Tracts containing I. suspicions about some hidden qualities of the air : with an appendix touching celestial magnets and some other particulars : II. animadversions upon Mr. Hobbes's Problemata de vacuo : III. a discourse of the cause of attraction by suction / by the honourable Robert Boyle Esq. ...

SVSPICIONS ABOUT Some Hidden QUALITIES in the AIR. (Book 1)

BEsides the four first Qua∣lities of the Air, (Heat, Cold, Dryness and Moi∣sture) that are known even to the Vulgar; and those more unobvious, that Philoso∣phers and Chymists have discovered, such as Gravity, Springiness, the power of Refracting the beams of Light; &c. I have often suspected, that there may be in the Air some yet more latent Qualities or Powers dif∣fering enough from all these, and principally due to the Substantial Parts or Ingredients, whereof it con∣sists.

And to this conjecture I have been led, partly (though not only or perhaps chiefly) by considering the Constitution of that Air we live and breath in, which, to avoid ambigui∣ties, I elsewhere call Atmospherical Air. For this is not, as many imagine, a Simple and Elementary Body, but a confus••d Aggregate of Effluviums from such differing Bodies, that, though they all agree in constituting, by their minuteness and various mo∣tions, one great mass of Fluid matter, yet perhaps there is scarce a more he∣terogeneous Body in the world.

And as by Air I understand not (as the Peripateticks are wont to do) a meer Elementary Body; so, when I speak of the Qualities of the Air, I would not be thought to mean such naked and abstracted Beings (as the Schools often tell us of,) but such as they call Qualities in concreto, name∣ly Corpuscles indued with Quali∣ties, or capable of producing them in the Subjects they invade and a∣bound in.

I have elsewhere shewn it to be highly probable, that,* 1.1 be∣sides those vapours and ex∣halations which by the Heat of the Sun are elevated into the Air, and there afford matter to some Meteors, as Clouds, Rain, Parhe∣lions and Rainbow••; there are, at least at some times, and in some pla∣ces, store of Effluviums emitted from the Subterraneal parts of the Terre∣strial Globe; and 'tis no less probable, (from what I have there and else∣where deliver'd,) that in the Subter∣raneal Regions there are many Bodies, some fluid and some consistent, which, though of an operative nature, and like upon occasion to emit steams, sel∣dom or never appear upon the surface of the Earth, so that many of them have not so much as names assigned them even by the Mineralists. Now a∣mong this multitude and variety of Bodies, that lye buried out of our sight, who can tell but that there may be some, if not many, of a nature very differing from those we are hi∣therto

familiarly acquainted with; and that, as divers wonderful and peculiar operations of the Loadstone, (though a Mineral many Ages ago fa∣mous among Philosophers and Phy∣sitians,) were not discovered 'till of later Ages, wherein its nobler Virtues have been disclosed; so there may be other Subterraneous Bodies, that are indowed with considerable powers, which to us are yet unknown, and would, if they were known, be found very differing from those of the Fossiles we are wont to deal with?

I also further consider, that, (as I have elsewhere endeavoured to make it probable) the Sun and Planets (to say nothing of the Fixt Stars) may have influences here below distinct from their Heat and Light. On which Supposition it seems not absurd to me to suspect, that the Subtil, but Cor∣poreal, Emanations even of these Bo∣dies may (sometimes at least) reach to our Air, and mingle with those of our Globe in that great receptacle or rendevouz of Celestial and Ter∣restrial

Effluviums, the Atmosphere. And if this suspition be not ground∣less, the very small knowledge we have of the structure and constitution of Globes so many thousands or hun∣dred of thousands of miles remote from us, and the great ignorance we must be in of the nature of the par∣ticular Bodies that may be presum'd to be contain'd in those Globes, (as Minerals and other Bodies are in the Earth,) which in many things ap∣pear of kin to those that we inhabit, (as with excellent Telescopes I have often with attention and pleasure ob∣served, particularly in the Moon,) this great imperfection, I say, of our knowledge may keep it from being unreasonable to imagine, that some, if not many, of those Bodies and their effluxions may be of a nature quite differing from those we take no∣tice of here about us, and conse∣quently may operate after a very diffe∣ring and peculiar manner.

And though the chief of the He∣teroclite Effluviums, that indow the

Air with hidden Qualities, may pro∣bably proceed from beneath the sur∣face of the Earth, and from the Ce∣lestial Bodies; yet I would not deny but that, especially at some times and in some places, the Air may derive multitudes of efficacious particles from its own operations, acting as a fluid Substance upon that vast number and variety of Bodies that are imme∣diately expos'd to it. For, though by reason of its great thinness, and of its being in its usual state devoid both of tast and smell, it seems whol∣ly unfit to be a Menstruum; yet I am not sure but it may have a dissol∣ving, or at least a consuming, power on many Bodies, especially such as are peculiarly dispos'd to admit its ope∣rations.

For I consider, that the Air has a great advantage by the vast Quantity of it, that may come to work in pro∣portion to the Bodies that are expos'd to it: And I have long thought, that, in divers cases, the Quantity of a Menstruum may much more conside∣rably

compensate its want of strength, than Chymists are commonly aware of, (as there may be occasion else∣where to exemplifie.) And there are liquors, which pass for insipid, (and are therefore thought to be altoge∣ther unfit to be Solvents,) which, though they have their active parts too thinly dispersed to be able pre∣sently to make sensible Impressions upon our Organs of Tasting, yet are not quite destitute of Corpuscles fit to act as a Solvent; especially if they have time enough to make with the other parts of the Fluid such nu∣merous and various motions, as must bring, now some of them, and then others, to hit against the Body ex∣pos'd to them. Which may be illu∣strated by the Rust like to Verdigrease, which we have observ'd in Copper that has been long expos'd to the Air, whose saline particles, little by little, do in tract of time fasten themselves in such numbers to the surface of the Metal as to corrode it, and produce that efflorescence colour'd like Verdi∣grease,

which you know is a facti∣tious Body, wont to be made of the same Metal, corroded by the sharp Corpuscles of Vineger, or of the Husks of Grapes: Besides, that by the power, which Mercury has to dissolve Gold and Silver, it appears, that it is not always necessary for the making a Fluid fit to be a Dissolvent, that it should affect the Tast. And as to those Bodies, on which the Ae∣rial Menstruum can, though but slow∣ly, work, the greatest quantity of it may bring it this advantage, that, whereas even the strongest Men∣struums, if they bear no great propor∣tion in bulk to the Bodies they are to work on, are easily glutted, and be∣ing unable to take up any more, are fain to leave the rest of the Body un∣dissolved, our Aerial Menstruum bears so vast a proportion to the Bodies ex∣pos'd to it, that when one portion of it has impregnated it self as much as 'tis able, there may still come fresh and fresh to work further on the re∣maining part of the expos'd Body.

Besides the Saline and Sulphureous particles, that, at least in some pla∣ces, may (as I have elsewhere shewn) impregnate the Air, and give it a greater affinity to Chymical Men∣struums more strictly so called; I am not averse from thinking, that the Air, meerly as a fluid Body, that consists of Corpuscles of differing sizes and so∣lidities restlesly and very variously moved, may upon the account of these Corpuscles be still resolving, or preying upon, the particles of the Bodies that are expos'd to their action. For, many of those Aerial Corpu∣scles, some hitting and some rubbing themselves every minute against those particles of expos'd Bodies that chance to lye in their way, may well, by those numerous occursions and affri∣ctions, strike off and carry along with them now some and then others of those particles; as you see it hap∣pens in water, which, as soft and fluid as it is, wears out such hard and solid Bodies as Stones themselves, if it often enough meet them in its

passage, according to the known saying,

Gutta cavat Lapidem non vi, sed saepe cadendo.

And though the Aerial Corpuscles be very minute, and the Bodies expos'd to them oftentimes large and see∣mingly solid; yet this needs not make you reject our supposition, because 'tis not upon the whole Body at once, that, according to us, the Aerial Corpuscles endeavour to work, but upon the Superficial particles, which may often be more minute than those Corpuscles; as you will the more ea∣sily believe, if you first observe with a good Microscope, how many ex∣tant particles may be met with on the surface of Bodies, that to the naked Eye seem very smooth, and even of those that are polish'd by Art with Tripoly or Puttee; and then consider, that one of these protuberancies, be∣ing yet manifestly visible, may well be presum'd to consist of a multitude

of lesser particles, divers of which may very well be as minute as those Aerial Corpuscles, that successively hit against them, and endeavour to carry them along with themselves. And this may be illustrated by a fami∣liar instance. For, if you take a lump of Loaf Sugar, or even of a much so∣lider and harder Body, Sal Gemmae, and cast it into common water, though this liquor be insipid, and the motions of its corpuscles but very languid; yet these corpuscles are ca∣pable to loosen and carry off the su∣perficial particles of Sugar or Salt, that chance to lye in their way, and fresh corpuscles of water still suc∣ceeding to work upon the remaining particles of the expos'd Body that stand in their way, the whole lump is by little and little dissolved, and ceases to appear to the Eye a thing di∣stinct from the liquor.

Some things that have occurr'd to me have made me suspect, that 'tis not impossible, but that some Bodies may receive a disposition to Volatility,

and consequently to pass into the Air by the action either of the Sun-beams, in the form of the Sun-beams, or of some substance that once issued out of the Sun and reach'd unto our Air. For, there may be certain Bo∣dies for the most part in the form of liquors, which, though they pass off from some peculiarly dispos'd Bo∣dies, may during their stay or con∣tact produce in them a great and strange aptness to be volatiliz'd. In favour of which conjecture, I might here alledge both the effects, which the Paracelsians and Helmontians ascribe to the Alkahest of volatilizing even fixt and ponderous Bodies barely by being often abstracted from them, and some other things, which I shall now leave unmention'd, because you may find them in my Notes about Vo∣latility and Fixity.

But, whatever become of this Con∣jecture, 'tis consonant to Experience, that, either upon the above-recited accounts, or also some others, those parts of the Atmosphere, which, in

a stricter sense, may be call'd the Air, are, at least in some places, so in∣termixt with particles of differing kinds, that among that great num∣ber of various sorts of them, 'tis very likely that there should be some kinds of an un-common and an un∣observed nature. And I could coun∣tenance what has been said by the wasting of Odorous Bodies, and espe∣cially Camphire, and by representing, that I have observed some solid Bodies actually cold, when their superficial parts were newly taken off, to emit, though invisibly, such copious steams into the Air, as to grow continually and manifestly lighter upon the bal∣lance, so as to suffer a notable decre∣ment of weight in a minute of an hour. But the mention I make of such things in an other paper, dis∣swades me from insisting on them here, where 'twill be seasonable to resume the discourse, which the men∣tion of the Dissolving power, that may be guess'd to be in the Air, has for some pages interrupted, and to tell

you, that those propounded, before I enter'd upon the digression, are the two main Consideration à priori (as they speak) whereon I have groun∣ded my surmize, which being pro∣pos'd but as a Suspicion, I presume it will not be expected, that the Argu∣ments à posteriori, which I shall bring to countenance it, should be more than Conjectures, much less that they should be Demonstrations. And there∣fore I shall venture to lay before you some few Phaenomena, which seem to be at least as probably referable to some latent Quality in the Air, as to any other cause I yet know. Upon which score such Phaenomena may be allowed to be pleaded in favour of our Suspicion, 'till some other certain cause of them shall be satisfactorily assign'd.

Having premis'd thus much to keep you from looking for stronger proofs than I think my task obliges me to give; the first Phaenomenon, I shall propose, shall be the appearing or growth of some Salts in certain

Bodies, which we observ'd to afford them either not at all, or at least nothing near in such plenty, or so soon, unless they be expos'd to the Air. Of such a Phaenomenon as this, that is not so much as mention'd by Vulgar Philosophers, and very rarely, if at all, to be met with in the La∣boratories of Chymists, you will not, I suppose, wonder, that I do not present you many Examples, and some few I am able to name. For I remember, that suspecting a solid Marchasite, hard as stone, to be fit to be made an instance for my pur∣pose, I caus'd it to be broken, that the internal more shining parts might be expos'd to the Air; but, though this were done in a room, where a good fire was usually kept, so that the Marchasite was not only shelter'd from the rain, but kept in a dry Air, yet after a while I discover'd upon the glistering parts an efflorescence of a vitriolate nature.

And afterwards meeting with a ponderous and dark colour'd Mineral,

and which, at the first breaking, discover'd to the Eye no appearance of any Salt, nor so much as any shi∣ning Marchasitical particles, we found nevertheless, that a good quantity of these hard and heavy Bodies, being kept expos'd to the Air, even in a room that preserved them from the rain, though probably they had lain many ages intire in the hill, wherein they were found under ground; yet in not many months, by the opera∣tion of the Air upon them, they were, in great part, crumbled to powder exceeding rich in Copperas. Nay, I remember, that having for Curio∣sities sake, laid up some of these stones in a room, where I constantly kept fire, and in the drawer of a Ca∣binet, which I did not often take out to give them fresh Air, some, if not most of them, were notwithstanding ••over'd with a copious efflorescence, which by its conspicuous colour be∣tween blew and green, by its taste, and by its fitness to make in a trice an inky mixture with infusion of

galls, sufficiently manifested it self to be Vitriol; whose growth by the help of the contact of the Air is the more considerable, because it is not a meer Acid Salt, but abounds in Sulphureous and Combustible parts, which I have divers times been able, by Methods elsewhere mentioned, actually to separate or obtain from common Vitriol without the addition of any combustible body, and some∣times without any additament at all. It was also uncommon, that our blackish Minerals requir'd no longer time, nor no rain, to make them af∣ford their Vitriolate Efflorescences: For I remember, I kept many of those Marchasites, both glittering ones and others, of which they make and sell great quantities of Vitriol at Deptford, without perceiving in them a change that came any thing near to what I have recited. And I observ'd those, whose trade it is to make Vitriol, to be often obliged to let their Vitriol-stones, as they call them, lye half a year, or even eighteen months, or

two years exposed, not only to the open Air, but to the Rain and Sun, to be able to obtain from them their Vitriolate parts.

That also the Earth or Ore of Al∣lum, being robb'd of its Salt, will in tract of time recover it by being expos'd to the Air, we are assur'd by the experienc'd Agricola, where, having deliver'd the way of making Allum, he subjoins this Advertise∣ment: Terra Aluminosa, quae in castel∣lis diluta, postquam effluxit, superfuit egesta et coacervata quotidie, rursus ma∣gis & magis fit aluminosa, non aliter atque terra ex qua halinitrum fuit con∣fectum, suo succo plenior fit; quare de∣nuo in Castella conjicitur & aquae affu∣sae ea percolantur.

I have likewise observ'd, as you also perchance have done, that some kind of Lime in old walls and moist places has gain'd in length of time a copious efflorescence, very much of a Nitrous Nature; as I was convinc'd by having obtain'd Salt-peter from it by barely dissolving it in common

water, and evaporating the filtrated Solution: And that in calcin'd Vi∣triol, whose saline parts have been driven away by the violence of the fire, particles of fresh Salt may be found after it has lain a competent time in the Air, I shall e're long have occasion to inform you.

But in the mean time, (to deal in∣genuously with you,) I shall freely confess to you, that, though these and the like observations have satis∣fied Learned men, without having been call'd in question, and conse∣quently have, at least, probability enough to ground our Suspicion upon; yet I, that am more concern'd for the Discovery of a Truth than the Reputation of a Paradox, propose the Argument drawn from the foregoing Observations, but as a Probationer. For it yet seems to me somewhat doubtful, whether the Salts, that ap∣pear in the forementioned cases, are really produc'd by the operation of the Air working as an Agent, or also concurring as an Ingredient; or whe∣ther

these saline substances be not the production of some internal thing that is analagous to a Seminal Prin∣ciple, which makes in these bodies a kind of maturation of some parts, which being once ripen'd, and per∣haps assisted by the moisture of the Air, disclose themselves in the form of saline Concretions; as in the fe∣culent or Tartareous parts of many Wines there will in tract of time be generated or produc'd store of Cor∣puscles of a saline nature, that pro∣duce the acid taste we find in Tartar, especially that of Rhenish wine. It may also be suspected, that the for∣merly mention'd Salts found in Mar∣chasites, in Nitrous and Aluminous Earths, &c. are made by the saline particles of the like nature, that among multitudes of other kinds swim in the Air, and are attracted by the congenerous particles, that yet remain in the Terrestrial bodies, that are, as it were, the wombs of such Minerals, (as I have elsewhere shewn, that Spirit of Nitre will, with fixt

Nitre and some other Alkalys, com∣pose Salt-peter;) or else, that these Aerial Salts, if I may so call them, assisted by the moisture of the Air, do soften and open, and almost cor∣rode or dissolve the more Terrestrial Substance of these wombs, and there∣by sollicit out and somewhat extri∣cate the latent Saline particles, and, by their union with them, compose those Emerging bodies that resemble Vitriol, Allum, &c.

But not only to suggest these scru∣ples, as if I had a mind they should but trouble you, and keep you irre∣solute, I shall propound something towards the removal of them; name∣ly, that a convenient quantity of Nitrous Earth, or that other of those Substances, which you would exa∣mine, be kept in a close vessel to which the Air has not access, for at least as long time as has been obser∣ved to be sufficient to impregnate the like substance, or rather a portion of the same parcel that was chosen to be included: For, if the body, that

was kept close, have either gain'd no Salt at all, or very much less in pro∣portion to its bulk than that which was kept expos'd, we may thence estimate, what is to be ascribed to the Air in the production of Nitre or other saline Concretions. And, be∣cause I have observed none of these bodies, that would so soon, and so manifestly, even to the eye, disclose a saline substance, as the blackish Vitriol-Ore, I lately told you I kept in a drawer of my Cabinet; I judg'd that a very fit subject, wherewith to try, what maturation or time, when the Air was secluded, would perform towards the deciding of our Diffi∣culty: And accordingly having ta∣ken some fragments of it, which we had carefully freed from the adhering Vitriolate efflorescence, by whose plenty we were assured that it was very well dispos'd to be wrought on by the Air, we put of these frag∣ments of differing sizes into two con∣veniently shap'd glasses, which be∣ing Hermetically sealed were ordered

to be carried away, and kept in fit places; by which means 'twas ex∣pected, that, even without opening the glasses, we should be able easily to see by the chang'd colour of the superficial parts, whether any Vitrio∣late efflorescence were produced; but, through the negligence or mistake of those, to whom the care was recom∣mended, the experiment was never brought to an issue; and though I afterwards got more of the Mineral, and made a second tryal of the same, I have not yet been inform'd of the event.

But, Sir, though, 'till the success of some such tryal be known, I dare not too confidently pronounce about the Production or Regeneration of Salts in bodies that have been robb'd of them, and ascribe it wholly to the Air; yet, when I consider the several and great effects of the Air upon divers other bodies, I think it not rash to conjecture in the mean time, that the operations of the Air may have a considerable share in these

Phaenomena, and so that there may be latent Qualities in the Air, in the sense I declar'd above, where I told you, that, when I speak of these Qualities, I look upon them in Con∣creto, (as they phrase it,) together with the Substances or ••orporeal efflu∣via they reside in: And of these Ae∣rial Qualities, taken in this sense, I shall now proceed to mention some other Instances.

The Difficulty we find of keeping Flame and Fire alive, though but for a little time, without Air, makes me some times prone to suspect, that there may be dispers'd through the rest of the Atmosphere some odd sub∣stance, either of a Solar, or Astral, or some other exotic, nature, on whose account the Air is so necessary to the subsistence of Flame; which Necessity I have found to be greater, and less dependent upon the manifest Attributes of the Air, than Natu∣ralists seem to have observed. For I have found by tryals purposely made, that a small flame of a Lamp, though

fed perhaps with a subtil thin Oyl, would in a large capacious glass-Re∣ceiver expire, for want of Air, ••••in a far less time than one would be••eve. And it will not much lessen the diffi∣culty to alledge, that either the gross fuliginous Smoak did in a close Ves∣sel stifle the flame, or that the pres∣sure of the Air is requisite to impel up the aliment into the wieck: For, to obviate these objections, I have in a large Receiver imploy'd a very small wieck with such rectified Spirit of Wine, as would in the free Air burn totally away; and yet, when a very small Lamp, furnished (as I was saying) with a very slender wieck, was made to burn, and, fill'd with this liquor, was put lighted into a large Receiver, that little flame, though it emitted no visible smoak at all, would usually expire within a∣bout one minute of an hour, and, not seldom, in a less time; and this, though the wieck was not so much as sing'd by the flame: Nor indeed is a wieck necessary for the experi∣ment,

since highly rectified Spirit of Wine will in the free Air flame away well without it. And indeed it seems to ••••erve our wonder, what that should be in the Air, which inabling it to keep flame alive, does yet, by being consum'd or deprav'd, so sud∣denly render the Air unfit to make flame subsist. And it seems by the sudden wasting or spoiling of this fine Subject, whatever it be, that the bulk of it is but very small in proportion to the Air it impregnates with its virtue. For after the ex∣tinction of the flame, the Air in the Receiver was not visibly alter'd, and, for ought I could perceive by the ways of judging I had then at hand, the Air retain'd either All, or at least far the greatest part of its Ela∣sticity, which I take to be its most genuine and distinguishing property.

And this undestroy'd springyness of the Air seems to make the necessity of fresh Air to the Life of hot Ani∣mals, (few of which, as far as I can guess after many tryals, would

be able to live two minutes of an hour, if they were totally and all at once deprived of Air,) suggest a great suspicion of some vital substance, if I may so call it, diffus'd through the Air, whether it be a volatile Nitre, or (rather) some yet anony∣mous substance, Sydereal or Subter∣raneal, but not improbably of kin to that, which I lately noted to be so necessary to the maintenance of o∣ther flames.

I know not, whether you will think it pertinent to our present Discourse, that I observe to you, that by keeping putrifying bodies in glasses, which by Hermes his seal were secur'd from the contact of the external Air, I have not been able to produce any Insect or other living Creature, though sometimes I have kept Animal Substances and even Blood so included for many months, and one or two of them for a longer time; and though also these Substan∣ces had a manifest change made in their consistence whilst they remain'd seal'd up.

On this occasion I shall add an odd Observation, that I met with in a little Dissertation de admirandis Hun∣gariae aquis, written by an Anony∣mous, but Ingenious, Nobleman of that Countrey, where, speaking of the native Salt that abounds in their Regions, he says, that in the chief Mine (by them call'd Desiensis) of Transylvania, there was, a few years before he writ, a great Oak like a huge beam dug out of the middle of the Salt; but, though it was so hard, that it would not easily be wrought upon by Iron-tools, yet being ex∣pos'd to the Air out of the Mine, it became so rotten, as he expresses it, that in four days it was easie to be broken and crumbled between ones fingers. And of that corruptive or dissolutive Power of the Air near those Mines, the same Author men∣tions other Instances.

Having found an Antimonial Pre∣paration to procure Vomits, in a case where I did not at all expect it, I was afterwards curious to inquire

of some Physitians and Chymists, that were of my Acquaintance, whe∣ther they had not taken notice, that Antimonium Diaphoreticum, which, as its name imports, is wont to work by sweat or transpiration, would not become vomitive, if 'twere not kept from the Air? To which one Phy∣sitian, that was a Learned Man, as∣sur'd me, it would, as he had found by particular tryals: And the like answer has been given me by more than one. And I find, that the ex∣perienc'd Zwelfer himself does some∣where give a caution against letting the Air have access to these Anti∣monial Medicines, lest it should ren∣der them, as he says it will, in tract of time, not only Emetic, but dispos'd to produce heart-burnings, (as they call them,) faintings, and other bad Symptoms. And I learnt by inquiry from a very Ingenious Doctor of Physic, that, having carefully pre∣par'd Antimonium Diaphoreticum, he gave many doses of it whilst it was fresh and kept stopt in a glass (without

finding that in any Patient it procur'd so much as one vomit,) but having kept a parcel of the self same Remedy for a pretty while in a glass only co∣ver'd loosely with a paper, the Me∣dicine, vitiated by the Air, proved emetic (strongly enough) to those, who neither by Constitution, or foulness of stomach, or on any other discernable account, were more than others that had taken it disposed to vomit. By which Observations, and from what I formerly told you of the Salt-peter obtainable from Quick-lime, a Man partial to the Air would be made forward to tell you, that this looks, as if either there were in the Air a substance dispos'd to be assimi∣lated by all kinds of bodies, or that the Air is so vast and rich a Rende∣vouz of innumerable seminal Cor∣puscles and other Analogous parti∣cles, that almost any body long ex∣pos'd to it may there meet with par∣ticles of kin to it, and fit to repair its wrongs and losses, and restore it to its natural Condition. But with∣out

taking any further notice of this odd surmize, I will proceed to mention two or three other Phaenomena of Na∣ture, that seem to favour the Suspi∣cion, that there may be Secret Qua∣lities in the Air in reference to some bodies.

The ingenious Monsieur de Roche∣fort, in the handsom account he gives of the Apple or Fruit of the Tree Iunipa, whose juice is imploy'd by the Indians to black their skins, that they may look the more terrible to their Enemies, observes, that, though the stain, or, as he speaks, the Tin∣cture of this Fruit cannot be wash'd out with Soap, yet within nine or ten days it will vanish of it self; which would make one suspect, that there may be in the Air some secret powerful substance, that makes it a Menstruum of more efficacy than Soap it self to obliterate stains. I re∣member, I have seen this Fruit, but not whilst it was succulent enough to have a tryal made with it; which I was therefore troubled at, because

the Author does not clearly express, whether this disappearing of the tin∣cture happens indifferently to the bo∣dies it chances to stain, or only is observed on the skins of Men. For, as in the former Case 'twill afford an instance pertinent to our present pur∣pose; so in the latter I should suspect, that the vanishing of the tincture may be due not so much to the ope∣ration of the Air upon it, as to the sweat and exhalations of a human body, which abounding with vola∣tile Salt, may either destroy or carry off with them the colour'd particles they meet with in their passage.

I have sometimes, not altogether without wonder, observ'd the excel∣lency of the better sort of Damasco-steel, (for I speak not of all that goes under that name,) in comparison of ordinary steel. And, besides what I have elsewhere taken notice of con∣cerning it, there is one Phaenomenon, which though I am not sure it belongs to the latent Qualities of the Air, yet because it may well do so, and I

am unwilling it should be lost, I will here tell you, that having inquired of an eminent and experienc'd Arti∣ficer, (whom I long since imployed in some difficult Experiments,) about the properties of Damasco-steel, this honest and sober Man averr'd to me, that when he made Instruments of it, and gave them the true temper, which is somewhat differing from that of other Steel, he generally ob∣served, that though, when Rasors or other Instruments made of it were newly forged, they would be some∣times no whit better, and sometimes less good, than those made of other Steel; yet when they had been kept a year or two or three in the Air, though nothing else were done to im∣prove them, they would be found much to surpass other Instruments of the same kind, and what themselves were before; in so much; that some of them have been laid aside at first, as no way answering the great expe∣ctation conceived of them, which after two or three years were found

to surpass it; of which also I am now making a tryal. I have several times made a substance that consists chiefly of a Metalline body, and is of a tex∣ture close enough to lye for many hours undissolv'd in a Corrosive Men∣struum; and yet this substance, that was fixt enough to endure the being melted by the Fire without losing its colour, would, when I had pur∣posely expos'd it to the Air, be dis∣coloured in a very short time, and have its superficial parts turned al∣most black.

And this brings into my mind that very pretty Observation, that has been newly made in Italy by an inge∣nious Man, who took notice, that, if after the opening of a Vein the blood be kept 'till it be concreted, and have excluded the superficial se∣rum, though the lower part be usu∣ally of a dark and blackish colour in comparison of the superficial parts, and therefore be counted far more feculent; yet, if the lump or clott of blood be broken, and the internal

and dark coloured parts of the blood be expos'd to the Air, it will after a time (for 'tis not said how long) be so wrought on by the contact of the Air, that the superficial part of the blood will appear as florid as the lately mention'd upper part (suppos'd to be, as it were, the flower of the blood,) did seem before. And this Observation I found to hold in the blood of some Beasts, whereon I tryed it, in which I found it to succeed in much fewer minutes, than the Italian Virtuoso's Experiment on Human blood would make me expect.

On the other side I have often pre∣par'd a Substance, whose effect ap∣pears quite contrary to this. For, though this factitious Concrete, whilst kept to the Fire or very care∣fully preserved from the Air, be of a red colour almost like the common opacous Bloodstone of the shops; yet, if I broke it, and left the lumps or fragments of it a little while in the Air, it would in a short time (some∣times perhaps not amounting to a

quarter of an hour) it would, I say, have its superficial parts turn'd of a very dark colour, very little, and sometimes scarce at all, short of blackness.

A very inquisitive Person of my acquaintance, having occasion to make, by Distillation, a Medicine of his own devising, chanc'd to ob∣serve this odd property in it, That at that time of the year, if it were kept stopt, it would be coagulated almost like Oyl of Anniseeds in cold weather; yet, if the stopple were taken out, and so access were for a while given to the Air, it would turn to a liquor, and the vessel being again stopt, it would, though more slow∣ly, recoagulate. The hints, that I guess'd might be given by such a Phae∣nomenon, making me desirous to know something of it more than barely by Relation, I express'd rather a curiosity than a diffidence about it; and the Maker of it telling me, he thought, he had in a small Vial about a spoonful of this Medicine left in a

neighbouring Chamber, I desired his leave to consider it my self, which Request being presently complied with, I found it, when he brought it into the Room which I stayed in, not liquid but consistent, though of but a slight and soft contexture. And having taken out the Cork, and set the Vial in a window, which (if I well remember) was open, though the Season, which was Winter, was cold, yet in a little time that I stayed talking with the Chymist, I found, that the so lately coagulated substance was almost all become fluid. And another time, when the Season was less cold, having occasion to be where the Vial was kept well stopt, and casting my Eyes on it, I perceiv'd the included substance to be coagulated much like Oyl of Anniseeds. And this substance having, as the Maker assur'd me, nothing at all of Mineral in it, nor any Chymical Salt, it con∣sisting only of two simple bodies, the one of a vegetable and the other of an animal substance, distill'd toge∣ther,

I scarce doubt but you will think with me, that these contrary operations of the Air, which seems to have a power in some Circumstan∣ces to coagulate such a body, and yet to dissolve and make it fluid when fresh and fresh parts are allow'd access to it, may deserve to be further re∣flected on, in reference (among other things) to the opportune operations, the inspired Air may have on the consistence and motion of the circu∣lating blood, and to the discharge of the fuliginous recrements to be sepa∣rated from the blood in its passage through the Lungs.

There are two other Phaenomena that seem favourable to our Suspicion, That there are Anonymous Substances and Qualities in the Air, which ought not to be altogether praeter∣mitted on this occasion; though, because to speak fully of them would require far more time than I can now spare, I shall speak of them but suc∣cinctly.

The latter of these two Phaenomena

is the growth or appearing produ∣ction of Metals or Minerals dug out of the Earth, and expos'd to the Air. And this, though it be the last of the two, I mention first, because it seems expedient, lest it should prove too long an interruption to our Dis∣course, to postpone the Observations and annex them to the end of this Paper; only intimating to you now, that the caution I formerly interposed about the Regeneration of Salts in Nitrous and other Earths, may, for greater security, be applied, mutatis mutandis, to that production of Me∣talline and Mineral bodies we are spea∣king of.

The other of the two Phaenomena, I lately promis'd to mention, is affor∣ded me by those various and odd Diseases, that at some times and in some places happen to invade and destroy numbers of Beasts, sometimes of one particular kind, and sometimes of another. Of this we have many instances in the Books of approved Authors; both Physitians and others;

and I have my self observ'd some no∣table Examples of it. But yet I should not mention it as a ground of Suspicion, that there may be, in some times and places, unknown Ef∣fluvia and powers in the Air, but that I distinguish these from those Di∣seases of Animals, that proceed, as the Rot in Sheep often does, from the exorbitancy of the Seasons, the immoderateness of Cold, Heat, or any other manifest Quality in the Air. And you will easily perceive, that some of these Examples probably argue, that the Subterraneal parts do sometimes (especially after Earth∣quakes or unusual cleavings of the ground) send up into the Air peculiar kinds of venomous Exhalations, that produce new and mortal Diseases in Animals of such a species, and not in those of another, and in this or that particular place, and not elsewhere: Of which we have an eminent In∣stance in that odd Plague or Murrain of the year 1514, which Fernelius tells us invaded none but Cats. And

even in Animals of the same species, sometimes one sort have been incom∣parably more obnoxious to the Plague than another; as Dionysius Halicarna∣séus mentions a Plague that attack'd none but Maids; whereas the Pe∣stilence that raged in the time of Gen∣tilis (a fam'd Physitian) kill'd few Women, and scarce any but lusty Men. And so Boterus mentions a great Plague, that assaulted almost only the younger sort of persons, few past thirty years of age being attack'd by it: Which last Observation has been also made by several later Physitians. To which may be added, what Lear∣ned Men of that Faculty have noted at several times concerning Plagues, that particularly invaded those of this or that Nation, though confu∣sedly mingled with other People; as Cardan speaks of a Plague at Basil, with which only the Switzers, and not the Italians, French, or Germans, were infected. And Iohannes Uten∣hovious takes notice of a cruel Plague at Copenhagen, which, though it raged

among the Danes, spared both the English, Dutch, and Germans, though they freely enter'd infected houses, and were not careful to shun the sick. In reciting of which Instances I would not be understood, as if I im∣puted these effects meerly to noxious Subterraneal fumes; for I am far from denying, that the peculiar Consti∣tutions of Mens Bodies are likely to have a great interest in them: But yet it seems less probable, that the pestilent venom diffused through the Air should owe its enormous and fa∣tal efficacy to the excess of the ma∣nifest Qualities of the Air, than to the peculiar nature of the pestilential poison sent up into the Air from un∣der ground, which when it is by dilution or dissipation enervated, or by its progress past beyond the Air we breath in, or render'd ineffectual by subterraneal or other Corpuscles of a contrary Quality, the Plague, which it, as a con-cause, produced, either quite ceases, or degenerates in∣to somewhat else. But I have not

time to countenance this Conjecture, much less to consider, whether some of those Diseases, that are wont to be call'd new, which either did begin to appear, or at least to be rise, with∣in these two or three Centuries, as the Sudor Anglicus in the fifteenth Century, the Scurvy, and the Morbus Hungaricus, the Lues Moraviae, No∣vus Morbus Luneburgensis, and some others, in the last Century of all, may be in part caus'd by the exotic steams this Discourse treats of. But this Consideration I willingly resign to Physitians.

And now, if the two foremen∣tioned Suspicions, the one about Sub∣terraneal, the other about Sydereal, Effluviums, shall prove to be well grounded, they may lead us to other Suspicions and further thoughts about things of no mean Consequence; three of which I shall venture to make mention of in this place.

• I. For we may hence be awakened to consider, whether divers changes of Temperature and Constitution in

• the Air, not only as to manifest Qua∣lities, but as to the more latent ones, may not sometimes in part, if not chiefly, be derived from the paucity or plenty, and peculiar nature of one or both of these sorts of Esfluviums. And in particular, we find in the most approved Writers such strange Phae∣nomena to have several times hap∣pen'd in great Plagues and conta∣gious Diseases, fomented and com∣municated, nay (as many eminent Physitians believed) begun, by some latent pestiferous, or other malig∣nant, Diathesis or Constitution of the Air, as have obliged many of the Learned'st of them to have re∣course to the immediate operation of the Angels, or of the Power and Wrath of God himself, or at least to some unaccountable influence of the Stars; none of the Solutions of which difficulties seems preferable to what may be gathered from our Con∣jecture; since of Physical Agents of which we know nothing so much, as that they are to us invisible and

• probably of a heteroclite nature, it need be no great wonder, that the operation should also be abstruse, and the effects uncommon. And on this occasion it may be consider'd, that there are clearer inducements to per∣swade us, that another Quality of the Atmosphere, its Gravity, may be alter'd by unseen Effluviums, ascending from the Subterraneous Regions of our Globe; and we have often perceived by the Mercurial Ba∣roscope the Weight of the Air to be no∣tably increased, when we could not perceive in the Air nor surface of Earth any cause to which we could ascribe so notable a change. And this gives me a rise to add, that I have sometimes allowed my self to doubt, whether even the Sun it self may not now and then alter the Gravity of the Atmosphere otherwise than by its Beams or Heat. And I remember, I desired some Virtuosi of my acquaintance to assist me in the inquiry, whether any of the Spots, that appear about the Sun, may not,

• upon their sudden dissolution, have some of their discuss'd and dispers'd matter thrown off, as far as to our Atmosphere, and that copiously e∣nough to produce some sensible alte∣rations in it, at least as to Gravity.
• II. Another thing, that our two foremention'd Suspicions, if allow'd of, will suggest, is, that it may not seem altogether improbable, that some bodies, we are conversant with, may have a peculiar disposition and fitness to be wrought on by, or to be associated with, some of those exotic Effluvia, that are emitted by un∣known bodies lodged under ground, or that proceed from this or that Planet. For what we call Sympa∣thies and Antipathies, depending in∣deed on the peculiar Textures and other Modifications of the bodies, between whom these friendships and hostilities are said to be exercised, I see not why it should be impossible, that there be a Cognation betwixt a body of a congruous or convenient Texture, (especially as to the shape

• and size of its Pores,) and the Efflu∣viums of any other body, whether Subterraneal or Sydereal. We see, that convex Burning-glasses, by vir∣tue of their figure and the disposition of their pores, are fitted to be per∣vaded by the beams of Light and to refract them, and thereby to kindle combustible matter; and the same beams of the Sun will impart a lucid∣ness to the Bolonian stone. And as for Subterraneal bodies, I elsewhere mention two Minerals,* 1.2 which being prepa∣red, (as I there inti∣mate,) the steams of the one, ascending without adventitious Heat and wan∣dering through the Air, will not sensibly work on other bodies; but if they meet with that which we pre∣pared, they will immediately have an operation on it, whose effect will be both manifest and lasting.
• III. I now pass on to the other thing, that the two formerly men∣tioned Suspicions may suggest, which

• is, that if they be granted to be well founded, we may be allow'd to con∣sider, whether among the bodies we are acquainted with here below, there may not be found some, that may be Receptacles, if not also Attra∣ctives, of the Sydereal, and other exotic Effluviums that rove up and down in our Air.

Some of the Mysterious Writers about the Philosophers-stone, speak great things of the excellency of what they call their Philosophical Magnet, which, they seem to say, attracts and (in their phrase) corporifies the Universal Spirit, or (as some speak) the Spirit of the World. But these things being abstrusities, which the Writers of them profess'd to be writ∣ten for, and to be understood only by, the Sons of Art; I, who freely ac∣knowledge I cannot clearly appre∣hend them, shall leave them in their own worth as I found them, and only, for brevity sake, make use of the receiv'd word of a Magnet, which I may do in my own sense, without

avowing the receiv'd Doctrine of Attraction. For by such a Magnet, as I here purpose to speak of, I mean not a body that can properly attract our foreign Effluviums; but such an one, as is fitted to detain and join with them, when by virtue of the various motions, that belong to the Air as a Fluid, they happen'd to accost the Magnet. Which may be illustrated by the known way of ma∣king Oyl of Tartar (as the Chymists call it) per Deliquium. For, though the Spagyrists and others suppose, that the fiery Salt draws to it the Aqueous Vapours, yet indeed it does but arrest, and imbody with, such of those that wander through the Air, as chance in their passage to ac∣cost it.

And, without receding from the Corpuscularian Principles, we may al∣low some of the bodies, we speak of, a greater resemblance to Magnets, than what I have been mentioning. For not only such a Magnet may upon the bare account of Adhesion by

Iuxta-position or Contact, detain the Effluviums that would glide along it, but these may be the more firmly arrested by a kind of precipitating faculty, that the Magnet may have in reference to such Effluviums; which, if I had time, I could illu∣strate by some Instances; nay I dare not deny it to be possible, but that in some Circumstances of time or place one of our Magnets may, as it were, fetch in such steams as would indeed pass near it, but would not otherwise come to touch it. On which occasion I remember, I have in certain cases been able to make some bodies, not all of them Electri∣cal, attract (as they speak) without being excited by rubbing, &c. far less light bodies, than the Effluviums we are speaking of.

But this it may suffice to have glanc'd at, it not being here my pur∣pose to meddle with the mystical Theories of the Chymists; but ra∣ther to intimate, that, without a∣dopting or rejecting them, one may

discourse like a Naturalist about Mag∣nets of Celestial and other Emana∣tions, that appear not to have been consider'd, not to say, thought of, either by the Scholastic, or even the Mechanical, Philosophers.

Notes

• * 1.1

  In a Paper a∣boue Subter∣raneal Steams.
• * 1.2

  See the Experiment in the Discourse of the Determinate Nature of Effluvi∣ums.