whether he must not acknowledge, that those Men argue much more juftly, who conclude from hence, that the great and gracious Benefactor of Mankind has produced all these differently colour'd Rays, to the end that the Beholder may be ゴ fo much more agreeably affected and refreshed with the Sight of God's Creatures; and that he has placed in them the laft Property, whereby all of 'em being mingled together, do compofe a clear and transparent Light, to the end that the Obfcurity of the Colours may not embarrass human Eyes?

Befides, his Wisdom and Beneficence must be acknowledged herein, that in the Parts which compofe different colour'd Bodies, he has placed fuch a Difpofition, whereby one Body when this compounded Light falls upon it, is adapted to reflect only one, or fome particular kinds of Rays; for Inftance one only Red, another only Yellow, a third, both of,'em equally, and no other (by which a kind of a Gold-colour between Red and Yellow is generated) I fay, to reflect thefe in a greater quantity, by which means each Body, according to one or more fort of Rays which it reflects, either Simple or Compound, represents its particular Colour, and from thence is denominated Red, Yellow, &c.

How ftrange foever this Language might have been to all former Philofophers, yet the fame is at prefent put out of all doubt by the afore quoted Optics, of Sir Ifaac Newton; who tho' he may be juftly reckoned by every Body amongst the moft famous Mathematicians of the World, yet to fet an Example to these less experienced Gentlemen, that they fhould not too much rely upon Conjectures and Hypothefes, has proved the fame to be unquestionably true, not by Demonftrations founded upon Arguments, but by manifold and exceeding

exceeding nice Experiments. Now those that have a mind to read and try the fame, may meet with 'em in the aforefaid Treatife of Opticks, efpecially in the First Book.

SECT. XLI. The Divifion of Light in IslandChrystal.

BESIDES the above-mentioned Divifions of Light, whereby it is split into various-coloured Rays, Mr. Huygens in his Treatife about Light, p. 61, and Sir Ifaac Newton in his Optics, Query 25. p. 328. do fhew us another Divifion or Splitting of Light, which it undergoes when it meets with Iland-Chryftal; upon which, as foon as a Ray of Light falls, it is divided into two other Rays that preferve however the fame Colour.

Of these Divifions or Splittings of the Subftances of Light into feveral other Parts, as well tinged in the firft Cafe, as fimple or untinged in the fecond, I don't know that there was ever the leaft mention made, or Track to be found among the ancient Naturalists; nor that this Matter has been put out of doubt fooner than in the laft Age by accurate Inquiries and undeniable Experiments.

SECT. XLII. The Usefulness of the Moon.

Now let the Reader return with us to Tab. XXI. Fig. 4. and fuppofe the Sun to be reprefented by A B, and the Earth by CD, in which Situation, as we have faid before, the Shadow of the Earth, or the pyramidal Figure CPD makes the Night, it will not be then difficult for him to fancy the great Darkness in which those that dwell at T muft be involved; forafmuch as not

the

the least Ray of Light flowing from the Sun AB, can come to them directly, or in a strait Line.

Now if you will please to obferve, that the Moon M being oppofite to the Sun AB, is at Full to thofe that live at T, that is to fay, they fee its whole enlighten'd Side; you will tell us whether you can think there is any Gratitude in thofe People that fhall deny their great Obligations to Him who has furnished them with this Light of the Moon in fuch their Darkness.

SECT. XLIII. Convictions from hence, and the Eclipfes.

Now the only Evasion that fuch People can make, is, that all this happens by Chance, or by neceffary Causes, and confequently that no Thankfulness is due: But if the Gracious Creator of the Moon had no Wisdom, nor the Benefit which Men enjoy from the Light thereof, is not to be reckoned one of his great Views and Designs, how will they account for the following Particulars?

I. That the Light of the Sun has a Property when it falls upon any Bodies (as here from N, the Center of the Sun, upon M the Moon) to rebound back from it again, and to produce a reflected Ray MT; by which means those that would otherwife remain in the midst of the dark Cone CPD, are enlightned. Now, that without this Faculty of Light, there could be no Rays reflected from the Moon to our Earth, is plain enough.

II. Why is the Moon M, which is much smaller than the Globe of the Earth, placed at no greater Distance from it; fo that (as we fee in Saturn, and other great Planets) its Breadth and Diameter disappearing almost out of Sight, would

be

be uncapable to communicate any Light to us that could be useful? And is there here no wife Purpose? And fince the Universe is so large, why is this Place, among Millions of others, juft chofen out, whereby it is best befitted to render fuch Service to those who inhabit the Earth?

III. How comes it, that the Moon is not of fuch a Contexture as our black or dark-coloured Bodies are; by which means it would be able to give little or no Light to us?

IV. Why is it not a convex, globular and fmooth Body, like Looking-Glaffes and other polished Things, when (as those who understand Optics know) there would be no more than one Point, or at least a very little part of the Moon vifible and capable of enlightning us?

V. Why does not the Moon move according to the Line GHFS, which lies in the Plane of the Sun's way Nn; by which means the fame at G being oppofite to the Sun, would never be feen Full, but would always be obfcured and eclipsed by the Shadow of the Earth CPD, and on the contrary, the Moon being at F when it is dark or new, the Sun A B would be always either totally or partially covered and eclipsed thereby, at least the World reaps this Benefit by the Declination of the Moon's Way MHRS from the Plane of the Ecliptic, or Sun's Way Nn, or GHFS, that the Places lying near the Poles may be enlightned by the Moon, whilft the Sun being ftill under the Horizon, occafions fuch a long and difmal Night ?

And moreover, does there appear no Wisdom therein, by which this continual Monthly Sun (as one may call it) is fecured, to the end that' Mankind may not be fo often deprived of the Ufe thereof? How comes it then to pafs, that the Moon's Way SMHR has just such an Obli

quity with respect to the Plane of the Sun's Way, or GHFS, that First, The most part of J the Time that the Moon is at M, or directly oppofite to the Sun, it is freed from the Shadow of the Earth CPD, and confequently from its Darkness, and that all that part of it that is turned to us, is seen at Full, and in its entire Luftre: Secondly, That when the Moon is at R, that is, in Conjunction with the Sun, and is feen at E, it is not hid from those that dwell upon the Farth?

VI. But farther, fince now the Planes of the Sun's and Moon's Way HFSG and HMSR (placed in refpe&t to each other after the manner of two Hoops laid obliquely upon one another) cut each other at two Points H and S; it follows, that when the Moon is not in its own Way at M, but at H or S, it will then be in the Plane of the Sun's Way: And when it happens at the time that the Sun is not at AB, but is directly oppofite at ab to the Moon at H or S, and that the Sun and the Earth are in a Right Line nK; it may be easily gather'd from the Figure, that when the Night-fhade extends itself to EKT, the Moon being at H, will be thereby eclipfed and obfcured; but when it is at S, it will then hide the Sun at ab, and fo caufe a Solar Eclipfe to those that dwell at S.

SECT. XLIV. The Advantages of Eclipfes.

BUT here feems an Objection to ftand in our Way, namely, that if Light be fo agreeable, and Darkness fo terrible; and if all this be fo order'd by a wife Governour of the World, why do thefe Eclipfes or Obfcurities of the Sun or Moon come to pass, fince Light alone feems fufficient to furVOL. III. Ccc

nifh