Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/323

This page has been proofread, but needs to be validated.
296
G. Galilæus, his Systeme.

seperate from the Earth, for the reasons that shall be more distinctly alledged hereafter.

Sagr.I expect that I shall hear more admirable things that depend upon this annual motion of the Earth, than were those dependant upon the diurnal revolution.

Salv.You do not therein erre:The annual motion of the Earth mixing with the motions of the other Planets produce extravagant appearances. For as to the operation of the diurnal motion upon the Celestial bodies, it neither was, nor can be other, than to make the Universe seem to run precipitately the contrary way; but this annual motion intermixing with the particular motions of all the planets, produceth very many extravagancies, which have disarmed and non-plust all the greatest Scholars in the World. But returning to our first general apprehensions, I reply that the centre of the Celestial conversions of the five planets Saturn, Jupiter, Mars, Venus and Mercury, is the Sun; and shall be likewise the centre of the motion of the Earth, if we do but succeed in our attempt of placing it in Heaven. And as for the Moon, this hath a circular motion about the Earth, from which (as I said before) it can by no means alienate it self, but yet doth it not cease to go about the Sun together with the Earth in an annual motion.

Simpl.I do not as yet very well apprehend this structure, but it may be, that with making a few draughts thereof, one may better and more easily discourse concerning the same.

Salv.Tis very true: yea for your greater satisfaction and admiration together, I desire you, that you would take the pains to draw the same; and to see that although you think you do not apprehend it, yet you very perfectly understand it; And onely by answering to my interrogations you shall designe it punctually. Take therefore a sheet of paper and Compasses;The Systeme of the Universe designed from the appearances. And let this white paper be the immense expansion of the Universe; in which you are to distribute and dispose its parts in order, according as reason shall direct you. And first, in regard that without my instruction you verily believe that the Earth is placed in this Universe, therefore note a point at pleasure, about which you intend it to to be placed, and mark it with some characters.

Simpl.Let this mark A be the place of the Terrestrial Globe.

Salv.Very well. I know secondly, that you understand perfectly that the said Earth is not within the body of the Sun, nor so much as contiguous to it, but distant for some space from the same, and therefore assign to the Sun what other place you best like, as remote from the Earth as you please, and mark this in like manner.

Simpl.Here it is done: Let the place of the Solar body be O.

Salv.These two being constituted, I desire that we may

think