Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/364

This page has been proofread, but needs to be validated.
Dialogue. III.
337

now deny their operation upon the Earth; or else that (still contradicting your self) you grant that their appearing very small doth not in the least lessen their influence; or else that (and this shall be a more sincere and modest concession) you acknowledg and freely confesse, that our passing judgment upon their magnitudes and distances is a vanity, not to say presumption or rashnesse.

Simpl.Truth is, I my self did also, in reading this passage perceive the manifest contradiction, in saying, that the Stars (if one may so speak) of Copernicus appearing so very small, could not operate on the Earth, and not perceiving that he had granted an influence upon the Earth to those of Ptolomy, and his sectators, which appear not only very small, but are, for the most part, very invisible.

Salv.But I proceed to another consideration: What is the reason, doth he say, why the stars appear so little? Is it haply, because they seem so to us?That remote objects appeare so small, is the defect of the eye, as is demonstrated. Doth not he know, that this commeth from the Instrument that we imploy in beholding them, to wit, from our eye? And that this is true, by changing Instrument, we shall see them bigger and bigger, as much as we will. And who knows but that to the Earth, which beholdeth them without eyes, they may not shew very great, and such as in reality they are? But it's time that, omitting these trifles, we come to things of more moment; and therefore I having already demonstrated these two things: First, how far off the Firmament ought to be placed to make, that the grand Orb causeth no greater difference than that which the Terrestrial Orb occasioneth in the remotenesse of the Sun; And next, how likewise to make that a star of the Firmament appear to us of the same bignesse, as now we see it, it is not necessary to suppose it bigger than the Sun; I would know whether Tycho, or any of his adherents hath ever attempted to find out, by any means, whether any appearance be to be discovered in the starry Sphere, upon which one may the more resolutely deny or admit the annual motion of the Earth.

Sagr.I would answer for them, that there is not, no nor is there any need there should;Tycho nor his followers ever attempted to see whether there are any appearances in the Firmament for or against the annual motion. seeing that it is Copernicus himself that saith, that no such diversity is there: and they, arguing ad hominem, admit him the same; and upon this assumption they demonstrate the improbability that followeth thereupon, namely, that it would be necessary to make the Sphere so immense, that a fixed star, to appear unto us as great as it now seems, ought of necessity to be of so immense a magnitude, as that it would exceed the bignesse of the whole grand Orb, a thing, which notwithstanding, as they say, is altogether incredible.

Salv.