there are no folid Orbs, as the Ancients fuppofed; and that there is no fubtile Matter, as the Cartefians imagin'd; but that all the vast Spaces between, and beyond the Planetary Syftem, are an immenfe Void or Vacuity, as to fenfible refifting Matter; and admit ordinarily of nothing but of the Rays of Light, unless it be near the Comets with their Atmospheres and Tails; and near the Planets with their Atmofpheres, all which Particles put together are almost nothing in comparison of those vaftly prodigious, thofe immenfely numerous Vacuities which are interfpers'd between them, as we have already feen from an exact Calculation, Pag. 19.

III, IV.

(16.) The Fixed Stars, vifible to the naked Eye of the Acuteft Obfervers, are in Number confiderably under 2000, and thofe feen only through Telescopes, about 10 or 20 times that Number. Their Distance is found by Mr. Huygens's conjectural Method to be about 2,200.000, 000.000. And the Distance of fome, from Dr. Hook's and Mr. Flamfted's Annual Parallax, See my Awhich I look on as much more certain,about the ftron. Lett. third Part of that diftance, or 700.000,000.000 Miles. However, 'tis certain that this Distance is vaftly great if compar'd with that of the Planets and Comets, when they are remotest from the Sun; and that in particular the famous Comet of 575 Years Period, which goes fometimes about 14 times as far off the Sun as Saturn, i. e. about 11.200,000 000 Miles, is not then near enough to them to be altered by that of the Fixed Stars Gravitation towards, or Influences from them. Thefe Stars feem to be of

3

the

the fame Nature with the Sun, as fhining with their own Native Light; and continuing fixed in the Centers of their feveral Planetary and Cometary Systems, as the Sun does.

(17.) The Fixed Stars feem to be really of very different Magnitudes, yet not of fuch very different Distances from this Syftem as is now generally fuppofed. As to the firft Affertion, it feems very agreeable to the reft of the vifible Bodies in the World, whether Planets or Comets, which are of very different Magnitudes alfo; and feems confirm'd from the fecond Affertion ; for if the Fixed Stars vifible to the naked Eye be at no very different Distances from our System, that vaft apparent Inequality of Light which they send hither, and according to which they are ranked under fix or seven different Magnitudes on our Globes and Planifpheres, will be next to a Demonftration, that they are themfelves really of very different Magnitudes alfo. Nor in that Cafe will it be proper to place the Telescopick Stars at any vaftly farther Distances, fince they do not at all feem different from the other, only still gradually fmaller. Now that the Fixed Stars, vifible to the naked Eye, are not at any very different Distances from our System, is most probable, because the best Method we yet have of knowing those Distances, I mean their Parallax, determine that the Diftance of those Three which have been try'd, tho' all of different apparent Magnitudes, is very nearly the fame. I do not deny that fome Fixed Stars may be vaftly farther off than others; and that there may be Systems of Worlds scattered every where in the Univerfal Immenfe Void: But I fay, that if far

ther

ther Obfervations confirm this Parallax, and any fort of Equality thereof, we muft accommodate our Opinions to our Evidence, and in that Cafe muft fuppofe, that the grand Systems themfelves of Sun, Planets, Comets, and Fixed Stars are like the Parts of fuch a Syftem, vastly remote from each other; nay, perhaps, out of the reach of each others Difcovery alfo. But as to this noble Theory, we cannot be at all pofitive till the Parallax and Distance of the Fixed Stars be more nicely obferv'd, and the Aftronomical World better fatisfy'd about it; the doing ofdwhich I would therefore earnestly recommen to the publick Confideration.

(18.) Several of thefe Fixed Stars, especially of the fmaller fort, do fometimes difappear, and new ones appear; and fome of them do appear or difappear, look Brighter or Duller by Turns; and this fometimes after certain Intervals of Time alfo. This is a known Fact; and has in fome measure been noted from almost the earliest Ages of Aftronomy. But then, what should be the Caufe of fuch mutable Appearances among these Fixed Stars, is by no means yet difcovered; nor have I hitherto ventur'd to propofe any Conjecture about them. However, fince others have already begun their Hypothefes, which feem to me commonly either intirely precarious or abfolutely impoffible, I fhall make bold here to offer my own, which fhall not only be free from fuch ftrong Objections, but agreeable to the nearest parallel Cafe of the World. We know that the Sun it felf, the only Fixed Star, as I may call it, that is fufficiently within the reach of our Telescopes, has several Times not a few Macule or Spots upon his Body; which fre

4

Quently

quently become Facule, or Parts brighter than the reft; and which come and go by turns. How many there may poffibly be of these Spots at certain times we cannot fay; but this is plain, that we do not know but fo many of them may fometimes arife, as may, in good part, cover over the Sun's Surface, and render its Light and Heat very Weak and Dull. Thefe Spots may be again diffipated, and become Fa cule, or Brighter than ordinary. Thefe Macule and Facula may fometimes, by Turns, gain ground on one another, after certain Intervals of Time, and cause the Sun to grow Darker and Brighter periodically. Nay, we do not know, but thefe Macule may fometimes, especially in Cafe the Sun were fmaller, cover over the greateft Part of its Surface, fo as to extinguish, or at least to obfcure its Light; which yet in Length of Time may be overcome, and the Sun may recover its former Splendor, if not one greater than that before. Since therefore fuch Phænomena of the Fixed Stars are like what our Sun appears by known Obfervations to be in fome fort liable to, I think it the best Guide, as to what we fee to happen in others of them; and that the Macula and Facule of thofe Stars may cause these furprizing Appearances. Nor can I eafily think in any other manner, about thofe fix Spaces of Light, or Starry Mifts, which have been lately discovered in the Heavens, than by Analogy to what we know of Things of a like Nature; viz. that they are a Company of Tranfact very fmall Fixed Stars, as invifible to us with noi. N. our ordinary Telefcopes, as the known Telefcopick Stars in the Milky Way are to our natural Eyes, which give fuch an irregular Appearance of indiftinct Light also.

347 for

A.D.1716.

PART