Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/103

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G. Galilæus, his Systeme.

towards the Sun it is bounded by the lucid horns of the Moon, and on the other part, its confining term is the obscure tract of the twilight; whose relation makes us think the candor of the Moons Discus to be so much the clearer; the which happens to be obfuscated in the opposite part, by the greater clarity of the crescents; but if this modern Author had essaied to make an interposition between the eye and the primary splendor,The way to observe the secondary light of the Moon. by the ridg of some house, or some other screen, so as to have left visible only the grose of the Moon, the horns excluded, he might have seen it all alike luminous.

Simpl, I think, now I remember, that he writes of his making use of such another Artifice, to hide from us the false lucidum.

Salv.Oh! how is this (as I believed) inadvertency of his, changed into a lie, bordering on rashnesse; for that every one may frequently make proof of the contrary. That in the next place,The Moons Discus in a solar Eclipse can be seen onely by privation. at the Suns Eclipse, the Moons Discus is seen otherwayes than by privation, I much doubt, and specially when the Eclipse is not total, as those must necessarily have been, which were observed by the Author; but if also he should have discovered somewhat of light, this contradicts not, rather favoureth our opinion; for that at such a time, the whole Terrestrial Hemisphere illuminated by the Sun, is opposite to the Moon, so that although the Moons shadow doth obscure a part thereof, yet this is very small in comparison of that which remains illuminated. That which he farther adds, that in this case, the part of the limb, lying under the Sun, doth appear very lucid, but that which lyeth besides it, not so; and that to proceed from the coming of the solar rayes directly through that part to the eye, but not through this, is really one of those fopperies, which discover the other fictions, of him which relates them: For if it be requisite to the making a secondary light visible in the lunar Discus, that the rayes of the Sun came directly through it to our eyes, doth not this pitiful Philosopher perceive, that we should never see this same secondary light, save onely at the Eclipse of the Sun? And if a part onely of the Moon, far lesse than half a degree, by being remote from the Suns Discus, can deflect or deviate the rayes of the Sun, so that they arrive not at our eye; what shall it do when it is distant twenty or thirty degrees, as it is at its first apparition? and what course shall the rayes of the Sun keep, which are to passe thorow the body of the Moon, that they may find out our eye?The Author of the Book of conclusions, accommodates the things to his purposes, and not his purposes to the things. This man doth go successively considering what things ought to be, that they may serve his purpose, but doth not gradually proceed, accommodating his conceits to the things, as really they are. As for instance, to make the light

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