made by GOD, as an Inftrument wrought by its Power, any Pneumatick Engine, to be contrived and made by Man! som

THUS HUS much for the firft Thing miniftering to the Terraqueous Globe, the Atmosphere, and its Meteors; the next Appendage is Light. (1) Concerning which, I have in my Survey of the Heavens (2) fhewed, what admirable Contrivances the infinitely wife Creator hath for the affording this noble, glorious, and comfortable Benefit to other Globes, as well as ours; the Provifion he hath made by Moons, as well as by the Sun, for the Communication of it.ki

hn(2) It is not worth while to enumerate the Opinions of the Ariftotelians, Cartefians, and others about the Nature of Light; Ariftotle making it a Quality; Cartes a Pulfion, or Motion of the Globules of the fecond Element, Vid. Cartes Princip. p. 3. §. 55, 6c. But with the Moderns, I take Light to confift of material Particles, propagated from the Sun, and other luminous Bodies, not inftantaneously, but in time, according to the Notes following in this Chapter. But not to infift upon other Arguments for the Proof of it, our noble Founder hath proved the Materiality of Light and Heat, from actual Experiments on Silver, Copper, Tin, -Lead, Spelter fron, Tutenag, and other Bodies, exposed (both naked, and closely shut up) to the Fire: All which were conftant ly found to receive an Increment of Weight. I with he could have met with a favourable Season, to have tried his Experiments with the Sun-beams as he intended. Vid. Boy! Exp, to make Fire and Flame ponderable. wi custo

(2) Aftro-Theol. Book 7.

And now let us briefly confider the great Neceffity and Ufe thereof to all our Animal World. And this we fhall find to be little lefs than the ve ry Life and Pleasure of all thofe Creatures. For what Benefit would Life be of, what Pleafure, what Comfort would it be for us to live in perpetual Darknefs? How could we provide our felves with Food and Neceffaries? How could we go about the leaft Bufinefs, correfpond with one another, or be of any Ufe in the World, or any Creatures be the fame to us, without Light, and thofe admirable Organs of the Body, which the great Creator hath adapted to the Perception of that great Benefit.

But now by the help of this admirable, this firftmade (3), because moft neceffary, Creature of God, by this, I fay, all the Animal World is enabled to go here and there, as their occafions call; they can tranfact their Bufinefs by Day, and refresh and recruit themselves by Night, with Reft, and Sleep. They can with Admiration and Pleafure, behold the glorious Works of God; they can view the Glories of the Heavens, and fee the Beauties of the flowry Fields, the gay attire of the feathered Tribe, the exquifite Garniture of many Quadru peds, Infects, and other Creatures; they can take in the delightfome Landskips of divers Countries, and Places; they can with admiration fee the great Creator's wonderful Art and Contrivance in the Parts of Animals and Vegetables: And in a word, behold the Harmony of this lower World, and of the Globes above; and furvey GOD's exquifite Workmanship in every Creature.

(3) Gen, 1. 3. And God said, Let there be Light, and there was Light.

To

To all which I might add the Improvements, which the Sagacity of Men hath made of this noble Creature of God, by the Refractions and Reflections of Glaffes. But it would be endless to enumerate all its particular Ufes and Benefits to our World.

But before I leave this Point, there are two things concerning Light, which will deferve an efpecial Remark; and that is, its fwift and almoft inftantaneous Motion; and its vaft Extenfion.

1. It is a very great Act of the Providence of God, that fo great a Benefit as Light is, is not long in its Pallage from Place to Place. For was the Motion thereof no fwifter than the Motion of the fwifteft Bodies on Earth, fuch as of a Bullet out of a great Gun, or even of a Sound (4) (which is the fwifteft Motion we have next Light), in this Cafe Light would take up, in its Progrefs from the Sun to us, above thirty two Years, at the Rate of the firft, and above feventeen Years, at the Rate of the latter Motion.

(4) It may not be ungrateful to the Curious, to take notice of the Velocity of these two Things.

1

According to the Obfervations of Mersennus, a Bullet-shot out of a great Gun, flies 92 Fathom in a Second of Time, (vid. Merfen. Balif.) which is equal to 589 Feet English, and according to the Computation of Mr. Huygens, it would be 25 Years in paffing from the Earth to the Sun. But according to my own Obfervations made with one of her Majefty's Sakers, and a very accurate Pendulum-Chronometer, a Bullet, at its first Discharge, flies 510 Yards in five Half-feconds, which is a Mile in a little above 17 Half-feconds. And allowing the Sun's Diftance, as in the next Note, a Bullet would be 324 Years in flying with its utmost Velocity to the Sun.

As to the Velocity of Sound,fee Book 4. Chap. 3. Note 28, according to which rate there mentioned, a Sound would be near 17 Years in flying as far as the diftance is from the Earth to the Sun. Confer here the Experiments of the Acad. del Ciment, p. 140, &c.

The

The Inconveniencies of which would be, its Energy and Vigour would be greatly cooled and abated ; its Rays would be lefs penetrant; and Darkness would with greater difficulty and much fluggifhnefs, be diffipated, efpecially by the fainter Lights of our fublunary luminous Bodies. But paffing with fuch prodigious Velocity, with nearly the inftantaneous Swiftnefs of almoft two Hundred Thoufand English Miles in one Second of Time, (5) or (which is the fame thing) being but about feven or Eight Minutes of an Hour in coming from

(5) Mr. Romer's ingenious Hypothefis about the Velocity of Light, hath been established by the Royal Academy, and in the Obfervatory for eight Years, as our Phil. Tranf. No. 136. obferve from the Journ. des Scavans; our most eminent Aftronomers alfo in England admit it: But Dr. Hook thinks with Monfieur Cartes, the Motion of Light inftantaneous, Hook Poft. Works, pag. 77. And this he endeavours to explain, pag. 130, &c.

What Mr. Romer's Hypothefis is, may be feen in the Phil. Tranfact, before-cited. As alfo in the before-mentioned Sir Ifaac Newton's Opticks Light is propagated from luminous Bodies in time, and fpends about feven or eight Minutes of an Hour in passing fram the Sun to the Earth. This was first obferved by Romer, and then by others, by means of the Eclipfes of the Satellites of Jupiter. For thefe Eclipfes, when the Earth is between the Sun and Jupiter, happen about feven or eight Minutes fooner than they ought to do by the Tables and when the Earth is beyond the O, they happen about feven or eight Minutes later than they ought to do: The reafon being, that the Light of the Satellites hath farther to go in the Latter Cafe, than in the former, by the Diameter of the Earth's Orbit. Newt. Opt. L. 2. Part. 3. Prop. 11

Now forafmuch as the Distance between the Sun and the Earth (according to the Computations in my Aftro-Theology, B. 1. Ch. 3. Note 2) is 86051398 English Miles; therefore, at the rate of 74 Minutes, or 450 Seconds in paffing from the Sun, Light will be found to fly above 191225 Miles in one Second of Time.

from the Sun to us, therefore, with all fecurity and fpeed, we receive the kindly Effects and Influences of that noble and useful Creature of God."

41

2. Another thing of great confideration about Light is, its vaft Expanfion, it's almoft incomprehenfible, and inconceivable Extenfion, which as a late ingenious Author (6) faith, "Is as boundless "and unlimited as the Univerfe it felf, or the Ex"panfum of all material Beings: The vastnefs of "which is fo great, that it exceeds the Comprehen"fions of Man's Understanding. Infomuch that very many have afferted it abfolutely Infinite, and without any Limits or Bounds.

And that this noble Creature of God is of this Extent, (7) is manifeft from our seeing fome of the fartheft diftant Objects, the heavenly Bodies, fome with our naked Eye, fome with the help of Optical

8

Dr. Hook Poft. Works. Left of Light, pag. 96.

Inftru

For the proof of this vaft Extent of Light, I fhall take the Computation of the fame great Man, pag. 77. If, faith he, we confider firft the vast Distance between us and the Sun, which from the best and latest Obfervations in Aftronomy, is judged to be about 10000 Diameters of the Earth, each of which is about 7925 English Miles; therefore, the Sun's diftance is 7925000 Miles; and if we confider that according to the Observation, which I published to prove the Motion of the Earth, [which were Observations of the Parallax of fome of the fixt Stars in the Head of Draco, made in 1699] the whole Diameter of the Orb, viz. 20000, made the Subtenfe but of one Minute to one of the fixt Stars, which cannot therefore be less diftant than 3438 Diameters of this great Orb, and confequently 68760000 Diameters of the Earth: And if this Star be one of the weareft, and that the Stars that are of one Degree leffer in Magnitude (I mean not of the Second Magnitude, because there may be many Degrees between the first and Second) be as much farther; and another fort yet fmaller be three times as far; and a fourth four times as far, and fo onward, poffibly to fome 100 Degrees of Magnitude such as may be difcovered by longer and longer Telescopes, that they may be 100 times as far; then certainly this material Expansion, a part of which we are, must be so great, that 'twill infinitely exceed our Shallow Conception to imagine. Now, by what I laft mentioned, it is

evident