Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/243

 differs in species from a right motion? If it be violent, how is it that a fiery dart flying upwards, sparkling over our heads at a distance from the Earth, but not turning about, &c.

It hath been said already very often, that the circular motion is natural to the whole, and to its parts, whilst they are in perfect disposure, and the right is to reduce to order the parts disordered; though indeed it is better to say, that neither the parts ordered or disordered ever move with a right motion, but with one mixed, which might as well be averred meerly circular: but to us but one part onely of this motion is visible and observable, that is, the part of the right, the other part of the circular being imperceptible to us, because we partake thereof. And this answers to the rays which move upwards, and round about, but we cannot distinguish their circular motion, for that, with that we our selves move also. But I believe that this Author never thought of this mixture; for you may see that he resolutely saith, that the rays go directly upwards, and not at all in gyration.

Quare centrum sphære delapsæ sub AEquatore spiram describit in ejus plano: sub aliis parallelis spiram describit in cono? sub Polo descendit in axe lineam gyralem, decurrens in superficie cylindricâ consignatam? (In English to this purpose:) Why doth the centre of a falling Globe under the Æquinoctial describe a spiral line in the plane of the Æquator; and in other parallels a spiral about a Cone; and under the Pole descend in the axis describing a gyral line, running in a Cylindrical Superficie?

Because of the lines drawn from the Centre to the circumference of the sphere, which are those by which graves descend, that which terminates in the Æquinoctial designeth a circle, and those that terminate in other parallels describe conical superficies; now the axis describeth nothing at all, but continueth in its own being. And if I may give you my judgment freely, I will say, that I cannot draw from all these Queries, any sense that interfereth with the motion of the Earth; for if I demand of this Author, (granting him that the Earth doth not move) what would follow in all these particulars, supposing that it do move, as Copernicus will have it; I am very confident, that he would say that all these effects would happen, that he hath objected, as inconveniences to disprove its mobility: so that in this mans opinion necessary consequences are accounted absurdities: but I beseech you, if there be any more, dispatch them, and free us speedily from this wearisom task.

In this which follows he opposes Copernicus & his Sectators, who affirm, that the motion of the parts separated from their whole, is onely to unite themselves to their whole; but that the moving