Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/74

 Sun; which were it not so, it could not do. Thirdly, I hold its matter to be most dense and solid as the Earth is, which I clearly argue from the unevenness of its superficies in most places, by means of the many eminencies and cavities discovered therein by help of the Telescope: of which eminencies there are many all over it, directly resembling our most sharp and craggy mountains, of which you shall there perceive some extend and run in ledges of an hundred miles long; others are contracted into rounder forms; and there are also many craggy, solitary, steep and cliffy rocks. But that of which there are frequentest appearances, are certain Banks (I use this word, because I cannot thing of another that better expresseth them) pretty high raised, which environ and inclose fields of several bignesses, and from sundry figures, but for the most part circular; many of which have in the midst a mount raised pretty high, and some few are replenished with a matter somewhat obscure, to wit, like to the great spots discerned by the bare eye, and these are of the greatest magnitude; the number moreover of those that are lesser and lesser is very great, and yet almost all circular. Fourthly, like as the surface of our Globe is distinguished into two principal parts, namely, into the Terrestrial and Aquatick: so in the Lunar surface we discern a great distinction of some great fields more resplendant, and some less: whose aspect makes me believe, that that of the Earth would seem very like it, beheld by any one from the Moon, or any other the like distance, to be illuminated by the Sun: and the surface of the sea would appear more obscure, and that of the Earth more bright. Fifthly, like as we from the Earth behold the Moon, one while all illuminated, another while half; sometimes more, sometimes less; sometimes horned, sometimes wholly invisibly; namely, when its just under the Sun beams; so that the parts which look towards the Earth are dark: Thus in every respect, one standing in the Moon would see the illumination of the Earths surface by the Sun, with the same periods to an hair, and under the same changes of figures. Sixtly,

Stay a little, Salviatus; That the illumination of the Earth, as to the several figures, would represent it self to a person placed in the Moon, like in all things to that which we discover in the Moon, I understand very well, but yet I cannot conceive how it shall appear to be done in the same period; seeing that that which the Suns illumination doth in the Lunar superficies in a month, it doth in the Terrestrial in twenty four hours.

Its true, the effect of the Sun about the illuminating these two bodies, and replenishing with its splendor their whole surfaces, is dispatch'd in the Earth in a Natural day, and in the Moon in a Month; but the variation of the figures in which the