Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/96

 be produced also; in the mean time, that I may not prevent any one, I will suppresse the answer which might be given, and onely for this time betake my self to satisfie the objections brought by Simplicius. I say therefore, that this reason of yours is too general, and as you apply it not to all the appearances one by one; which are seen in the Moon, and for which my self and others are induced to hold it mountainous, I believe you will not find any one that will be satisfied with such a doctrine; nor can I think, that either you, or the Author himself, find in it any greater quietude, than in any other thing wide from the purpose. Of the very many several appearances which are seen night by night in the course of Moon, you cannot imitate so much as one, by making a Ball at your choice, more or less opacous and perspicuous, and that is of a polite superficies; whereas on the contrary, one may make Balls of any solid matter whatsoever, that is not transparent, which onely with eminencies and cavities, and by receiving the illumination several ways, shall represent the same appearances and mutations to an hair, which from hour to hour are discovered in the Moon. In them you shall see the ledges of Hills exposed to the Suns light, to be very shining, and after them the projections of their shadows very obscure; you shall see them greater and less, according as the said eminencies shall be more or less distant from the confines which distinguish the parts of the Moon illuminated, from the obscure: you shall see the same term and confine, not equally distended, as it would be if the Ball were polish'd, but craggie and rugged. You shall see beyond the same term, in the dark parts of the Moon many bright prominencies, and distinct from the rest of the illuminations: you shall see the shadows aforesaid, according as the illumination gradually riseth, to deminish by degrees, till they wholly disappear; nor are there any of them to be seen when the whole Hemisphere is enlightned. Again on the contrary, in the lights passage towards the other Hemisphere of the Moon, you shall again observe the same eminencies that were marked, and you shall see the projections of their shadows to be made a contrary way, and to decrease by degrees: of which things, once more I say, you cannot shew me so much as one in yours that are opacous and perspicuous.

One of them certainly he may imitate, namely, that of the Full-Moon, when by reason of its being all illuminated, there is not to be seen either shadow, or other thing, which receiveth any alteration from its eminencies and cavities. But I beseech you, Salviatus, let us spend no more time on this Argument, for a person that hath had but the patience to make observation of but one or two Lunations, and is not satisfied with this most sensible truth, may well be adjudged void of all judgment; and upon