Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/107

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G. Galilæus, his Systeme.

Simpl.Here I see the west part shine more than all the rest of the pavement, and I see that it so hapneth, because the reflection of the light which entereth in at the window, cometh towards me.

Salv.That moisture hath done no more but filled those little cavities which are in the brick with water, and reduced its superficies to an exact evenesse; whereupon the reflex rayes issue unitedly towards one and the same place; but the rest of the pavement which is dry, hath its protuberances, that is, an innumerable variety of inclinations in its smallest particles; whereupon the reflections of the light scatter towards all parts, but more weakly than if they had gone all united together; and therefore, the same sheweth almost all alike, beheld several wayes, but far lesse clear than the moistned brick. I conclude therefore, that the surface of the Sea, beheld from the Moon, in like manner, as it would appear most equal, (the Islands and Rocks deducted) so it would shew lesse clear than that of the Earth, which is montanous and uneven. And but that I would not seem, as the saying is, to harp too much on one string, I could tell you that I have observed in the Moon that secondary light which I told you came to her from the reflection of the Terrestrial Globe, to be notably more clear two or three dayes before the conjunction,The secondary light of the Moon clearer before the conjunction, than after. than after, that is, when we see it before break of day in the East, than when it is seen at night after Sun-set in the West; of which difference the cause is, that the Terrestrial Hemisphere, which looks towards the Eastern Moon, hath little Sea, and much Land, to wit, all Asia, whereas, when it is in the West, it beholds very great Seas, that is, the whole Atlantick Ocean as far as America: An Argument sufficiently probable that the surface of the water appears lesse splendid than that of the Earth.

Simpl.So that perhaps you believe, those great spots discovered in the face of the Moon, to be Seas, and the other clearer parts to be Land, or some such thing?

Salv.This which you ask me, is the beginning of those incongruities which I esteem to be between the Moon and the Earth, out of which it is time to dis-ingage our selves, for we have stayed too long in the Moon. I say therefore, that if there were in nature but one way onely, to make two superficies illustrated by the Sun, to appear one more clear than the other, and that this were by the being of the one Earth, and the other Water; it would be necessary to say that the surface of the Moon were part earthy and part aquatick; but because we know many wayes to produce the same effect (and others there may be which we know not of;) therefore I dare not affirm the Moon to consist of one thing more than another: It hath been seen already