Chapter 8

CHAP. I.Of the Atmosphere in general.

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 itsNatureandMake[a], and itsUseto 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 thewhole Animal World breatheth, and liveth by; not only the Animals inhabiting the Earth[c]andAir[d], but those of the Waters[e]too. Without itmost 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 cannotascend 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 butjust 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 approacheththem; 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 aSparrowwithout 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 theGreat Titmouse, the other with aSparrow. 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 theDiving-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 theDiving-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 famousCornelius Drebellcontrived 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 KingJamesI. It carried twelve Rowers, besides the Passengers. It was tried in the River ofThames; 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.Boylsaith, he discovered by a Doctor of Physick, who marriedDrebell’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 LiquorDrebellwould never disclose to above one Person, who himself assured Mr.Boylwhat it was.Vid.Boyl. Exp. Phys. Mech. of the Spring of the Air, Exp. 41.in theDigres. 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, inthe 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 ofArmenia, (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 theCevennes. So a learned Traveller, and curious Person, on one of the highest Ridges of thePyrenees, call’dPic 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, orLowthorp’s Abridg.Vol. 2. p. 226.Such another Relation the learnedJoseph Acostagives of himself and his Company, that, when they passed the high Mountains ofPeru, which they callPeriacaca, (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 toRespiration, and theDiastoleof the Heart. Of which seeBook 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 theDiving-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 followingNote (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 inthe preceding Note. So Insects bear the Air-Pump long, as in the followingNote (f).[e]Creatures inhabiting the Waters need the Air, as well as other Animals, yea, and fresh Air too. TheHydrocanthariof all Sorts, theNymphæofGnats, 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, theHydrocantharicome and thrust their Tails out of the Water, and take in a Bubble of Air, at the tip of theirVaginæand 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. ButCarpswill live out of the Water, only in the Air; as is manifest by the Experiment of their way of Fatting them inHolland, and which hath been practised hereinEngland,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, inSeptemberandOctober, 1704; I observed that Animals whose Hearts have twoVentricles, and noForamen 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.AMole(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. ABat(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 theBatnever revived.As forInsects:Wasps,Bats,Hornets,Grashoppers, andLady-Cowsseemed dead in appearance in two Minutes, but revived in the open Air in two or three Hours time, notwithstanding they had been inVacuotwenty four Hours.TheEar-wig, the greatStaphylinus, the great black lowsyBeetle, and some other Insects would seem unconcerned at theVacuuma good while, and lie as dead; but revive in the Air, although some had lain sixteen Hours in the exhausted Receiver.Snailsbear 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.FrogsandToadsbear 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 inPepper-Waterremained inVacuotwenty 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,Borelliproves in his excellent BookDe 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 Rulede Insidentibus humidois, 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.Boylto 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.fromPhil. 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 avoida Vacuum, and such unintelligible Stuff; but the justly famous Mr.Boylwas 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 fromNoah’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.Boylgives an Instance (from theDissertation de admirandis Hungar. Aquis) of a great Oak, like a huge Beam, dug out of a Salt Mine inTransylvania,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 atWest-ThurrockandDagenham, near me, although probably no other thanAlder, 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 inPhilos. 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 SirIsaac Newtonattributes 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’sPost. 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.CaptainJames’s Journ. inBoylof 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.

[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 aSparrowwithout 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 theGreat Titmouse, the other with aSparrow. 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 theDiving-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 theDiving-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 famousCornelius Drebellcontrived 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 KingJamesI. It carried twelve Rowers, besides the Passengers. It was tried in the River ofThames; 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.Boylsaith, he discovered by a Doctor of Physick, who marriedDrebell’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 LiquorDrebellwould never disclose to above one Person, who himself assured Mr.Boylwhat it was.Vid.Boyl. Exp. Phys. Mech. of the Spring of the Air, Exp. 41.in theDigres. 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, inthe 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 ofArmenia, (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 theCevennes. So a learned Traveller, and curious Person, on one of the highest Ridges of thePyrenees, call’dPic 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, orLowthorp’s Abridg.Vol. 2. p. 226.Such another Relation the learnedJoseph Acostagives of himself and his Company, that, when they passed the high Mountains ofPeru, which they callPeriacaca, (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 toRespiration, and theDiastoleof the Heart. Of which seeBook 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 theDiving-Bell, when we descend into great Depths of the Waters.

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 theGreat Titmouse, the other with aSparrow. 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 theDiving-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 theDiving-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 famousCornelius Drebellcontrived 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 KingJamesI. It carried twelve Rowers, besides the Passengers. It was tried in the River ofThames; 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.Boylsaith, he discovered by a Doctor of Physick, who marriedDrebell’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 LiquorDrebellwould never disclose to above one Person, who himself assured Mr.Boylwhat it was.Vid.Boyl. Exp. Phys. Mech. of the Spring of the Air, Exp. 41.in theDigres. 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, inthe 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 ofArmenia, (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 theCevennes. So a learned Traveller, and curious Person, on one of the highest Ridges of thePyrenees, call’dPic 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, orLowthorp’s Abridg.Vol. 2. p. 226.

Such another Relation the learnedJoseph Acostagives of himself and his Company, that, when they passed the high Mountains ofPeru, which they callPeriacaca, (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 toRespiration, and theDiastoleof the Heart. Of which seeBook 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 theDiving-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 followingNote (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 inthe preceding Note. So Insects bear the Air-Pump long, as in the followingNote (f).

[e]Creatures inhabiting the Waters need the Air, as well as other Animals, yea, and fresh Air too. TheHydrocanthariof all Sorts, theNymphæofGnats, 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, theHydrocantharicome and thrust their Tails out of the Water, and take in a Bubble of Air, at the tip of theirVaginæand 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. ButCarpswill live out of the Water, only in the Air; as is manifest by the Experiment of their way of Fatting them inHolland, and which hath been practised hereinEngland,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.

So Fishes also are well known to use Respiration, by passing the Water through their Mouths and Gills. ButCarpswill live out of the Water, only in the Air; as is manifest by the Experiment of their way of Fatting them inHolland, and which hath been practised hereinEngland,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, inSeptemberandOctober, 1704; I observed that Animals whose Hearts have twoVentricles, and noForamen 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.AMole(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. ABat(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 theBatnever revived.As forInsects:Wasps,Bats,Hornets,Grashoppers, andLady-Cowsseemed dead in appearance in two Minutes, but revived in the open Air in two or three Hours time, notwithstanding they had been inVacuotwenty four Hours.TheEar-wig, the greatStaphylinus, the great black lowsyBeetle, and some other Insects would seem unconcerned at theVacuuma good while, and lie as dead; but revive in the Air, although some had lain sixteen Hours in the exhausted Receiver.Snailsbear 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.FrogsandToadsbear 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 inPepper-Waterremained inVacuotwenty four Hours. And after they had been exposed a Day or two to the open Air, I found some of them dead, some alive.

AMole(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. ABat(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 theBatnever revived.

As forInsects:Wasps,Bats,Hornets,Grashoppers, andLady-Cowsseemed dead in appearance in two Minutes, but revived in the open Air in two or three Hours time, notwithstanding they had been inVacuotwenty four Hours.

TheEar-wig, the greatStaphylinus, the great black lowsyBeetle, and some other Insects would seem unconcerned at theVacuuma good while, and lie as dead; but revive in the Air, although some had lain sixteen Hours in the exhausted Receiver.

Snailsbear 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.

FrogsandToadsbear 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 inPepper-Waterremained inVacuotwenty 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,Borelliproves in his excellent BookDe 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.

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 Rulede Insidentibus humidois, 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.Boylto 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.fromPhil. 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 avoida Vacuum, and such unintelligible Stuff; but the justly famous Mr.Boylwas 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 fromNoah’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.Boylgives an Instance (from theDissertation de admirandis Hungar. Aquis) of a great Oak, like a huge Beam, dug out of a Salt Mine inTransylvania,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 atWest-ThurrockandDagenham, near me, although probably no other thanAlder, 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 inPhilos. 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 SirIsaac Newtonattributes to Vapours beginning to condense, and that are not able to reflect the other Colours.V.Optic.l. 2.Par. 3. Prop. 7.

The Azure Colour of the Sky SirIsaac Newtonattributes 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’sPost. Works. Lect. of Navig. p. 466.

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’sPost. 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.CaptainJames’s Journ. inBoylof Cold. Tit. 18. p. 190.

[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.CaptainJames’s Journ. inBoylof 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.

Back to Index Next