1 66 Sir I s a a c N e w t o n’s Book II.

the fun. But the motions of these shall be more fully ex-plained hereafter a . And there is, besides the planets, anotherfort of bodies, which in all probability move round the fun ;J mean the comets. The farther description of which bodiesI also leave to the place, where they are to be particularlytreated on b .

9. Far without this system the fixed stars are placed.These are all so remote from us, that we seem almost incapa-ble of contriving any means to estimate their distance. Theirnumber is exceeding great. Besides two or three thousand,which we fee with the naked eye, telescopes open to our viewvast numbers ; and the farther improved these instrumentsare, we still discover more and more. Without doubt theseare luminous globes, like our fun, and ranged through thewide extent of space ; each of which, it is to be supposed,perform the fame office, as our fun, affording light and heatto certain planets moving about them. But these conjecturesare not to be pursued in this place.

10. I shall therefore now proceed to the particular de-sign of this chapter, and shew, that there is no sensible mat-ter lodged in the space where the planets move.

11. That they suffer no sensible resistance from anysuch matter, is evident from the agreement between the obser-vations of astronomers in different ages, with regard to the'time, in which the planets have been found to perform their

periods.

a Ch. of this present book.

>- Ch.4.'