, and especially towards the Equinoctial; whereas in the currents of the open Sea, it moveth but very few miles an hour. And thus the voiages towards the West shall come to be commodious and expeditious, not onely by reason of the perpetual Eastern Gale, but of the course also of the Waters; from which course also perhaps the Ebbing and Flowing may come, by reason of the different scituation of the Terrestrial Shores:The flux and reflux may depend on the diurual motion of Heaven. against which the Water coming to beat, may also return backwards with a contrary motion, like as experience sheweth us in the course of Rivers; for according as the Water in the unevenness of the Banks, meeteth with some parts that stand out, or make with their Meanders some Reach or Bay, here the Water turneth again, and is seen to retreat back a considerable space. Upon this I hold, That of those effects from which you argue the Earths mobility, and alledge it as a cause of them, there may be assigned a cause sufficiently valid, retaining the Earth stedfast, and restoring the mobility of Heaven.

Salv.It cannot be denied, but that your discourse is ingenious, & hath much of probability, I mean probability in appearance, but not in reality & existence: It consisteth of two parts: In the first it

assignes