gency or Scattering of its Rays more and more, which chiefly diminish the force of Burning; and that the faid Distance or Remotenefs does hardly contribute more towards preferving the Earth from an entire Conflagration, than by the diffipating and feparating the Rays more and more from each other, in proportion to the Length which they run.

SECT. XXX. Two great Ufes of the faid Divergency.

FROM this Divergency of the Rays of Light from all Points whatsoever (which must be confidered as a Wonder by all Men) we may deduce these two Advantages, which the adorable Creator bestows upon us, and which we have before already hinted:

First, That the Earth is thereby fecured from being confumed by the Sun.

Secondly, That by fuch Divergency all Bodies are enlighten'd on all Sides by the Rays that are fcatter'd upon 'em, and thereby render'd visible to every one. Thus we find in Vol. I. Tab. X. Fig. 1. that the Rays of Light KP falling from the Candle K upon a Point P (for Inftance upon the Point of a Needle) separate themselves from one another there, as well as at the Candle itself, and fo render the faid Point vifible in every Part.

SECT. XXXI. Refractions and their Uses.

BUT forafmuch as (Tab. X. Fig. 3.) these Rays from A, diverging and filling the Space AS T, the fame would alfo happen from all the other Points N, L, M, B, &c. of the Object A B, and therefore the fame Rays diverging, for inftance, from B and A, will be entirely mingled with each other at SOT, and fo reprefent to

the

the Eye at S T a confused Light of all the furrounding Objects, but no diftin&t View of any one; there feemed therefore fomething to be still deficient to render the Light compleatly useful to us; and that befides the rectilinear and divergent Motions of Light, there was yet another Law requifite, by which all the Rays proceeding from A or B might be again inflected towards each other, and gather'd together in fo many particular Points a and b, which has been alrea dy proved to be the fole Caufe of diftinct Vifion.

Befides this, to the end that the Light may be as useful to us as poffible, fince the Sun when it Sets would turn the perfect Day in a very small fpace of Time into thick Darkness, and when it Rifes, would change a Night as dark as Pitch in a few Minutes into a bright Day; by which means our Eyes paffing fo fuddenly from one Extream to the other, might be much prejudiced and weaken'd, as Experience often fhews; there feemed to be a Means neceffary to cause the Brightnefs of the ftrong Light of the Sun to advance and recede gradually; and this is brought about by the Morning and Evening Twilights.

Now I wou'd ask an Atheift, who pretends not yet to be able to discover the wife Purposes of him that has prescribed fuch Laws to the Light, and which it strictly obeys, Whether he could have found out a better way to avoid the abovemention'd Inconveniences, than by enduring Light with the Properties of Refraction, whereby, as we have already fhewn, the two aforefaid Diffi= culties may be obviated? And fince they are actually prevented by this Method; what Rea fon has fo unhappy a Philofopher to deny the Wisdom of the Creator and Ruler of fo glorious a Body?

V OL. ÍIÍ.

Bbb

SECT.

SECT. XXXII. The Reafon of the Angles.

Now to fhew that thefe Refractions of the Rays of Light can't be ascribed to mere Chance, let, (Tab. XXI. Fig. 3.) a Ray SO proceed from the Sun S to the Superficies of the Water F G; and fuppofe from the Center O a Circle FBGP defcribed as large as you will, it is experimentally true, that the Ray BO does not proceed ftrait forwards to R, but at O makes the Angle BOP, for which Reason the fame Ray being thereby refracted proceeds from O to P, according to PO, which is termed the refracted Ray.

After the fame manner the Ray b O, does not proceed ftrait forwards to r, but breaks at Op: Now whether these refracted Rays O P and PO do likewife run in ftrait Lines, or elfe as often as they meet with frefh Refiftance or Reverberations are again inflected, we don't here difpute.

Now I leave any one, that is reasonable, to judge whether he imagines it poffible to happen without any Direction, that all the Rays OS, Os, and all others that with different Obliquity fall upon the Water F G, as here at O, with fo dreadful a Velocity, with which they are protruded; and that being entirely ignorant of all things elfe as well as of themfelves, they can obferve fuch a Law without once departing from it, that their broken Rays, OP, O p, do exactly ever take the fame Way; that (fuppofing the Lines A B, DP, ab, dp to be all at Right Angles to ad, which is likewife at right Angles with Refpe&t to FG) the faid A B and PD, as alfo a b and pd, will always have the fame Ratio to each other fo that to speak more plainly, as A B is two or three times as long as PD, in all the other Incident

;

Rays,

Rays, as here at b o, ab will be twice or thrice as long as pd; nor will there be, in fo many Millions of Rays that fall in fuch various Obliquities upon F G, and penetrate into the Water, one fingle Ray to be found, notwithstanding their furprizing Swiftnefs, that don't perfectly follow this Rule, at least if all the Rays are of the fame Kind.

SECT. XXXIII. The Structure of the Eyes with rem Spect to Light.

AND as when we treated of the Eye, we mention'd the Properties of Light as an unconteftable Proof of the Wifdom of the Creator; fo whilft we are here fpeaking of Light, we fhall briefly apply the Structure of the Eye, fo far as it relates to Light, to the fame Purpofe; and the moft obdurate Atheist, unlefs he abfolutely refufes to liften to any convincing Proofs, is intreated by us, that he would again attend to what we have faid in the Contemplation about Vision.

SECT. XXXIV. The Power of Bodies to reflect Light.

BUT now tho' Light fhould fall upon the Eye, and tho' the Eye were furnished with all the aforefald Qualities for receiving the fame; yet that whole Difpofition, and all those Properties would be in vain, and the noble Globe of the Earth would be of no more Advantage to the Inhabitants than it is to any Body now who is ftark blind; unlefs befides all this, the Bodies upon which Light falls had the Faculty of caufing the fame to rebound back from them, and to reflect the Rays thereof to all Places round about 'em.

Now fince this Property occurs in almost all vifible Objects, will an Atheist say, that this was likewife by Chance, nor that the great End thereof was, to render Bodies visible?

And if it fhould appear to him too abfurd to ascribe all this to meer Chance only, let him then tell us, what Neceffity there is in the Combination of Caufes, why almost all Bodies do enjoy this reflecting Power, with refpect to Light; whereas there are many which in relation to others that ftrike upon or against 'em, do not exert fuch a Power, nor drive them back again with any Repercuffion. Thus we fee, for inftance, That every thing which falls with any Degree of Swiftnefs upon foft Clay, remains fticking in it, and is not reflected; and yet the contrary happens when thofe exceeding swift Particles of Light fall upon the fame; for how fmall foever they be, they rebound from it, and thereby render the Clay vifible. We might relate many more Wonders concerning this Matter, which we fhall pass by here, having occafion to say something of them hereafter.

SECT. XXXV. The AIR Invifible.

MOREOVER, fince this Property of Reflecting Light, is in a manner common to all Bodies, excepting perhaps fuch as are black (which by many is fuppofed to be occafion'd hereby, namely that Bodies fo tinged do not reflect any of the Rays of Light that fall upon them, for which Reason they have no other Idea of this Colour but as of meer Darkness) Now muft we not herein again confefs a wife Difpofition of the Great and Gracious Creator, who, notwithstanding that he has made Water and many other fluid Matters vifible, yet feems to have excluded