their Progress from S to A, C, D, E, continually diverge or recede from each other: Now there need not be much pains taken to fhew, that the fame Rays, which at the Distance S B, fall upon the Plane Circle AECD, when they are nearer to the Sun; and for Inftance, when they have proceeded no farther from it than Sb, are all within the Circumference of a fmaller Circle aecd; and confequently, that the Fire of which thefe Rays confift, or at least which accompanies them, is fo much thicker, or preffed together in the little Circle aecd, than in the great one AECD, as this laft is bigger than the former; or to speak in the Language of the Mathematicians, the Heat which the little Circle a ecd undergoes, is fo much greater than that which the bigger Circle A ECD feels from the fame Rays, as the Square of the Distance of the great Circle, or of SB or SA, &c. is greater than the Square of the Distance of the little Circle, or of Sb or Sa; that is to fay, when SB is twice as great ab Sb, the Heat at a e c d is twice two times, or four times greater than at AECD; and fo if SB be 100, and Sb 5, their Squares are 100 times roo, and five times 5, or 10,000 and 25; and confequently the Heat at aecd: Is to the Heat at AECD:: As 10,000: To 25, or as 400 to 1, which is likewife confirmed by Expe

rience.

From whence it is then manifeft, that if one knows how much one Place is nearer to the Sun than another, one may likewise, according to this Rule, make an exa& Calculation how much more Heat is produced by the Rays of the Sun at one Place than at another upon Occasion of their Diftance; and generally that 'tis true, that by how much the nearer any thing is to the Sun, fo much the greater Heat it must undergo from the united

and

and compacted Rays thereof; as also the farther it is from the Sun, the lefs will it feel of its Heat.

Now as this is known to be true by all Mathematicians, let an unhappy Atheist confider in his Retirement, whether he thinks it can be by Chance, that a glowing Sea of Fire above 100,000 times bigger than the whole Globe of the Earth, is about the Sun at S, the burning Rays whereof SB, SA, SE, SC, SD, &c. come down with fo unspeakable a Swiftnefs inceffantly (and therefore in fuch a Number as is hardly to be conceived) upon the Earth ADCE; and yet that this terrible Fire does not immediately, and in the most dismal manner confume every thing upon it.

'Tis true indeed, that the Distance SB, which is between the Earth B and the Sun S, being of the Length of 12,000 Diameters of the Earth, may contribute fomething thereto; but yet this beautiful Globe is by no means preferved from the aforefaid terrible Deftruction by this only. To understand which, let it be fuppofed, that there comes down from the Point of the Sun S upon the Earth, the Rays Sa, Se, Sb, Sc, Sd, &c. without Diverging, or in parallel Lines, and closely joyned together; or (to render the Notion thereof yet clearer) that the faid Rays being near the Sun at the Point B, are diverged and feparated from each other as they go, but proceeding farther, lofe their Divergency; and defcending down in their Parallelifm, or Equidiftance, from the circular Column a cm k, it is plain that all of 'em will fall upon the Circle k m, and there produce a Heat, which is fo much greater than that which would be perceived in the great Circle A ECD from the fame diverging Rays, as this laft Circle is bigger than the little one km.

This

This appears from the Burning-Glaffes, the Force of which does only confift herein, that the Rays are collected into a fmaller Compass; fo that they give a clear Proof of this Truth, that the Rays of the Sun being collected into a narrower Compass, even at fo great a Distance from the Sun itself as is the Earth, are yet capable of producing a terrible Heat. From whence then it does follow certainly enough, that it is not so much the Distance of the Sun, but the Divergenicy or Scattering of its Rays more and more, which chiefly diminish the force of Burning; and that the faid Diftance 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 adoreable 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) feparate themselves from one another there, as well as at the Candle itself, and by that Divergence render the faid Point vi fible all round about it, SECT.

SECT. XXXI. Refractions and their Ufes.

BUT forafmuch as (Tab. X. Fig. 3.) these Rays from A, diverging and filling the Space AS T, the fame would also happen from all the other Points N, L, M, B, &c. of the Obje& A B, and therefore the fame Rays diverging, for inftance, from B and A, will be entirely mingled with each other at SO T, and so represent to the Eye at ST a confused Light of all the furrounding Objects, but no diftin&t View of any one; there seemed 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 already proved to be the fole Cause of diftin& Vision.

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 Brightness 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 would ask an Atheift, who pretends not yet to be able to difcover the wife Purposes of him that has prescribed fuch Laws to the Light, and which it ftri&ly obeys, Whether he could VOL. III.

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have

have found out a better way to avoid the abovemention'd Inconveniencies, than by enduing Light with the Properties of Refraction, whereby, as we have already fhewn, the two aforefaid Difficulties may be obviated? And fince they are aЯually prevented by this Method, what Reafon has fo unhappy a Philofopher to deny the Wisdom of the Creator and Ruler of fo glorious a Body?

SECT. XXXII. The Proportion of the Angles made by the refracted Rays.

Now to fhew that thefe Refractions of the Rays of Light can't be afcribed 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 forward 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 thefe refracted Rays OP and O do likewife run in ftrait Lines, or elfe as often as they meet with fresh Resistance or Reverberations are again inflected, we don't here determine.

Now I leave any one, that is reasonable, to judge whether he imagines it poffible to happen without the Direction of an intelligent Being, that all the Rays OS, Os, and all others that with different Obliquity fall upon the Water FG, (as here at O, with fo dreadfull a Velocity, with which they are protruded, and being entirely ignorant of all things elfe as well as of themfelves) can obferve fuch a Law without once departing