BOOK I.

_Of the Out-works of the Terraqueous Globe; the Atmosphere, Light, and Gravity._

[Illustration]

CHAP. I.

_Of the Atmosphere in general._

The Atmosphere, or Mass of Air, Vapours and Clouds, which surrounds our Globe, will appear to be a matter of Design, and the infinitely wise Creator’s Work, if we consider its _Nature_ and _Make_[a], and its _Use_ to the World[b].

1. Its Nature and Make, a Mass of Air, of subtile penetrating Matter, fit to pervade other Bodies, to penetrate into the inmost Recesses of Nature, to excite, animate, and spiritualize; and in short, to be the very Soul of this lower World. A thing consequently

2. Of greatest Use to the World, useful to the Life, the Health, the Comfort, the Pleasure, and Business of the whole Globe. It is the Air the whole Animal World breatheth, and liveth by; not only the Animals inhabiting the Earth[c] and

Air[d], but those of the Waters[e] too. Without it most Animals live scarce half a Minute[f]; and others, that are the most accustomed to the want of it, live not without it many Days.

And not only Animals themselves, but even Trees and Plants, and the whole vegetable Race, owe their Vegetation and Life to this useful Element; as will appear when I come to speak of them, and is manifest from their Glory and Verdure in a free Air, and their becoming Pale and Sickly, and Languishing and Dying, when by any means excluded from it[g].

Thus useful, thus necessary, is the Air to the Life of the animated Creatures; and no less is it to the Motion and Conveyance of many of them. All the winged Tribes owe their Flight and Buoyancy[h] to it, as shall be shewn in proper place: And even the watery Inhabitants themselves cannot ascend and descend into their Element, well without it[i].

But it would be tedious to descend too far into Particulars, to reckon up the many Benefits of this noble Appendage of our Globe in many useful Engines[k]; in many of the Functions and Operations of Nature[l] in the Conveyance of Sounds; and a Thousand Things besides. And I shall but just mention the admirable use of our Atmosphere in ministring to the enlightening of the World, by its reflecting the Light of the heavenly Bodies to us[m]; and refracting the Sun-beams to our Eye, before it ever surmounteth our Horizon[n]; by which means the Day is protracted throughout the whole Globe; and the long and dismal Nights are shorten’d in the frigid Zones, and Day sooner approacheth them; yea the Sun itself riseth in Appearance (when really it is absent from them) to the great Comfort of those forlorn Places[o].

But passing by all these Things with only a bare mention, and wholly omitting others that might have been named, I shall only insist upon the excellent Use of this noble circumambient Companion of our Globe, in respect of two of its Meteors, the Winds, and the Clouds and Rain[p].

FOOTNOTES:

[a] _Mundi pars est Aer, & quidem necessaria: Hic est enim qui cœlum terramque connectit, ~&c.~_ Senec. Nat. Qu. l. 2. c. 4.

[b] _Ipse Aer nobiscum videt, nobiscum audit, nobiscum sonat; nihil enim eorum sine eo fieri potest, ~&c.~_ Cic. de Nat. Deor. l. 2. c. 33.

[c] As the Air is of absolute Necessity to Animal Life, so it is necessary that it should be of a due Temperament or Consistence; not foul, by reason that suffocateth: not too rare and thin, because that sufficeth not; with Examples of each of which, I shall a little entertain the Reader. In one of Mr. _Hawksbee_’s Compressing Engines, I closely shut up a _Sparrow_ without forcing any Air in; and in less than an Hour the Bird began to pant, and be concerned; and in less than an Hour and half to be sick, vomit, and more out of Breath; and in two Hours time was nearly expiring.

Another I put in and compressed the Air, but the Engine leaking, I frequently renewed the Compressure; by which means, (although the Bird panted a little after the first Hour,) yet after such frequent Compressures, and Immission of fresh Air, it was very little concerned, and taken out seemingly unhurt after three Hours.

After this I made two other Experiments in compressed Air, with the Weight of two Atmospheres injected, the Engine holding tight and well; the one with the _Great Titmouse_, the other with a _Sparrow_. For near an Hour they seemed but little concerned; but after that grew fainter, and in two Hours time sick, and in three Hours time died. Another thing I took notice of, was, that when the Birds were sick and very restless, I fancied they were somewhat relieved for a short space, with the Motion of the Air, caused by their fluttering and shaking their Wings, (a thing worth trying in the _Diving-Bell_). I shall leave the ingenious Reader to judge what the cause was of both the Birds living longer in compressed, than uncompressed Air; whether a less quantity of Air was not sooner fouled and rendred unfit for Respiration, than a greater.

From these Experiments two Things are manifested; one is, that Air, in some measure compressed, or rather heavy, is necessary to Animal Life: Of which by and by. The other, that fresh Air is also necessary: For pent up Air, when overcharged with the Vapours emitted our of the Animal’s Body, becomes unfit for Respiration. For which Reason, in the _Diving-Bell_, after some time of stay under Water, they are forced to come up and take in fresh Air, or by some such means recruit it. But the famous _Cornelius Drebell_ contrived not only a Vessel to be rowed under Water, but also a Liquor to be carried in that Vessel, that would supply the want of fresh Air. The Vessel was made for King _James_ I. It carried twelve Rowers, besides the Passengers. It was tried in the River of _Thames_; and one of the Persons that was in that submarine Navigation was then alive, and told it one, who related the Matter to our famous Founder, the Honourable, and most Ingenious Mr. _Boyl_. As to the Liquor, Mr. _Boyl_ saith, he discovered by a Doctor of Physick, who married _Drebell_’s Daughter, that it was used from time to time when the Air in the submarine Boat was clogged by the Breath of the Company, and thereby made unfit for Respiration; at which time, by unstopping a Vessel full of this Liquor, he could speedily restore to the troubled Air such a proportion of vital Parts, as would make it again for a good while fit for Respiration. The Secret of this Liquor _Drebell_ would never disclose to above one Person, who himself assured Mr. _Boyl_ what it was. _Vid._ _Boyl. Exp. Phys. Mech. of the Spring of the Air, Exp. 41._ in the _Digres_. This Story I have related from Mr. _Boyl_, but at the same time much question whether the Virtues of the Liquor were so effectual as reported.

And as too gross, so too rare an Air is unfit for Respiration. Not to mention the forced Rarefactions made by the Air-Pump, in the following Note; it is found, that even the extraordinary natural Rarefactions, upon the tops of very high Hills, much affect Respiration. An Ecclesiastical Person, who had visited the high Mountains of _Armenia_, (on which some fancy the Ark rested) told Mr. _Boyl_, that whilst he was on the upper part of them, he was forced to fetch his Breath oftner than he was wont. And taking notice of it when he came down, the People told him, that it was what happen’d to them when they were so high above the Plane, and that it was a common Observation among them. The like Observation the same Ecclesiastick made upon the top of a Mountain in the _Cevennes_. So a learned Traveller, and curious Person, on one of the highest Ridges of the _Pyrenees_, call’d _Pic de Midi_, found the Air not so fit for Respiration, as the common Air, but he and his Company were fain to breath shorter and oftner than in the lower Air. _Vid._ _Phil. Transact._ No. 63, or _Lowthorp’s Abridg._ Vol. 2. p. 226.

Such another Relation the learned _Joseph Acosta_ gives of himself and his Company, that, when they passed the high Mountains of _Peru_, which they call _Periacaca_, (to which he saith, _the Alps themselves seemed to them but as ordinary Houses, in regard of high Towers,) He and his Companions were surprized with such extreme Pangs of Straining and Vomiting, (not without casting up of Blood too,) and with so violent a Distemper, that he concludes he should undoubtedly have died; but that this lasted not above three or four Hours, before they came into a more convenient and natural Temperature of the Air._ All which he concludes proceeded from the too great Subtilty and Delicacy of the Air, which is not proportionable to humane Respiration, which requires a more gross and temperate Air, _Vid._ _Boyl_, _ubi supra_.

Thus it appears, that an Air too Subtile, Rare and Light, is unfit for Respiration: But the Cause is not the Subtilty or too great Delicacy, as Mr. Boyl thinks, but the too great Lightness thereof, which renders it unable to be a Counterbalance, or an Antagonist to the Heart, and all the Muscles ministring to _Respiration_, and the _Diastole_ of the Heart. Of which see _Book 4. Chap. 7. Note 1._

And as our Inability to live in too rare and light an Air may discourage those vain Attempts of Flying and Whimsies of passing to the Moon, &c. so our being able to bear an heavier State of the Air is an excellent Provision for Mens Occasions in Mines, and other great Depths of the Earth; and those other greater Pressures made upon the Air, in the _Diving-Bell_, when we descend into great Depths of the Waters.

[d] That the Inhabitants of the Air, (Birds and Insects,) need the Air as well as Man and other Animals, is manifest from their speedy dying in too feculent, or too much rarefied Air; of which see the preceding and following _Note (f)._ But yet Birds and Insects (some Birds at least) can live in a rarer Air than Man. Thus Eagles, Kites, Herons, and divers other Birds, that delight in high Flights, are not affected with the Rarity of the Medium, as those Persons were in the preceding Note. So Insects bear the Air-Pump long, as in the following _Note (f)._

[e] Creatures inhabiting the Waters need the Air, as well as other Animals, yea, and fresh Air too. The _Hydrocanthari_ of all Sorts, the _Nymphæ_ of _Gnats_, and many other Water-Insects, have a singular Faculty, and an admirable Apparatus, to raise their back Parts to the top of the Waters, and take in fresh Air. It is pretty to see, for Instance, the _Hydrocanthari_ come and thrust their Tails out of the Water, and take in a Bubble of Air, at the tip of their _Vaginæ_ and Tails, and then nimbly carry it down with them into the Waters; and, when that is spent, or fouled, to ascend again and recruit it.

So Fishes also are well known to use Respiration, by passing the Water through their Mouths and Gills. But _Carps_ will live out of the Water, only in the Air; as is manifest by the Experiment of their way of Fatting them in _Holland_, and which hath been practised herein _England_, _viz._ they hang them up in a Cellar, or some cool Place, in wet Moss in a small Net, with their Heads out, and feed them with white Bread soaked in Milk for many Days. This was told me by a Person very curious, and of great Honour and Eminence, whose Word (if I had leave to name him) no Body would question: And it being an Instance of the Respiration of Fishes very singular, and somewhat out of the way, I have for the Reader’s Diversion taken notice of it.

[f] By Experiments I made my self in the Air Pump, in _September_ and _October_, 1704; I observed that Animals whose Hearts have two _Ventricles_, and no _Foramen Ovale_, as Birds, Dogs, Cats, Rats, Mice, _&c._ die in less than half a Minute counting from the very first Exsuction; especially in a small Receiver.

A _Mole_ (which I suspected might have born more than other Quadrupeds) died in one Minute (without Recovery) in a large Receiver; and doubtless would hardly have survived half a Minute in a small Receiver. A _Bat_ (although wounded) sustained the Pump two Minutes, and revived upon the re-admission of the Air. After that, he remained four Minutes and a half and revived. Lastly, After he had been five Minutes, he continued gasping for a time, and after twenty Minutes I re-admitted the Air, but the _Bat_ never revived.

As for _Insects_: _Wasps_, _Bats_, _Hornets_, _Grashoppers_, and _Lady-Cows_ seemed dead in appearance in two Minutes, but revived in the open Air in two or three Hours time, notwithstanding they had been in _Vacuo_ twenty four Hours.

The _Ear-wig_, the great _Staphylinus_, the great black lowsy _Beetle_, and some other Insects would seem unconcerned at the _Vacuum_ a good while, and lie as dead; but revive in the Air, although some had lain sixteen Hours in the exhausted Receiver.

_Snails_ bear the Air Pump prodigiously, especially those in Shells; two of which lay above twenty four Hours, and seemed not much affected. The same Snails I left in twenty eight Hours more after a second Exhaustion, and found one of them quite dead, but the other revived.

_Frogs_ and _Toads_ bear the Pump long, especially the former. A large Toad, found in the House, died irrecoverably in less than six Hours. Another Toad and Frog I put in together, and the Toad was seemingly dead in two Hours, but the Frog just alive. After they had remained there eleven Hours, and seemingly dead, the Frog recovered in the open Air, only weak, but the Toad was quite dead. The same Frog being put in again for twenty seven Hours, then quite died.

The Animalcules in _Pepper-Water_ remained in _Vacuo_ twenty four Hours. And after they had been exposed a Day or two to the open Air, I found some of them dead, some alive.

[g] That the Air is the principal Cause of the Vegetation of Plants, _Borelli_ proves in his excellent Book _De Mot. Animal._ Vol. 2. Prop. 181. And in the next Proposition, he assureth, _In Plantis quoque peragi Aeris respirationem quandam imperfectam, à quâ earum vita pendet, & conservatur._ But of this more when I come to survey Vegetables.

_Some Lettice-Seed being sown upon some Earth in the open Air, and some of the same Seed at the same time upon other Earth in a Glass-Receiver of the Pneumatick Engine, afterwards exhausted of Air: The Seed exposed to the Air was grown up an Inch and half high within Eight Days; but that in the exhausted Receiver not at all. And Air being again admitted into the same emptied Receiver, to see whether any of the Seed would then come up, it was found, that in the Space of one Week it was grown up to the Height of two or three Inches._ Vid. Phil. Trans. No. 23. Lowth. Abridg. Vol. 2. p. 206.

[h] _In volucribus pulmones perforati aerem inspiratum in totam ventris cavitatem admittunt. Hujus ratio, ut propter corporis truncum Aere repletum & quasi extensum, ipsa magis volatilia evadant, faciliusque ab aere externo, proper intimi penum, sustententur. Equidem pisces, quò leviùs in aquis natent, in Abdomine vesicas Aere inflatas gestant: pariter & volucres, propter corporis truncum Aere impletum & quasi inflatum, nudo Aeri incumbentes, minus gravantur, proindeque levius & expeditiùs volant._ Willis de Anim. Brut. p. 1. c. 3.

[i] _Fishes by reason of the Bladder of Air within them, can sustain, or keep themselves in any Depth of Water: For the Air in that Bladder being more or less compressed, according to the Depth the Fish swims at, takes up more or less Space; and consequently, the Body of the Fish, part of whose Bulk this Bladder is, is greater or less according to the several Depths, and yet retains the same Weight. Now the Rule ~de Insidentibus humido~ is, that a Body, that is heavier than so much Water, as is equal in Quantity to the Bulk of it, will sink, a Body that is lighter will swim; a Body of equal Weight will rest in any part of the Water. By this Rule, if the Fish, in the middle Region of the Water, be of equal Weight to the Water, that is commensurate to the Bulk of it, the Fish will rest there, without any Tendency upwards or downwards: And if the Fish be deeper in the Water, the Bulk of the Fish becoming less by the Compression of the Bladder, and yet retaining the same Weight, it will sink, and rest at the Bottom. And on the other side, if the Fish be higher than the middle Region, the Air dilating it self, and the Bulk of the Fish consequently increasing, but not the Weight, the Fish will rise upwards and rest at the top of the Water. Perhaps the Fish by some Action can emit Air out of its Bladder——, and, when not enough, take in Air,——and then it will not be wondred, that there should be always a fit Proportion of Air in all Fishes to serve their Use, ~&c.~_ Then follows a Method of Mr. _Boyl_ to experiment the Truth of this. After which, in Mr. _Lowthorp_’s Abridgment, follow Mr. _Ray_’s Observations. _I think that——hath hit upon the true Use of the Swimming-Bladders in Fishes. For, 1. It hath been observed, that if the Swimming-Bladder of any Fish be pricked or broken, such a Fish sinks presently to the Bottom, and can neither support or raise it self up in the Water. 2. Flat Fishes, as Soles, Plaise, &c. which lie always grovelling at the Bottom, have no Swimming-Bladders that ever I could find. 3. In most Fishes there is a manifest Chanel leading from the Gullet——to the said Bladder, which without doubt serves for the conveying Air thereunto.——In the Coat of this Bladder is a musculous Power to contract it when the Fish lifts._ See more very curious Observations relating to this Matter, of the late great Mr. _Ray_, as also of the curious anonymous Gentleman in the ingenious Mr. _Lowthorp_’s Abridgment, before cited, _p. 845._ from _Phil. Trans. N._ 114, 115.

[k] Among the Engines in which the Air is useful, Pumps may be accounted not contemptible ones, and divers other Hydraulical Engines, which need not to be particularly insisted on. In these the Water was imagined to rise by the power of Suction, to avoid _a Vacuum_, and such unintelligible Stuff; but the justly famous Mr. _Boyl_ was the first that solved these Phænomena by the Weight of the Atmosphere. His ingenious and curious Observations and Experiments relating hereto, may be seen in his little Tract, _Of the Cause of Attraction by Suction_, and divers others of his Tracts.

[l] It would be endless to specify the Uses of the Air in Nature’s Operations: I shall therefore, for a Sample only, name its great Use to the World in conserving animated Bodies, whether endowed with animal or vegetative Life, and its contrary Quality of dissolving other Bodies; by which means many Bodies that would prove Nuisances to the World, are put out of the Way, by being reduced into their first Principles, (as we say), and so embodied with the Earth again. Of its Faculty as a Menstruum, or its Power to dissolve Bodies; I may instance in Crystal Glasses, which, with long keeping, especially if not used, will in Time be reduced to a Powder, as I have seen. So divers Minerals, Earths, Stones, Fossil-Shells, Wood, _&c._ which from _Noah_’s Flood, at least for many Ages, have lain under Ground, so secure from Corruption, that, on the contrary, they have been thereby made much the stronger, have in the open Air soon mouldered away. Of which last, Mr. _Boyl_ gives an Instance (from the _Dissertation de admirandis Hungar. Aquis_) of a great Oak, like a huge Beam, dug out of a Salt Mine in _Transylvania_, _so hard, that it would not easily be wrought upon by Iron Tools, yet, being exposed to the Air out of the Mine, it became so rotten that in four Days it was easy to be broken, and crumbled between one’s Fingers_. Boyl’s Suspic. about some hid. Qual. in the Air, p. 28. So the Trees turned out of the Earth by the Breaches at _West-Thurrock_ and _Dagenham_, near me, although probably no other than _Alder_, and interred many Ages ago in a rotten oazy Mold, were so exceedingly tough, hard, and found at first, that I could make but little Impressions on them with the Strokes of an Ax; but being exposed to the Air and Water, soon became so rotten as to be crumbled between the Fingers. See my Observations in _Philos. Transact._ Nᵒ. 335.

[m] _By reflecting the Light of the heavenly Bodies to us_, I mean that Whiteness or Lightness which is in the Air in the Day-time, caused by the Rays of Light striking upon the Particles of the Atmosphere, as well as upon the Clouds above, and the other Objects beneath upon the Earth. To the same Cause also we owe the Twilight, _viz._ to the Sun-beams touching the uppermost Particles of our Atmosphere, which they do when the Sun is about eighteen Degrees beneath the Horizon. And as the Beams reach more and more of the airy Particles, so Darkness goes off, and Day light comes on and encreaseth. For an Exemplification of this, the Experiment may serve of transmitting a few Rays of the Sun through a small Hole into a dark Room: By which means the Rays which meet with Dust, and other Particles flying in the Air, are render’d visible; or (which amounts to the same) those swimming small Bodies are rendered visible, by their reflecting the Light of the Sun-beams to the Eye, which, without such Reflection, would it self be invisible.

The Azure Colour of the Sky Sir _Isaac Newton_ attributes to Vapours beginning to condense, and that are not able to reflect the other Colours. _V._ _Optic._ l. 2. _Par. 3. Prop. 7._

[n] By the Refractive Power of the Air, the Sun, and the other heavenly Bodies seem higher than really they are, especially near the Horizon. What the Refractions amount unto, what Variations they have, and what Alterations in time they cause, may be briefly seen in a little Book called, _The Artificial Clock-Maker_, Chap. 11.

_Although this inflective Quality of the Air be a great Incumbrance and Confusion of Astronomical Observations;——yet it is not without some considerable Benefit to Navigation; and indeed in some Cases, the Benefit thereby obtained is much greater than would be the Benefit of having the Ray proceed in an exact straight Line._ [Then he mentions the Benefit hereof to the Polar Parts of the World.] _But this by the by_ (saith he.) _The great Advantage I consider therein, is the first Discovery of Land upon the Sea; for by means hereof, the tops of Hills and Lands are raised up into the Air, so as to be discoverable several Leagues farther off on the Sea than they would be, were there no such Refraction, which is of great Benefit to Navigation for steering their Course in the Night, when they approach near Land; and likewise for directing them in the Day-time, much more certainly than the most exact Celestial Observations could do by the Help of an uninflected Ray, especially in such Places as they have no Soundings._ [Then he proposes a Method to find by these means the Distance of Objects at Sea.] V. Dr. _Hook_’s _Post. Works_. Lect. of Navig. p. 466.

[o] _Cum Belgæ in novâ Zemblâ hybernarent, Sol illis apparuit 16 diebus citiùs, quàm revera in Horizonte existeret, hoc est, cùm adhuc infra Horizontem depressus esset quatuor circiter gradibus, & quidem aere sereno._ Varen. Geog. c. 19. Prop. 22.

_~[These Hollanders]~ found, that the Night in that place shortened no less than a whole Month; which must needs be a very great Comfort to all such Places as live very far towards the North and South Poles, where length of Night, and want of seeing the Sun, cannot chuse but be very tedious and irksome._ Hook Ibid.

_~[By means of the Refractions]~ we found the Sun to rise twenty Minutes before it should; and in the Evening to remain above the Horizon twenty Minutes (or thereabouts) longer than it should._ Captain _James_’s Journ. in _Boyl_ of Cold. Tit. 18. p. 190.

[p] _Aer—in Nubes cogitur: humoremque colligens terram auget imbribus: tum effluens huc & illuc, ventos efficit. Idem annuas frigorum & calorum facit varietates: idemque & volatus Alitum sustinet, & spiritu ductus alit & sustentas animantes._ Cic. de Nat. Deor. l. 2. c. 39.

CHAP. II.

_Of the Winds[a]._

To pass by other Considerations, whereby I might demonstrate the Winds to be the infinite Creator’s Contrivance, I shall insist only upon their great usefulness to the World. And so great is their Use, and of such absolute Necessity are they to the Salubrity of the Atmosphere, that all the World would be poisoned without those Agitations thereof. We find how putrid, fetid, and unfit for Respiration, as well as Health and Pleasure, a stagnating, confined, pent up Air is. And if the whole Mass of Air and Vapours was always at Rest, and without Motion, instead of refreshing and animating, it would suffocate and poison all the World: But the perpetual Commotions it receives from the Gales and Storms, keep it pure and healthful[b].

Neither are those Ventilations beneficial only to the Health, but to the Pleasure also of the Inhabitants of the Terraqueous Globe; witness the Gales which fan us in the heat of Summer; without which, even in this our temperate Zone, Men are scarce able to perform the Labours of their Calling, or not without Danger of Health and Life[c]. But especially, witness the perpetual Gales which throughout the whole Year do fan the Torrid Zone, and make that Climate an healthful and pleasant Habitation, which would otherwise be scarce habitable.

To these I might add many other great Conveniencies of the Winds in various Engines, and various Businesses. I might particularly insist upon its great Use to transport Men to the farthest distant Regions of the World[d] and I might particularly speak of the general and coasting Trade-Winds, the Sea, and the Land-Breezes;[e] the one serving to carry the Mariner in long Voyages from East to West; the other serving to waft him to particular Places; the one serving to carry him into his Harbour, the other to bring him out. But I should go too far to take notice of all Particulars[f]. Leaving therefore the Winds, I proceed in the next Place to the Clouds and Rain.

FOOTNOTES:

[a] _Ventus est aer fluens_, is _Seneca_’s Definition, _Na. Qu. l. 5._ And as Wind is a Current of the Air, so that which excites or alters its Currents may be justly said to be the Cause of the Winds. An Æquipoise of the Atmosphere produceth a Calm; but if that Æquipoise be more or less taken off, a Stream of Air, or Wind, is thereby accordingly produced either stronger or weaker, swifter or slower. And divers things there are that may make such Alterations in the Æquipoise or Balance of the Atmosphere, _viz._ Eruptions of Vapours from Sea or Land; Rarefactions and Condensations in one Place more than another; the falling of Rain, pressure of the Clouds, _&c._ _Pliny_, l. 2. c. 45. tells us of a certain _Cavern_ in _Dalmatia_, called _Senta_, _in quem_, saith he, _dejecto levi pondere, quamvis tranquillo die, turbini similis emicat procella_. But as to Caves it is observed, that they often emit Winds more or less. Dr. _Connor_, taking notice of this matter, specifies these, _In regno Neapolitano ex immani Cumanæ Sibyllæ antro tenuem ventum effluentem percepi_. The like he observed at the Caves at _Baiæ_, and in some of the Mines of _Germany_, and in the large Salt-Mines of _Cracow_ in _Poland_. _Ubi_, saith he, _opifices, & ipse fodinæ dominus Andreas Morstin, Nob. Polonus, mihi asseruerunt, quòd tanta aliquando Ventorum tempestas ex ambagiosis hujus fodinæ recessibus surgere solebat, quod laborantes fossores humi prosternebat, nec non portas & domiciliæ (quæ sibi in hâc fodinâ artifices exstruunt) penitùs evertebat_. Bern. Connor. Dissert. Med. Phys. p. 33. Artic. 3.

And as great Caves, so great Lakes sometimes send forth Winds. So _Gassendus_ saith the _Lacus Legnius_ doth, _E quo dum exoritur fumus, nubes haud dubiê creanda est, quæ sit brevi in tempestatem sævissimam exoneranda_. Gassend. Vit. Peiresk. l. 5. P. 417.

But the most universal and constant Alterations of the Balance of the Atmosphere are from Heat and Cold. This is manifest in the General Trade-Winds, blowing all the Year between the Tropicks from East to West: if the Cause thereof be (as some ingenious Men imagine) the Sun’s daily Progress round that part of the Globe, and by his Heat rarefying one part of the Air, whilst the cooler and heavier Air behind presseth after. So the Sea and Land Breezes in _Note (d)._ And so in our Climate, the Northerly and Southerly Winds (commonly esteemed the Causes of cold and warm Weather), are really the Effects of the Cold or Warmth of the Atmosphere: Of which I have had so many Confirmations, that I have no doubt of it. As for Instance, it is not uncommon to see a warm Southerly Wind, suddenly changed to the North, by the fall of Snow or Hail; to see the Wind in a frosty, cold Morning North, and when the Sun hath well warmed the Earth and Air, you may observe it to wheel about towards the Southerly Quarters; and again to turn Northerly or Easterly in the cold Evening. It is from hence also, that in Thunder-Showers the Wind and Clouds are oftentimes contrary to one another, (especially if Hail falls) the sultry Weather below directing the Wind one way; and the Cold above the Clouds another way. I took Notice upon _March_ the 10ᵗʰ 1710/1, (and divers such like Instances I have had before and since) that the Morning was warm, and what Wind stirred was West-South-West, but the Clouds were thick and black (as generally they are when Snow ensues): A little before Noon the Wind veered about to North by West, and sometimes to other Points, the Clouds at the same time flying some North by West, some South-West: About one of the Clock it rained apace, the Clouds flying sometimes North-East, then North, and at last both Wind and Clouds settled North by West; At which time Sleet fell plentifully, and it grew very cold. From all which I observe, 1. That although our Region below was warm, the Region of the Clouds was cold, as the black, snowy Clouds shewed. 2. That the struggle between the warmth of ours, and the cold of the cloudy Region, stopped the airy Currents of both Regions. 3. That the falling of the Snow through our warmer Air melted into Rain at first; but that it became Sleet after the superiour Cold had conquered the inferiour Warmth. 4. That, as that Cold prevailed by Degrees, so by Degrees it wheeled about both the Winds and Clouds from the Northwards towards the South.

_Hippocrates_, l. 2. _De Vict. Orat._ _Omnes Ventos vel à nive, glacie, vehementi gelu, fluminibus, ~&c.~ spirare necesse judicat_, Bartholin. de usu Nivis, c. 1.

[b] _It is well observed in my Lord ~Howard~s Voyage to ~Constantinople~, that at ~Vienna~ they have frequent Winds, which if they cease long in Summer, the Plague often ensues: So that it is now grown into a Proverb, that if ~Austria~ be not windy, it is subject to Contagion._ Bohun of Wind, _p. 213._

From some such Commotions of the Air I imagine it is, that at _Grand Cairo_ the Plague immediately ceases, as soon as the _Nile_ begins to overflow; although Mr. _Boyl_ attributes it to nitrous Corpuscles. _Determ. Nat. of Effluv._ Chap. 4.

_Nulla enim propemodum regio est, quæ non habeat aliquem flatum ex se nascentem, & circa se cadentem._

_Inter cætera itaq; Providentiæ opera, hoc quoq; aliquis, ut dignum admiratione suspexerit. Non enim ex unâ causâ Ventos aut invenit, aut per diversa disposuit: sed primum ut aera non sinerent pigrescere, sed assiduâ vexatione utilem redderens, vitaiemq; tracturis._ Sen. Nat. Quæst. l. 5. c. 17, 18.

All this is more evident, from the Cause assigned to malignant epidemical Diseases, particularly the Plague, by my ingenious, learned Friend, Dr. _Mead_; and that is, an hot and moist Temperament of the Air, which is observed by _Hippocrates_, _Galen_, and the general Histories of Epidemical Diseases, to attend those Distempers. _Vid._ _Mead of Poisons, Essay 5._ p. 161. But indeed, whether the Cause be this, or poisonous, malignant Exhalations or Animalcules, as others think, the Winds are however very salutiferous in such Cases, in cooling the Air, and dispersing and driving away the moist or pestiferous Vapours.

[c] _July 8. 1707_, (called for some time after the _Hot Tuesday_,) was so excessively hot and suffocating, by reason there was no Wind stirring, that divers Persons died, or were in great Danger of Death, in their Harvest-Work. Particularly one who had formerly been my Servant, a healthy, lusty, young Man, was killed by the Heat: And several Horses on the Road dropped down and died the same Day.

In the foregoing Notes, having Notice of some Things relating to Heat, although it be somewhat out of the way, I hope the Reader will excuse me, if I entertain him with some Observations I made about the Heat of the Air under the Line, compared with the Heat of our Bodies. _J. Patrick_, who, as he is very accurate in making Barometrical and Thermometrical Instruments, had the Curiosity for the nicer adjusting his Thermometers, to send two abroad under the Care of two very sensible, ingenious Men; one to the Northern Lat. of 81; the other to the Parts under the Æquinoctial: In these two different Climates, the Places were marked where the Spirits stood at the severest Cold and greatest Heat. And according to these Observations he graduates his Thermometers. With his Standard I compared my Standard Thermometer, from all the Degrees of Cold, I could make with _Sal Armoniack_, &c. to the greatest Degrees of Heat our Thermometers would reach to. And with the same Thermometer (of mine) I experimented the greatest Heat of my Body, in _July 1709_. First in an hot Day without Exercise, by patting the Ball of my Thermometer under my Armpits, and other hottest Parts of my Body. By which means the Spirits were raised 284 Tenths of an Inch above the Ball. After that, in a much hotter Day, and indeed nearly as hot as any Day with us, and after I had heated my self with strong Exercise too, as much as I could well bear, I again tried the same Experiment, but could not get the Spirits above 288 Tenths; which I thought an inconsiderable Difference, for so seemingly a very different Heat of my Body. But from some Experiments I have made (altho’ I have unfortunately forgotten them) in very cold Weather, I imagine the Heat of an healthy Body to be always much the same in the warmest Parts thereof, both in Summer and Winter. Now between those very Degrees of 284 and 288, the Point of the equatorial Heat falleth. From which Observation it appears, that there is pretty nearly an equal Contemperament of the Warmth of our Bodies, to that of the hottest Part of the Atmosphere inhabited by us.

If the Proportion of the Degrees of Heat be desired from the Freezing-Point, to the Winter, Spring, and Summer Air, the Heat of Man’s Body, of heated Water, melted Metals, and so to actual Fire; an Account may be met with of it, by my most ingenious Friend, the great Sir _Isaac Newton_, in _Phil. Transact._ Nᵒ. 270.

[d] _In hoc ~Providentia~ ac ~Dispositor~ ille Mundi ~Deus~, aera ventis exercendum dedit,——non ut nos classes partem freti occupaturas compleremus milite armato, ~&c.~ Dedit ille ventos ad custodiendam cœli terrarumq; temperiem, ad evocandas supprimendásq; aquas, ad alendos satorum atq; arborum fructus; quos ad maturitatem cum aliis causis adducit ipsa jactatio, attrahens cibum in summa, & ne torpeat, promovens. Dedit ventos ad ulteriora noscenda: fuisset enim imperitum animal, & fine magnâ experientiâ rerum Homo, si circumscriberetur natalis soli fine. Dedit ventos ut commoda cujusq; regionis fierent communia; non ut legiones equitemq; gestarent, nec ut perniciosa gentibus arma transveherent._ Seneca, ibid.

[e] _~Sea-Breezes~ commonly rise in the Morning about nine a Clock.——They first approach the Shore gently, as if they were afraid to come near it.——It comes in a fine, small, black Curle upon the Water, whereas all the Sea between it and the Shore (not yet reached by it) is as smooth and even as Glass in Comparison. In half an Hours time after it has reached the Shore, it fans pretty briskly, and so encreaseth gradually till twelve a Clock; then it is commonly strongest, and lasts so till two or three, a very brisk Gale.——After three it begins to die away again, and gradually withdraws its force till all is spent; and about five a Clock——it is lulled asleep, and comes no more till next morning._

_And as the Sea Breezes do blow in the Day, and rest in the Night; so on the contrary ~[The Land-Breezes]~ blow in the Night, and rest in the Day, alternately succeeding each other.——They spring up between six and twelve at Night, and last till six, eight, or ten in the Morning._ Dampier’s Disc. of Winds, _ch._ 4.

[f] One Thing more I believe some of my Friends will expect from me is, that I shew the Result of comparing my own Observations of the Winds, with others they know I have from _Ireland_, _Switzerland_, _Italy_, _France_, _New-England_, and some of our Parts of _England_. But the Observations being some of them but of one Year, and most of the rest of but a few Years, I have not been able to determine any great Matters. The chief of what I have observed is, that the Winds in all these Places seldom agree, but when they most certainly do so, it is commonly when the Winds are strong, and of long continuance in the same Quarter: And more I think in the Northerly and Easterly, than other Points. Also a strong Wind in one Place, is oftentimes a weak one in another Place, or moderate, according as Places have been nearer or farther distant. _Vid._ _Phil. Trans._ Nᵒ. 297, and 321. But to give a good and tolerable Account of this or any other of the Weather, it is necessary to have good Histories thereof from all Parts; which, as yet we have but few of, and they imperfect, for want of longer and sufficient Observations.

CHAP. III.

_Of the Clouds and Rain._

The Clouds and Rain[a] we shall find to be no less useful Meteors than the last mentioned; as is manifest in the refreshing pleasant Shades which the Clouds afford, and the fertile Dews and Showers which they pour down on the Trees and Plants, which would languish and die with perpetual Drought, but are hereby made Verdant and Flourishing, Gay and Ornamental; so that (as the Psalmist saith, _Psal._ lxv. 12, 13.) _The little Hills rejoice on every side, and the Valleys shout for Joy, they also sing._

And, if to these Uses, we should add the Origine of Fountains and Rivers, to Vapours and the Rains, as some of the most eminent modern Philosophers[b] have done, we should have another Instance of the great Use and Benefit of that Meteor.

And now, if we reflect upon this necessary Appendage of the Terraqueous Globe, the _Atmosphere_; and consider the absolute Necessity thereof to many Uses of our Globe, and its great Convenience to the whole: And in a Word, that it answereth all the Ends and Purposes that we can suppose there can be for such an Appendage: Who can but own this to be the Contrivance, the Work of the great Creator? Who would ever say or imagine such a Body, so different from the Globe it serves, could be made by Chance, or be adapted so exactly to all those forementioned grand Ends, by any other Efficient than by the Power and Wisdom of the infinite God! Who would not rather, from so noble a Work, readily acknowledge the Workman[c] and as easily conclude the Atmosphere to be made by GOD, as an Instrument wrought by its Power, any Pneumatick Engine, to be contrived and made by Man!

FOOTNOTES:

[a] Clouds and Rain are made of Vapours raised from Water, or Moisture only. So that I utterly exclude the Notion of Dry, Terrene Exhalations, or Fumes, talked much of by most Philosophers; Fumes being really no other than the humid Parts of Bodies respectively Dry.

These Vapours are demonstratively no other than small Bubbles, or Vesiculæ detached from the Waters by the Power of the Solar, or Subterraneous Heat, or both. Of which see _Book 2. Chap. 5. Note (b)._ And being lighter than the Atmosphere, are buoyed up thereby, until they become of an equal Weight therewith, in some of its Regions aloft in the Air, or nearer the Earth; in which those Vapours are formed into Clouds, Rain, Snow, Hail, Lightning, Dew, Mists, and other Meteors.

In this Formation of Meteors the grand Agent is Cold, which commonly, if not always, occupies the superior Regions of the Air; as is manifest from those Mountains which exalt their lofty Tops into the upper and middle Regions, and are always covered with Snow and Ice.

This Cold, if it approaches near the Earth, presently precipitates the Vapours, either in _Dews_; or if the Vapours more copiously ascend, and soon meet the Cold, they are then condensed into _Misting_, or else into Showers of _small Rain_, falling in numerous, thick, small Drops: But if those Vapours are not only copious, but also as heavy as our lower Air it self, (by means their Bladders are thick and fuller of Water,) in this Case they become visible, swim but a little Height above the Earth, and make what we call a _Mist_ or _Fog_. But if they are a Degree lighter, so as to mount higher, but not any great Height, as also meet not with Cold enough to condense them, nor Wind to dissipate them, they then form an heavy, thick, _dark Sky_, lasting oftentimes for several Weeks without either Sun or Rain. And in this Case, I have scarce ever known it to Rain, till it hath been _first Fair, and then Foul_. And Mr. _Clarke_, (an ingenious Clergyman of _Norfolk_, who in his Life-time, long before me, took notice of it, and kept a Register of the Weather for thirty Years, which his learned Grandson, Dr. _Samuel Clarke_ put into my Hands, he, I say) saith, he scarce ever observed the Rule to fail in all that Time; only he adds, _If the Wind be in some of the easterly Points_. But I have observed the same to happen, be the Wind where it will. And from what hath been said, the Case is easily accounted for, _viz._ whilst the Vapours remain in the same State, the Weather doth so too. And such Weather is generally attended with moderate Warmth, and with little or no Wind to disturb the Vapours, and an heavy Atmosphere to support them, the Barometer being commonly high then. But when the Cold approacheth, and by condensing drives the Vapours into Clouds or Drops, then is way made for the Sun-beams, till the same Vapours, being by further Condensation formed into Rain, fall down in Drops.

The Cold’s approaching the Vapours, and consequently the Alteration of such dark Weather I have beforehand perceived, by some few small Drops of Rain, Hail, or Snow, now and then falling, before any Alteration hath been in the Weather; which I take to be from the Cold meeting some of the straggling Vapours, or the uppermost of them, and condensing them into Drops, before it arrives unto, and exerts it self upon the main Body of Vapours below.

I have more largely than ordinary insisted upon this part of the Weather, partly, as being somewhat out of the way; but chiefly, because it gives Light to many other _Phænomena_ of the Weather. Particularly we may hence discover the Original of Clouds, Rain, Hail and Snow; that they are Vapours carried aloft by the Gravity of the Air, which meeting together so as to make a Fog above, they thereby form a _Cloud_. If the Cold condenseth them into Drops, they then fall in _Rain_, if the Cold be not intense enough to freeze them: But if the Cold freezeth them in the Clouds, or in their Fall through the Air, they then become _Hail_ or _Snow_.

As to _Lightning_, and other enkindled Vapours, I need say little in this Place, and shall therefore only observe, that they owe also their Rise to Vapours; but such Vapours as are detached from mineral Juices, or at least that are mingled with them, and are fired by Fermentation.

Another _Phænomenon_ resolvable from what hath been said is, why a _cold_, is always a _wet_ Summer, _viz._ because the Vapours rising plentifully then, are by the Cold soon collected into Rain. A remarkable Instance of this we had in the Summer of 1708, part of which, especially about the _Solstice_, was much colder than usually. On _June 12_, it was so cold, that my Thermometer was near the Point of hoar Frost, and in some Places I heard there was an hoar Frost; and during all the cool Weather of that Month, we had frequent and large Rains, so that the whole Month’s Rain amounted to above two Inches Depth, which is a large Quantity for _Upminster_, even in the wettest Months. And not only with us at _Upminster_, but in other Places, particularly at _Zurich_ in _Switzerland_, they seem to have had as unseasonable Cold and Wet as we. _Fuit hic mensis——præter modum humidus, & magno quidem vegetabilibus hominibusque damno. Multum computruit Fœnum, ~&c.~_ complains the industrious and learned Dr. _J. J. Scheuchzer_: Of which, and other Particulars, I have given a larger Account in _Phil. Trans._ Nᵒ. 321.

In which _Transaction_ I have observed farther, that about the Equinoxes we (at _Upminster_ at least) have oftentimes more Rain than at other Seasons. The Reason of which is manifest from what hath been said, _viz._ in Spring, when the Earth and Waters are loosed from the brumal Constipations, the Vapours arise in great Plenty: And the like they do in Autumn, when the Summer Heats, that both dissipated them, and warmed the superior Regions, are abated; and then the Cold of the superior Regions meeting them, condenseth them into Showers, more plentifully than at other Seasons, when either the Vapours are fewer, or the Cold that is to condense them is less.

The manner how Vapours are precipitated by the Cold, or reduced into Drops, I conceive to be thus: Vapours being, as I said, no other than inflated _Vesiculæ_ of Water; when they meet with a colder Air than what is contained in them, the contained Air is reduced into a less Space, and the watery Shell or Case rendered thicker by that means, so as to become heavier than the Air, by which they are buoyed up, and consequently must needs fall down. Also many of those thickned _Vesiculæ_ run into one, and so form Drops, greater or smaller, according to the Quantity of Vapours collected together.

As to the Rain of different Places, I have in some of our _Transactions_ assigned the Quantities; particularly in the last cited _Transaction_, I have assigned these, _viz._ the Depth of the Rain one Year with another, in _English_ Measure, if it was to stagnate on the Earth, would amount unto, at _Townely_ in _Lancashire_, 42½ Inches; at _Upminster_ in _Essex_ 19¼ Inches; at _Zurich_ in _Switzerland_ 32¼ Inches; at _Pisa_ in _Italy_ 43¼ Inches; at _Paris_ in _France_ 19 Inches; and at _Lisle_ in _Flanders_ 24 Inches.

It would be endless to reckon up the _bloody_ and other _prodigious Rains_ taken notice of by Historians, and other Authors, as præternatural and ominous Accidents; but, if strictly pried into, will be found owing to natural Causes: Of which, for the Reader’s Satisfaction, I will give an Instance or two. A bloody Rain was imagined to have fallen in _France_, which put the Country People into so great a Fright, that they left their Work in the Fields, and in great haste flew to the Neighbouring Houses. _Peirise_ (then in the Neighbourhood) strictly enquiring into the Cause, found it to be only red Drops coming from a sort of Butterfly that flew about in great Numbers at that Time, as he concluded from seeing such red Drops come from them; and because these Drops were laid, _Non supra ædificia, non in devexis lapidum superficiebus, uti debuerat contingere, si è cœlo sanguine pluisset; sed in subcavis potius & in foraminibus.——Accessit, quòd parietes iis tingebantur, non qui in mediis oppidis, sed qui agrorum vicini erant, neque secundum partes elatiores, sed ad mediocrem solùm altitudinem, quantam volitare Papiliones solent._ Gassend in vit. Peiresk. L. 2. p. 156.

So Dr. _Merret_ saith also, _Pluvia Sanguinis quàm certissimè constat esse tantùm Insectorum excrementa: Pluvia Tritici quàm nihil aliud esse quàm Hederæ bacciferæ grana à Sturnis devorata excretaque comparanti liquidissimè patet_. Pinax rerum, _&c._ _p. 220._

The curious _Worm_ tells of the raining of Brimstone, _An. 1646. Maii 16._ _Hic Hafniæ cùm ingenti pluviâ tota urbs, omnesque ita inundarentur plateæ, ut gressus hominum impediret, Sulphureoque odore aërem inficeret, dilapsis aliquantulum aquis, quibusdam in locis colligere licuit Sulphureum pulverem, cujus portionem servo, colore, odore, & aliis verum Sulphur ferentem._ Mus. Worm. L. 1. c. 11. Sect. 1.

Together with the Rain we might take notice of other Meteors, particularly _Snow_; which although an irksome Guest, yet hath its great Uses, if all be true that the famous _T. Bartholin_ saith of it, who wrote a Book _de Nivis usu Medico_. In which he shews of what great Use Snow is in fructifying the Earth, preserving from the Plague, curing Fevers, Colicks, Head-Aches, Tooth-Aches, Sore Eyes, Pleurisies, (for which Use he saith his Country-Women of _Denmark_ keep Snow-Water gathered in _March_), also in prolonging Life, (of which he instanceth in the _Alpine_ Inhabitants, that live to a great Age,) and preserving dead Bodies; Instances of which he gives in Persons buried under the Snow in passing the _Alps_, which are found uncorrupted in the Summer, when the Snow is melted; which sad Spectacle he himself was an Eye-Witness of. And at _Spitzberg_ in _Greenland_, dead Bodies remain entire and uncorrupted for thirty Years. And lastly, concerning such as are so preserv’d when slain, he saith they remain in the same Posture and Figure: Of which he gives this odd Example, _Visum id extra urbem nostram ~[Hafniam]~ quum, 11 Feb. 1659. oppugnantes hostes repellerentur, magnâque strage occumberent; alii enim rigidi iratum vultum ostendebant, alii oculos elatos, alii ore diducto ringentes, alii brachiis extensis Gladium minari, alii alio situ prostrati jacebant_. Barthol. de usu Niv. c. 12.

But although Snow be attended with the Effects here named, and others specified by the learned _Bartholin_; yet this is not to be attributed to any peculiar Virtue in the Snow, but some other Cause. Thus when it is said to _fructify the Earth_, it doth so by guarding the Corn or other Vegetables against the intenser cold of the Air, especially the cold piercing Winds; which the Husbandmen observe to be the most injurious to their Corn of all Weathers. So for _Conserving dead Bodies_, it doth it by constipating such Bodies, and preventing all such Fermentations or internal Conflicts of their Particles, as would produce Corruption.

Such an Example as the preceding is said to have happened some Years ago at _Paris_, in digging in a Cellar for supposed hidden Treasure; in which, after digging some Hours, the Maid going to call her Master, found them all in their digging Postures, but dead. This being noised abroad, brought in not only the People, but Magistrates also, who found them accordingly; _Ille qui ligone terram effoderat, & socius qui palâ effossam terram removerat, ambo pedibus stabant, quasi sua quisque operâ affixus incubuisset; uxor unius quasi ab opere defessa in scamno, solicito quodam vultu, sedebat, inclinato in palmam manûs genibus innitentis capite; puerulus laxatis braccis in margine excavatæ foveæ defixis in terram oculis alvum exonerabat; omnes in naturali situ, carneæ tanquam statuæ rigidi, apertis oculis & vultu vitam quasi respirante, exanimes stabant._ Dr. Bern. Connor, Dissert. Med. Phys. _p. 15._

The Doctor attributes all this to Cold; but I scarce think there could be Cold enough to do all this at _Paris_, and in a Cellar too. Bur his following Stories are not improbable, of Men and Cattle killed with Cold, that remained in the very same Posture in which they died; of which he gives, from a _Spanish_ Captain, this Instance, that happened two Years before, of a Soldier who unfortunately straggled from his Company that were foraging, and was killed with the Cold, but was thought to have fallen into the Enemies Hands. But soon after their return to their Quarters, they saw their Comrade returning, sitting on Horseback, and coming to congratulate him, found him dead, and that he had been brought thither in the same Posture on Horseback, notwithstanding the jolting of the Horse. _Ibid. p._ 18.

[b] Of this Opinion was my late most ingenious and learned Friend, Mr. _Ray_, whose Reasons see in his _Physico-Theolog. Discourses_, Disc. 2. ch. 2. p. 89, _&c_. So also my no less learned and ingenious Friends, Dr. _Halley_, and the late Dr. _Hook_, many of the _French_ Vertuoso’s also, and divers other very considerable Men before them, too many to be specified here.

[c] _An Polycletum quidem admirabimur propter partium Statuæ—convenientiam ac proportionem? Naturam autem non modò non laudabimus, sed omni etiam arte privabimus, quæ partium proportionem non solùm extrinsecus more Statuariorum, sed in profundo etiam servavit? Nonne & Polycletus ipse Naturæ est imitator, in quibus saltem eam potuit imitari? Potuit autem in solis externis partibus in quibus artem consideravit._ With much more to the like Purpose, _Galen. de Us. Part. l. 17. c. 1._

CHAP. IV.

_Of Light._

Thus much for the first Thing ministring to the Terraqueous Globe, the Atmosphere and its Meteors; the next Appendage is _Light_.[a] Concerning which I have in my Survey of the Heavens[b] shewed what admirable Contrivances the infinitely wise Creator hath for the affording this noble, glorious and comfortable Benefit to other Globes, as well as ours; the Provision he hath made by Moons, as well as by the Sun, for the Communication of it.

And now let us briefly consider the great Necessity and Use thereof to all our Animal World. And this we shall find to be little less than the very Life and Pleasure of all those Creatures. For what Benefit would Life be of, what Pleasure, what Comfort would it be for us to live in perpetual Darkness? How could we provide ourselves with Food and Necessaries? How could we go about the least Business, correspond with one another, or be of any Use in the World, or any Creatures be the same to us, without Light, and those 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 first-made[c], because most necessary, Creature of God, by this, I say, all the Animal World is enabled to go here and there, as their Occasions call; they can transact their Business by Day, and refresh and recruit themselves by Night, with Rest and Sleep. They can with Admiration and Pleasure, behold the glorious Works of God; they can view the Glories of the Heavens, and see the Beauties of the flowry Fields, the gay Attire of the feathered Tribe, the exquisite Garniture of many Quadrupeds, Insects, and other Creatures; they can take in the delightsome Landskips of divers Countries and Places; they can with Admiration see 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 survey God’s exquisite Workmanship in every Creature.

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 Glasses. But it would be endless to enumerate all its particular Uses and Benefits to our World.

But before I leave this Point, there are two Things concerning Light, which will deserve an especial Remark; and that is, its swift and almost instantaneous Motion, and its vast Extension.

1. It is a very great Act of the Providence of God, that so great a Benefit as Light is, is not long in its Passage from Place to Place. For was the Motion thereof no swifter than the Motion of the swiftest Bodies on Earth, such as of a Bullet out of a great Gun, or even of a Sound[d] (which is the swiftest Motion we have next Light), in this Case Light would take up, in its Progress from the Sun to us above thirty two Years at the rate of the first, and above seventeen Years at the rate of the latter Motion.

The Inconveniencies of which would be, its Energy and Vigour would be greatly cooled and abated; its Rays would be less penetrant; and Darkness would with greater Difficulty and much Sluggishness, be dissipated, especially by the fainter Lights of our sublunary, luminous Bodies. But passing with such prodigious Velocity, with nearly the instantaneous Swiftness of almost Two hundred thousand _English_ Miles in one Second of Time,[e] or (which is the same Thing) being but about seven or eight Minutes of an Hour in coming from the Sun to us, therefore with all Security and Speed, we receive the kindly Effects and Influences of that noble and useful Creature of God.

2. Another Thing of great Consideration about Light is, its vast Expansion, it’s almost incomprehensible, and inconceivable Extension, which as a late ingenious Author[f] saith, “Is as boundless and unlimited as the Universe it self, or the Expansum of all material Beings: The vastness of which is so great, that it exceeds the Comprehensions of Man’s Understanding. Insomuch that very many have asserted it absolutely infinite, and without any Limits or Bounds.”

And that this noble Creature of God is of this Extent,[g] is manifest from our seeing some of the farthest distant Objects, the heavenly Bodies, some with our naked Eye, some with the help of Optical Instruments, and others in all Probability farther and farther, with better and better Instruments: And had we Instruments of Power equivalent to the Extent of Light, the luminous Bodies of the utmost Parts of the Universe, would for the same Reason be visible too.

Now as Light is of greatest Use to impower us to see Objects at all, so the Extension thereof is no less useful to enable us to see Objects afar off. By which means we are afforded a Ken of those many glorious Works of the infinite Creator, visible in the Heavens, and can improve them to some of the noblest Sciences, and most excellent Uses of our own Globe.

FOOTNOTES:

[a] It is not worth while to enumerate the Opinions of the _Aristotelians_, _Cartesians_, and others, about the Nature of Light, _Aristotle_ making it a Quality; _Cartes_ a Pulsion, or Motion of the Globules of the second Element, _Vid._ _Cartes Princip._ p. 3. §. 55, _&c._ But with the Moderns, I take _Light_ to consist of material Particles, propagated from the Sun, and other luminous Bodies, not instantaneously, but in time, according to the Notes following in this Chapter. But not to insist 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, Iron, Tutenage, and other Bodies, exposed (both naked and closely shut up) to the Fire: All which were constantly found to receive an Increment of Weight. I wish he could have met with a favourable Season to have tried his Experiments with the Sun-beams as he intended. _Vid._ _Boyl Exp. to make Fire and Flame ponderable_.

[b] Astro-Theol. Book 7.

[c] Gen. i. 3. _And God said, Let there be Light, and there was Light._

[d] It may not be ungrateful to the Curious, to take notice of the Velocity of these two Things.

According to the Observations of _Mersennus_, a Bullet-shot out of a great Gun, flies 92 Fathom in a Second of Time, (_Vid._ _Mersen. Balist._) which is equal to 589½ Feet _English_, and according to the Computation of Mr. _Huygens_, it would be 25 years in passing from the Earth to the Sun. But according to my own Observations made with one of her Majesty’s _Sakers_, and a very accurate Pendulum-Chronometer, a Bullet, at its first Discharge, flies 510 Yards in five half Seconds, which is a Mile in a little above 17 half Seconds. And allowing the Sun’s Distance to be, as in the next Note, a Bullet would be 32½ Years in flying with its utmost Velocity to the Sun.

As to the Velocity of Sound, see _Book 4. Chap. 3. Note 28._ according to which rate there mentioned, a Sound would be near 17½ Years in flying as far as the distance is from the Earth to the Sun. Confer here the Experiments of the _Acad. del Ciment._ p. 140, _&c._

[e] Mr. _Romer_’s ingenious Hypothesis about the Velocity of Light, hath been established by the _Royal Academy_, and in the _Observatory_ for eight Years, as our _Phil. Trans._ Nᵒ. 136. observe from the _Journ. des Scavans_; our most eminent Astronomers also in _England_ admit it: But Dr. _Hook_ thinks with Monsieur _Cartes_, the Motion of Light Instantaneous, _Hook Post. Works, pag. 77._ And this he endeavours to explain, _pag. 130_, &c.

What Mr. _Romer_’s Hypothesis is, may be seen in the _Phil. Transact._ before-cited: As also in the before commended Sir _Isaac Newton_’s _Opticks_: _Light is propagated from luminous Bodies in time, and spends about seven or eight Minutes of an Hour in passing from the Sun to the Earth. This was first observed by ~Romer~, and then by others, by means of the Eclipses of the Satellites of ~Jupiter~. For these Eclipses, when the Earth is between the Sun and ~Jupiter~, happen about seven or eight Minutes sooner than they ought to do by the Tables; and when the Earth is beyond the ☉, they happen about seven or eight Minutes later than they ought to do: The reason being, that the Light of the Satellites hath farther to go in the latter Case than in the former, by the Diameter of the Earth’s Orbit._ Newt. Opt. L. 2. Part. 3. Prop. 11.

Now forasmuch as the Distance between the Sun and the Earth (according to the Computations in my _Astro-Theology_, _B. 1. ch. 3. Note 2._) is 86051398 _English_ Miles; therefore, at the rate of 7½ Minutes, or 450 Seconds in passing from the Sun, Light will be found to fly above 191225 Miles in one Second of Time.

[f] Dr. _Hook_ Post. Works. Lect. of Light, _pag. 76._

[g] For the proof of this vast Extent of Light, I shall take the Computation of the same great Man, _pag. 77_. _If_, saith he, _we consider first the vast Distance between us and the Sun, which from the best and latest Observations in Astronomy, is judged to be about 10000 Diameters of the Earth, each of which It about 7925 ~English~ Miles; therefore the Sun’s distance is 7925000 Miles; and if we consider that according to the Observations, which I published to prove the Motion of the Earth, ~[which were Observations of the Parallax of some of the fixt Stars in the Head of _Draco_, made in 1699]~ the whole Diameter of the Orb, ~viz.~ 20000, made the Subtense but of one Minute to one of the fixt Stars, which cannot therefore be less distant than 3438 Diameters of this great Orb, and consequently 68760000 Diameters of the Earth: And if this Star be one of the nearest, and that the Stars that are of one Degree lesser 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 sort yet smaller be three times as far; and a fourth four times as far, and so onward, possibly to some 100 Degrees of Magnitude, such as may be discovered 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 last mentioned, it is evident that Light extends it self to the utmost imaginable Parts, and by the help of Telescopes we collect the Rays, and make them sensible to the Eye, which are emitted from some of the almost inconceivably remote Objects, ~&c.~——Nor is it only the great Body of the Sun, or the vast Bodies of the fixt Stars, that are thus able to disperse their Light through the vast Expansum of the Universe; but the smallest Spark of a lucid Body will do the very same Thing, even the smallest Globule struck from a Steel by a Flint, ~&c.~_

CHAP. V.

_Of Gravity._

The last Thing subservient to our Globe, that I shall take notice of, is _Gravity_[a], or that Tendency which Bodies have to the Centre of the Earth.

In my _Astro-Theology_, _Book 6. Ch. 2._ I have shewn of what absolute Necessity, and what a noble Contrivance this of Gravity is, for keeping the several Globes of the Universe from shattering to Pieces, as they evidently must do in a little Time by their swift Rotation round their own Axes[b]. The Terraqueous Globe particularly, which circumvolves at the rate of above 1000 Miles an Hour[c], would by the centrifugal force of that Motion, be soon dissipated and spirtled into the circumambient Space, was it not kept together by this noble Contrivance of the Creator, this natural inherent Power, namely, the Power of Attraction or Gravity.

And as by this Power our Globe is defended against Dissipation, so all its Parts are kept in their proper Place and Order. All material Things do naturally gravitate thereto, and unite themselves therewith, and so preserve its Bulk intire[d]. And the fleeting Waters, the most unruly of all its Parts, do by this means keep their constant æquipoise in the Globe[e], and remain in _that Place which_, the Psalmist saith, _God had founded for them; a bound he had set, which they might not pass; that they turn not again to cover the Earth_, Psal. civ. 8, 9. So, that even in a natural Way, by virtue of this excellent Contrivance of the Creator, the Observation of the Psalmist is perpetually fulfilled, _Psal._ lxxxix. 9. _Thou rulest the raging of the Sea; when the Waves thereof arise, thou stillest them._

To these, and an hundred other Uses of Gravity that I might have named, I shall only just mention another Thing owing to it, and that is _Levity_[f], that, whereby what we call light Bodies swim, a Thing no less useful to the World than its opposite, _Gravity_, is in many Respects, to divers Tribes of Animals, but particularly serviceable to the raising up of Vapours[g], and to their Conveyance about the World.

And now from this transient View of no other than the Out-works, than the bare Appendages of the Terraqueous Globe, we have so manifest a Sample of the Wisdom, Power, and Goodness of the infinite Creator, that it is easy to imagine the whole Fabrick is of a Piece, the Work of at least a skilful Artist. A Man that should meet with a Palace[h], beset with pleasant Gardens, adorned with stately Avenues, furnished with well-contrived Aqueducts, Cascades, and all other Appendages conducing to Convenience or Pleasure, would easily imagine, that proportionable Architecture and Magnificence were within: But we should conclude the Man was out of his Wits that should assert and plead that all was the Work of Chance, or other than of some wise and skilful Hand. And so when we survey the bare Out-works of this our Globe, when we see so vast a Body, accouter’d with so noble a Furniture of Air, Light and Gravity; with every Thing, in short, that is necessary to the Preservation and Security of the Globe it self, or that conduceth to the Life, Health, and Happiness, to the Propagation and Increase of all the prodigious Variety of Creatures the Globe is stocked with; when we see nothing wanting, nothing redundant or frivolous, nothing botching or ill-made, but that every thing, even in the very Appendages alone, exactly answereth all its Ends and Occasions: What else can be concluded, but that all was made with manifest Design, and that all the whole Structure is the Work of some intelligent Being; some Artist, of Power and Skill equivalent to such a Work?

FOOTNOTES:

[a] That there is such a Thing as _Gravity_, is manifest from its Effects here upon Earth; and that the Heavenly Bodies attract or gravitate to one another, when placed at due Distances, is made highly probable by Sir _Isaac Newton_. This attractive or gravitating Power, I take to be congenial to Matter, and imprinted on all the Matter of the Universe by the Creator’s _Fiat_ at the Creation. What the _Cause_ of it is, the _Newtonian Philosophy_ doth not pretend to determine for want of Phænomena, upon which Foundation it is that that Philosophy is grounded, and not upon chimerical and uncertain Hypotheses: But whatever the Cause is, that _Cause penetrates even to the Centers of the Sun and Planets, without any Diminution of its Virtue; and it acteth not according to the Superficies of Bodies (as Mechanical Causes do) but in proportion to the Quantity of their solid Matter; ~and lastly~, it acteth all round it at immense Distances, decreasing in duplicate proportion to those Distances_, as Sir _Isaac Newton_ saith, _Princip._ pag. ult. What useful Deductions, and what a rational Philosophy have been drawn from hence, may be seen in the same Book.

This Attraction, or Gravity, as its Force is in a certain proportion, so makes the Descent of Bodies to be at a certain rate. And was it not for the Resistence of the Medium, all Bodies would descend to the Earth at the same rate; the lightest Down, as swiftly as the heaviest Mineral: As is manifest in the _Air-Pump_, in which the lightest Feather, Dust, _&c._ and a piece of Lead, drop down seemingly in the same Time, from the top to the bottom of a tall exhausted Receiver.

The rate of the Descent of heavy Bodies, according to _Galileo_, Mr. _Huygens_, and Dr. _Halley_ (after them) is 16 Feet one Inch in one Second of Time; and in more Seconds, as the Squares of those Times. But in some accurate Experiments made in St. _Paul_’s _Dome_, June 9. 1710, at the Height of 220 Feet, the Descent was scarcely 14 Feet in the first Second. The Experiments were made in the Presence of some very considerable Members of the Royal Society, by Mr. _Hawksbee_, their Operator, with glass, hollow Balls, some empty, some filled with Quick-silver, the Barometer at 297, the Thermometer 60 Degrees above Freezing. The Weight of the Balls, their Diameters, and Time of the Descent is in this Table.

+----------------------------------+-----------------------------------+ | Balls filled with ☿. | Empty Balls. | +---------+-------------+----------+---------+--------------+----------+ | Weight. | Diameter. | Time. | Weight. | Diameter. | Time. | +---------+-------------+----------+---------+------+-------+----------+ | Grains. | Tenth inch. | ½ Secᵈˢ. | Grains. | Inch.| Tenth.| ½ Secᵈˢ. | +---------+-------------+----------+---------+------+-------+----------+ | 908 | 8 | 8 | 510 | 5 | 1 | 17 | | | | | | | | | | 993 | 8 | 8 less. | 642 | 5 | 2 | 16 | | | | | | | | | | 866 | 8 | 8 | 599 | 5 | 1 | 16 | | | | | | | | | | 747 | 7½ | 8 more. | 515 | 5 nearly | 16½ | | | | | | | | | | 808 | 7½ | 8 | 483 | 5 nearly | 17 | | | | | | | | | | 784 | 7½ | 8 more. | 641 | 5 | 2 | 16 | +---------+-------------+----------+---------+------+-------+----------+

The Reason why the heavy, full Balls fell in half the Time of the hollow ones, was the Resistence of the Air: Which Resistence is very ingeniously and accurately assigned by Dr. _Wallis_, in _Philos. Trans._ Nᵒ. 186. And the cause of the Resistence of all Fluids, (as Sir _Isaac Newton_, _Opt._ Q. 20.) is partly from the _Friction_ of the Parts of the Fluid, partly from the _Inertia_ thereof. The Resistence a spherical Body meets with from Friction, is as the right Angle under the Diameter, and the Velocity of the moving Body: And the Resistence from the _Vis Inertia_, is as the Square of that Product.

For a farther Account of the Properties and Proportions, _&c._ of Gravity in the Fall or Projection of Bodies, I shall refer to the larger Accounts of _Galilæus_, _Torricellius_, _Huygens_, Sir _Isaac Newton_, &c. or to the shorter Accounts of Dr. _Halley_ in Philos. Trans. abridged by Mr. _Lowthorp_, Vol. I. p. 561. or Dr. _Clarke_ in his Notes on _Rohault_, _Phys._ 2. c. 28. §. 13, 16. And for the Resistence of Fluids, I refer to Dr. _Wallis_ before-cited, and the _Act. Erudit. Lips._ May 1693. where there is a way to find the Force of Mediums upon Bodies of different Figures.

[b] That the heavenly Bodies move round their own Axes, is, beyond all doubt, manifest to our Eye, in some of them, from the Spots visible on them. The Spots on the Sun (easily visible with an ordinary Glass) do manifest him to revolve round his own Axis in about 25¼ Days. The Spots on ♃ and ♂ prove those two Planets to revolve also from East to West, as Dr. _Hook_ discover’d in 1664, and 1665. And ♀ also (although near the strong Rays of the Sun) hath, from some Spots, been discovered by Mr. _Cassini_, in 1666, and 1667, to have a manifest Rotation. _V._ _Lowth. Abridg._ Vol. 1. p. 382, and 423, 425. And such Uniformity hath the _Creator_ observ’d in the Works of Nature, that what is observable in one, is generally to be found in all others of the same kind. So that since ’tis manifest the Sun, and three of his Planets whirl round, it is very reasonable to conclude all the rest do so too, yea, every Globe of the Universe.

[c] The Earth’s Circumference being 25031½ Miles, (according to _Book II. Chap. 2. Note (a)._) if we divide that into 24 Hours, we shall find the Motion of the Earth to be nearly 1043 Miles in an Hour. Which, by the by, is a far more reasonable and less rapid Rate, than that of the Sun would be, if we suppose the Earth to stand still, and the Sun to move round the Earth. For according to the Proportions in _Note (e)_, of the preceding Chapter, the Circumference of the _Magnus Orbis_ is 540686225 _English_ Miles, which divided by 24 Hours, gives 22528364 Miles in an Hour. But what is this to the Rapidity of the fixt Stars, if we suppose them; not the Earth, to move? Which is a good Argument for the Earth’s Motion.

[d] _Nihil majus, quàm quòd ita stabilis est Mundus, atque ita cohæret ad permanendum, ut nihil nè excogitari quidem possit aptius. Omnes enim partes ejus undique medium locum capessentes, nituntur æqualiter: maximè autem corpora inter se juncta permanent, cum quodam quasi vinculo circumdata colligantur: quod facit ea natura, quæ per omnem mundum omnia Mente, & Ratione conficiens, funditur, & ad medium rapit, & convertit extrema_, Cic. de Nat. Deor. l. 2. c. 45.

[e] _Eâdem ratione Mare, cùm supra terram sit, medium tamen terræ locum expetens, conglobatur undique æqualiter, neque redundat unquam, neque effunditur._ Id. paulo post.

[f] That there is no such Thing as _positive Levity_, but that Levity is only a less Gravity, is abundantly manifested by the acute _Seig. Alph. Borelli de Mot. à Grav. pend._ cap. 4. See also the Annotations of the learned and ingenious Dr. Clark on _Rohaulti Phys._ p. 1. c. 16. Note 3. Also the Exper. of the _Acad. del Cimento_, p. 118, &c. Dr. _Wallis_’s _Disc. of Gravity and Gravitation before the Royal Society_, Nov. 12. 1674. p. 28, _&c._

[g] I have before in _Note (a), Chap. 3._ shewn what _Vapours_ are, and how they are rais’d. That which I shall here note, is their Quantity: Concerning which the before-commended Dr. _Halley_ hath given us some curious Experiments in our _Phil. Transact._ which may be met with together in Mr. _Lowthorp_’s _Abridg._ Vol. II. _p. 108._ and _126._ Mr. _Sedileau_ also at _Paris_ observed it for near three Years. By all their Observations it appears, that in the Winter Months the Evaporations are least, and greatest in Summer, and most of all in windy Weather. And by _Monsieur Sedileau_’s Observations it appears, that what is raised in Vapours, exceeds that which falleth in Rain. In the seven last Months of the Year 1688, the Evaporations amounted to 22 Inches 5 Lines; but the Rain only to Inches 6⅓ Lines: In 1689, the Evaporations were 32 Inches 10½ Lines; but the Rain 18 Inches 1 Line: In 1690, the Evaporations 30 Inches 11 Lines; the Rain 21 Inches ⅓ of a Line. _Vid._ _Mem. de Math. Phys. Ann. 1692._ p. 25.

If it be demanded, What becomes of the Overplus of Exhalations that descend not in Rain? I answer, They are partly tumbled down and spent by the Winds, and partly descend in Dews, which amount to a greater quantity than is commonly imagined. Dr. _Halley_ found the descent of Vapours in Dews so prodigious at St. _Helena_, that he makes no doubt to attribute the Origine of Fountains thereto. And I my self have seen in a still, cool Evening, large thick Clouds hanging, without any Motion in the Air, which in two or three Hours Time have been melted down by Degrees, by the cold of the Evening, so that not any the least Remains of them have been left.

[h] See _Book II. Chap. 3. Note (c)._

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