Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/77

 our our parts must needs be very observable; certain spots and other notable things in those parts, being one while discernable, and another while not. A like variation may also be observed towards the North and South extremities of the same Discus (or Surface) according as the Moons position is in its greatest North or South Latitude; For, if it be North, some of its parts towards the North are hid, and some of those parts towards the South are discovered, and so on the contrary. Now that these consequences are really true, is verified by the Telescope, for there be in the Moon two remarkable spots, one of which, when the Moon is in the meridian, is situate to the Northwest, and the other is almost diametrically opposite unto it; and the first of these is visible even without the Telescope; but the other is not. That towards the Northwest is a reasonable great spot of oval figure, separated from the other great ones; the opposite one is lesse, and also severed from the biggest, and situate in a very cleer field; in both these we may manifestly discern the foresaid variations, and see them one after another; now neer the edge or limb of the Lunar Discus, and anon remote, with so great difference that the distance betwixt the Northwest and the circumference of the Discus is more than twice as great at one time, as at the other; and as to the second spot (because it is neerer to the circumference) such mutation importeth more, than twice so much in the former. Hence its manifest, that the Moon, as if it were drawn by a magnetick vertue, constantly beholds the Terrestrial Globe with one and the same aspect, never deviating from the same.

Oh! when will there be an end put to the new observations and discoveries of this admirable Instrument?

If this succeed according to the progresse of other great inventions, it is to be hoped, that in processe of time, one may arrive to the sight of things, to us at present not to be imagined. But returning to our first discourse, I say for the sixth resemblance betwixt the Moon and Earth, that as the Moon for a great part of time, supplies the want of the Suns light, and makes the nights, by the reflection of its own, reasonable clear; so the Earth, in recompence, affordeth it when it stands in most need, by reflecting the Solar rayes, a very cleer illumination, and so much, in my opinion, greater than that which cometh from her to us, by how much the superficies of the Earth is greater than that of the Moon.

Hold there, Salviatus hold there, and permit me the pleasure of relating to you, how at this first hint I have penetrated the cause of an accident, which I have a thousand times thought upon, but could never find out. You would say, that the imperfect light which is seen in the Moon, especially when it is horned,