ESSAYS Of the STRANGE SUBTLETY GREAT EFFICACY DETERMINATE NATURE OF EFFLUVIUMS.  
To which are annexed NEW EXPERIMENTS To make FIRE and FLAME Ponderable: Together with A Discovery of the Perviousness of GLASS.  
BY The Honourable ROBERT boil, Fellow of the Royal Society.  — Consilium est, universum opus Instaurationis (Philosophiae) potius promovere in multis, quam perficere in paucis. Verulamius. 
LONDON: Printed by W. G. for M. Pitt, near the little North Door of St Paul's Church. 1673.   

An Advertisement to the READER.  
'TIS hoped, the Reader will not think it strange, not to meet with in the following Papers a more close and uniform contexture of the passages that make them up, if he be seasonably informed of the rise and occasion of penning them, which was this. The Author having many years ago written an Essay about an Experiment he made of Nitre, by whose Phaenomena he endeavoured to exemplify some parts of the Corpuscular Philosophy, especially the Production of Qualities; he afterwards threw together divers occurring thoughts and experiments, which he supposed might be employed by way of Notes, to prove or illustrate those Doctrines, and especially those that concerned the Qualities of Bodies; and among these observing those that are called Occult, to be Subjects uncultivated enough, (at least in the way that seemed to him proper,) he proposed to handle them more largely than most of the rest; and in order to that Design he judged it almost necessary, to premise some Considerations and experimental Collections about the Nature and power of Effluviums, about the Pores of Bodies and Figures of Corpuscles, and about the efficacy of such Local-motions as are wont either to be judged very faint, or to be passed by unheeded. For he had often looked upon these three Doctrines, of Effluvia, of Pores and Figures, and of Unheeded Motions, as the three principal Keys to the Philosophy of Occult Qualities. But having hereupon made such Collections, as upon review appeared too large to pass for Notes on so short a Text, he was induced to draw them into the form (they now appear in) of Essays; but he would not put himself to the trouble of doing it, with care to keep them from retaiaing much of their first want of exact Method and Connexion. Nor was the Author solicitous to finish them up, in regard that his other Studies and occasions made him perceive, that in what he had designed about Occult Qualities, he had cut himself out more work than probably he should during many years have opportunity to set upon in earnest, and complete. And in this Condition these Papers lay for divers years, (as is well known to several that saw them, or even transcribed some of them,) and might have continued to do so, if the Author had not been induced to let them come abroad, partly by considering, that though the Subjects, (however he handled them) were as well important as curious, yet he did not find himself prevented by others in what he had to publish about them; and partly by the References he had made to them in some other Papers, that he had promised his Friends, wherein several things here delivered are vouched, and others supposed. And because the Notes concerning the Porosity of greater Bodies and the Figurations of minute Particles, together with the Paper about unregarded Motions, having been long laid aside among other neglected papers, were some of them missing, and others so misused, that they could not easily be made ready to accompany those that now come abroad; the Author, that he might keep this Book from having its dimensions too disproportionate, was content to add to the thickness of it, by subjoyning one of those little Tracts, that lay by him, concerning Flame, because of the Affinity betwixt the preceding Doctrine about Effluviums in general, and Experiments that show in particular the Subtlety and the Efficacy of those of Fire and Flame. And though, to that Tract itself, there belong another, designed to examine, Whether the matter of what we call the Sunbeams, may be brought to be ponderable; yet supposing this, hitherto cold and wet Summer, to be like to be as unfriendly to the Trials to be made with Burning-glasses as of late years some other Summers have proved, he was easily prevailed with, not to make those Experiments that were ready, wait any longer for those, that probably will not in a short time be so; especially since those that now come abroad have no dependency upon the others.   

OF THE Strange SUBTLETY OF EFFLUVIUMS.  
BY The Honourable ROBERT boil.  
LONDON: Printed by W. G. for M. Pitt at the sign of the White Hart, over-against the little North Door of St Paul's Church. 1673.   

OF The strange SUBTLETY OF EFFLWIUMS'.  

CHAP. I.  
WHether we suppose with the Ancient and Modern Atomists, that all sensible Bodies are made up of Corpuscles, not only insensible, but indivisible; or whether we think with the Cartesians, and (as many of that Party teach us) with Aristotle, that Matter, like Quantity, is indefinitely, if not infinitely divisible: It will be consonant enough to either Doctrine, that the Effluvia of Bodies may consist of Particles extremely small. For if we embrace the Opinion of Aristotle or Des-Cartes, there is no stop to be put to the sub-division of Matter, into Fragments, still lesser and lesser. And though the Epicurean Hypothesis admit not of such an interminate division of Matter, but will have it stop at certain solid Corpuscles, which for their not being further divisible are called Atoms (〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉,) yet the Assertors of these do justly think themselves injured, when they are charged with taking the Motes or small Dust, that fly up and down in the Sunbeams, for their Atoms; since, according to these Philosophers, one of those little grains of Dust, that is visible only when it plays in the Sunbeams, may be composed of a multitude of Atoms, and exceed many thousands of them in Bulk. This the Learned Gassendus in his Notes on Diogenes Laertius makes probable by the instance of a small Mite, which, though scarce distinctly discernible by the naked Eye, unless when 'tis in motion, does yet in a good Microscope appear to be a complete Animal, furnished with all necessary Parts; which I can easily allow, having often in Cheese-Mites very distinctly seen the Hair growing upon their Legs. And to the former Instance I might add, what I have elsewhere told you of a sort of Animals far lesser than Cheese-Mites themselves, namely those that may be oftentimes seen in Vinegar. But what has been already said may suffice for my present purpose, which is only to show, that the wonderful minuteness I shall hereafter ascribe to Effluvia, is not inconsistent with the most received Theories of Naturalists. For otherwise in this Essay the Proofs I mean to employ, must be taken, not à Priori, but à Posteriori. And the Experiments and Observations I shall employ on this occasion will be chiefly those, that are referrible to one of the following Heads.  

I. The strange Extensibility of some Bodies whilst their Parts yet remain tangible.  
II. The multitude of Visible Corpuscles, that may be afforded by a small portion of Matter.  
III. The smallness of the Pores at which the Effluvia of some Bodies will get in.  
IV. The small decrement of Bulk or Weight, that a Body may suffer by parting with great store of Effluvia.  
V. The great quantity of Space that may be filled, as to sense, by a small quantity of Matter when rarified or dispersed.   
But though to these distinct Heads I shall design distinct Chapters, yet you must not expect to find the Instances solicitously marshaled, 
This Essay was designed to be but a part of the Author's Notes upon his Essay about Saltpetre.  but set down in the order they occurred to me; such a liberty being allowable in a Paper, where I pretend not to write Treatises, but Notes   

CHAP. II.  
AMong many things that are gross enough to be the Objects of our Touch, and to be managed with our Hands, there are some that may help us to conceive a wonderful minuteness in the small Parts they consist of.  
I do not remember what Cardan, and since him another Writer have delivered about the Thinness and Slenderness to which Gold may be brought. And therefore without positively assenting to, or absolutely rejecting what may have been said about it by others, I shall only borrow on this occasion, 
In a Paper about Improbable Truths.  what I have mentioned on another upon my own Observation; namely, That Silver, whose Ductility and Tractility are very much inferior to those of Gold, was, by my procuring, drawn out to so slender a Wire, that, when we measured it, which was somewhat troublesome to do, with a long and accurate measure, we found, that eight Yards of it did not yet fully counterpoise one Grain: So that we might add a Grain more without making the Scale, wherein 'twas put, manifestly preponderate, notwithstanding the Tenderness of the Balance. Whence we concluded, that a single Grain of this Wire amounted to 27 Foot, that is, 324 Inches. And since Experience informs us, that half an English Inch can by Diagonal Lines be divided into 100 parts great enough to be easily distinguished, even for Mechanical uses, it follows, that a Grain of this wiredrawn Silver may be divided into 64800 parts, and yet each of these will be a true metalline, though but slender and short, Cylinder, which we may very well conceive to consist yet of a multitude of minuter parts. For though I could procure no Gilt Wire near so slender as our newly mentioned Silver-wire; yet I tried that some which I had by me was small enough to make one Grain of it fourteen foot long: At which rate an Ounce did amount to a full Mile, consisting of 1000 Geometrical Paces, (of 5 foot apiece,) and 720 foot over and above. And if now it be permitted to suppose the Wire to have been, as in probability it might have been, further drawn out to the same slenderness with the abovementioned Silver-wire, the Instance will still be far more considerable; for in this case, each of those little Cylinders, of which 64800 go to the making of one Grain, will have a superficial Area, which, except at the Basis, will be covered with a Case of Gold; which is not only separable from it by a mental Operation, but perhaps also by a Chemical one. For I remember, that from very slender gilt Wire, though I could get none so slender as this of mere Silver, I did more than once, for Curiosities sake, so get out the Silver, that the golden Films, whilst they were in a Liquor that plumped them up, seemed to be solid wires of Gold: But when the Liquor was withdrawn, they appeared, (as indeed they were) to be oblong and extremely thin and double Membranes of that Metal, which, with an Instrument that had been delicate enough, might have been ripped open, and displayed, and been made capable of further. Divisions and Subdivisions. To this I shall add, that each of the little silver Cylinders I lately spoke of, must not only have its little Area, but its Solidity; and yet I saw no reason to doubt, but that it might be very possible, if the Artificer had been so skilful and willing as I wished, to have drawn the same quantity of Metal to a much greater length, since even an Animal substance is capable of being brought to a slenderness much surpassing that of our Wire, supposing the Truth of an Observation of very credible Persons critical enough in making Experiments, which, for a Confirmation and an Improvement of our present Argument, I shall now subjoin. An Ingenious Gentlewoman of my Acquaintance, Wife to a Learned Physician, taking much pleasure to keep Silkworms, had once the Curiosity to draw out one of the Oval Cases, (which the Silkworm spins, not, as 'tis commonly thought, out of its Belly, but out of the Mouth, whence I have taken pleasure to draw it out with my Fingers,) into all the Silkenwire it was made up of, which, to the great wonder as well of her Husband, as herself, who both informed me of it, appeared to be by measure a great deal above 300 Yards, and yet weighed but two Grains and a half: so that each Cylindrically shaped Grain of Silk may well be reckoned to be at least 120 Yards long.  
Another way, I remember, I also employed to help men by the extensibility of Gold the better to conceive the Minuteness of the Parts of Solid Bodies.  
We took six beaten Leaves of Gold, which we measured one by one with a Ruler purposely made for nice Experiments, and found them to have a greater equality in Dimensions, and to be nearer true Squares, than could be well expected: The side of the Square was in each of them exactly enough three Inches and 2/8, (or 1/4,) which number being reduced to a Decimal Fraction, viz. 3125/100, and multiplied by itself, affords 105625/10000 for the Area, or superficial Content of each square Leaf: And this multiplied by 6, the number of the Leaves, amounts to 633750/10000 square Inches, for the Area of the six Leaves. These being carefully weighed in a pair of tender Scales, amounted all of them to one Grain and a quarter: And so one Grain of this foliated Gold was extended to somewhat above fifty Inches; which differed but about a fifth part from an Experiment of the like nature, that I remember I made many years ago in a pair of exact Scales; and so small a difference may very well be imputed to that of the pains and diligence of the Gold-Beaters, who do not always work with equal strength and skill, nor upon equally fine and ductile Gold.  
Now if we recall to mind what I was lately saying of the actual divisibility of an Inch into an hundred sensible parts, and suppose an Inch so divided to be applied to each side of a square Inch of the Leaf-Gold newly mentioned, 'tis manifest that by subtle parallel Lines, drawn between all the opposite Points, a Grain of Gold must be divisible into five hundred thousand little Squares, very minute indeed, but yet discernible by a sufficiently sharp-sighted Eye. And if we suppose an Inch to be divided into two hundred parts, as I lately told you it was in a Ruler I employ, then, according to the newly recited way, the number of the Squares, into which a single Grain is capable of being divided, will amount to no less than two Millions.  
There is yet another way that I took to show, that the extensibility, and consequently the divisibleness of Gold is probably far more wonderful, than by the lately mentioned Trial it appears.  
For this purpose I went to a great Refiner, whom I used to deal with for purified Gold and Silver, and enquired of him, how many Grains of Leaf-Gold he was wont to allow to an Ounce of Silver, when it was to be drawn into gilt Wire as slender as an Hair? To this he answered me, that eight Grains was the proportion he allowed to an Ounce when the Wire was to be well gilded; but if it were to be more slightly gilded, six Grains would serve the turn. And to the same purpose I was answered by a skilful Wiredrawer. And I remember, that desiring the Refiner to show me an Ingot of Silver, as he did at first gilled it; he showed me a good fair Cylindrical Bar, whereon the Leaf-Gold, that overlaid the surface, did not appear to be by odds so thick as fine Venetian Paper; and yet comparing this with gilt Wire, which I also desired to see, the Wire appeared to be the better gilt of the two; possibly because the Gold in passing through the various Holes, was by the sides of them not only extended but polished, which made it look more vividly than the unpolished Leaves that gilded the Ingot.  
So that, if we suppose an Ounce of the gilt Wire formerly mentioned to have been gilded with six Grains of Leaf-Gold, it will appear by an easy calculation, that at this rate one Ounce of Gold, employed on gilding Wire of that slenderness, would reach between ninety and an hundred Miles. But if now we further suppose, as we lately did, that the slender Silver-wire, mentioned at the beginning of this Chapter, were gilded; though we should allow it to have (because of its exceeding slenderness,) not, (as the former) 6 Grains, but 8 Grains of Leaf-Gold to an Ounce of Siver, it must be acknowledged, that an hollow Cylinder or sheathe of Gold weighing but eight Grains, may be so stretched, that 'twill reach to no less than 60 times as much (in weight) of Silver-wire as it covers: [I said 60 times, for so often is 8 contained in 480, the number of Grains in an Ounce;] and consequently (a Grain of that Wire having been found to be 27 foot long,) the Ounce of Gold would reach to seven hundred seventy seven thousand six hundred foot, that is, an hundred fifty five Miles and above a half. And if we yet further suppose this superficial or hollow Cylinder of Gold to be slit all along, and cut into as slender lists or thongs as may be, we must not deny that Gold may be made to reach to a stupendious length. But we need not this last supposition to make what preceded it an amazing thing: which yet though it be indeed Stupendious and seem Incredible, ought not at all to be judged Impossible, being no more than what upon the Suppositions and Observations above laid down, does evidently follow.   

CHAP. III.  
AFter what has been said of the minuteness of tangible Objects, 'twill be proper to subjoin some instances of the smallness of such as yet continue visible. But in regard these Corpuscles are singly too little to have any common measure applied to any of them, we must make an estimate of their minuteness by the number of those into which a small portion or fragment of matter may be actually divided, the multitude of these being afforded by so inconsiderable a Quantity of matter, sufficiently declaring, that each of them, in particular, must be marvellously little.  
Among the instances, where the smallness of Bodies may be deduced from what is immediately the Object of Sight, it may not be unfit to take notice of the evaporation of Water, which though it be granted to consist of gross particles in comparison of the spirituous and odoriferous ones of divers other Liquors, as of pure Spirit of Wine, Essential Oils of Spices, etc. yet to show that a small Quantity of it may be dispersed into a multitude of manifestly visible Corpuscles, I thought upon, and more than once tried, the rarefaction of it into Vapours by help of an Aeolipile, wherein, when I made the Experiment the last time, I took the pains to register the Event as follows.  
We put an Ounce of common Water into an Aeolipile, and having put it upon a Chasing-dish of coals, we observed the time when the streams of Vapours began to be manifest. This stream was for a good while impetuous enough, as appeared by the noise it made, which would be much increased, if we applied to it at a convenient distance a kindled brand, in which it would blow up the fire very vehemently. The stream continued about a quarter of an hour (sixteen minutes or better,) but afterwards the Wind had pauses and gusts for two or three minutes before it quite ceased. And by reason of the shape of the Aeolipile, (which being framed chiefly for other purposes, was not so convenient for this) a great portion of the Vapours condensed in the upper part of it, and fell down in drops; so that supposing that they also had come out in the form of Wind, and the blast had not been intermitted toward the latter end, I guessed it might have continued uninterruptedly 18 or 20 minutes. Note, That applying a measure to the Smoke, that came out very visible in a form almost conical, where it seemed to have an Inch or more in Diameter, 'twas distant from the hole of the Aeolipile about twenty Inches; and five or six Inches beyond that, though it were spread so much, as to have four or five Inches in Diameter, yet the not uniform but still-cohering Clouds (which was the form wherein the Vapours appeared) were manifest and conspicuous.  
After the rarefaction of Water when 'tis turned into Vapours, we may consider that of Fuel when 'tis turned into Flame; to which purpose I might here propose several Trials as well of our own as others, about the prodigious Expansion of some Inflammable Bodies upon their being actually turned into Flame. But in this place to mention all these, would perhaps too much entrench upon another Paper; and therefore I shall here propose to your consideration but one instance, and that very easy to be tried; of which I find this account among my Adversaria.  
Having oftentimes burnt Spirit of Wine, and also Oil in Glass-lamps, that for certain uses were so made, that the surface of the Liquor was still circular, 'twas obvious to observe, how little the Liquor would subside by the waist that was made of it, in about half a quarter of an hour. And yet if we consider, that the naked Eye after some Exercise, may, as I have often tried, discern the motions of a Pendulum that swings fast enough to divide a single minute of an hour into 240 parts, and consequently half a quarter of an hour into 1800 parts; if we also consider into how many parts of the time employed by a Pendulum, the Vibrations, slow enough to be discernible by the Eye, may be mentally subdivided; and if we further consider, that without intermission, the Oil is preyed upon by an actual Flame, and the particles of it do continually furnish a considerable stream of shining matter, that with a strange celerity is always flying away; we may very well conceive, that those parts of Flame into which the Oil is turned, are stupendiously minute, since, though the wasting of the Oil is in its progress too slow to be perceived by the Eye, yet 'tis undoubted that there is a continual decrement of the depth of the Oil, the Physical surfaces whereof are continually and successively attenuated and turned into flame; and the strange subtlety of the Corpuscles of flame would be much the stronglier argued, if we should suppose, that instead of common Oil the flame were nourished by a fuel so much more compact and durable, as is that inflammable substance made of a Metalline Body, of whose lastingness I have elsewhere made particular mention, 
In some Papers about Flame.  after having taught the way of preparing it.  
Having in a pair of tender Scales carefully weighed out half a Grain of good Gunpowder, we laid it on a piece of Tile, and whelmed over it a vessel of glass (elsewhere described, and often mentioned) with a Brass-plate to cover the upper orifice of it. Then having fired the Gunpowder, we observed that the smoke of it did opacate, and as to sense so fill the whole cavity of the Glass, though its Basis were eight inches, its perpendicular height above twenty inches, and its figure far more capacious than if it were conical, and this smoke, not containing itself within the vessel, issued out at two or three little intervals, that were purposely left between the orifice of the vessel and the plate that lay upon it. This cover we then removed, that we might observe how long the smoke would continue to ascend; which we found it would do for about half a quarter of an hour, and during near half that time, (viz. the three first minutes) the continually ascending smoke seemed to be, at its going out, of the same Diameter with the orifice at which it issued; and it would ascend sometimes a foot, sometimes half a yard, sometimes two foot or more into the Air, before it would disperse and vanish into it.  
Now if we consider, that the cavity of this round Orifice was two inches in Diameter, how many myriads of visible Corpuscles may we easily conceive thronged out at so large an outlet in the time abovementioned, since they were continually thrusting one another forwards? And into so many visible Particles of smoke must we admit, that the half Grain of Powder was shattered, beside those multitudes, which, having been turned into actual flame, may probably be supposed to have suffered a comminution, that made them become invisible. And though I shall not attempt so hopeless a work, as to compute the number of these small Particles, yet to make an estimate whereby it would appear to be exceeding great, I thought fit to consider, how great the Proportion was between the spaces, that to the Eye appeared all full of smoke, and the dimensions of the Powder that was resolved into that smoke. Causing then the Glass to be filled with common Water, we found it to contain above two and twenty Pints of that liquor, and causing one of those measures to be weighed, it was found to weigh so near a pound (of sixteen ounces,) that the computation of the whole Water amounted to at least 160000 grains, and consequently 320000 half grains. To which if we add, that this Gunpowder would readily sink to the bottom of Water, as being (by reason of the Saltpetre and Brimstone, that make up at least six parts of seven of it) in specie heavier than it, and in likelihood twice as heavy, (for 'tis not easy to determine it exactly,) we may probably guests the space to which the smoke reached to exceed 500000 times that, which contained the unfired Powder; and this, though the smoke, being confined in the vessel, was thereby kept from diffusing itself so far as by its streaming out it seemed likely that it would have done.  
To these Instances from Inanimate Bodies I shall subjoin one more taken from Animals. Whereas then men have with Reason wondered, that so small a Body as a Cheese-mite, which by the naked Eye is oftentimes not to be taken notice of, unless it move, (if even then it be so,) should by the Microscope appear to be an Animal furnished with all necessary parts; whereas this, I say, has given just occasion to conclude, that the Corpuscles that make up the parts of so small an Animal, must themselves be extremely small; I think the Argument may be much improved by the following Consideration. Those that have had the Curiosity to open from time to time Eggs that are sat upon by a hatching Hen cannot but have observed, how small a proportion in reference to the bulk of the whole Egg the Chick bears; when that, which the Excellent Harvey calls Punctum saliens, discloses the motion of the Heart, and the colour of the Blood; and that even about the seventh or eighth day the whole Chick now visibly formed, bears no great proportion to the whole Egg, which is to supply it with Aliment, not only for its nourishment, but speedy growth for many days after.  
To apply this now to the matter in hand, having several times observed and shown to others, that Cheese-mites themselves are generated of Eggs, if we conceive, that in these Eggs, as in ordinary one, the Animal at its first formation bears but a small proportion to the bulk of the whole Egg, the remaining part being to suffice for the food and growth of the Embryo probably for a pretty while; since, if an Ingenious person, that I desired to watch them, did not mis-inform me, they used to be about ten or twelve days in hatching; this whole Egg itself will be allowed to be but little in reference to the Mite it came from, how extremely and unimaginably minute may we suppose those parts to be, that make up the Alimental Liquors, and even the Spirits, that passing through the Nerves or Analogous parts, serve to move the Limbs and Sensories of but, as it were, the Model of such an Animal, as, when it rests, would not (perhaps) itself to the naked Eye be so much as visible; and in which we may presume the nobler sort of stabler parts to be of an amazing slenderness, if we consider, that, though in other hairy Animals, the Optic or some other of the larger Nerves do, I know not how many times, in thickness and circuit surpass a hair of the same Animal; yet in a Cheese-Mite, though none of the largest of those Creatures, we have divers times manifestly seen, as is before intimated, single Hairs that grow upon the Legs.  
Another way there is, that I employed to give men cause to think, that the invisible Effluvia of Bodies that wander through the Air may be strangely minute; and this was, by showing how small a fragment of matter may be resolved into particles minute enough to associate themselves in such numbers with a Fluid so much more dense than Air, as Water is, as to impart a determinate Colour to the whole liquor. What I did with Cocheneel in prosecution of this design, my Experiments about Colours may inform you; but I shall now relate the success of an attempt made another way, for which perhaps some of your friends the Chemists will thank me; though I was not solicitous to carry on the Experiment very far with Gold, not because I judged that less divisible into a number of coloured particles, but because I found, as I expected, that the paleness of the native colour of the Gold may make it in the end less conspicuous, though, if I had then had by me a Menstruum, as I sometimes had, that would dissolve Gold blood-red, perhaps the experiment with Gold would have surpassed that, which 'tis now time I should begin to relate, as soon as I have hinted to you by the way, that, for variety's sake, I made a trial with Copper calcined per se, that I might not be accused of having omitted to employ a Metal whose Body Chemists suppose to be much opened by Calcination. And though the event were notable even in Comparison of that of the experiment made with Cocheneel, yet my conjectures inclined me much to prefer the way described in the following Account.  
We carefully weighed out in a pair of tender Scales one grain of Copper not-calcined, but barely filled; and because, as we made choice of this Metal for its yielding in most Menstruums a Blue, which is a deep and conspicuous colour; we also chose to make a solution, not in Aqua fortis or Aqua regis, but the Spirit of Sal Armoniac (as that is an urinous Spirit,) having found by former trials, that this Menstruum would give a far deeper solution than either of the others. This lovely Liquor, of which we used a good proportion, that all the Copper might be throughly dissolved, we put into a tall cylindrical Glass of about four inches in Diameter, and by degrees poured to it of distilled Water, which is more proper in this case than common Water, which has oftentimes an inconvenient Saltishness, till we had almost filled the Glass, and saw the colour grow somewhat pale, without being too dilute to be manifest; and then we warily poured this liquor into a conical Glass, that it might be the more easy to fill the vessel several times to the same height. This conical Glass we filled to a certain mark four times consecutively, weighing it, and the liquor too, as often in a pair of excellent Scales purposely made for Statical experiments, and which, though strong enough to weigh some pounds in each Scale, would, when not too much loaden, turn with about one grain. These several weights of the Glass, together with the contained liquor, we added together, and then carefully weighing the empty Glass again, we deducted four times its weight from the abovementioned sum, and thereby found the weight of the liquor alone, to be that, which reduced to grains amounted to 28534; so that a grain of Copper, which is not full half so heavy in specie as fine Gold, communicated a Tincture to 28534 times its weight.  
But now if you please to take notice, that the scope of my Experiment was to show, into what a number of parts one grain of Copper might be divided, you will allow me to consider, as I did, that this multitude of parts must be estimated by the Proportion, not so much in weight as in bulk, of the ting Metal to the tinged Liquor, and consequently, since that divers Hydrostatical trials have informed me, that the weight of Copper to the weight of Water of the same bulk is proximè as 9 to 1, a grain-weight of Copper is in bigness but the ninth part of as much Water as weighs a grain; and so the formerly mentioned number of the grains of Water must be multiplied by 9, to give us the Proportion between the ting and tinged Bodies, that is, that a single grain of Copper gave a blewness to above 256806 parts of limpid Water, each of them as big as it. Which, though it may seem stupendious, and scarce credible; yet I thought fit to prosecute the Experiment somewhat farther, by pouring all the liquor out of the tall cylindrical Glass into another clean vessel, whence filling the conical Glass twice, and emptying it as often into the same cylindrical Glass, the third time I filled the conical Glass with colourless distilled Water, and pouring that also into the cylindrical Glass, we found the mixed liquor to have yet a manifest, though but a pale, blewness. And, lastly, throwing away what was in the cylindrical Glass, we poured into it, out of the same conical Glass, equal parts of distilled colourless Water, and of the tincted Liquor we had formerly set apart in the clean Vessel, and found, that, though the colour were very faint and dilute, yet an attentive Eye could easily discern it to be bluish; and so it was judged by an intelligent Stranger that was brought in to look upon it, and was desired to discover of what colour he thought it to be. Whereby it appears, that one grain of Copper was able to impart a colour to above double the quantity of Water above mentioned.  
This Experiment I have allowed myself to be the longer and more particular in relating, both because I know not, that any such has been hitherto either made or attempted, and because it will probably gratify your Chemists, that love to have the Tinctures of Metals believed very diffusive; and because, if Circumstances were not added, it would seem to you as well incredible, as perhaps it does seem stupendious, that a portion of matter should be able to impart a conspicuous colour to above 256806 times its bulk of Water, and a manifest tincture to above 385200, (for so it did, when the proportion of the tinging part to the whole mixture, made of it and the untinged part, was as 2 to 31,) and a faint, but yet discernible and distinguishable colour to above five hundred and thirteen thousand six hundred and twenty times its bulk of Water.   

CHAP. IU.  
IT were easy for me (Pyroph.) to give you several Instances, to show, that the Effluvia of Liquors may get in at the Pores of Bodies that are reputed of a close Texture, but I shall at present forbear to mention such Examples, not only because they belong to another place 
* A Discourse of Pores of Bodies, and Figures of Corpuscles. , where I take notice of them, but because many such would not seem so remarkable, nor be so considerable to our present purpose, as a few taken from Bodies that are not Fluid.  
And first, it is delivered by Writers of good credit, that several Persons, (for the Experiment does not hold in all) by barely holding for some time dried Cantharideses in their hands, have been put to much pain at the neck of the Bladder, and have had some other parts ministering to the secretion of Urine sensibly injured. That this is true, I am induced to believe, by what I have elsewhere related to you of the unwelcome experiment I had of the effect of Cantharideses applied but outwardly to my neck, and that unknown to me, upon the Urinary Passages; and that these Operations are due to material Effluxes, which, to get into the Mass of Blood, must pass through the pores of the skin, you will not, I presume, put me to prove.  
Scaliger Exercit. 186. relates, that in Gascony, his Country, there are Spiders of that virulency, that, if a man treads upon them to crush them, their poison will pass through the very soles of his Shoes. Which story, notwithstanding the Reputation of the Author, I should perhaps have left unmentioned, because of a much stranger about Spiders, which he relates in the same Section, but that I met with one that is analogous in the diligent Piso's late History of Brasile; where, having spoken of another venomous Fish of that Country, and the Antidotes he had successfully used to cure the hurts it inflicts, he proceeds to that Fish the Natives call Amoreatim, of one kind whereof, called by the Portugal's Peise Sola, his words are these; Quae mira sanè efficacia non solum manum vel levissimo attactu, sed & pedem, licet optimè calceatum, Piscatoris incautè pisciculum conterentis, Paralysi & Stupore afficit, instar Torpedinis Europaeae, sed minus durabili. Lib. 5. cap. 14.  
What I shall ere long have occasion to tell you of the power of the Torpedo, and some other Animals, to affect the Hand and Arm of him that strikes them, seems applicable to the matter under consideration: For, though their affecting the striker at a distance, may very well be ascribed to the stupefactive or other venomous Exhalations that expire (and perhaps are as it were darted) from the Animal irritated by the stroke, and are breathed in together with the air they infect; yet their benumbing, or otherwise affecting the Arm that struck them, rather than any other part, seems to argue, that the poisonous steams get in at the pores of the skin of the Limb, and so stupefy, or otherwise injure, the nervous and musculous parts of it.  
Other Examples belonging to this Section may be referred hither from divers other places in these Papers about Occult Qualities, and therefore I shall only add here that most remarkable Proof, That some Emanations, even of solid Bodies, may be subtle enough to get through the pores, even of the closest Bodies; which is afforded us by the Effluvia of the Loadstone, which are by Magnetical Writers said to penetrate without resistance all kind of Bodies. And though I have not tried this in all sorts, yet having tried it in Metals themselves, I am apt to think, the general Rule admits of very few Exceptions, especially, if that can be fully made out, which is affirmed about the perviousness of Glass to the Effluxions of the Loadstone. For, not only Glass is generally reputed to be as close a Body as any is, but (which weighs more with me) I have by Trials purposely made, had occasion to admire the closeness of very thin pieces of Glass. But the reason why I just now expressed myself with an If, was, because I was not entirely satisfied with the Proof wont to be acquiesced in, of the perviousness of Glass; namely, that in Dial's and Sea-Compasses that are covered with plates of Glass, the Needle may be readily moved to and fro by a Loadstone held over it. For these Plates being commonly but fastened on with Wax, or at best with Cement, a Sceptic may pretend, that the magnetical Effluvia pass not through the Glass, but through that much more pervious matter, that is employed to secure the Commissures, only from the access of the Air. To put then the matter past doubt, I caused some Needles to be Hermetically sealed up in Glass-pipes, which being laid upon the surface of water (whereon by reason of the bigness of the Cavities they would lightly float,) the included Needles did not only readily feel the virtue of an externally applied Loadstone, (though but a weak one) but complied with it so well, that I could easily, by the help of the Needle, lead, without touching it, the whole Pipe, this was shut up in, to what part of the surface of the water I pleased. And I also found, that by applying a better Loadstone to the upper part of a sealed Pipe, and a Needle in it, I could make the Needle leap up from the lower part as near to the Loadstone as the interposed Glass would give it leave.  
But I thought it would be more considerable, to manifest that the Magnetical Effluvia, even of such a dull Body, as the Globe of the Earth, would also penetrate Glass. And though this seem difficult to be tried, because no ordinary Loadstone, nor any Iron touched by it, was to be employed to work on the included Iron; yet I thought fit to attempt it after this manner: I took a cylindrical piece of Iron of about the bigness of ones little finger, and between half a foot and foot long, (for I had formerly observed, that the quantity of unexcited Iron furthers its Operation upon excited Needles,) and having Hermetically sealed it up in a Glass-pipe but very little longer than it; I supposed, that if I held it in a perpendicular posture; the Magnetical Effluvia of the Earth, penetrating the Glass, would make the lower extreme of the Iron answerable to the North Pole; and therefore having applied this to the point of the Needle in a Dial, or Sea-Compass, that looked toward the North, (for Authors mean not all the same thing by the Northern Pole of a Needle or Loadstone,) I presumed it would, according to the Laws Magnetical (elsewhere mentioned) drive it away, which accordingly it did. And having for farther trial inverted the included Iron, (so that the end which was formerly the lowermost, was now the uppermost) and held it in a perpendicular posture just under the same point of the Needle, that extreme of the Iron-rod, which before had driven away this point, being by this inversion become (in a manner) a South-Pole, did (according to the same Laws) attract it: By which sudden change of Poles, merely upon the change of situation, it also appeared, that the Iron owed its Virtue only to the Magnetism of the Earth, not that of another Loadstone, which would not have been thus easily alterable. And this Experiment I the more particularly relate, because this is not the only place, where I have occasion to make use of it.   

CHAP. V.  
ANother proof of the great Subtlety of Effluviums, may be taken from the small Decrement of weight or bulk that a Body may suffer by parting with great store of such Emanations.  
That Bodies, which infused in Liquors impregnate them with new Qualities suitable to those of the immersed Bodies, do so by imparting to them somewhat of their own Substance, will, I presume, be readily granted by those that conceive not, how one Body should communicate to another a solitary and naked Quality, unaccompanied by any thing Corporeal to support and convey it. But I would not have you think, Pyrophilus, that the only matter of fact I have to countenance this notion, is that Experiment, which has convinced divers Chemists and Physicians, otherwise not friends to the Corpuscular Philosophy, that Medicines may operate without any consumption of themselves. For, though divers of these, some of them Learned men, have confidently written, that Glass of Antimony and Crocus Metallorum, being either of them infused in a great proportion of Wine, will make it vomitive; and if that liquor be poured off, and new be poured on, every new portion of such liquor will be impregnated with the same virtue, and this though the liquor be changed a thousand times, and yet the Antimonial Glass or Crocus will continue the same as well in weight as virtue; and though thence some of them, especially Chemists, argue, that some Metals without imparting any thing substantial, but only, as Helmont speaks of some of his Arcana, by irradiation: Yet, I confess, I have some doubts, whether the Experiment have been competently tried, and shall not fully acquiesce in what has been said, till some skilful Experimenter deliver it upon his own Trial, and acquaint us too, with what Instruments and what Circumspection he made it. For, besides that the Ingeniousest Physicians I have questioned about it, acknowledged the Taste, and sometimes the Colour of the Wine to be altered by the infused Mineral, I could not acquiesce in the affirmation of an ordinary Chemist or Apothecary, or even Physician, if he should barely aver, that he had weighed an Antimonial Medicine before 'twas put to infuse, and after the infusion ended, and observed no decrement of weight. For I have had too much experience (as I elsewhere mention) of the difficulty of making exact Statical trials; not to know, that such Scales, as are wont to be employed by Chemists and Apothecaries in weighing Drugs, are by no means fit to make trials with the nicety which that I am speaking of requires: It being easy, even with the better sort of such unaccurate Scales, especially if they be not suspended from some fixed thing, but held with the hand, to mistake half a grain or a grain; and perhaps a greater quantity, and at least more than by divers of the Experiments of this Essay appears necessary to be spent upon the impregnating of a considerable proportion of Liquor with Corporeal Effluxions. Besides, that if, when the beaten Crocus or Glass be taken out of the Wine to be weighed again, the Experimenter be not cautious enough to make allowance for the Liquor that will adhere to the Medicament, 'tis plain that he may take notice of no decrement of weight, though there may be really Effluviums of the Mineral amounting to several grains, imbibed by the Liquor. And though he be aware of this, and dry the powder, yet 'tis not so easy, even for a skilful man, to be sure that none of the more viscous particles of the Liquor stick to the Mineral, and being sensible upon the Balance, though not to the Eye or Hand, repair the recess of those emetic Corpuscles that diffused themselves into the Menstruum. And the sense of these difficulties put me upon the attempting to make so noble an Experiment with excellent Scales, and the care that it deserves: But after a long trial, an unlucky accident frustrated at last my endeavours. But though, till competent Relators give us an account of this matter upon their own trial, and repeat the Infusion very much oftener, than, for aught I find, any man has yet done, I must not acquiesce in all that is said of the Impregnation of Wine or other Liquors by Antimonial Glass and Crocus Metallorum; yet that after divers repeated Infusions the Mineral substance should not be sensibly diminished in bulk or virtue, may well suffice to make this Instance, though not the only or chief that may be brought for our purpose, yet a pertinent one to it. For that there is a powerful Emetic Quality imparted to the Liquor, is manifest by experience; and that the Mineral does not impart this virtue as 'twere by irradiation, but by substantial effluxion, seems to me very probable; not only because I conceive not, how this can be done otherwise, but because, as 'tis noted above, the Wine does oftentimes change colour by being kept a competent time upon the Mineral, as if it drew thence a Tincture; and even when it is not discoloured, I think it unsafe to conclude, that the Menstruum has not wrought upon it. For I have kept good Spirit of Vinegar for a considerable time upon finely powdered Glass of Antimony made per se, without finding the Spirit to be at all tinging, though 'tis known, that Antimonial Glass is soluble in Spirit of Vinegar, as mine afterwards appeared to be, by a longer digestion in the same Liquor. But there may be a great number of minute particles dissolved in the Menstruum before they be numerous enough to change the Colour of it. And with this agrees very well what is observed, That though too great a quantity of the prepared Antimony be put into the liquor, yet it will not be thereby made too strongly Emetic. For the Wine, being a Menstruum, will, like other Menstruums, be impregnated but to a certain measure, without dissolving the overplus of the matter that is put into it. And Mars, which is a harder and heavier body than Glass of Antimony, is itself in part soluble in good Rhenish or other white Wine, (and that in no long time,) and sometimes even in Water.  
I do not therefore reject the Emetic Infusion, as unfit to have a place in this Chapter, but till the experiment have been a little more accurately made, I think it inferior, as to our purpose, to some of the Instances to be met with in the next Chapter, and perhaps also to that mentioned by Helmont, and tried by more than one of my Acquaintance, concerning the Virtue of kill Worms, that Mercury imparts to the water or wine wherein it has been long enough infused, or else for a while decocted. Though Quicksilver given in substance is commended as an effectual Medicine against Worms, not only by many professed 
* As Quercetanus, Libavius, Zabata, Burggravius.  Spagyrists, but by divers 
** As Vidius, Paraeus, Caesalpinus, etc.  Methodists of good Note. And though, some other things, Chemical and Philosophical, keep me from being of their opinion, who think that in this case the Mercury impregnates the liquor as it were by Irradiation, rather than in a Corporeal manner, yet the Eye does not perceive, that even limpid water takes any thing from clean and well purged Mercury, which we know that divers corrosive liquors themselves will not work upon.  
To this Instance I must add one that is yet freer from exceptions, which is, that having for Curiosity sake suspended in a pair of exact Scales, that would turn with a very small part of a grain, a piece of Ambergris bigger than a Walnut, and weighing betwixt an hundred and sixscore grains, I could not in three days and a half that I had opportunity to make the trial, discover, even upon that Balance, any decrement of weight in the Ambergris; though so rich a perfume, lying in the open Air, was like in that time to have parted with good store of odoriferous Steams. And a while after suspending a Lump of Assa foetida five days and a half, I found it not to have sustained any discernible loss of weight, though, in spite of the unfavourable cold weather, it had about it a neighbouring Atmosphere replenished with foetid exhalations. And when twelve or fourteen hours after, perhaps upon some change of weather, I came to look upon it, though I found that in that time the Aequilibrium was somewhat altered, yet the whole Lump had not lost half a quarter of a grain; which induced me to think, that there may perhaps be Steams discernible even by our Nostrils, that are far more subtle than the odorous exhalations of Spices themselves. For, having in very good Scales suspended in the Month of March an ounce of Nutmegs, it lost in about six days five grains and a half. And an ounce of Cloves in the same time lost seven grains and five eigths.  
You will perhaps wonder, why I do not prefer to the Instances I make mention of in this Chapter, that which may be afforded by the Loadstone, that is acknowledged continually to emit multitudes of Magnetical Steams without decrement of weight. But though I have not thought fit to pass this wholly under silence; yet I forbear to lay so much stress on it, not only because my Balances have not yet satisfied me about the Effluvia of Lodestones, (for I take them not all to be equally diffusive of their Particles;) but because I foresee it may be doubted, whether Lodestones, like odorous Bodies, do furnish afresh of their own, all the Corpuscles▪ that from time to time issue from them? Or, whether they be not continually repaired, partly by the return of the Magnetical Particles to one Pole that sallied out of the other; and partly by the continued passage of Magnetical matter (supplied by the Earth or other Mundane Bodies) it make the Pores or Channels of the Loadstone their constant Thorow-fares.  
I doubt not but it will make it more probable, that a small Quantity of matter being scattered into invisible Effluvia may be exceedingly rarified and expanded, if it can be made appear, that this little portion of matter shall, for a considerable time, emit multitudes of visible parts, and that in so close an order among themselves, as to seem in their Aggregate but one entire liquor, endowed with a stream-like motion, and a distinct superficies, wherein no interruption is to be seen, even by an Eye placed near it. To devise this Experiment, I was induced, by considering, that hitherto all the (total) dissolutions that have been made of Pigments, have been in liquors naturally cold, and consisting probably of much less subtle, and certainly of much less agitated parts, than that fluid aggregate of shining matter that we call Flame; whereas I argued, that if one could totally dissolve a Body composed of parts so minute as those of a Metal into actual Flame, and husband its Flame so, as that it should not immoderately waste, I should thereby dissolve the Metal in a far more subtle Menstruum than our common water, or Aqua fortis, or Aqua Regis, or any other known Menstruum I have yet employed. And consequently the attenuation and expansion of the Metal in this truly Igneous Menstruum would much surpass not only what happens in ordinary Metalline solutions, but possibly also what I have noted in the third Chapter of this Essay, about the strange diffusion of Copper dissolved in Spirit of Urine and Water. In prosecution of this design, I so prepared one single grain of that Metal, by a way that I elsewhere teach, that it was dissolved in about a spoonful of an appropriated Menstruum. And then having caused a small Glass-lamp to be purposely blown to contain this liquor, and fitted it with a socket and wieck, we lighted the Lamp, which, without consuming the wieck, burnt with a flame large enough and very hot, and seemed to be all the while of a greenish blue, as if it were a but finer and shining solution of Copper. And yet this one grain of prepared Metal tinged the flame that was from moment to moment produced, during no less than half an hour and six minutes. And now if we consider, that in this flame there was an uninterrupted Succession of multitudes of coloured Particles newly extricated, and flying off in every of those many parts wherein a minute of time may either actually or mentally be divided; and, if we consider Flame as a light and very agitated body, passing with a stream upwards through the Air, and if we also consider the quantity of liquor that would (as I shall by and by tell you) run through a Pipe of a much lesser diameter than that Flame, within the compass of the forementioned time: What a quantity of the streaming fluid we call Flame, if it could have been preserved and collected into one Body, may we suppose would appear to have issued out of one grain of Copper in the space of thirty-six minutes; and what a multitude of metalline Corpuscles may we suppose to have been supplied for the ting of that Flame during so long a time? since a Cylindrical stream of water falling but through a very short Pipe of glass, constantly supplied with liquors, did pass at such a rate, that, though the aqueous Cylinder seemed more slender by half, (or perhaps by two thirds or better) than the Flame, yet we estimated, by the help of a Minute-watch and a good pair of Scales, that, if I had had conveniencies to let it run long enough, the water effluxed in thirty-six minutes (the time of the Flames duration) would have amounted to above nine gallons, or, (reckoning a pint of water to contain a pound of sixteen ounces) seventy-two pounds.   

CHAP. VI  
THE last sort of Instances I shall propose to show the strange Subtlety of Effluvia, is of such, as discover the great quantity of space that may by a small quantity of matter, when rarified or dispersed, be either filled as to sense, or, at least, made (as they speak) the sphere of its activity.  
To manifest this Truth, and thereby as well confirm the foregoing Chapter, as make out what is designed in this, I shall endeavour to show, and help your imagination to conceive, how great a space may be impregnated with the Effluxions of a Body, oftentimes without any sensible, and oftener without any considerable decrement in bulk or weight of the Body that affords them. And in order to this, though I shall not pretend to determine precisely how little the substances, I am to instance in, would waste upon the Balance, because you will very easily see they are not that way to be examined; yet I presume, you will as easily grant, that the decrement of weight would be but inconsiderable, since of such light substances the loss even of bulk is so; which last clause I shall now attempt to make good, by setting down some Observations, partly borrowed from the writings of approved Physicians, and partly that my friends and I have made about the durable Evaporation of such small particles of the Effluxions of Animals, as are actually not to be discerned by the Eye to have any of those things sticking to them, which are so very long in flying successively away.  
'Tis wont to be somewhat surprising to men of Letters, when they first go a hawking with good Spaniels, to observe, with how great sagacity those dogs will take notice of, and distinguish by the scent, the places where Partridges, Quails, etc. have lately been. But I have much more wondered at the quick scent of an excellent Setting-dog, who by his way of ranging the fields, and his other motions, especially of his Head, would not only intimate to us the kinds of game, whose scent he chanced to light on, but would discover to us where Partridges had been (though perhaps without staying in that place) several hours before, and assist us to guests how long they had been gone before we came.  
I have had strange answers given me in Ireland, by those who make a gain if not an entire livelihood by killing of Wolves in that Country, (where they are paid so much for every head they bring in) about the sagacity of that peculiar race of dogs they employ in hunting them; but not trusting much to those Relators, I shall add, that a very sober and discreet Gentleman of my acquaintance, who has often occasion to employ Bloodhounds, assures me, that if a man have but passed over a field, the scent will lie (as they speak) so as to be perceptible enough to a good dog of that sort for several hours after. And an ingenious Hunter assures me, that he has observed, that the scent of a flying and heated Deer will sometimes continue upon the ground from one day to the next following.  
And now we may consider these three things; First, That the substance left upon the grass or ground by the transient tread of a Partridge, Hare, or other animal, that does but pass along his way, does probably communicate to the grass or ground but some of those Effluxions, that transpire out of his feet, which being small enough to escape the discernment of the Eye, may probably not amount to one grain in weight, or perhaps not to the tenth part of it. Next, That the parts of fluid Bodies, as such, are perpetually in motion, and so are the invisible particles that swim in them, as may appear by the dissolution of Salt or Sugar in water, and the wandering of aqueous Vapours through the Air, even when the Eye perceives them not. And thirdly, That though the Atmosphere of one of these small parcels of the exhaling matter we are speaking of, may oftentimes be exceeding vast in comparison of the emittent Body, as may be guessed by the distance, at which some Setters, or Bloodhounds, will find the scent of a Partridge, or Deer; yet in places exposed to the free air or wind, 'tis very likely that these steams are assiduously carried away from their Fountain, to maintain the forementioned Atmosphere for six, eight, or more hours, that is, as long as the scent has been observed to lie, there will be requisite a continual recruit of steams succeeding one another And that so very small a portion of matter as that which we were saying the foams of these steams may be judged to be, being sensibly to impregnate an Atmosphere incomparably greater than itself, and supply it with almost continual recruits, we cannot but think, that the steams it parts with, must be of an extreme and scarce conceivable minuteness.  
And we may further consider, that the substances, which emit these steams, being such as newly belonged to Animals, and were, for the most part, transpired through the pores of their feet, must be in likelihood a far more evaporable and dissipable kind of Bodies than Minerals or adust Vegetables, such as Gunpowder is made of; so that if the grains of Gunpowder emit Effluviums' capable of being by some Animals perceived at a distance by their smell, one may probably suppose, that the small grains of this powder may hold out very many times longer to supply an Atmosphere with odorable steams, than the Corpuscles left on the ground by transient Animals.  
Now though it be generally agreed on, that very few Birds have any thing near so quick a sense of smelling as Setting-dogs or Bloodhounds, yet that the odour of Gunpowder, especially when assisted by the steams of the Caput mortuum of Powder formerly fired in the same Gun, may be Fowls be smelled at a notable distance, particularly when the wind blew from me towards them, I often persuaded myself I observed, especially as to Crows, when I went a shooting; and was confirmed in that opinion, both by the common Tradition, and by sober and ingenious persons much exercised in the kill of Wildfowl, and of some fourfooted Beasts.  
I had forgotten to take notice of one Observation of the experienced Julius Palmarius: Whence we may learn, that Beasts may leave upon the Vegetables, that have touched their bodies for any time, such Corpuscles, as, though unheeded by other Animals, may, when eaten by them, produce in them such diseases as the infected Animals had. For this Author writes in his useful Tract de morbis Contagiosis, that he observed Horses, Beefs, Sheep and other Animals, to run mad upon the eating of some of the straw on which some mad Swine had lain.  
And now to resume and prosecute our former discourse, you may take notice, that the Effluvia, mentioned to have been smelled by Animals, are, though invisible, yet big enough to be the objects of sense; so that 'tis not improbable, that, among the steams that no sense can immediately perceive, there should be some far more subtle than these, and consequently capable of furnishing an Atmosphere much longer, without quite exhausting the effluviating matter that afforded them.  

* Lib. 6. Observ. 22.  Forestus, an useful Author, recites an Example of Pestilential contagion long preserved in a Cobweb.  
Alexander Benedictus writes also, that at Venice a Flock-bed did for many years harbour a pestiferous malignity to that degree, that when afterwards it came to be beaten, it presently infected the bystanders with the Plague.  
And the Learned 
* Lib. 4. de Eeb. cap. 3.  Sennertus himself relates, that in the year 1542. there did in the City of Uratislavia (vulgarly Breslaw,) where he afterwards practised Physic, die of the Plague, in less than six Months, little less than six thousand men, and that from that time the Pestilential Contagion was kept folded up in a linen cloth about fourteen years, and at the end of that time being displayed in another City, it began a Plague there, which infected also the neighbouring Towns and other places.  

* Libr. 3. Con. 17.  Trincavella makes mention of a yet lastinger Contagion, (which occasioned the death of ten thousand persons) that lay lurking in certain Ropes, with which at Justinopolis those that died of the Plague had been let down into their Graves.  
But, though none of these Relations should to some Critics appear scarce credible, it may be objected, that all these things, wherein this Contagion resided, were kept close shut up, or at least were not exposed to the Air. Wherefore having only intimated, that the exception, which I think is not irrational, would, though never so true, but lessen the wonder of these strange Relations, without rendering them unfit for our present purpose, I shall add, that though 'tis the opinion of divers Learned Physicians, that the matter harboring Contagion cannot last above Twenty or a few more days, if the Body it adheres to be exposed to the free air and the wind, and though I am not forward to deny, that their judgement may hold in ordinary cases; yet I must not deny neither, that a Contagion may sometimes happen to be much more tenacious and obstinate: Of which I shall give but that one, almost recent instance observed by the Learned 
* Lib. 4. de Peste.  Dimmerbrook in his own Apothecary, who having but removed with his foot, from one side to the other of a little Arbour (in his Garden) some straw, that had lain under the Pallet, on which near eight Months before a Bed had lain, wherein a Servant of the Apothecaries, that recovered, had been sick of the Plague; the infectious steams presently invaded the lower part of his leg, and produced a pungent pain and blister, which turned to a pestilential Carbuncle, that could scarce be cured in a Fortnight after, though during that time the Patient were neither feverish, nor, as to the rest of his Body, ill at ease. This memorable instance, together with some others of the like kind, that our Author observed in the same City (of Nimmegen) obtained, not to say, extorted, even from him, this Confession; which I add, because it contains some considerable, and not yet mentioned Circumstances of the recited case: Hoc exemplo Medicorum Doctrina de Contagio in fomite latente satis confirmatur. Mirum tamen est, hoc Contagium tanto tempore in praedicto stramine potuisse subsistere, utpote quod tota hyeme ventis & pluviis, (he adds in another place) nivibus & frigori, expositum fuisset.  
And now I will shut up this Chapter with an instance, that some will think, perhaps, no less strange than any of the rest, which is, that though they that are skilful in the perfuming of Gloves, are wont to imbue them with but an inconsiderable quantity of odoriferous matter, yet I have by me a pair of Spanish Gloves, which I had by the favour of your fair and virtuous Sister (F.) that were so skilfully perfumed, that partly by her, partly by those, that presented them her as a Rarity, and partly by me, who have kept them several Years, they have been kept about eight or nine and twenty years, if not thirty, and they are so well scented, that they may, for aught I know, continue fragrant divers years longer. Which instance, if you please to reflect upon, and consider, that such Gloves cannot have been carried from one place to another, or so much as uncovered (as they must often have been) in the free Air, without diffusing from themselves a fragrant Atmosphere, we cannot but conclude those odorous Steams to be unimaginably subtle, that could for so long a time issue out in such swarms, from a little perfumed matter lodged in the pores of a Glove, and yet leave it richly stocked with particles of the same nature; though, (especially by reason of some removes, in which I took not the Gloves along with me,) I forgot ever since I had them, to keep them so much as shut up in a Box.    

Of the GREAT EFFICACY OF EFFLUVIUMS: BY The Honourable ROBERT boil.   

OF THE GREAT EFFICACY OF EFFLWIUMS'.  

CHAP. I.  
THey that are wont in the Estimates they make of Natural Things, to trust too much to the negative informations of their Senses, without sufficiently consulting their Reason, have commonly but a very little and slight opinion of the Power and Efficacy of Effluviums; and imagine that such minute Corpuscles (if they grant that there are such,) as are not, for the most part of them, capable to work upon the tenderest and quickest of Senses, the Sight, cannot have any considerable Operation upon other Bodies. But I take this to be an error, which, as it very little becomes Philosophers, so it has done no little prejudice to Philosophy itself, and perhaps to Physick too. And therefore though the nature of my design at present did not require it, yet the importance of the subject would invite me to show, That this is as ill-gounded as prejudicial a Supposition.  
And indeed if we Consider the subject attentively, we may observe, That though it be true, that, caeteris paribus, the greatness of Bodies doth, in most cases, contribute to that of their Operation upon others, yet Matter or Body being in its own precise nature an unactive or moveless Subject, one part of the Mass acts upon another but upon the account of its Local Motion, whose Operations are facilitated and otherwise diversified by the Shape, Size, Situation and Texture both of the Agent and of the Patient. And therefore if Corpuseles, though very minute, be numerous enough, and have a competent degree of motion, even these small Particles, especially if fitly shaped, when they chance to meet with a Body, which the congruity of its texture disposes to admit them at its Pores, and receive their either friendly or hostile impressions, may perform such things in the patient, as visible and much grosser Bodies, but less conveniently shaped and moved, would be utterly unable (on the same Body) to effect.  
And that you may with the less difficulty allow me to say, that the Effluviums of Bodies, as minute as they are, may perform Considerable things, give me leave to observe to you, that there are at least six ways, by which the Effluviums of a Body may notably operate upon another; namely, 1. By the great number of emitted Corpuscles. 2. By their penetrating and pervading nature. 3. By their celerity, and other Modifications of their Motion. 4. By the congruity and incongruity of their Bulk and Shape to the Pores of the Bodies they are to act upon. 5. By the motions of one part upon another, that they excite or occasion in the Body they work upon according to its Structure. And 6ly, By the Fitness and Power they have to make themselves be assisted, in their Working, by the more Catholic Agents of the Universe. And though it may perhaps be sufficiently proved, that there are several cases wherein a Body that emits Particles, may act notably upon another Body by this or that single way of those I have been naming; yet usually the great matters are performed by the association of two, three or more of them, concurring to produce the same Effect. Upon which score when I shall in the following Paper refer an Instance or a Phenomenon to any one of the forementioned Heads, I desire to be understood as looking upon that but as the Head, to which it chiefly relates, without excluding the rest.   

CHAP. II.  
TAking those things for granted, that have, I hope, been sufficiently proved in the former Tract about the subtlety of Effluviums, I suppose it will readily be allowed, That the Emanations of a Body may be extremely minute; whence it may be rightly inferred, that a small portion of matter may emit great multitudes of them.  
Now that the great number of Agents may in many cases compensate their littleness, especially where they Act or Resist per modum unius, (as they speak,) men would perhaps the more easily grant, if they took notice to this purpose of some familiar Instances.  
We see that not only lesser Land-floods that overflow the neighbouring Fields, but those terrible Inundations that sometimes drown whole Countries, are made by Bodies singly so so small and inconsiderable as Drops of Rain when they continue to fall in those multitudes we call Showers.  
So the aggregates of such minute Bodies as grains of Sand being heaped together in sufficient Numbers, make Banks wherewith greatest Ships are sometimes split, nay and serve in most places for Bounds to the Sea itself.  
And though a single Corn of Gunpowder, or two or three together, are not of Force to do much mischief, yet two or three Barrels of those Corns taking Fire all together are able to blow up Ships and Houses, and perform prodigious things.  
But instead of multiplying such Instances, afforded by Bodies of small indeed but yet visible Bulk, I shall (as soon as I have intimated, that the abovementioned drops of Rain themselves consist of convening Multitudes of Vapours most commonly Invisible in their Ascent,) endeavour to make out what was proposed, by two or three Instances drawn from the Operations of Invisible particles.  
And first, we see, that though Aqueous Vapours be looked upon as the faintest and lest active Effluviums that we know of, yet when multitudes of them are in Rainy weather dispersed thorough the Air, and are thereby qualified to work on the Bodies exposed to it, their Operations are very considerable, not only in the dissolution of Salts, as Sea-Salt, Salt of Tartar, etc. and in the putrefactive changes they produce in many Bodies, but in the intumescence they cause in Oak and other solid Woods; as appears by the difficulty we often find in and before Rainy weather, to shut and open Doors, Boxes, and other Wooden pieces of work, that were before fit enough for the Cavities they had been adjusted to.  
I might here urge, that though the strings of Viols and other Musical Instruments are sometimes strong enough to sustain considerable weights, yet if they be left screwed to their full tension, (as it frequently happens) they are oftentimes by the supervening of moist weather made to break, not without impetuosity and noise. But it may suit better with my present aim, if I mention on this occasion, (what I elsewhere more fully take notice of:) Being desirous to try what a multitude even of Aqueous Steams may do, I caused a Rope that was long, but not thick, and was in part sustained by a Poultry, to have a Weight of Lead so fastened to the end of it, as not to touch the ground, and after the Weight had leisure allowed it to stretch the Cord as far as it could, I observed that in the moist weather the waterish particles, that did invisibly abound in the Air, did so much work upon and shorten the Rope, as to make it lift up the hanging Weight, which was, if I mis-remember not, about an hundred Pounds.  
The invisible Steams, issuing out of the Walls of a newly plastered or whited Room, are not sensibly prejudicial to those that do but transiently visit it, or make but a very short stay in it, though there be a Charcoal-fire in the Chimney; but we have many instances of persons, that by lying for a night in such Rooms, have been the next morning or sooner found dead in their Beds, being suffocated by the multitude of the noxious Vapours emitted during all that time.  
And here I think it proper to observe, That it may much assist us to take notice of the multitude of Effluvia, and make us expect great matters from them, to consider, that they are not emitted from the Body that affords them all at once, as Hail-shot out of a Gun, but issue from it as the Vaporous Winds do out of an Aeolipil well heated, or Waters out of a Springhead in continued Streams, wherein fresh parts still succeed one another; so that though as many Effluxions of a Body as can be sent out at one time were numerous enough to Act but upon its Superficial parts, yet the Emanation of the next minute may get in a little farther, and each smallest portion of time supplying fresh Recruits, and perhaps urging on the Steams already entered, the Particles may at length get into a multitude of the pores of the invaded Body, and penetrate it to the very innermost parts.   

CHAP. III.  
I Come now to show in the second place, That the subtle and penetrating nature of Effluviums, may in many cases cooperate with their multitude in producing notable effects; and that there are Effluviums of a very piercing nature, though we shall not now inquire upon what account they are so, we may evince by several Examples. For not only the invisible Steams of good Aqua Fortis and Spirit of Nitre do usually in a short time, and in the cold, so penetrate the corks wherewith the Glasses that contained them were stopped, as to reduce them into a yellow pap; but also the emanations of Mercury have been sometimes found in the form of coagulated, or even of running Mercury in the heads or very bones of those Gilders, or Venereal Patients, that have too long or too unadvisedly been exposed to the fumes of it, though they never took Quicksilver in its gross substance. Chemist's too often find in their Laboratories, that the steams of Sulphur, Antimony, Arsenic, and divers other Minerals, are able to make those stagger, or perhaps strike them down, that without a competent wariness unlute the Vessels wherein they had been distilled or sublimed; of which I have known divers sad Examples. And of the Penetrancy even of animal Steams we may easily be persuaded, if we consider, how soon in many Plagues the contagious, though invisible, Exhalations are able to reach the Heart, or infect other internal parts; though in divers of these cases the Blood helps to convey the infection, yet still the Morbific particles must get into the body before they can infect the mass of Blood. And in those stupefactions that are caused at a distance by the Terpedo, the parts mainly affected seem to be the Nervous ones of the Hand and Arm, which are of the most retired and best fenced parts of those members. And there is a Spirit of Sal Armoniac, that I make to smell to, whose invisible Steams, unexcited by heat, are of so piercing a nature, that not only they will powerfully affect the Eyes and Nostrils, and Throats, and sometimes the Stomaches too (yet without proving Vomitive,) of the Patients they invade, but also when a great cold has so clogged the organs of smelling, that neither sweet nor stinking odours would at all affect them, these piercing Steams have not only in a few minutes both made themselves a way, and which is more, so opened the passages, that soon after the Patient has been able to smell other things also. And by the same penetrating Spirit, a person of Quality was, some time since, restored to a power of smelling, which he had lost for divers Years, (if he ever had it equally with other men.) I could easily subjoin Examples of this kind, but they belong to other places. And here I shall only add, that the steams of Water itself assisted by warmth, are capable of dissolving the Texture of even hard and solid bodies, that are not suspected to be Saline; as appears by the Philosophical calcination (as Chemists call it) wherein solid pieces of Hartshorn are brought to be easily friable into powder, by being hung over waters, whilst their steams rise in distillation and without the help of Furnaces. The Exhalations, that usually swim every night in the air, and almost every night fall to the ground in the form of Dews (which makes them be judged Aqueous,) are in many places of the Torrid Zone of so penetrating a nature, that, as Eye-witnesses have informed me, they would in a very short time make Knives rust in their sheaths, and Swords in their scabbards, nay and Watches in their cases, if they did not constantly carry them in their pockets. And I have known even in England divers hard bodies, into which the Vapours swimming in the air have insinuated themselves, so far as to make them friable throughout. But of the penetration of Effluviums, I have given, in several places, so many instances, that 'tis not necessary to add any here. And therefore to show, that, as I intimated at the beginning of this Chapter, the Penetrancy and the multitude of Effluviums may much assist each other, I shall now subjoin; That we must not for the most part look upon Effluviums as swarms of Corpuscles, that only beat against the outsides of the Bodies they invade, but as Corpuscles, which by reason of their great and frequently recruited numbers, and by the Extreme smallness of their Parts, insinuate themselves in multitudes into the minute pores of the bodies they invade, and often penetrate to the innermost of them; so that, though each single Corpuscle, and its distinct action, be inconsiderable, in respect of the multitude of parts that compose the body to be wrought on; yet a vast multitude of these little Agents working together upon a correspondent number of the small parts of the body they pervade, they may well be able to have powerful effects upon the Body, that those parts constitute; as, in the case mentioned in the former Chapter, the Rope would not probably have been enabled to raise so great a weight, though a vehement Wind had blown against it, to make it lose its perpendicular straightness, but a vast multitude of Watery Particles, getting by degrees into the pores of the Rope, might, like an innumerable company of little wedges, so widen the pores as to make the thirds or splinters of Hemp, the Rope was made up of, swell, and that so forcibly, that the depending weight could not hinder the shortening of the Rope, and therefore must of necessity be raised thereby. And I have more than once known solid and even heavy Mineral Bodies, burst in pieces by the moisture of the Air, though we kept them within-doors carefully sheltered from the Rain.   

CHAP. IU.  
THat the Celerity of the motion of very minute Bodies, especially conjoined to their multitudes, may perform very notable things, may be argued from the wonderful effects of fired Gunpowder, Aurum fulminans, of Flames that invisibly touch the Bodies they work on, and also Whirlwinds, and those streams of invisible Exhalations and other aerial Particles we call Winds. But because instances of this sort suit not so well with the main scope of this Tract, I shall not insist on them, but subjoin some others, which, though less notable in themselves, will be more congruous to my present Design. That the Corpuscles whereof Odours consist, swim to and fro in the Air, as in a fluid Vehicle, will by most, I presume, be granted, and may be easily proved. But I have elsewhere shown, That the motion of the Effluviums of some sufficiently odorous Bodies, has too little Celerity to make a sensible impression on the organs of smelling, unless those Steams be assisted to beat more forcibly upon the Nostrils by the Air, which hurries them along with it, when it enters the Nostrils in the form of a stream, in the act of Inspiration. And I have by familiar observation of Hunters, Fowlers, and partly of my own made manifest, that Setting-dogs, Hounds, Crows and some other animals, will be much more affected with scents, or the odorous Effluvia of Partridges, Hares, Gunpowder, etc. when the Wind blows from the object towards the sensory, than when it sits the contrary way, which way soever the Nostrils of the animal be obverted, so the Air be imbued with the odorous Steams: And consequently the difference seems to proceed from this, that when the Nostrils are obverted to the Wind, the Current of the Air drives the Steams forcibly upon the Sensory, which otherwise it does not.  
That there is a briskness of motion requisite, and more than ordinarily conducive to Electrical attractions, may be argued from the necessity that we usually find by rubbing Amber, Jet, and other Electrical bodies, to make them emit those Steams, by which 'tis highly probable their action is performed: And though I have elsewhere shown, that this precedent rubbing is not always necessary to excite all Electrical bodies; yet in those that I made to attract without it, it would operate much more vigorously after attrition; which I conconceive makes a reciprocal motion amongst the more stable parts, and does thereby as 'twere discharge and shoot out the attracting Corpuscles; whose real emission, though it may be probably argued from what has been already said, seems more strongly provable by an Observation that I made many years ago, and which I have been lately informed to have been long since made by the very Learned Fabri. The Observation was this; That if, when we took a vigorously excited Electrick, we did at a certain nick of time (which circumstances may much vary, but was usually almost as soon as the body was well rubbed) place it at a just distance from a suspended Hair or other light body, or perhaps from some light powder; the Hair, etc. would not be attracted to the Electrick, but driven away from it, as it seemed, by the briskly moving steams that issue out of the Amber or other light body.  
This Argument I could confirm by another Phaenomenon or two of affinity with this, if I should not borrow too much of what I have elsewhere noted about the History of Electricity.  
I know a certain substance, which though made by distillation, does in the cold emit but a very mild and inoffensive smell, but when the vessel that holds it is heated, though no separation of constituent Principles appear to be thereby made, (the Body being in all usual trial's homogeneous,) the Effluviums will be so altered, that I remember a Virtuoso, that, to satisfy his curiosity▪ would needs be smelling to it, when 'twas heated, complained to me, that he thought the Steams would have killed him, and that the Effluviums of Spirit of Sal Armoniac itself were nothing near so strong and piercing as those.  
And even among solid Bodies, I know some, which, though abounding much in a substance wherein some rank smells principally reside, yet (if they were not chafed) were scarce at all sensibly odorous; but upon the rubbing of them a little one against the other, the attrition making them, as it were, dart out their Emissions, would in a minute or two make them stink egregiously.  
And as the Celerity of motion may thus give a vigour to the Emanations of Bodies, so there may be other modifications of motion, that may contribute to the same thing, and are not to be wholly neglected in this place. For as we see, that greater Bodies do operate differingly according to such and such modifications; as there is a great difference between the effects of a Dart or Javelin, so thrown as that its point be always forwards, and the same weapon if it be so thrown, that during its progressive motion the extremes turn about the Centre of gravity or some inward parts, as it happens when Boys throw sticks to beat down fruit from the tops of trees; so there is little doubt to be made, but that in Corpuscles themselves 'tis not all one, as to their effects, whether they move with or without rotation, and whether in such or such a line, and whether with or without undulation, trembling or such a kind of consecution; and in short, whether the motion have or have not this or that particular modification; which how much it may diversify the Effects of the Bodies moved, may appear by the Motion, that the Aerial particles are put into by Musical Instruments. For, though the effects of harmony, discord and peculiar sounds be sometimes very great, not only in Human bodies, but, as we shall show in the following Tract, in Organical ones too; the whole efficacy of Music and of Sounds that are not extraordinarily loud and different, seems, as far as 'tis ascribable to Sonorous bodies, to depend upon the different manners of motion whereinto that Air is put, that makes the immediate impression on our organs of hearing.   

CHAP. V.  
I Should now proceed to show, how the Celerity and other modes, that diversify the motion of Effluviums, may be assisted to make them operative by their determinate sizes and figures, and the congruity or incongruity which they may have upon that score with the Pores of the grosser Bodies they are to work on: But I think it not fit to entrench upon the subject of another 
* Of the Pores of Bodies, and Figures of Corpuscles.  Tract, where the relation between the figures of Corpuscles and the Pores of grosser bodies is amply enough treated of. And therefore I shall only in this place take notice of those effects of Lightning, which seem referable, partly to the Celerity and manner of Appulse, and partly to the distinct sizes and shapes of the Corpuscles that compose the destructive matter, and to the peculiar relation between the particles of that matter and the structure of the bodies they invade. I know that many strange things that are delivered about the Effects of what the Latins call Fulmen (which our English word Lightning does not adaequately render) are but fabulous; but there are but too many that are not so; some of which I have been an Eye-witness of, within less than a quarter of an hour after that the things happened. And though it be very difficult to explicate particularly many of these true Phenomena, yet it seems warrantable enough to argue from them, that there may be Agents so qualified, and so swiftly moved, that notwithstanding their being so exceedingly minute, as they must be, to make up a flame, which is a fluid Body, they must in an imperceptible time pervade solid Bodies, and traversing some of them without violating their Texture, burn, break, melt, and produce other very great changes in other Bodies that are fitted to be wrought on by them. And of this I must not forget to mention this remarkable instance; That a person Curious enough to collect many rarities, bringing me one day into the Study where he kept the choicest of them, I saw there among other things a fine pair of Drinking-glasses that were somewhat slender, but extraordinarily tall; they seemed to have been designed to resemble one another, and made for some drinking entertainment. But before I saw them, that resemblance was much lessened by the Lightning, that fell between them in so strange a manner, that, without breaking either of them, that I could perceive, it altered a little the figure of one of them, near the lower part of the Cavity; but the other was so bend near the same place as to make it stand quite awry, and give it a posture, that I beheld not without some amazement. And I cannot yet but look upon it as a very strange thing, and no less considerable to our present purpose, that Nature should in the free Air make of Exhalations, and that such as probably when they ascended were invisible, such an aggregate of Corpuscles, as should without breaking such frail Bodies as Glasses, be able in its passage thorough them, that is, in the twinkling of an Eye, to melt them; which to do is wont even in our Reverberatory Furnaces to cost that active flames a pretty deal of time.  
And this calls into my memory, that upon a time, hearing not far off from me such a clap of Thunder as made me judge and say, that questionless some of the neighbouring places were thunderstruckk, I sent presently to make inquiry; which having justified my conjecture, I forthwith repaired to the house, where the mischief was done, by something, which those, that pretended to have seen it coming thither, affirmed to be like a flame moved very obliquely. To omit the hurt, that seemed to have been done by a Wind that accompanied it, or was perhaps produced by it, to divers persons and cattle; that which makes me here mention it, was, that observing narrowly what had happened in an upper room, where it first fell, I saw, that it had in more than one place melted the Lead in its passage, (though that possibly outlasted not the twinkling of an Eye,) without breaking to pieces the glass-casements, or burning (that I took notice of) either the Bed or Hangings or any other combustible householdstuff; though near the window it had thrown down a good quantity of the solid substance of the Wall, through which it seemed to have made its passage in or out. And that, which made me the less scruple to mention this accident, is, that having curiously pried into the Effects of the Fulmen, not only in that little upper room, but in other parts of the House, beneath whose lowermost parts it seemed to have ended its extravagant course, I could not but conclude, That if so be it were the same Fulmen, it must have more than once gone in and out of the House, and that the line of its motion was neither strait, nor yet reducible to any curve or mixed line, that I had met with among Mathematicians; but that, as I then told some of my Friends, it moved to and fro in an extravagant manner, not unlike the irregular and wriggling motion of those fired Squibs that Boys are wont to make by ramming Gunpowder into Quills. But about Thunder more perhaps elsewhere. I shall here only add, That whereas 'tis a known Tradition, which my own Observations heedfully made seem now and then to confirm, that vehement Thunder, if Beer be not very strong, will usually (for I do not say always) sour it in a day or two; if this degeneration be not one of the consequences of the great and peculiar kinds of the concussions of the Air that happens in loud Thunder (in which case the Phenomenon will belong to the next Discourse,) the effect may probably be imputed to some subtle Exhalations diffused thorough the Air, which, penetrating the pores of the Wooden vessels, whose contexture is not very close, imbue the liquor with a kind of acetous Ferment; which conjecture I should think much confirmed by a trial, it suggested to me, if I had made it often enough to rely upon it. For considering that the pores of Glass are strait enough to be impervious (for aught I have yet observed) to the Steams or spirituous parts of Sulphur as well as to other odorous Exhalations, I thought it worth trying, whether there be any sulphureous Steams or other Corpuscles diffused thorough the Air in time of Thunder, that would not be too gross to get in at such minute pores as those of Glass. And accordingly having Hermetically sealed up both Beer and Ale apart, I kept them in Summer time till there happened a great Thunder, a day or two, after which the Beer which we drank, that was good before, being generally complained of as soured by the Thunder, I suffered my liquors to continue at least a day or two longer, that the souring Steams, if any such there were, might have time enough to operate upon them, and then breaking the Glasses, I found not that the liquors had been soured, though we had purposely forborn to fill the Glasses, to facilitate the degeneration of the liquors. Perhaps it will be pardonable on this occasion to mention a practice, which is usual in some places where I have been, and particularly employed by a great Lady, that is a great housekeeper, and is very curious and expert in divers Physical Observations; for, talking with her about the remedies of the Souring of Beer and other drinks by Thunder, which is sometimes no small prejudice to her, she affirmed to me, that she usually found the practice, I was mentioning, succeed: And that before the then last great Thunder, of which I had observed the Effects upon Beer, she preserved hers by putting, at a convenient distance, under the Barrels, Chaffing-dishes of Coals, when she perceived that the Thunder was like to begin, which practice, if it constantly succeed, may put one a considering, whether the Fire do not by rarifying the Air and discussing the sulphureous or other Steams, by altering them, or by uniting with them the Exhalations of the Coals, or by some such kind of way, render ineffectual these souring Corpuscles, which perhaps require a determinate bulk and shape, besides their being crowded very many of them together, to have their full Operation on Barrelled Liquors. But these things are but mere Conjectures, and therefore I proceed.   

CHAP. VI  
THE fifth way whereby Effluviums may perform notable things, is the Motion of one part upon another, that they may excite or occasion in the Body they work on according to its structure.  
I shall in the following Tract have occasion to say something of the Motions into which the Internal parts of Inanimate Bodies may put one another; but the Examples now produced are designed to manifest the Efficacy, that Effluviums may, on the newly mentioned accounts, have on Organical and living Bodies. To which Instances it would yet be proper to premise, That even Inanimate and Solid Bodies may be of such a structure as to be very much alterable by the appropriated Effluviums of other Bodies, as may be instanced in the power, that I have known some vigorous Lodestones to have, of taking away in a trice the attractive virtue of an excited Needle, or giving a verticity directly contrary to the former without so much as touching it.  
And we may pertinently take notice of the attractive virtue of the Loadstone, as that, which may afford us an eminent Example of the great power of a multitude of invisible Effluviums, even from Bodies that are not great, upon Bodies that are Inorganical or liveless: For taking it for granted, what both the Epicureans, Cartesians, and almost all other Corpuscularian Philosophers agree in, that Magnetism is performed by corporeal Emissions, we may consider, that these passing unresistedly thorough the pores of all solid Bodies, and even Glass itself, which neither the subtlest Odours nor Electrical Exhalations are observed to do, seem to be almost incredibly minute, and much smaller than any other Effluviums, though themselves too small to be visible; and yet these so incomparably little Magnetical Effluxions proceeding from vigorous Lodestones, will be able to take up considerable quantities of so ponderous a Body as Iron; in so much that I have seen a Loadstone not very great, that would keep suspended a weight of Iron, that I could hardly lift up to it with one Arm; and I have seen a little one, with which I could take up above eighty times its weight. And these Effluvia do not only for a moment fasten the Iron to the Stone, but keep the Metal suspended as long as one pleases.  
This being premised, I come now to observe, That the chief effects of Effluvia belonging to the fifth Head are wrought upon Animals, which by virtue of their curious and elaborate structure, have their parts so connected and otherwise contrived, that the motions or changes that are produced in one, may have by the consent of Parts a manifest operation upon others, although perhaps very distant from it, and so framed as to declare their being affected by actions that seem to have no affinity at all with the Agents that work upon the part first affected.  
I have shown at large in another 
* The usefulness of Experimental Philosophy.  Treatise, that a Humane Body ought not to be looked upon merely as an aggregate of Bones, Flesh, and other consistent parts, but as a most curious and a living Engine, some of whose parts, though so nicely framed as to be very easily affected by external Agents, are yet capable of having great Operations upon the other parts of the Body, they help to compose. Wherefore without now repeating what is there already delivered, I shall proceed to deliver such Effects as are wrought on Human Bodies by these Effluviums without any immediate contact of the Bodies that emit them.  
And first, not to mention Light, because its being or not being a Corporeal thing is much disputed even among the Moderns; 'tis plain, that our organs of Smelling are sensibly affected by such minute Particles of matter as the finest odours consist of. Nor do they always affect us precisely as odours, since we see, that many persons, both men and women, are by Smells, either sweet or stinking, put into troublesome Headaches.  
If it were not almost ordinary, it would be more than almost incredible, that the smell of a pleasing Perfume should presently produce in a Human Body, that immediately before was well and strong, such faintnesses, swoons, loss of sensible respiration, intumescence of the Abdomen, seeming Epilepsies, and really convulsive motions of the Limbs, and I know not how many other frightful Symptoms, that by the unskilful are often taken for the effects of Witchcraft, and would impose upon Physicians themselves, if their own or their Predecessors Experience did not furnish them with Examples of the like Phaenomena produced by Natural means. Those Symptoms manifest, what the consent of Parts may do in a Humane Body; since even Morbific Odours, if I may so call them, by immediately affecting the organs of Smelling, affect so many other parts of the genus Nervosum, as oftentimes to produce Convulsive motions, even in the extreme parts of the Hands and Feet.  
Nor is the efficacy of Effluviums confined to produce Hysterical fits, since these invisible Particles may be able (and sometimes as suddenly as Perfumes are wont to excite them) to appease them, as I have very frequently, though not with never-failing success, tried, by holding a Spirit, I usually make of Sal Armoniac, under the Nostrils of Hysterical persons. My remedy did not only often recover, in a trice, those whose Fits were but ordinary, but did more than once, somewhat to the wonder of the Bystanders, relieve, within a Minute or two, persons of differing Ages and Constitutions, that were suddenly fallen down by Fits, that the Bystanders judged Epileptical, (but I, Hysterical.)  
I attribute the good and evil Operations of the forementioned Steams, rather in general to the consent of the parts that make up the genus Nervosum, than to any hidden Sympathy or Antipathy betwixt them and the Womb, not only for other reasons, not proper to be insisted on here, but because I have known Odours have notable Effects even upon Men. I know a very eminent person, a Traveller, and a man of a strong constitution, but considerably Sanguine, who is put into violent headaches by the Smell of Musk. And I remember, that one day being with him and a great many other men of note about a Public Affair, a man that had a parcel of Musk about him, having an occasion to make an application to us, this person was so disordered by the smell, which to most of us was delightful, that in spite of his Civility he was reduced to make us an Apology, and send the perfumed man out of the room, notwithstanding whose recess this person complained to me, a good while after, of a violent pain in his Head, which I perceived had somewhat unfit him for the Transaction of the Affair whereof he was to be the chief manager. I know another person, whose happy Muse hath justly made him many Admirers, that is subject to the Headache upon so mild a smell as that of Damask-Roses, and sometimes even of Red-Roses, in so much that walking one day with him in a Garden, whose Alleys were very large, so that he might easily keep himself at a distance from the Bushes, which bore many of them Red-Roses; he abruptly broke off the discourse we were engaged in, to complain of the harm the Perfume did his Head, and desired me to pass into a Walk, that had no Roses growing near it.  
If it were not for the Sex of this person, I could relate an Instance that would be much more considerable of the Operation of Roses. For I know a discreet Lady to whom their smell is not unpleasing, (for she answered me that 'twas not so at all,) but so hurtful, that it presently makes her sick, and would make her swoon if not seasonably prevented: And she told me that being once at a Court in which she was a Maid of Honour, though she herself did not know whence it came, she found herself extremely ill on a sudden, and ready to sink down for faintness; but being then in discourse with a person, whose High Quality she paid her profound respect to, her Civility, that kept her from complaining or withdrawing, might have been dangerous if not fatal to her, had not the Princess who was speaking with her, and who knew her Antipathy to Roses, taken notice that her Face grew strangely pale, and was covered with a cold sweat. For thereby presently guessing what might be the cause, which the sick Lady herself did not, she asked aloud whether some body had not brought Roses (which were then in season) into the Bedchamber, which question occasioned a speedy withdrawing of a Lady, that stood at a distance off, and had about her Roses, which were not seen by the Patient, who was by this means preserved from falling into a swoon, though not from being for a while very much discomposed.  
But this you may tell me was the case of a Woman, who complained her malady affected her Heart, not her Head. Wherefore returning to what I was speaking of before I mentioned Her, I shall proceed to tell you, that as Odours may thus give Men the Headache, so I have often found the smell of rectified-Spirit of Sal Armoniac to free Men as well as Women from the Fits of that distemper; and that sometimes in so few Minutes, that the person relieved could scarcely imagine, they could so quickly be so.  
To which I shall not add the Trials that I have successfully made upon myself, because being, thanks be to God, very seldom troubled with that distemper, the occasions I have had of making them have not been many. And though I have not always found so slight a Remedy to work the desired Cure, yet that it does it often, even in Men, is sufficient to show the Efficacy of Sanative Effluviums.  
Now, to manifest, that Steams do not Operate only upon Hysterical Women, or persons subject to the Headache, I will add some Instances of the Effects they may produce upon other persons, and parts.  
'Tis but too well known an Observation, that Women with Child have been often made to miscarry by the stink of an ill-extinguisht Candle, though perhaps the smoke ascending from the Snuff were dissipated into the invisible Corpuscles, a good while before it arrived at the Nostrils of the unhappy Woman; and what violent and straining motions Abortions are frequently accompanied with, is sufficiently known already.  
I think I have elsewhere mentioned, that a Gentleman of my acquaintance, a proper and lusty man, will be put into the fits of Vomiting by the smell of Coffee, boiled in Water; I shall therefore rather mention, that I know a Physician, who having been, for a long time when he was young, frequently compelled to take Electuarium lenitivum, one of the gentlest and least unpleasant Laxatives of the Shops, conceived such a dislike of it, that still, as himself has complained to me, if he smell to it, as he sometimes happens to do in Apothecary's Shops, it will work (now and then for several times) upwards and downwards with him.  
I know another very ingenious persons of the same faculty, that has been a Traveller by Sea and Land, who has complained to me, that the smell of the Grease of the Wheels of a Hackney-coach, though it do but pass by him, is wont to make him sick and ready to Vomit.  
Every body knows, that Smoak is apt to make men's Eyes water, and excite in the organs of Respiration that troublesome and vehement commotion we call Coughing. But we need not have recourse at all to visible Fumes, for the production of the like Effects; since we have often observed them, and repeated Sneezing to boot, to proceed from the invisible Steams of Spirit of Sal Armoniac, when Vials containing that liquor, though they were perhaps but very small, were approached too hastily, or perhaps too near to the Nostrils.  
And because in most of the foregoing Instances, the chief Effects seem to be wrought, by the consent of parts, on the genus Nervosum and the action of one of them upon the other, and thereby upon several other parts of the Body, I will subjoin a remarkable instance of the Operation of a mild and grateful Odour upon the Humours themselves, and that in a Man.  
A famous Apothecary, who is a very tall and big man, several times told me, that though he was once a great lover of Roses, yet having had occasion to employ great quantities of them at a time, he was so altered by their Steams, that now, if he come among the Rose-bushes, the smell does much discompose him. And the odour of Roses, (I mean Incarnate-Roses, which we commonly call Damask-Roses, though they be not the true ones,) makes such a colliquation of Humours in his Head, that it sets him a coughing, and makes him run at the Nose, and gives him a sore throat; and by an affluence of Humours makes his Eyes sore, in so much that during the season of Roses, when quantities of them are brought into his House, he is obliged for the most part to absent himself from home.   

CHAP. VII.  
ONE may show on this occasion, that as there might be considerable things performed by Effluviums, as they make one part of a living Engine work upon another by virtue of its structure, so the action of such invisible Agents may in divers cases be much promoted by the fabric and laws of the Universe itself, upon this account, that, by the Operation of Effluvia upon particular Bodies, they may dispose and qualify those Bodies to be wrought upon, which before they were not fit to be, by Light, Magnetisms, the Atmosphere, Gravity or some other of the more Catholic Agents of Nature, as the World is now constituted. But not to injure another Tract, I shall conclude this, when I shall have taken notice, that in the Instances hitherto produced, there has been a visible Local distance between the Body that emits Steams, and that on which they work. But if I thought it necessary, it were not difficult to show, that one might wool enough refer to the title of this Tract divers Effects of Bodies that are applied immediately to ours; such as are Bloodstones, Cornelions, Nephritick-stones, Lapis Malacensis, and some Annulets, and other solid substances applied by Physicians outwardly to our Bodies. For in these applications the gross Body touches but the Skin, and the great Effects, which I elsewhere relate myself to have sometimes (though not often, much less always) observed to have followed upon this External contact or near application, may reasonably be derived from the subtle Emanations, that pass thorough the Pores of the Skin to the inward parts of the Body: As is evident in those, who by holding Cantharideses in their Hands, or having them applied to some remote External part, have grievous pains produced in their Urinary parts, as it has happened to Me as well as to many others. And to the insinuation of these minute Corpuscles, that get in at the Pores of the Skin, seems to be due the Efficacy of some Medicines, that purge, vomit, resolve the Humours, or otherwise notably alter the Body being but externally applied; of which I could here give several Instances, but that they belong more properly to another place, and are not necessary in this, where it may suffice to name the notorious Power, that Mercurial Ointments or Fumes, either together or apart, have of producing Copious Salvations, to show in general, that both the Steams and the Emanations of outwardly applied Medicinal Bodies may have some great Effects on Human ones.    

OF THE Determinate Nature OF EFFLUVIUMS.   

OF THE DETERMINATE NATURE OF EFFLWIUMS'.  

CHAP. I.  
THE Effluviums of Bodies, Pyrophilus, being for the most part invisible, have been wont to be so little considered by vulgar Philosophers, that scarce vouchsafing to take notice of their Existence, 'tis no wonder that men have not been solicitous to discover their distinct Natures and Differences. Only 
* Lib. 1. Meteor. cap. 3, & 4.  Aristotle, and (upon his account) the Schools, have been pleased to think, that the two grand parts of our Globe do sometimes emit two kinds of Exhalations or Steams; the Earthy part affording those that are hot and dry, which they name Fumes, and very often, simply, Exhalations; and the Aqueous part, others that are (not as many of his Disciples mistake him to have taught, Cold and Moist, but) Hot and Moist 
* Cap. 3. 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉. , which they usually call Vapours, to discriminate them from the Fumes (or Exhalations,) though otherwise, in common acceptation, those Appellations are very frequently confounded.  
But, though the Aristotelians have thus perfunctorily handled this Subject, it would not become Corpuscularian Philosophers, who attribute so much as they do to the Insensible Particles of Matter, to acquiesce in so slight and jejune an account of the Emanations of Bodies. And since we have already shown, that besides the greater and more simple Masses of Terrestrial and Aqueous matter newly mentioned, there are very many mixed Bodies, that emit Effluviums, which make, as it were, little Atmospheres about divers of them, it will be congruous to our Doctrine and Design, to add in this place, That besides the slight and obvious differences, taken notice of by Aristotle, the Steams of Bodies may be almost as various as the Bodies themselves that emit them; and that therefore we ought not to look upon them barely under the general and confused notion of Smoke or Vapours, but may probably conceive them to have their distinct and determinate Natures, oftentimes (though not always) suitable to that of the Bodies from whence they proceed.  
And indeed the newly mentioned Division of the Schools gives us so slight an account of the Emanations of Bodies, that, methinks, it looks like such another, as if one should divide Animals into those that are Horned, and those that have Two Feet: For, besides that the Distinction is taken from a Difference that is not the considerablest, there are divers Animals (as many fourfooted Beasts and Fishes) that are not comprised in it; and each member of the Division comprehends I know not how many distinct sorts of Animals, whose differences from one another are many times more considerable, than those that constitute the two supreme Genus', the one having Bulls and Goats, and Rhinoceros', and Deer, and Elks, and certain Sea-Monsters whose Horns I have seen; and the other Genus comprising also a greater Variety, namely, a great part of fourfooted Beasts, and, besides Men, all the Birds (for aught we know) whether of Land or Water. And as it would give us but a very slender Information of the Nature of an Elk or an Unicorn, to know that 'tis an Horned Beast; or of the Nature of a Man, an Eagle, or a Nightingale, to be told, that 'tis an Horn-less Beast; so it will but very little instruct a man in the Nature of the Steams of Quicksilver or of Opium, to be told, that they are Vapours Hot (or rather Cold) and Moist; or of the Steams of Amber or Cantharideses, or Cinnamon, or Tobacco, to be told, that they are Hot and Dry. For, besides that there may be Effluviums, which, even by their Elementary Qualities, are not of either of these two supreme Genus', (for they may be Cold and Dry, or Cold and Moist,) these Qualities are often far from being the Noblest, and consequently those that deserve to be most considered in the Effluviums of this, or that, Body; as we shall by and by have occasion to manifest.   

CHAP. II.  
ANd here it may not be improper to mention an Experiment, that, I remember, I divers years since employed to illustrate the Subject of our present Discourse.  
I considered then, that Fluid Bodies may be of very unequal density and gravity, as is evident in Quicksilver, Water and pure Spirit of Wine; which, notwithstanding their great difference in specific gravity, may yet agree in the conditions requisite to Fluid Bodies. Therefore presuming, that by what I could make appear visible in one, what happens analogically in the other, may be ocularly illustrated, I took some Ounces of Roch-allom, and as much of fine Saltpetre. I took some Ounces of each, because, if the quantity of the ingredients be too small, the concoagulated grains will be so too, and the success will not be so conspicuous. These being dissolved together in fair Water, the filtrated solution was set to evaporate in an openmouth Glass, and being then left to shoot in a cool place, there were fastened to the sides and other parts of the Glass several small Crystals, some Octoedrical, which is the figure proper to Roch-allom, and others of the Prismatical shape of pure Saltpetre; besides some other Saline concretions, whose being distinctly of neither of these two shapes, argued them to be concoagulations of both the Salts. And this we did by using such a degree of Celerity in Evaporating the liquor, as was proper for such an effect. For, by another degree, which is to be employed when one would recover the Salts more distinctly and manifestly, the matter may (as I found by trial) be so ordered, that the aluminous Salt may, for the most part, be first coagulated by itself, and then from the remaining liquor curiously shaped Crystals of Nitre may be copiously obtained.  
Trials like this we also made with other Salts, and particularly with Sea-Salt, and with Allom and Vitriol; the Phaenomena of which you may meet with in their due places. For the recited Experiment may, I hope, alone serve to assist the imagination to conceive, how the Particles of Bodies may swim to and fro in a Fluid, (which the Air is,) and though they be little enough to be invisible, may many of them retain their distinct and determinate natures, and their aptness to cohere upon occasion; and others may, by their various occursions and coalitions, unite into lesser Corpuscles or greater Bodies differing from the more simple Particles, that composed them, and yet not of indeterminate though compounded Figures.   

CHAP. III.  
THese things being premised, we may now proceed to the particular Instances of the Determinate Nature of Effluviums; and these we may not inconveniently reduce to the three following Heads, to each of which we shall assign a distinct Chapter; the first of these I shall briefly treat of in this third Chapter, and treat somewhat more largely of the others in the two following.  
In the first place then, That the Effluviums of many Bodies retain a determinate Nature oftentimes in an invisible smallness, and oftener in such a size as makes them little enough to fly or swim in the Air; may appear by this, that these Effluvia being by Condensation or otherwise reunited, they appear to be of the same nature with the Body that emitted them. Thus in moist weather, the Vapours of Water, that wander invisibly through the Air, meeting with Marble-Walls or Pavements, or other Bodies, by their Coldness and other Qualifications, fit to condense and retain them, appear again in the form of Drops of Water; and the same Vapours return to the visible form of Water, when they fall out of the Air in Dews, or Rains.  
Quicksilver itself, if it be made to ascend in distillation with a convenient degree of Fire, will almost all be found again in the Receiver in the form of running Mercury. Which strange and piercing Fluid, is in some cases so disposed to be stripped of its Disguises, and reappear in its own form, that divers Artificers, and especially Gilders, have found, to their cost, that the fumes of it need not be, as in Distillation, included in close Vessels to return to their pristine nature, Mercury having been several times found in the Heads and other parts of such People, who have in tract of time been killed by it, and sometimes made to discover itself during the Lives of those that dealt so much in it; of which I elsewhere give some Instances. Wherefore I shall only observe at present, that 'tis a common Practice, both among Gilders, and some Chemists, that, when they have occasion to make an Amalgam, or force away the Mercury from one by the fire, they keep Gold in their Mouths, which by the Mercurial fumes, that wander through the Air, will now and then, by that time 'tis taken out of their Mouths, be turned white almost, as if it had been silvered over.  
A mass of purified Brimstone being sublimed, the ascending fumes will condense into what the Chemists call Flores Sulphuris, which is true Sulphur of the same nature with that, formerly exposed to sublimation; and may readily by melting be reduced into such another mass.  
And to give you another like Example of dry Bodies; I tried, that by subliming good Camphire in close vessels, it would all, as to sense, be raised into the upper vessel, or part of the Subliming-glass in the form of dry Camphire as it was before.  
Nay though a Body be not by Nature, but Art compounded of such differing Bodies as a Metal and another Mineral, and two or three Salts; yet, if upon Purification of the mixture from its grosser parts, the remaining and finer parts be minute enough and fitly shaped, the whole liquor will ascend, and yet in the Receiver altogether recover its pristine form of a transparent Fluid, composed of differing Saline and Mineral parts. This is evident in the Distillation of what Chemists call Butter, or Oil of Antimony, very well rectified. For, this Liquor will pass into the Receiver diaphanous and fluid, though, besides the Particles of the Sublimate, (which is itself a factitious compounded Body) it abounds with Antimonial Corpuscles, carried over and kept invisible by the corroding Salts; whatever Angelus Sala, and those Chemists that follow him, have affirmed to the contrary; as might be easily here proved, if this were a fit place to do it in.  
I found by enquiring of an Ingenious person, that had an interest in a Tin-Mine, that I was not deceived in guessing, that Tin itself, though a Metal whose Ore is of a very difficult fusion, and which I have by itself kept long upon the Cupel without finding it to fly away, would yet retain its Metalline nature in the form of fumes or flowers. For this experienced Gentleman answered me, that divers times they would take great store of a whitish Sublimate from the upper part of the Furnaces or Chimneys, where they brought their Ore to fusion, or wrought further upon it; and that this Sublimate, though perhaps elevated to the height of an ordinary Man, would, when melted down, afford at once many Pounds of very good Tin. On which occasion I shall add, that I have myself more than once raised this Metal in the form of white Corpuscles by the help of an Additament, that did scarce weigh half so much as it.   

CHAP. IU.  
THe second way, by which we may discover the Determinate Nature of Effluviums, is, by the difference that may sometimes be observed in their Sensible Qualities. For, these Effluviums that are endowed with them, proceed from the same sort of Bodies, and yet those afforded by one kind of Bodies being in many cases manifestly differing from those that fly off from another, this evident disparity in their Exhalations argues their retaining distinct natures, according to those of the respective Bodies whence they proceed.  
I will not now stay to examine, whether in the Steams, that are made visibly to ascend from the Terrestrial Globe by those grand Agents and usual raisers of them, the Sun, and the agitation of the Air, the Eye can manifestly distinguish the diversity of colours: But in some productions of Art such different colours may be discovered in the Exhalations, even without the application of any external heat to raise them. For, when Spirit of Nitre, for example, has been well rectified, I have often observed, that even in the cold the fumes would play in the unfilled part of the stopped Vials it was kept in, and appear in it of a reddish colour, and, if those vessels were opened, the same fumes would copiously ascend into the Air, in the form of a reddish or orange-tawny Smoke. Spirit or Oil of Salt also, if it be very well dephlegmed, though it will scarce in the cold visibly ascend in the empty part of a Vial, whilst it is kept well stopped; yet, if the free Air be allowed access to it, it will, in case it be sufficiently rectified, fly up in the form of a whitish fume. But this is inconsiderable in comparison of what happens in a volatile Tincture of Sulphur, I have elsewhere taught you to make with Quicklime. For, not only upon a slight occasion the vacant part of the Vial will be filled with white fumes, though the Glass be well stopped; but upon the opening the Vial these fumes will copiously pass out at the neck, and ascend into the Air in the form of a Smoke, more white than perhaps you ever saw any. And both this and that of the Spirit of Saltpetre do by their operation, as well as smell, disclose what they are; the latter being of a Nitrous nature, (as is confessed) and the former, of a Sulphureous: In so much that having for curiosities sake in a fitly shaped Glass caught a competent quantity of the ascending white fumes, I found them to have convened into Bodies transparent and Geometrically figured, wherein 'twas easy to discover by their sensible qualities, that there were store of Sulphureous particles mixed with the Saline ones. That the liquors of Vegetables, distilled in Balneo or in Water, are not wont to retain any thing of the colour of the Bodies that afforded them, is a thing easy to be observed in Distillations made without Retorts or the violence of the Fire. But it may be worth while to make trial, whether the Essential Oil of Wormwood ascend coloured like the Plant, whence 'tis first drawn over with Water in the Limbec, or rectified in Balneo. For, I forgot to take notice of it, when upon some particularities, I observed in that Plant, my curiosity led me to find, that not only in the first distillation in a Copper Limbec, tinned on the inside, the Oil came over green, but by a rectification purposely made in a Glass-vessel, the purified liquor was not deprived of that colour.  
The mention of these Essential Oils, as Chemists call those that are drawn in Limbecs, leads me to tell you, that, though these liquors be but Effluvia of the Vegetables they are distilled from, condensed again in the Receiver into liquors; yet, as subtle as they are, many of them retain the genuine taste of the Bodies, whence the heat elevated them; as you will easily find, if you will taste a few drops of the Essential Oil of Cinnamon, for example, or of Wormwood dissolved by the intervention of Sugar or Spirit of Wine in a convenient quantity of Water, Wine, or Beer. For, by this means you have the natural taste of this Spice or Herb. And Wormwood is a Plant, whose Effluvia do so retain the nature of the Body that parts with them, that I must not forbear to allege here an Observation of mine, that may show you, that 'tis possible, though not usual, that even without the help of the Fire the expirations of a Body may communicate its taste. For, among other things, that I had occasion to observe about some quantity of Wormwood laid up together, I remember, I took notice, and made others do the like, that coming into a room, where 'twas kept, not only the organs of smelling were powerfully wrought upon by the Corpuscles that swarmed in the Air, but also the Mouth was sensibly affected with a bitter taste. Perhaps you will scarce think it worth while, that after this instance I should add, that I found the expirations of Amber, kept a while in pure Spirit of Wine, taste upon the tongue like Amber itself, when I chewed it between my teeth. But I choose to mention this instance, because it will connect those lately mentioned with another sort, very pertinent to our present purpose. For, the expirations that I have obtained from Amber, both with pure Spirit of Wine, and a more piercing Menstruum, did manifestly retain in both those liquors a peculiar smell, with which I found it to affect the Nostrils, when, for trial's sake, I excited the Electrical faculty of Amber by rubbing. And as for Odours, 'tis plain, that the Essential Oils of Chemists, well drawn, do many of them retain the peculiar and genuine sent of the Spices or Herbs that afforded them. And that these Odours do really consist of, or reside in certain invisible Corpuscles that fly off from the visible Bodies, that are said to be endowed with such Smells, I have elsewhere proved at large; and it may sufficiently appear from their sticking to divers of the Bodies they meet with, and their lasting adhesion to them.  
Other Examples may be given of the settled difference of Effluviums directly perceivable by Humane Organs of Sense, as dull as they are; which last expression I add, because I scarce doubt, but that, if our Sensories were sufficiently subtle and tender, they might immediately perceive in the size, shape, motion, and perhaps colour too of some now invisible Effluviums, as distinguishable differences, as our naked Eyes in their present constitution see, between the differing sorts of Birds, by their appearances, and their manner of flying in the Air, as Hawks, and Partridges, and Sparrows, and Swallows. To make this probable I will not urge, that in fine white Sand, whose grains by the unassisted Eye are not wont to be distinguished by any sensible Quality, I have often observed in an excellent Microscope, a notable disparity as to bulk, figure, and sometimes as to colour: And that in small Cheese-mites, which the naked Eye can very scarcely discern, so far is it from discovering any difference between them, one may (as was noted in the last essay) plainly see, besides an obvious difference in point of bigness, many particular parts, on whose accounts the structure of those moving points may difference them from each other. And I have sometimes seen a very evident disparity even in point of shape between the very Eggs of these living Atoms, (as a Poet would perhaps style them.) But these kinds of proofs (as I was saying) I shall forbear to insist on, that I may proceed to countenance my conjecture by the effects of the Effluviums, that are properly so called, upon Animals.  
And first, though the Touch be reckoned one of the most dull of the five Senses, and be reputed to be far less quick in Men than in divers other Animals; yet the gross Organs of that, may, in Men themselves, even by accident, be so disposed, as to be susceptible of impressions from Effluvia: Of this in another Paper I give some Instances. And I know not whether divers of the Presages of Wether to be observed in some Animals, and the Aches and other pains, that, in many crazy and wounded men, are wont to forerun great changes of Wether, do not often (for I do not say always) proceed (at least in part) from invisible and yet incongruous Effluxions, which, either from the subterraneal parts, or from some Bodies above ground, do copiously impregnate the Air. And on this occasion it will not be impertinent to mention here what an experienced Physician being (if I much misremember not) the Learned Dimmerbrook, relates concerning himself, who having been infected with the Plague by a Patient that lay very ill of it, though by God's blessing, which he particularly acknowledges, upon a slight but seasonable Remedy, he was very quickly cured, and that without the breaking of any Tumour; yet it left such a change in some parts of his Body, that he subjoins this memorable passage; Ab illo periculo ad contagiosos mihi appropinquanti in emunctoriis successit dolour, vix fallax Pestis indicium.  
Two or three other Observations of the like nature you meet with in another of my Papers 
* About Cosmical Suspicions. . And I shall now add, that I know an ingenious Gentlewoman (Wife to a famous Physician) who was of a very curious and delicate complexion, that has several times assured me, that she can very readily discover, whether a person, that comes to visit her in Winter, came from some place where there is any considerable quantity of Snow; and this she does, (as she tells me) not by feeling any unusual cold (for if the ground be frozen but not covered with Snow, the Effect succeeds not,) but from some peculiar impression, which she thinks, she receives by the organs of Smelling. I might add, that I know also (as I may have formerly told you) a very ingenious Physician, who falling into an odd kind of Fever, had his sense of Hearing thereby made so very nice and tender, that he very plainly heard soft whispers, that were made at a considerable distance off, and which were not in the least perceived by the healthy bystanders, nor would have been by him before his sickness. Which (sickness) I mention as the thing, that gave his organs of Hearing this preternatural quickness, because when the Fever had quite left him, he was able to hear but at the rate of other men. And I might tell you too, that I know a Gentleman of eminent parts and note, who, during a distemper he had in his Eyes, had his organs of Sight brought to be so tender, that both his friends and himself also have assured me, that when he waked in the Night he could for a while plainly see and distinguish Colours, as well as other objects, discernible by the Eye, as was more than once tried, by pinning Ribbons or the like Bodies of several colours, to the inside of his Curtains in the dark. For if he were awakened in the Night, he would be able to tell his bedfellow, where those Bodies were placed, and what colour each of them was of.  
I have mentioned these Instances only to show you, that if our Sensories were more delicate and quick, they would be sufficiently affected by Objects, that, as they are generally constituted, make no impressions at all upon them. For otherwise I know, that the Species (as they call them) both of Sounds and Colours, are not held by many of the Moderns, (from whom in that I descent not,) to be so much corporeal Effluxions, trajected through the medium, as peculiar kinds of Local Motion conveyed by it. Therefore I shall now confirm the conjecture I would countenance by the discrimination made by the organs of other Animals of such Effluvia as to us men are not only invisible but insensible. And therefore partly to strengthen what I delivered, and partly to confirm what I am now discoursing of, it will not be impertinent to subjoin two or three Relations, that I had from persons of very good credit, whom I thought likely to make me no unsatisfactory returns to my Questions about things they were very well versed in.  
A person of Quality, to whom I am near allied, related to me, that to make a trial, whether a young Bloodhound was well instructed, (or as the Huntsmen call it, made) he caused one of his Servants, who had not killed, or so much as touched any of his Deer, to walk to a Countrey-town, four Mile off, and then to a Market-town three Miles distant from thence; which done, this Nobleman did, a competent while after, put the Bloodhound upon the scent of the man, and caused him to be followed by a Servant or two, the Master himself thinking it also fit to go after them to see the event; which was, that the Dog, without ever seeing the Man he was to pursue, followed him by the scent to the abovementioned places, notwithstanding the multitude of Market-people that went along in the same way, and of Travellers that had occasion to cross it. And when the Bloodhound came to the chief Market-town, he passed through the streets, without taking notice of any of the people there, and left not till he had gone to the House, where the Man, he sought, rested himself, and found him in an upper Room to the wonder of those that followed him. The particulars of this Narrative the Nobleman's Wife, a person of great veracity, that happened to be with him when the trial was made, confirmed to me.  
Enquiring of a studious person, that was Keeper of a Red-dear-park and versed in making Bloodhounds, in how long time, after a Man or Deer had passed by a grassy place, one of those Dogs would be able to follow him by the scent? He told me, that it would be six or seven Hours: Whereupon an ingenious Gentleman, that chanced to be present, and lived near that Park, assured us both, that he had old Dogs of so good a scent, that if a Buck had the day before passed in a Wood, they will, when they come where the scent lies, though at such a distance of time after, presently find the scent and run directly to that part of the Wood where the Buck is. He also told me, that though an old Bloodhound will not so easily fix on the scent of a single Deer, that presently hides himself in a whole herd; yet if the Deer be chased a little till he be heated, the Dog will go nigh to single him out, though the whole herd also be chased. The abovenamed Gentleman also affirmed, that he could easily distinguish whether his Hounds were in chase of a Hare or a Fox by their way of running, and their holding up their Nose higher than ordinary when they pursue a Fox, whose scent is more strong. These Relations will not be judged incredible by him that reflects on some of the Instances that have already (in the foregoing Essay) been given of the strange subtlety of Effluvia: To which I shall now add, that I remember, that to try whether I could in some measure make Art imitate Nature, I prepared a Body of a vegetable substance, which, though it were actually cold, and both to the Eye and Touch dry, did for a while emit such determinate and piercing, though invisible, Exhalations, that having for Trials sake applied to it a clear Metalline Plate (and that of none of the very softest kind neither) for about one Minute of an Hour, I found, that, though there had▪ been no immediate contact between them, I having pursposely interposed a piece of Paper to hinder it; yet there was imprinted on the surface of the Plate a conspicuous stain of that peculiar colour, that the Body, with whose Steams I had imbued the vegetable substance, was fitted to give a Plate of that mixed Metal. And though it be true, that in some circumstances, the lately mentioned Instances about Bloodhounds have a considerable advantage of this I have now recited; yet that advantage is much lessened, not to say countervailed, by some circumstances of our Experiment. For, not to repeat, that the emittent Body was firm and cold, the Effect produced by the Effluvium that guided the Setting-dog, was wrought upon the Sensory of a living and warm Animal; and such an one, whose organs of Smelling are of an extraordinary tender Constitution above those of Men and other Animals, and probably the Impression was but transient; whereas in our case the invisible Steams of the vegetable substance wrought upon a Body which was of so strong and inorganical a Texture as a (compounded) Metal, though it were fenced by being leapt up in Paper, notwithstanding which these Steams invaded it in such numbers, and so notably, as to make their Operation on it manifest to the Eye, and considerably permanent too; since coming to look upon the Plate after the third day, I found the induced Colour yet conspicuous, and not like suddenly to vanish.  
Hitherto in this Chapter I have argued from the constant and settled difference of the sensible Qualities of Effluviums, that they do not always lose their distinct natures, when they seem to have lost themselves by vanishing into Air. But before I dismiss this Subject, I must consider an Objection, which I know may be made against the Opinion we have been countenancing. For it may be alleged, that there may be many cases, wherein the Effluviums of Bodies are, in their passage through the Air, sensibly altered, or do affect the Organs of sense otherwise than each kind of them apart would do: Nor is this difficulty altogether irrational. For it seems consonant enough to Experience, that some such cases should be admitted, and therefore in the foregoing Discourse I have, where I thought it necessary, forborn to express myself in such general and absolute terms, as otherwise I might have done. But, as for such cases as I have insisted upon, and many more, I shall now represent, that the objected alterations need not hinder, but that Effluviums at their first parting from the Bodies, whence they take wing (if I may so speak,) may retain as much of the nature of those Bodies, as we have ascribed to them, since the subsequent change may very probably be deduced from the combinations or coalitions of divers Steams associating themselves in the Air, and acting upon the Sensory, either altogether and conjointly, or at least so near it, that the Sense cannot perceive their Operations as distinct. This I shall elucidate, but not pretend to prove, by what happens in Sounds and Tastes. For if, by way of instance, in a Musical instrument, two strings tuned to an eight, be touched together, they will strike the Ear with a sound, that will be judged one, as well as pleasing, though each of the trembling strings make a distinct noise, and the one vibrates as fast again as the other. And if, into Oil of Tartar per Deliquium, you drop a due proportion of Spirit of Nitre, and exhale the superfluous moisture, the Acid and Alcalizate Corpuscles, that were so small as to swim invisibly in those liquors, will convene into Nitrous Concretions, whose taste will be compounded of, but very differing from, both the tastes of the Acid and Tartareous Particles; which Particles may yet, for the most part, by a skilful Distillation, be divorced again. And so, if to a strong solution of Pot-ashes or Salt of Tartar you put as much in weight of Sal Armoniac, as there is of either of those fixed Salts contained in the liquor; you may, besides a subtle Urinous Spirit that will easily come over in the distillation, obtain a dry Caput mortuum, which is almost totally a compounded Salt, differing enough from either of the ingredients, especially the Alcalizate, as well in Taste as in some other Qualities: This Salt (freed from its faeces) being that Diuretic Salt, I several years ago gave quantities of, to some Chemists and Physicians, from the most of whom I received great thanks, accompanied with the (more acceptable) accounts of the very happy success they had employed it with, though usually but in a small Dose, as from six, eight or ten Grains to a Scruple. But this being mentioned only upon the by, I shall proceed to tell you, that, since I intimated to you already, that I would mention Examples of Sounds and Tastes only to illustrate what I had been delivering; I shall now add some Instances by way of Proof, of the Coalition and resulting change of Steams in the Air. 'Tis easily observable in some Nosegays, where the differing Flowers happen to be conveniently mixed, that in the smell afforded by it, at a due distance, the Odours of the particular Flowers are not perceived, but the Organ is affected by their joynt-action, which makes on it a confused but delightful impression. And so, when in a Ball of Pomander, or a perfumed Skin, Musk, and Amber, and Civet, and other sweets are skilfully mixed, the coalition of the distinct Effluvia of the ingredients, that associate themselves in their passage through the Air, produce in the Sensory one grateful perfume, resulting from all those Odours. But if you take Spirit of fermented Urine and Spirit of Wine, both of them Phelgmatick, and mix them together, they will incorporate like Wine and Water, or any other such liquors, without affording any dry concretions. But if you expose them in a convenient Vessel but to the mild heat of a Bath or Lamp, the ascending Particles will associate themselves, and adhere to the upper part of the Glass in the form of a white but tender Sublimate, consisting both of Urinous and Vinous Spirits, associated into a mixture, which differs from either of the liquors, not only in Consistence, Taste and Smell, but in some considerable Operations performable by this odd mixture; which, this is not the place, to take further notice of. And if Spirit of Salt and Spirit of Nitre be, by Distillation, elevated in the form of Fumes, so ordered as to convene into one liquor in the Receiver, this liquor will readily dissolve crude Gold, though neither the Spirit of Nitre alone, nor that of Salt would do so.  
And that you may have an ocular proof of the Possibility of the distinctness and subsequent Commixture of Steams in the Air; I shall now add an Experiment, which I long since devised for that purpose, and which I soon after showed to many curious persons, most of whom appeared somewhat surprised at it. The Experiment was; that I took two small Vials, the one filled with Spirit of Salt, but not very strong, the other with Spirit of fermented Urine or of Sal Armoniac very well rectified: These Vials being placed at some distance, and not being stopped, each liquor afforded its own smell, at a pretty distance, by the Steams it emitted into the Air, but yet these Steams were invisible. But when these Vials, (which should be of the same size) came to be approached very near to each other, though not so, as to touch; as when the two liquors are put together in the form of liquors, they will notably act upon one another; so their respective Effluviums meeting in the Air, would, answerably to the littleness of their bulk, do the like, and, by their mutual occursions, become manifestly visible, and appear moving in the Air like a little portion of Smoke or of a Mist, which would quickly cease, if either of the Vials were removed half a Foot or a Foot from the other. And I remember, that, to add to the oddness of the Phaenomenon, I sometimes made a drop of the Spirit of Salt hang at the bottom of a little stick of Glass or some other convenient Body, and held this drop thus suspended in the Orifice of a Vial that had Spirit of Sal Armoniac in it, and was furnished with a somewhat long neck; for by this means it happened, as I expected, that the ascending Urinous Particles, though invisible before, invading plentifully the Acid ones of the drop, produced a notable Smoke, which, if the drop were held a little above the neck of the Glass, would most commonly fly upwards to the height of a Foot or half a Yard: But if the drop were held somewhat deep within the Cavity of the neck, a good part of the produced Smoke would oftentimes fall into the Cavity of the Vial, which was left in great part empty, sometimes in the form of drops, but usually in the form of a slender and somewhat winding stream of a white colour, that seemed to flow down just like a Liquor from the depending drop, till it had reached the Spirit of Sal Armoniac; upon whose surface it would spread itself like a Mist. But this only upon the by. As for the main Experiment itself, it may be, as I have found, successfully tried with other Liquors than these; but 'tis not necessary in this place to give an account of such Trials; though perhaps, if I had leisure, it might be worth while to consider, whether these Coalitions of differing sorts of Steams in the Air, and the Changes resulting thence of their particular precedent Quantities, may not assist us to investigate the causes of divers sudden Clouds and Mists, and some other Meteorological Phaenomena, and also of divers changes that happen in the Air in reference to the coming in and ceasing of several either Epidemical or contagious Diseases, and particularly the Plague, that seem to depend upon some occult temperature and alterations of the Air, which may be copiously impregnated by the differing subterraneal (not to add here, Sidereal) Effluviums, that not unfrequently ascend into it (or otherwise invade it,) with Pestiferous or other Morbific Corpuscles, and sometimes with others of a contrary Nature, and sometimes too perhaps, neither the one sort of Steams, which may be supposed to have imbued the Air, is in itself deleterious; nor the other salutary, but becomes so upon their casual coalition in the Air. You will perhaps think this Conjecture of the resultancy of pestilential Steams, the less improbable, if I here add that odd Observation, which was frequently made in the formerly mentioned Plague at Nimmegen by a Physician so Judicious as 
* Tract. de Peste, lib. 2. cap. 3.  Dimmerbrook, whose words are these; Illud notatu dignum saepissime observavimus, nempa in illis aedibus in quibus nulla adhuc pestis erat, si linteamina sordida aquâ & sapone nostrate (ut in Belgio moris est) ilio lavarentur, eo ipso die, vel interdum postridie, duos tres-ve simul peste correptos fuisse, ipsique aegri test abantur faetorem aquae saponatae illis primam & maximam alterationem intulisse. Hoc ipsum quoque in meo ipsius hospitio infelix experientia docuit, in quo post lota linteamina statim gravem alterationem perceperunt plaerique domestici, & proximè sequenti nocte tres peste correptae, ac brevi post mortuae fuere. I omit the Instances he further sets down to confirm this odd Phaenomenon, of which, though perhaps some other 'Cause may be devised, yet that I lately assigned seems at least a probable one, if not the most probable; since, as 'tis manifest by daily experience, that the smell occasioned by the washing of foul Linen with the Soap commonly used in the Netherlands, produces not the Plague; so by our Learned Author's Observation it appears, either that there were not yet any Pestilential Effluxions in the Air of those places, which on the occasions of those washings became infected, or at least that by the addition of the fetid Effluvia of the soapy Water, those Morbific Particles, that were dispersed through the Air before, had not the power to introduce a malignant constitution into the Air, and to act as truly Pestilential, till they were enabled to do so by being associated with the ill-scented Effluvia of the Soap.  
Whether also Salutary, and, if I may so call them, Alexipharmacal Corpuscles may not be produced in the Air by Coalition, might be very well worth our Enquiry: Especially if we had a competent Historical Account of the yearly ceasing of the Plague at Grand Cayro. For, as I have elsewhere noted out of the Learned Prosper Alpinus, who practised Physic there; and as I have also been informed by some of my Acquaintance who visited that vast City, that almost in the midst of Summer as soon as the River begins to rise 
* The Plague which here miserably rageth upon the first of the Flood doth instantly cease; in so much as when five Hundred dye at Cayro the day before, which is nothing rare, (for the sound keep company with the sick, holding Death fatal, and, to avoid them, Irreligion,) not one doth die the day following; says Mr. Sandys in his Travels, Lib. 2. , the Plague has its malignity suddenly checked, even as to those that are already infected, and soon after ceases; so if other Circumstances contradict not, one might guests, that this strange Phaenomenon may be chiefly occasioned by some Nitrous or other Corpuscles that accompany the overflowing Nile, and by associating themselves with what Hypocrates somewhere calls 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉, disable them to produce their wont pernicious Effects. To which Hypothesis suits well what is delivered by more than one Traveller into Egypt, and more particularly by our Ingenious Countryman Mr. George Sandys, who not only takes notice, that about the time of the overflowing of Nilus, whose abounding with Nitre has been observed even by the Ancients, there is a certain moistening Emanation diffused thorough the Air. To prove, says he 
* Mr. Sandys in the Book abovecited. , speaking of the overflowing of Nilus, that it proceedeth from a natural Cause, this one, though strange, yet true Experiment will suffice. Take of the Earth of Egypt adjoining to the River, and preserve it carefully, that it neither come to be wet nor wasted, weight it daily, and you shall find it neither more nor less heavy until the seventeenth of June, at which day it beginneth to grow more ponderous, and augmenteth with the augmentation of the River, whereby they have an infallible knowledge of the state of the Deluge, proceeding without doubt from the Humidity of the Air, which having a recourse through all passable places, and mixing therewith increaseth the same, as it increaseth in moisture.  
That these Sanative Steams perform their Effects merely because they are moist, I presume Naturalists will scarce pretend; but that they may be of such a nature as by their Coalition with the Morbific Corpuscles to increase their Bulk and alter their Figure, or precipitate them out of the Air, or clog their Agility, or pervert their Motions, and in a word destroy all or some Tat lest of those Mechanical▪ Affections which made those Corpuscles Pestilential: That, I say, these Antidotal Vapours (if I may so call them) may have these Effects upon those that formerly were Morbific, and that so there may result from the Association of two sorts of Particles, whereof one was of a highly noxious nature, a harmless mixture, might here be made probable by several things; but that I hope what I have lately recited about the Coalitions of the Effluvia of Spirit of Salt and of Urine (Liquors known to be highly contrary to each other) is not already forgotten by you.  
And the Experiment with which I am to conclude this Essay will perhaps make you think it possible, that the Pestiferous Steams that have already passed out of the Air, and invaded, but not too much vitiated, the Bodies of Men, may have their malignity much debilitated by the supervening of these Antidotal Particles. For in that Experiment you will find, that the Steams emitted into the Air from the Liquor there described, though that were actually cold, were able to reach, and manifestly to Operate, (and that probably by way of Precipitation,) upon Corpuscles that were fenced from them by the Interposition of other Bodies; not more porous than those of living Men. Whether the fume of Sulphur, which by many is extolled to prevent the Infection of the Air, do by its acid or other Particles disarm, if I may so speak, the Pestilential ones, I have not now time to inquire: No more than whether in Ireland and some few other Countries, that breed or brook no poisonous Animals, that hostility may proceed, at least in great part, from the peculiar Nature of the Soil, which both from its superficial and deeper parts, constantly supplies the Air with Corpuscles destructive to venomous Animals. And some other Particulars, that may be pertinently enough considered here, you may find treated on in other Papers. And therefore at present I shall only intimate in a word, that having purposely made a visible and lasting Stain on a solid Body barely by cold Effluvia, I did by the invisible and cold Steams of another Body make in two or three Minutes a visible change in the colour of that Stain.  
And as for the other part of the Conjecture, (viz.) That Meteors may sometimes be produced by the Occursions of Subterraneal Effluvia, some of them of one determinate Nature, and some of another, I think I could, to countenance it, give you divers Instances of the plentiful Impregnation) of the Air at some times, and in some places, with Steams of very differing Natures, and such as are not so likely to be attracted by the Heat of the Sun, as to be sent up from the Subterraneal Regions, and sometimes from Minerals themselves. But for Instances of this kind, I shall, for brevity's sake, refer you to another Paper 
* An Essay of Subterraneal Exhalations. , where I have purposely treated of this Subject, and particularly shown, That though usually the Effluxions that come from under ground are ill-scented, yet they are not always so; and also that Sulphureous Exhalations even from cold, and, for the most part, Aqueous Liquors may retain their determinate nature in the Air, and act accordingly upon solid Bodies themselves, to whose Constitution those Effluvia chance to be proportionate.  
But one memorable Story not mentioned 〈…〉 that Discourse is too much to our present purpose to be here omitted, especially having met with it in so approved an Author as the experienced Agricola, who having mentioned out of ancient Historians the Raining of White and Red liquors, which they took (erroneously I doubt not) for Milk and Blood, subjoins, 
* Agric. de Nat. eorum quae effluunt è Terra, Lib. 12. pag. 236.  Ut autem majorèm fidem habe amus Annalium monumentis facit res illa decantata, quae Patrum memoriâ (in another place he specifies the Year of our Lord) in Suevia accidit; Aer enim ille stillavit guttas, quae lineas vestes crucibus rubris quasi sanguineis imbuebant. Which I the rather mention, because it does not only prove what I allege it for; but may keep, what is lately and very credibly reported to have happened in divers places of the Kingdom of Naples soon after the Fiery Eruption of Vesuvius, from being judged a Phaenomenon either altogether fabulous, (as doubtless many have thought it,) or a Prodigy without all example, as is presumed even by those that think it not miraculous. And to this I add, that 'twill be the less improbable, that the more agile Corpuscles of Subterraneal Salts, Sulphurs and Bitumens', may be raised into the Air, and keep distinct natures there, if so fixed a Body as common Earth itself can be brought to swim in the Air. And yet of this the worthy Writer newly quoted gives us, besides what Annals relate, this Testimony upon his own knowledge: 
* Agric. de Nat. eorum quae è Terra effluunt, Lib. 12. pag. 263.  Certè hîc Kempnicii undecimum abhinc annum mense Septembri effluxerunt imbres, sic cum terra lutea commisti, ut eâ passim plateas scilicet stratas viderem conspersas.  
And to show you that in some cases the Particles even of Vegetable Bodies may not so soon perish in the Air as they vanish there, but may retain distinct natures at a greater distance, than one would think, from the Bodies that copiously emit them; I shall add, that having desired an ingenious Gentleman, that went on a considerable Employment to the East-Indies, to make some Observations for me in his Voyage; he sent me among other things this Remark: That having sailed along the Coast of Ceylon, (famous for Cinnamon-trees and well-scented Gums,) though they Coasted it almost a whole day, the Wind, that then chanced to blow from the shore, brought them a manifestly odoriferous Air from the Island, though they kept off many miles (perhaps twenty or twenty-five) from the shore. Nor should this be thought incredible, because the diffusion seems so disproportionate to that of other Bodies dissolved by Fluids'; as, for instance, though Salt be an active Body and resoluble into abundance of minute Particles, yet one part of Salt will scarce be tastable in an hundred parts of Water. For sensibly to affect so gross an Organ as that of our Taste, there is usually required in sapid Particles a bigness far exceeding that which is necessary to the making Bodies fit Objects for the sense of Smelling, and, which is here mainly to be considered, there is a great difference between the power a Body has to impregnate so thin and fine a Fluid as Air, whose parts are so rare and lax, and that which it has to impregnate Liquors, such as Water or Wine, whose parts are so constipated as to make it not only visible and tangible, but ponderous. On which occasion I remember that having had a Curiosity to try how far a sapid Body could be diluted without ceasing to be so, I found by Trial, that one drop of good Chemical, and, as Artists call it, Essential Oil of Cinnamon being duly mixed by the help of Sugar with Wine, retained the determinate taste of Cinnamon, though it were diffused into near a quart of Wine. So that making a moderate estimate, I concluded, that upon the common supposition, according to which a drop is reckoned for a Grain, one part of Oil had given the specific Taste of the Spice, it was drawn from, to near fourteen thousand parts of Wine. By comparing which Experiment with what I noted about the proportion of Salt requisite to make Water taste of it, you will easily perceive; that there may be a very great difference in point of diffusiveness between the little Particles that make Bodies sapid: Which may serve to confirm both some part of the first Chapter of the foregoing Essay of the Subtlety of Effluvia▪ and what I was lately saying to show it possible, that Antimonial Glass might impart store of Steams to the Emetic Wine, without appearing upon common Scales to have lost of its weight; since we see, that one Drop of so light a Body as Oil may communicate not insensible Effluvia, but tastable Corpuscles to near a Quart of Liquor. But this is not all for which I mention our Experiment: for I must now add, that besides the almost innumerable Sapid parts of a spicy Drop communicated to the Wine, it thence diffused a vast number of odorous Particles into the Air, which both I, and others perceived to be imbued with the distinct scent of Cinnamon, and which perhaps the Liquor would have been found able to have Aromatized for I know not how long a time, if I had had leisure to prosecute the Observation.   

CHAP. V.  
THE third and last way I shall mention of showing the Determinate Nature of Effluviums, is to be taken from the Consideration of their Effects upon other Bodies than the Organs of our Senses; (for of their Operations upon these we have already spoken in the foregoing Chapter▪) For the Effects, that certain Bodies produce on others by their Effluviums, being constant and determinate, and oftentimes very different from those, which other Agents by their Emissions work upon the same and other subjects, the distinct nature of the Corpuscles emitted may be thence sufficiently gathered.  
We may from the foregoing Tract of the Subtlety of Effluvia, borrow some Instances very pertinent to this place. For the temporary benumbedness or stupefaction, for example, produced in the Fisherman's Foot by the Effluvia 
* See the Essay of the Subtlety of Effluviums, Chap. 4.  of the Fish (Amoreatim) mentioned by the Ingenious Piso, manifests, that those stupifying Emanations retained a peculiar and venomous nature during their whole passage through the Shoe, Stocking and Skin, interposed betwixt the Fish and the nervous part of the Foot benumbed by it. And though there are very few other Bodies in the World, that are minute enough to pass through the pores of Glass, 'tis apparent, by the Experiment there recited of the oblong Iron Hermetically sealed up in a Glass-pipe, that the Magnetical Effluvia of the Earth may retain their peculiar and wonderful nature in a smallness that qualifies them to pass freely through the pores of Glass itself.  
But that I may neither repeat what you have already met with in the foregoing Tract, nor anticipate what I have to say in the next; I will employ in this Chapter some Instances that may be spared from both.  
That divers Bodies of a Venomous nature may exercise some such Operations upon others by their Effluviums transmitted through the Air, as they are wont to do in their gross substance, is a Truth, whereof though I have not met with many, yet I have met with some Examples among Physicians.  
The Learned 
* Lib. 6. parte 7. cap. 1.  Sennertus observes as a known thing, that the Apprentices of Apothecaries have been cast into profound Sleeps, when in distilling Opiate and Hypnotick Liquors they have received in at their Nostrils the Vapours exhaling from those Bodies.  
'Tis recorded by the 
* In Explicatione Herbarum Biblicarum, cap. 2.  Writers about Poisons, that the root and juice of Mandragora casts those, that take it, into a deep Sopor not unlike a Lethargy. And though the Apples of the same Plant be thought to be much less malignant; yet Levinus Lemnius relates that it happened to him more than once, that having laid some Mandrake-Apples in his Study, he was by their Steams made so sleepy, that he could hardly recover himself; but the Apples being taken away he regained alacrity, and threw off all drowsiness.  
Among all Poisons there is scarce any whose Phaenomena are in my opinion more strange than those that proceed from a mad Dog; and yet even this Poison, which seems to require Corpuscles of so odd and determinate a nature, is recorded by Physicians to have been conveyed by Exhalations. Aretaeus writes (as a Learned modern quotes him,) Quòd à rabido cane, qui in faciem, dum spiritus adducitur, tantummodò inspiraverit, & nullo modo momorderit, in rabiem homo agatur. And as there are relations, among Physicians, of Animals, that have become Rabiosi by having eaten of the parts or excrements of rabid Animals; so 
* Libro 3. Acutor. Morbor.  Caelius Aurelianus, who writes, that some have been made to run mad, not by being bitten, but wounded only with the Claws of a mad Dog, tells us also of a man, that fell into a Hydrophobia (which is wont to be a high degree of the Rabbis, and by some of the ancienter Writers was employed to signify that Disease) without being bitten by a mad Dog, but infected solo odore ex rabido cane attracto. By which Odours in this and other Narratives of Poisons I understand not a bare Scholastic species, but a swarm of Effluvia, which most commonly are all or at least some of them odorous. And though it may justly seem strange to many, that the Venom of a mad Dog should be communicated otherwise than by biting, which is supposed to be the only way he can infect by, it may appear less improbable, because Matthaeus de Gradibus names a person, who, he says, proved infected after many days, by only having put his Hand into the Mouth of a mad Dog, who did not bite him. And the formerly mentioned Matthiolus relates, that he saw two, that were made rabid without any would by the slabber of a mad Dog, with which they had the misfortune to be besmeared.  

* Sennert. Libr. 6. part. 6. cap. 2.  Sennertus himself affirms of a Painter of his acquainance, that, when he had opened a Box, in which he had long kept included Realgar, a noxious Mineral, sometimes used by Painters and not unknown to Chemists, and had unfortunately snuffed in the Steams of it, he was seized with a giddiness in his Head and fainting fits, his whole Face also swelling, though by taking of Antidotes he escaped the danger.  
Divers other Examples we have met with in the writings of Physicians, which I forbear to add to these, because, I confess, I very much doubt the Truth of them, though the deliverers of some of them be men of Note. But the probability of most of the things already cited out of credible Authors may be strengthened by what I shall now subjoin, as a further proof of the distinct Nature of Effluvia; of which it will be a very considerable Proof, if Medicines, which are of a milder and more familiar nature and operation than Poisons, shall yet be able in some cases to retain, in their invisible Particles swimming in the Air, the same, (though not so great) power of Purging, which is known to belong to them when their gross Body is taken in at the Mouth. Of this I have elsewhere, on another occasion, given some Examples. To which I shall now add, that I know a Doctor of Physic, that is usually Purged by the Odours or Exhalations of a certain Electuary, whose Cathartick Operation, when it is taken in substance, is wont to be but languid. And another Doctor of my acquaintance, causing good store of the root of black Hellebore to be long pounded in a mortar, most of those, that were in the room, and especially the party that pounded it, were thereby purged, and some of them strongly enough. And the Learned Sennertus somewhere affirms, that some will be purged by the very Odour of Colocynthis. And 'tis not to be passed by unregarded; that in the cases I have alleged, Exhalations, that are endowed with Occult Qualities, (for those of Cathartick Medicines are reckoned among such) ascend into the Air without being forced from the Bodies they belonged to by an External heat.  
And if I would in this place allege Examples of the Operations of such Effluvia, as do not pass into the Air, but yet operate only by the contact of the External parts of the Body, I could give Instances, not only of the Purgative, but the Emetic Qualities of some Medicines exerted without their being taken in at the Mouth, or injected with Instruments.  
There are also other sorts of Examples than those hitherto mentioned, that argue a Determinate Nature in the Effluxions of some Bodies emitted into the Air. Approved Writers tell us, that the Shadow of a Walnut-tree with the Leaves on it is very hurtful to the Head; and some Instances they give us of great mischief it has sometimes done. And though the Shadow, as such, is not likely to be guilty of such bad Effects; yet the Effluvia of the neighbouring Plant may be noxious enough to the Head. For I, that was not at all prepossessed with an opinion that it was so, and therefore without scruple resorted to the Shade of Walnut trees in a hot Country, was by experience forced to think it might give others the Headache, since it did to me, who, thanks be to God, both was, and am still very little subject to that distemper. And this brings into my mind an Observation that I have met with among some ingenious Travellers into the West-Indies, who observe in general, and of late a Countryman of our own affirms it in particular, of the poisonous Manchinello-tree, that Birds will not only forbear to eat of the Fruit of venomous Plants, but, as to some of them, will not so much as light on the Trees: Which I therefore mention, because probably Nature instructs them to avoid such Trees by some noxious Smell, or other Emanation, that offends the approaching Birds. And I remember, that some of our Navigators give it for a Rule to those that happen to land in unknown Islands or Coasts, that they may venture to eat of those parts of Fruits which they can perceive, the Birds, like kind Tasters, to have been pecking at before.  
Nicolaus Florentinus (cited by Sennertus) tells us of a certain Lombard, that having in a House, that he named, at Florence, burned a great black Spider at the flame of a Candle, so unwarily, that he drew in the Steams of it at his Nostrils, presently began to be much disordered and fell into a fainting fit, and for the whole night had his Heart much disaffected, his Pulse being so weak, that one could scarce perceive he had any; though afterwards he was cured by Treacle, Diamose, and the powder of Zedoary mixed together.  
And I remember, that being some years ago in Ireland, I gathered a certain Plant (peculiar to some parts of that Country) which the Natives call Maccu-buy, because of strange Traditions that go about it; the chief of which I found by trial not to be true: But yet being satisfied, that its Operations were odd and violent enough, I was willing to gratify the chief Physician of the Country, who was desirous I should propose to him some ways of correcting it; and whilst I was speaking of one that required the pounding of it, he told me on that occasion, that intending to make an extract of it with Vinegar, he caused his man to beat it well in a Mortar, which the man soon repented he had begun to do: And the Doctor himself, though at a pretty distance off, was so wrought upon by the Corpuscles that issued out into the Air, that his Head, and particularly his Face, swelled to an enormous and disfiguring bulk, and continued tumid for no inconsiderable time after.  
I have not leisure to subjoin many more Instances to show the Determinate Nature of Effluviums, small enough to wander through the Air; nor perhaps will it be necessary, if you please but to consider these two things. The first, that many odoriferous Bodies, as Amber, Musk, Civet, etc. as they will, by the adhesion of their whole substance, perfume Skins, Linen, etc. so they will in time perfume some Bodies disposed to admit their action, though kept at a distance from them. And the other is, that in Pestilential Fevers and divers other Contagious sicknesses, as the Plague, Smallpox, or Measles, the same determinate Disease is communicable to found persons, not only by the immediate contact of the infected party; but without it, by the Contagious Steams that exhale from his Body into the Air. And having said this and desired you to reflect upon it, I shall conclude this Chapter with an Experiment, that possibly will not a little confirm a great part of it.  
Considering then with myself, how I might best devise a way of showing to the very Eye, That Effluvia elevated without the help of Heat, and wandering in the Air, may both retain their own Nature, and upon determinate Bodies produce Effects, that a Vulgar Philosopher would ascribe to Occult Qualities: I remembered, that I had found by trials (made to other purposes) that Volatile and Sulphureous Salts would so work upon some Acid ones sublimed with Mercury, as to produce an odd diversity of Colours, but chiefly an Inky one; on which account I judged it likely that my aim would by answered by the following Experiment.  
I took an Ounce, or better, of such a Volatile Tincture of Sulphur, as I have elsewhere 
* The Liquor here mentioned is, for the main, the same with that described by the Author in his Book of Colours, Experiment the 〈…〉  taught you to make of Quicklime, Sulphur and Sal Armoniac, and stopped it up in a Vial capable of containing at least twice as much; then taking a Paper whereon something had been written with invisible Ink, I laid it down six Inches off of the Vial, which, being unstopped, began, upon the access of the Fire, to emit white Fumes into it; and by these, what was written upon the Paper, notwithstanding its distance from the Liquor, quickly became very legible, though not quite so suddenly, as if a Paper, written with the same clear Liquor, were held at the like distance directly over the orifice of the Vial. And having caused several pieces of clean Paper to be written on, with a new Pen dipped in the clear Solution of Sublimate made in Water, 'twas pleasant to see, how divers of the Letters of several of these Papers, being placed within some convenient distance of the Vial, would be made plainly legible, and some of them more, some less blackish, according to their distances from the smoking Liquor, and other Circumstances. But 'twas more surprising to see, that when I held or laid some of these Papers, though with the written side upwards, just upon or over the orifice of the Vial, though the contained Liquor did not by some Inches reach so high, yet the latent Letters would become not only legible but conspicuous in about a quarter of a Minute of an Hour (measured by a good Watch fit for the purpose, as more than one trial assured me.) And as it may be observed, that in some Circumstances the smoking Liquor and the Solution of Sublimate will make an odd Precipitate almost of a silverish colour, so in one or two of our Trials we found a like colour produced, by the Steams of that Liquor, in some of the colourless Ink. Nor is it so necessary to employ a visibly smoking Liquor for the denigrating of invisible Ink at a distance. For I have, to that purpose, with good success, though not equal to that I have recited, employed a couple of Liquors, wherein there was neither Sulphur, nor Shall Armoniac, nor Sublimate. What other Trials I made with our Volatile Tincture of Sulphur, 'tis not necessary here to relate, only one Experiment, which you will possibly think odd enough, I shall not omit; because it will not only confirm the precedent Trials, but also much of the foregoing Essay, by showing the great Subtlety and penetrating power of Effluviums that seem rather to issue out very faintly, than to be darted out with any briskness.  
Causing then something to be written with dissolved Sublimate upon a piece of Paper, we folded the Paper with the written side inwards, and then enclosed this in the midst of six sheets of Paper, laid one upon another, not placed one within another, and folded up in the form of an ordinary Letter or packet to be sealed, that, the edges of the enclosing Paper being inserted one within the other, the Fumes might not get into this written Paper but by penetrating through the Leaves themselves: This done, that side of the Packet, on which there was no commissure, and on which, were it to be sent away, the Superscription should be written, was laid upon the orifice of the Vial, which (as was before intimated) was some Inches higher than the surface of the Liquor, and left there about ten Minutes; after which taking off the folded Papers, and opening them, we found, that the Steams had pervaded all the Leaves, in which the written Paper had been enclosed. For, though the Leaves did not appear stained or altered, yet the formerly latent Characters appeared conspicuous. I have not time to discourse, whether and how far this Experiment may assist us to explain some odd Effects of Thunder, or of that strange Phaenomenon, (glanced at in the foregoing Chapter,) which is said to have happened lately in the Kingdom of Naples after the great Eruption of Vesuvitus, which is said to have been followed by the appearing of the Crosses formerly mentioned, some of which have been found on the innermost parts of Linen, that had been carefully folded up. But of these and the like things, I say, I have now no time to discourse, whether any thing derivable from our Experiment may be pertinently applied to their Explication. For which reason I shall add no more than that afterwards for further trial we took a printed Book, that chanced to be at hand, and which we judged the fittest for our purpose, because the leaves being broad they might the better preserve a small Paper to be placed in the midst of them from being accessible to the Exhalations sidewise, and having put the designed Paper into this Book, and held it to the orifice of the Vial, though there were no less than twelve leaves between them; yet those Letters, that happened to be the most rightly placed, were made inky in the short space of three Minutes at the utmost; though this Liquor had been so long kept and so often unstopped to try Conclusions with it, that it had probably lost a good part of the most spirituous and piercing Particles.    

NEW EXPERIMENTS, To make the PARTS OF FIRE and FLAME Stable & Ponderable.  
BY The Honourable Robert boil.  
LONDON: Printed by WILLIAM GODBID, for Moses Pitt, at the Sign of the White Hart in Little Britain. 1673.   

A PREFACE; SHOWING The Motive, Design, and Parts of the ensuing Tract.  
THE Inducements which put me upon the Attempt, expressed in the Title of this Essay, were chiefly these:  
First, I considered, that the Interstellar part of the Universe, consisting of Air and Aether, or Fluids' analogous to one of them, is diaphanous; and that the Aether is, as it were, a vast Ocean, wherein the Luminous globes, that here and there like Fishes swim by their own motion, or like Bodies in Whirlpools are carried about by the Ambient, are but very thinly dispersed, and consequently that the proportion, that the Fixed Stars and Planetary Bodies bear to the diaphanous part of the World, is exceeding small and scarce considerable; though we should admit the Sun and Fixed Stars to be Opacous Bodies upon the account of their terminating our sight: Which diffident Expression I employ, because I have elsewhere shown by two or three Experiments, purposely devised, that a Body may appear opacous to our Eyes, and yet allow free passage to the beams of Light.  
I further considered, that there being so vast a disproportion between the diaphanous part of the World and the Globes, about which 'tis every way diffused, and with which it is sometimes in great portions mingled, as in the water, which together with the Earth makes up the Globe we inhabit; and the nature of Diaphanous Bodies being such, that, when the Sun or any other Luminous Body illustrates them, that which we call Light does so penetrate and mix itself per minima with them, that there is no sensible part of the transparent Body uninlightned; I thought it worth the enquiry, whether a thing, so vastly diffused as Light is were some thing Corporeal or not? And whether, in case it be, it may be subjected to some other of our Senses besides our Sight, whereby we may examine; whether it hath any affinity with other Corporeal beings, that we are acquainted with here below?  
I did not all this while forget, that the Peripatetics make Light a mere Quality, and that Cartesius ingeniously endeavours to explicate it by a modification of Motion in an Aetherial matter: But I remembered too, that the Atomists of old, and of late the Learned Gaffendus, and many other Philosophers assert Light to be Corporeal; and that some Tears since, though I declined to pass my Judgement about the Question, yet I had employed Arguments, that appeared plausible enough to show, That 'twas not absurd to suppose, that the Sun, which is the Fixed Star most known to us, might be a Fiery Body. And therefore doubting, whether the Corporeity of Light would be in haste Determined by mere Ratiocinations, I thought it very well worth the endeavouring to try whether I could do any thing towards clearing the dispute of it by Experiments; especially being persuaded, that, though such an attempt should be ineffectual, it would but leave the controversy in its former state, without prejudicing either of the contending Hypotheses; and yet, if it should prove successful, the consequences of it would be very great and useful towards the explicating of divers Phaenomena in divers parts of Natural Philosophy, as in Chemistry, Botanics, and (if there be any such) the allowable part of Astrology. (Nor perhaps would it be impossible by the help of slight Theorical alterations; to reconcile the Experiments, I designed, to either of the abovementioned Hypotheses, and so as to the Explication of Light, to one another.)  
To compass then, what I aimed at, I thought, 'twas fit in the first place to try, what I could do by the Union of the Sunbeams, they being on all hands confessed to be Portions (as I may so speak) of true and Celestial Light: And then, I thought fit to try, what could be obtained from Flame; not only because that is acknowledged to be a Luminary but because I hoped, the difficulties, I foresaw in the other Trials, might be in some measure avoided in those made with Flame; and if both sorts of them should succeed, the later and former would serve to confirm each other. According to the Method I proposed of handling these two Subjects, I should begin with some account of what I attempted to perform in the Sunbeams: But the truth is, that when I chanced to fall upon the Enquiry that occasioned this Paper, besides that the time of the Year itself was not over-favourable, the weather proved so extraordinary dark and unseasonable that it was wondered at; so that, though I was furnished with good Burning-glasses, and did several times begin to make trials upon divers Bodies, as Led, Quicksilver, Antimony, etc. yet the frequent interposition of Clouds and Mists did so disfavour my Attempts, that, however they were not all alike defeated, yet I could not prosecute the greatest part of them to my own satisfaction. And therefore being unwilling to build on them as yet; I shall reserve an account of them for another opportunity; and now proceed to the mention of that sort of Experiments which depending less on Casualties, 'twas more in my power to bring to an Issue.  
I know I might have saved both you and myself some time and pains by omitting several of these Trials, and by a more compendious way of delivering the rest. But I rather chose the course I have taken; partly because the Novelty and Improbabilities of the Truth I deliver seems to require, that it be made out by a good number of Trials; partly because I thought it might not be altogether useless to you and your Friends, to see upon what Inducements the several steps were made in this Inquiry; partly because I was willing to contribute something towards the History that now perhaps will be thought fit to be made of the Increment or Decrement that particular Bodies may receive by being exposed to the Fire; and partly (in fine) because the Incongruity of the Doctrine here asserted to the Opinions of the Schools, and the general Prepossessions of Mankind, made me think it fit by a considerable Variety, as well as number, of Experiments to obviate, as far as may be, the differing Objections and Evasions wherewith a Truth so paradoxical may expect to be encountered.   

New EXPERIMENTS, To make FIRE and FLAME PONDERABLE.  
THough there be among the following Trials a Diversity that invites me, as to rank them into four or five differing sorts, so to assign them as many distinct Sections; yet for the conveniency of making the References, there will be occasion to make betwixt them, I shall wave the Distinction, and set them down in one continued Series.  
And because I am willing to comply with my haste, as well as to deal frankly and without Ceremony with you, I shall venture to subjoin the naked Transcripts of my Experiments, as I had in an artless manner set them down with many others for my own remembrance among my Adversaria, without so much as retrenching some Circumstances that relate less to my present Argument, than to some other purposes.  
I shall then begin with the mention of a couple of Experiments, which though they might conveniently enough be referred to another Paper; yet I shall here set them down, because it seems very proper to endeavour to show in the first place, that Flame it-self may be as 'twere incorporated with close and solid Bodies so as to increase their bulk and weight.  

Trials of the First sort.  

EXPERIMENT I.  
[A Piece of Copperplate not near so thick as a Half-crown, and weighing two Drachmas and twenty-five Grains, was so placed with its broad part Horizontal, in a Crucible, whose bottom had a little hole in it, for Fumes to get out at, that it could not be removed from its Position, nor be easily made to drop down or lose its Level to the Horizon, though the Crucible were turned upside down: Then about an Ounce and half of common Sulphur being put into a taller and broader Crucible, that, wherein the Copper stuck, was inverted into the orifice of it, that the Sulphur being kindled, the flame, but not the melted Brimstone in substance, might reach the Plate, and have some vent beyond it at the abovementioned hole. This Brimstone burned about two Hours, in which time it seemed all to have been resolved into Flame, no flowers of Sulphur appearing to have sublimed into the inside of the upper Crucible; and though the Copperplate were at a considerable distance from the ignited Sulphur, yet the Flame seemed to have really penetrated it, and to have made it visibly swell or grow thicker; which appeared to be done by a real accession of substance: since, after we had wiped off some little adhering sordes, and with them divers particles of Copper that stuck close to them, the Plate was found to weigh near two and thirty Grains more than at first, and consequently to have increased its former weight by above a fifth part.]   

EXPER. II.  
[Having, by refining one Ounce of sterling Silver with Saltpetre, according to our way reduced it to seven Drachms or somewhat less; we took a piece of the thus purified Silver, that weighed one Drachm wanting two Grains, and having ordered it as the Copperplate had been in the former Experiment, after the flame of above one Ounce and a quarter of Sulphur, (that Quantity chancing to be suitable to the Capacity of the Crucible) had for about an Hour and a half beat upon it, the Silver-plate seemed to the Eye somewhat swelled, and the lower surface of it, that was next the flame, was brought to a great smoothness, the weight being increased to one Drachm five Grains and three quarters; which increase of weight falling so short of that which was gained by the Copper, I leave it to you to consider, whether the difference may be attributed to the closeness and compactness of the Silver, argued by its being heavier in specie than Copper; or to the greater congruity of the pores of Copper to be wrought on by the fiery Menstruum; or to some other cause.]  
If you should here ask me, by what Rational inducements I could be led to entertain so extravagant an expectation, as that such a light and subtle Body as Flame should be able to give an augmentation of weight to such ponderous Bodies as Minerals and Metals; I shall now, to avoid making anticipations here, or needless repetitions hereafter, return you only this Answer: That the expectation you wonder at may justly be entertained upon the same or such like inducements, as you may easily discover in another Paper, entitled Corollarium Paradoxum. For, supposing upon the grounds there laid, that Flame may act upon some Bodies as a Menstruum, it seems no way incredible, that, as almost all other Menstruums, so Flame should have some of its own Particles united with those of the Bodies exposed to its action: And the generality of those Particles being, (as 'tis shown in the Paradox about the Fuel of Flames,) either Saline, or of some such piercing and Terrestrial nature, 'tis no wonder, that being wedged into the Pores, or being brought to adhere very fast to the little Parts of the Bodies exposed to their action, the accession of so many little Bodies, that want not gravity, should, because of their multitude, be considerable upon a Balance, whereon one or two, or but few of these Corpuscles would have no visible Effect.  
I could here, if it were expedient, mention some odd scruples about the preceding Experiments, and some also of the subsequent; but, lest you should, with some other of my Friends, upbraid me with being too jealous and Sceptical, I will not trouble you with them; but proceed to the next sort of Trials, wherein, though the matter were not always manifestly beaten on by a shining Flame; yet it was wrought on by that, which would be called Flame by those who take not that word strictly, but in a latitude, and which this Igneous substance may more properly be styled, than it can be called common Fire, this being visibly harboured in burning Coals or other gross materials, from which our Metals were fenced. And I have elsewhere shown by experiment, that Visibility is not in all cases necessary to Actual Flame, particularly when the Eye receives a predominant impression from another Light.    

Trials of the Second sort.  

EXPER. III.  
INto a Crucible, whose sides had been purposely taken down to make it very shallow, was put one Ounce of Copper-plates; and this being put into our Cupelling-furnace, and kept there two Hours, and then being taken out we weighed the Copper (which had not been melted) having first blown off all the ashes, and we found it to weigh one Ounce and thirty Grains.   

EXPER. IU.  
[Supposing that Copper, being reduced to filings, and thereby gaining more of Superficies in proportion to its bulk, would be more exposed to the Action of the Fire, than when 'tis in places as it was formerly; we took one Ounce of that Metal in filings, and putting them upon a very shallow Crucible, and under a Muffler, we kept them there about three Hours, (whilst other things that required so long a time were Cupelling;) and afterwards taking them off, we found them of a very dark colour, not melted but caked together in one Lump, and increased in weight (the ashes and dust being blown off) no less than about forty-nine Grains. Part of which increment, above that obtained by the Copper-plates in the former Experiment, may not improbably be due to the longer time that in this Experiment the filled Copper was kept in the Fire.]   

EXPER. V.  
[Being willing to see, whether calcined Hartshorn, that I did not find easy to be wrought on by corrosive Menstruums, would retain any thing of the Flame or Fire to which it should be exposed; we weighed out one Ounce of small Lumps of Hartshorn, that had been burnt till they appeared white, and having put them into a Crucible, and kept them in a Cupelling-furnace for two Hours, whilst some Metals were driving off there by the violence of the Fire; we found, that when they were taken out, they had lost six or seven Grains of their former weight; perhaps either because, notwithstanding the external whiteness of the Lumps, the internal Parts of some of them might not be so tightly calcined, but retain some Oleaginous or other Volatile Substance▪ or, because, having omitted to ignite them well before they were weighed, they may have since their first Calcination imbibed some moist Particles of the Air. Which conjecture seemed the likelier, because, having kept them a while in the Scales they were weighed in, they did within two or three Hours make it somewhat preponderate. On which occasion I shall add, that, at the same time, with the Hartshorn we put in one Ounce of well-heated Brick, and kept that likewise in the Furnace for above two Hours; at the end of which weighing it whilst it continued hot, we did not find it to have either sensibly got or lost; but, some time after, it seemed upon the Balance to have imbibed some, though but very little, moisture from the Air.]   

EXPER. VI  
[Upon a good Cupel we put one Ounce of English Tin of the better sort, and having placed it in the Furnace under a Muffler, though it presently melted, yet it did not forsake its place, but remained upon the concave surface of the Cupel, till at the end of about two Hours it appeared to have been well calcined; and then being taken out and weighed by itself, the Ounce of Metal was found to have gained no less than a Drachm.]   

EXPER. VII.  
[An Ounce of Lead was put upon the Cupel, made of calcined Hartshorn, and placed under the Muffler after that the Cupel was first made hot and then weighed. This Lead did not enter into the Cupel, but was turned into a pretty kind of lethargy on the top of it, and broke the Cupel, whereby some part of the Cupel was lost in the Furnace, and yet the rest, together with the lethargy, weighed seven Grains more than the Ounce of Lead and the heated Cupel did when they were put in.]  
But because, though this trial showed that some weight was gained either by the Metal or Cupel, or both; yet it did not by this appear, what either of them acquired; it seemed fit to subjoin a further trial.   

EXPER. VIII.  
[We took a Cupel about two Ounces in weight, made of about ten parts of Bone-ashes, and one of Charcoal-ashes, made up together with Ale. This was by itself put in a Cupelling-furnace, under a Muffler; and the Laborant, well versed in weighing, was ordered to take it out, when 'twas thoroughly and highly heated, and to weigh it whilst 'twas in that condition (I being then present:) This being done, 'twas forthwith placed again under the Muffler, where some Metalline Bodies were Cupelling, and kept there for about two Hours; at the end of which time 'twas taken out red-hot, and presently put into the same Balance, as before, which was already fastened to a Gibbet; where having caused the adhering ashes to be blown off, I found, that whereas, when 'twas first taken from under the Muffler, we had but two Ounces and two Grains, now the same weight being put into the opposite Scale, it had gained very near one and twenty Grains. And here note, that 'twas not without some cause, that I was careful to have the Cupel weighed red-hot. For I had a suspicion, that, notwithstanding the dryness of the Bone, it might receive some little alteration of weight by imbibing some little Particles wandering in the Air; which suspicion the event justified. For leaving the Cupel counterpoised to cool in the Balance, in a short time it began sensibly to preponderate; and suffering it to continue there nine or ten hours, till we had occasion to use the Balance, I found it at the end of that time to be about three Grains heavier than before.]  
This was not the only trial we made about the augmenting the weight of Cupels; but this being the fairest, and exempt from those mischances, from which the other were not altogether free; I shall content myself to have set down this: In the mention of which I thought fit to take notice of the increase of the weight of the Cupel after it had lain in the Scales, and also that we weighed it at first whilst it was throughly hot, because those Circumstnces, as not being suspected, may easily be left unthought on, even by skilful Experimenters; and yet the weighing of the Cupel, when it had been well nealed, and the not weighing it soon enough after 'tis taken from the Fire, may keep those, that shall reiterate this Experiment, from making it cautiously and accurately enough. For if the former Circumstance be omitted, that which the Cupel may seem to have lost of its substance, was nothing but the adventitious moisture of the Air; and if the later Circumstance be neglected, the weight, it may seem to have gained from the Fire, was indeed due to the waterish Particles of the Air. I could wish also, that trial were made, whether the success would be the same in Cupels made in differing sorts of Bone-ashes, and other materials, wont to be employed for that purpose. For That I had not opportunity to do.   

EXPER. IX.  
Iron being a Metal, that experience had informed me will more easily be wrought on by Fluids that have Particles of a Saline nature in them, than is commonly believed; 'twas not unreasonable to expect, that Flame would have a greater Operation on it, (especially if it were beforehand reduced to small Parts) than on any of the Bodies hitherto described. Which supposition will be confirmed by the short ensuing Note.  
[Four Drachms of filings of Steel being kept two Hours on a Cupel under a Muffler, acquired one Drachm six Grains and a quarter increase of weight.]   

EXPER. X.  
[A piece of Silver, refined in our own Laboratory, being put upon a Cupel under a Muffler, and kept there for an hour and half, whilst other things were refining, was taken out and weighed again, and, whereas before it weighed three Drachms, thirty-two Grains and a quarter, it now weighed in the same Scales three Drachms, thirty-four Grains and a half, or but little less.]  
Finding this Memorial among divers others about the Weight of Bodies, exposed to the Fire, I thought it not amiss to annex it in this place; though finding it to be but single, I would not have it to be relied on till further trial have been made to discover, whether it was more than a casual and anomalous Experiment; and if the Silver had not been refined, I should have suspected, that the Copper, that was blended with it, as 'tis usually blended with common Silver, might have occasioned the increased of weight.  

(Postcript.)  
Since the foregoing Experiment was first set down, meeting with an opportunity to reiterate the trial once more, we did it with half an Ounce of filings of Silver, well refined with Lead in our own Laboratory, and kept it about three hours upon the Cupel; after the end of which time taking it out, we found it to be of a less pleasant colour than it was of before, and melted (though not so perfectly) into a Lump, which weighed four Drachms and six Grains; and yet, the success being so odd, and, if it prove constant, of such moment, I could wish the trial were further repeated in differing quantities of the Metal.    

EXPER. XI.  
[We took a Drachm of filings of Zink or Spelter, and having put it upon a Cupel under a Muffler, we kept it there in a Cupelling-fire about three Hours, (having occasion to continue the Cupellation so long for other trials;) then taking it off the Cupel, we found it to be caked into a brittle and dark-coloured Lump, which looked as if the filings had been calcined. This being weighed in the same Scales gained full six Grains, and so a tenth part of its first weight.]   

EXPER. XII.  
Among our various trials upon common Metals, we thought fit to make one or two upon a Metal brought us from the East-Indies, and there called Tutenâg, which name being unknown to our European Chemists, I have elsewhere endeavoured to give some account of the Metal itself; whence I shall borrow the ensuing Note, as directly belonging to our present purpose.  
[Two Drachms of filings of Tutenâg being put upon a Cupel, and kept under the Muffler for about two hours, the filings were not melted into a Lump of Metal, but looked as if Ceruse and Minium being powdered had been mingled together; some of the parts appearing distinctly white; and others red: The Calx being put into the Balance appeared to have gained twentyeight Grains and a quarter. Another time the Experiment being reiterated with the like Circumstances, we found, that two Drachms of the filled Tutenâg gained the like increase of weight, abating less than one Grain.]  
So that this Indian Metal seems to have gained more in the fire, in proportion to its weight, than any we have hitherto made trial of.   

EXPER. XIII.  
[Being desirous to confirm by a clear Experiment, what I elsewhere deliver contrary to the vulgar Opinion of those that believe, that in all Cupellations almost all the Lead that is employed about them, does, together with the base Metals that are to be purged off from the Silver or Gold, fly away in Smoke, as indeed in some sort of Cupellations a good proportion may be blown off that way: We took two Ounces of good Lead and one Drachm of filings of Copper, and having caused a Cupel to be ignited, and nimbly taken out of the Furnace, and weighed, whilst 'twas very hot, 'twas presently put back, together with the two Metals laid on it, into the Cupelling-furnace, where having been kept for about two hours, it was taken out again, and 'twas found, according to what (as I elsewhere 
* Essay the sixth of the Useful. of Nat. Philos.  note) uses to happen in such Circumstances, to have nothing on the surface of it worth weighing distinctly in the Scales, in which the Cupel with what was sunk into it amounted to four Ounces three Drachms and eleven Grains, which wanted but nine Grains of the whole weight of the Cupel and the two Metals, when they were all three together committed to the Fire.] So that, though we make a liberal allowance for the increment of weight that may with any probability be supposed to have been attained by the Cupel and what was put upon it, yet it will easily be granted, that very much the greater part of the Metals was not driven off in Fumes, but entered into the Substance of the Cupel.    

Trials of the Third sort.  
AFter having shown that either Flame or the Analogous Effluxions of the Fire will be, what Chemists would call, Corporified with Metals and Minerals exposed naked to its action; I thought it would be a desirable thing to discover, whether this Flame or igneous Fluid were subtle enough to exercise any such Operation upon the Light Bodies sheltered from its immediate contact by being included in close Vessels; but it being very difficult to expose Bodies in Glasses to such vehement Fires without breaking or melting the Glass, and thereby losing the Experiment; I thought fit, first to employ Crucibles carefully luted together, that nothing might visibly get in or out, and of that attempt I find among my Notes the following Account.  

EXPER. XIV.  
[We took an Ounce of Steel freshly filled from a Lump of that Metal, that the filings might not be rusty, and having included them betwixt two Crucibles, as formerly, kept them for two hours in a strong Fire, and suffered them to continue there till the Fire went out; the Crucibles being unluted, the filings appeared hard caked together, and had acquired a dark colour somewhat between black and blue, and were increased five Grains in weight.]  
The foregoing Experiment being the first I mention of this kind, 'twill not be amiss to confirm it by annexing the following Memorial.  
[An Ounce of filings of Steel being put between the Crucibles luted together, after they had been kept about an hour and half in the fire, were taken out, and being weighed, were found to have gained six Grains.]   

EXPER. XV.  
[Two Ounces of Copperplate were put into a new Crucible, over which a lesser was whelmed, and the commissures were closed with lute, that nothing might fall in. After the same manner two Ounces of Tin were included betwixt Crucibles, and also two Ounces of Lead; these being put into the Cupelling-furnace were kept in a strong Fire about an hour and a half, while something else was trying there. And then being taken out, the event was, that the Copper-plates, though they stuck together, were not quite melted, and seemed some of them to have acquired scales like Copper put into a naked Fire, and the two Ounces had gained eight Grains in weight. The Lead had broke through the bottom of the Crucible, and thereby hindered the designed Observation. The Tin acquired six Grains in weight, and was in part brought to a pure white Calx, but much more of it was melted into a Lump of a fine yellow colour, almost like Gold, but deeper.] The prosecution of this trial as to the Copper-plates you will meet with in Experim. XXI. to which I therefore refer you.  
N. B. Because Lead in Cupellation enters the Cupel, we were willing to try, if we could so far hinder it from doing so, as to make some estimate what change of Weight the Operation of the Fire would make in it: And therefore being able already to make a near guess, how much a quantity of Tin may gain by being calcined on a Cupel, and remembering also from some of my former trials the indisposition which Tin gives Lead to Cupellation, we mixed a Drachm of Tin with two Ounces of Lead, and exposing the mixture (in a Cupel) to the Fire under a Muffler, we first brought it to fusion, and then it seemed at the top dry and swelled and discoloured; notwithstanding which, having continued the Operation a good while, because of other things that were to be done with the same Fire, we were not lucky enough to bring the Experiment to an issue worth the relating here, in reference to the scope above-proposed, though in relation to another the success was welcome enough.]   

EXPER. XVI.  
[Supposing that if Copper were beaten into thinner plates than those we lately used, and kept longer in the fire, this would have a more considerable Operation upon them, we took one Ounce of very thinly hammered pieces of Copper, and putting them betwixt two Crucibles (one whelmed over another) as in Experim. XV. with some lute at the corners of the juncture, to keep the fire from coming immediately at the Metal, we kept them in the Cupelling-furnace about three hours, and then disjoining the Vessels, we found the Metal covered with a dark and brittle substance, like that described in the above recited Experiment. Which substance, when scaled off, disclosed a finely coloured Metal, which, together with these burnt scales, amounted to one and twenty Grains above the weight that was first put in.]  
If, when these things were doing, I had been furnished with a very good Lute, which is no such easy thing to procure, as Chemists, that have not frequently employed vulgar Lutes, are wont to think; I would have made a trial of the ensuing Experiment for a good while in the naked Fire, notwithstanding that divers Metalline Minerals will scarce be brought to fusion in Glasses, especially without such a Fire, whose violence makes them break the Vessels. For I thought, that by making a fit choice of the Metals to be employed, I could prevent that inconvenience: But wanting the Accommodations I desired, and yet presuming, that in a Sand-furnace I might by degrees administer heat enough to melt so fusible a Metal as fine Tin, and keep it in fusion; I resolved to make some trials, first upon that, and then upon another Metal. For though I was not sure of being then able to prosecute the Experiment far enough; yet I hoped, I might at least see some Effects of my first trial, which would enable me to guests, what I was to expect from a complete one.   

EXPER. XVII.  
[We took then a piece of fine Block-Tin, and in a pair of good Scales weighed out carefully half a Pound of it; this we put into a choice Glass-retort, and kept it for two days or thereabouts in a Sand-furnace, which gave heat enough to keep the Metal in fusion without cracking the Glass. Then taking out the mixture, we carefully weighed it in the same Scales, and found the superficies a little altered (as if it were disposed to calcination) and the weight to be increased about two Grains or somewhat better.]   

EXPER. XVIII.  
[The other Experiment, I tried in Glasses, was with Mercury, hoping, that, if I could make a Precipitate per se in a Hermetically sealed Glass, I should by comparing the weight of the Precipitate, and the Quicksilver that afforded it, have a clear Experiment to my purpose; and I should have no bad one, if I could but make it succeed with a Glass, though not sealed, yet well stopped; instead of those Infernal-glasses (as they call them) which are commonly used and wont to be left open (though some slightly stop them with a little Paper or Cotton:) But though, partly that I might a little diversify the Experiment, and make it the more likely to succeed in one or other of the Glasses, I divided the Mercury and distributed it amongst several of them, and but a little to each, the success did not answer expectation, the Hermetically sealed Glasses being unluckily broken; and the Precipitation in the others proceeding so slowly, that I was by a remove obliged to leave the trial imperfect; only I was encouraged, (in case of a future opportunity) to renew it another time, by finding that most of the Glasses, though tall, and stopped with fit Corks, afforded some very fair Precipitate, but not enough to answer my Design.]    

Trials of the Fourth sort.  
MOst of the Experiments hitherto recited, having been made as it were upon the by with others, whose exigencies 'twas fit these should comply with; very few of the exposed Bodies were kept in the Cupelling-fire above two hours or thereabouts. Upon which account I thought fit to try, how much some Bodies, that had been already exposed to the Fire, would gain in weight by being again exposed to it; especially considering, that most calcinable Bodies, (for I affirm it not of all) which yield rather calces than ashes by being without additament reduced in the Fire to fine powder, seemed to be by that Operation opened, or (as a Chemist would speak) unlocked, and therefore probably capable of being further wrought upon and increased in weight by such a Menstruum as I supposed Flame and igneous Exhalations to be. And about this Conjecture I shall subjoin the ensuing Trials.  

EXPER. XIX.  
[One Ounce of Calx of Tin, that had been made per se for an Experiment in our own Laboratory, being put in a new Cupel and kept under the Muffler for about two hours, was taken out hot and put into the Scales, where the powder appeared to have gained in weight one Drachm and thirty-five Grains by the operation of the Fire, which made it also look much whiter than it did before, as appeared by comparing it with some of the Calx that had not been exposed to the second Fire: No part of the Puttie was, as we could perceive, melted by the vehemence of the Fire, much less reduced into Metal.]   

EXPER. XX.  
[Out of a parcel of filings of Steel, that had been before exposed to the fire and had its weight thereby increased some Grains, not Scruples; we took an Ounce, and having exposed it at the same time with the Calx of Tin, and, for the same time, kept it in the Fire, we took it out at the two hours' end; and found the weight to be increased two Drachms and two and twenty Grains. The filings were very hard baked together, and, the Lump being broken, looked almost like Iron.]   

EXPER. XXI.  
The following Experiment, though it may seem in one regard but a Continuation of the XVth; yet it has in this something peculiar from all the foregoing, that not only it affords an instance of the increase of Weight obtained by a Metal at the second time of its being exposed to the fire, but shows also, that such an increment may be had, though this second ignition be made in close Vessels.]  
[Some of the Copper mentioned in Experim. XV. being accidentally lost, one Ounce and four Drachms of what remained was included betwixt two Crucibles and exposed to a strong fire for two hours, and suffered to continue there till the fire went out: When it was taken out, it appeared to have gained ten Grains in weight, and to have upon the superficial parts of the Plates (as we observed) divers dark coloured flakes, some of which stuck to the Metal, but more, upon handling it, fell off.]  
And here I shall conclude One of the Two Parts of our designed Treatise: For, though I remember, that these were not all the Trials that were made and set down upon the Subject hitherto treated of; yet these are the chief, that having escaped the mischances, which befell some others, I can meet with among my promiscuous Memorials; whose number, when I drew them together, I could scarce increase, having by all these and other Trials of differing kinds wasted my Cupels and commodious Glasses, where I could not well repair my loss. Whether I should have been able by Reduction, specific Gravity, or any other of the ways, which I had in my thoughts, to make any discovery of the Nature of the Substance that made the Increment of Weight in our Ignited Bodies; the want as well of leisure, as of accommodations requisite to go through with so difficult a task, keeps me from pretending to know. But these three things, I hope, I may have gained by what has been delivered. The First, That we shall henceforth see cause to proceed more warily in the Experiments we make with Metals in the Fire, especially by Cupellation. The next, That it will justify and perhaps procure an easier assent to some passages in my other Writings, that have Relation to the Substance, whatever it be, that we are speaking of. And the third, (which is the principal,) That it will probably excite you, and your inquisitive Friends, to exercise their sagacious Curiosity, in discovering what kind of Substance that is, which, though hitherto overseen by Philosophers themselves, and, being a Fluid, far more subtle than visible Liquors, and able to pierce into the Compact and Solid Bodies of Metals, can yet add something to them, that has no despicable Weight upon the Balance, and is able for a considerable time to continue fixed in the Fire.    

Additional Experiments, ABOUT ARRESTING and WEIGHING OF Igneous Corpuscles.  
EXperiments to discover the Increase in Weight of Bodies, though enclosed in Glasses, being those that I considered as likeliest to answer what I designed in the hitherto prosecuted Attempt, and finding the seventeenth Experiment as well as the next (tried upon Mercury) to be very slow, and its performance not to be very great, I began to call to mind, what, many years ago, Experience had shown me possible to be performed, as to the managing Glass-vessels, even without coating them, in a naked Fire, provided a wary person were constantly employed to watch them. And supposing hereupon, that, in no longer time than a Laborant might, without being tired, hold out to attend a Glass, a Metal exposed in it to a naked fire might afford us a much more prosperous trial than that lately referred to, I afterwards resolved, when I should be able to procure some Glasses conveniently shaped, to prosecute my Design; in pursuance of which though I had not any Furnaces fitted for my purpose, I directed a Laborant to make the following Trials.  

EXPER. I.  
[We took eight Ounces (Troy weight) of Block-Tin, which being cut into bits was put into a good round Vial with a long neck, and then warily held over quick Coals without touching them till it was melted; after which it was kept almost continually shaken, to promote the Calcination, near an hour, the Metal being all the while in fusion, and the Glass kept at some distance from the throughly kindled Coals. The most part of this time the orifice of the Vial was covered with a Cap of Paper (which sometimes fell off by moving the Glass) to keep the Air and Steams of the Coals from getting into the neck. And at the end of this time, he that held the Glass being tired, and having his Hand almost scorched, the Vial being removed from the fire was broken, that we might take out the Metalline Lump, which had a little darkish Calx here and there upon the upper surface, but much more beneath, where it had been contiguous to the bottom of the Glass; then putting all this carefully freed from little fragments of broken Glass into the same Balance with the selfsame counterpoise I had used before, I found, according to my Expectation, an increase of weight, which amounted to eighteen Grains, that the Tin had acquired by this Operation.]   

EXPER. II.  
[This done we separated the Calx for fear of losing it, and having melted the Metal in a Crucible, that by pouring it out it might be reduced to thin Plates capable of being cut in pieces, and put into such another Vial as the last; we weighed it again together with the ●●tely reserved Calx, but found, that, notwithstanding all our oar, we had lost three Grains of the eighteen we had gained. This done we put the Metal into another Vial. But in regard the neck was shorter than that of the former, and could not like it be long held in one's Hand; and because also I was willing to see what Interest the shaking of melted Tin has in the quickness of the Calcination, the Glass, which had a stopple of Paper put to it to keep out Smoak and Air, was held at some distance from the Coals, only whilst the Tin was melting; and then was warily laid upon them and kept there for two hours, at the end of which 'twas again taken off, and the Metal weighed with the same Counterpoise and Balance as formerly; and than it appeared to amount to eight Ounces twenty-four Grains, and to have much more separable Calx than at the first time. Nor did I much wonder, that the weight should be increased in this last Operation but nine Grains in two hours, and in the former twice so many in half the time; since, during the two hours, the Glass was kept in one posture, whereas in the first Operation, it was almost perpetually shaken all the while 'twas kept in fusion. And 'tis observed, that the agitation of melted Minerals will much promote the Effect of the Fire upon them, and conduce to their Calcination.]   

EXPER. III.  
Though these Trials might well satisfy a person not very scrupulous, yet to convince even those that are so, I undertook, in spite of the difficulties of the Attempt, to make the Experiment in Glasses Hermetically sealed, to prevent all suspicion of any accession of Weight accrueing to the Metal from any Smoke or Saline Particles getting in at the mouth of the Vessel. And in prosecution of this design I thought upon a way of so Hermetically sealing a Retort, that it might be exposed to a naked fire without being either cracked or burst; an Account of which Trial was thus set down.  
[Eight Ounces of good Tin carefully weighed out was Hermetically sealed up in a new small Retort with a long neck, by which 'twas held in one's Hand, and warily approached to a kindled Charcoal-fire, near which the Metal was kept in fusion, being also ever now and then shaken for almost half an hour, in which time it seemed to have acquired on the surface such a dark colour as argued a beginning of Calcination, and it both emitted Fumes that played up and down, and also afforded two or three drops of Liquor in the neck of the Retort. The Laborant being not able to hold the Glass any longer, 'twas laid on quick Coals, where the Metal continued above a quarter of an hour longer in fusion; but before the time was come that I intended to suffer it to cool in order to the removing it, it suddenly broke in a great multitude of pieces, and with a noise like the Report of a Gun; but (thanks be to God) it did no harm neither to me nor others that were very near it. In the neck we found some drops of a yellowish Liquor, which a Virtuoso that tasted it affirmed to be of an odious but peculiar Sapor; and as for the Smell, I found it to be very stinking, and not unlike that of the distilled Oil of Fish.]  
But, though our first Attempt of this kind had thus miscarried, we were not thereby discouraged, but in prosecution of the same design made the ensuing Trial.   

EXPER. IU.  
[The Tin which had been before (in the first or some such Experiment) partly calcined in a Glass, being melted again in a Crucible, that it might be reduced to pieces small enough to be put into another Glass, was put again into the Scales, and the surplusage being laid aside, that there might remain just eight Ounces; these were put into a Bolt-head of white Glass with a neck of about twenty Inches long, which being Hermetically sealed (after the Glass had been a while kept over the fire, lest that should break by the rarefaction of the Air,) the Metal was kept in fusion for an hour and a quarter, as (being hindered by a Company of strangers from being there myself) the Laborant affirmed. Being unwilling to venture the Glass any longer, it was taken from the fire, and when 'twas grown cold, the sealed end was broken off; but before I would have the bottom cut out, I observed, that the upper surface of the Metal was very darkly coloured, and not at all smooth, but much and very oddly asperated; and the lower part had between the bottom and the lower part of the Lump a pretty deal of loose dark-coloured Calx, though the neighbouring surface and some places of the Lump itself looked by Candle-light (it being then Night) of a golden Colour. The Lump and Calx together were weighed in the same Scales carefully, and we found the weight to have increased twenty-three Grains and better, though all the Calx, we could easily separate, being weighed by itself amounted not to four Scruples or eighty Grains.]  
For Confirmation of this Experiment I shall subjoin another, wherein but a quarter of so much Metal was employed with such success as the annexed Memorial declares.   

EXPER. V.  
[Two Ounces of filings of Tin were carefully weighed and put into a little Retort, whose neck was afterwards drawn slenderly out into a very small Apex; then the Glass was placed on kindled Coals, which drove out fumes at the small orifice of the neck for a pretty while. Afterwards the Glass; being sealed up at the Apex, was kept in the fire above two hours; and then being taken off was broken at the same Apex; whereupon I heard the outward Fire rush in, because when the Retort was sealed the Air within it was highly rarified. Then the body of the Glass being broken, the Tin was taken out, consisting of a Lump, about which there appeared some grey Calx and some very small globuls, which seemed to have been filings melted into that form. The whole weighed two Ounces twelve Grains, the later part of which weight appeared to have been gained by the Operation of the Fire on the Metal. In the neck of the Retort, where it was joined to the body, there appeared a yellowish and clammy substance thinly spread, which smelled almost like the foetid Oil of Tartar.]   

EXPER. VI  
To vary the foregoing Experiments by making Trials on a Mineral that is held to be of a very Metalline nature, but is not a true Metal, nor will be brought to fusion by so moderate a Heat as will suffice to melt Tin, and yet has parts less fixed than Tin, as being far more easily sublimable, we thought fit to make the following Experiment.  
[We took an Ounce of filings of Zinke carefully weighed, and having as carefully put them into a round Bolt-glass, we caused the neck to be drawn out very slender, and then ordered the Laborant to keep it upon quick Coals for the appointed time. Afterwards returning home, I called for the Glass, which he said he had kept four hours upon the Coals; answering me also, that there did for a great part of the time Smoak appear to ascend from the Zink and get out at the unstopped Apex. And in effect I observed, that the upper part of the Glass was lined with Flores or Sublimate of a darkish grey. The Glass being dextrously cut asunder, we took out not only the filings of Zinke, some of which were melted into little globuls, but the Flores too, and yet weighing all these in the same Scales, we had used before, we found five Grains and somewhat better wanting of an Ounce. Which we the less wondered at, because of the continuance of the lately mentioned Exhalations emitted by the filled Mineral.]   

EXPER. VII.  
For more ample confirmation of the truth discovered by what I have been reciting about Tin, I thought fit to try the like Experiment upon another Metal, which though of somewhat more difficult fusion than Tin, I had reason to think might, if employed in a moderate quantity, and warily managed, be kept melted in Glass without breaking it. And accordingly having carefully weighed out four Ounces of good Lead cut beforehand into pieces little enough for the orifice of the Glass, I caused them to be put into a small Retort with a long neck, wherein was afterwards left but an orifice not much bigger than a pins head: Then leaving directions with the Laborant what to do, because I was myself called abroad, at my return he brought me together with the Glass, this Account: That he had kept it over and upon the Coals two hours, or better, and then supposing the danger of breaking the Glass was over, he had sealed it up at the little Orifice newly mentioned, and kept it on the Coals two hours longer. Before the Glass (which I found to be well sealed) was broken, I perceived the pieces of Lead to have been melted into a Lump, whose surface was dark and rugged, and part of the Metal to have been turned into a dark-coloured Powder or Calx: All this being taken out of the Retort, was weighed in the same Balance, whereon the Lead appeared to have gained by the Operation somewhat above thirteen Grains.   

EXPER. VIII.  
To show that Metals are not the only Bodies that are capable of receiving an increase of Weight from the Fire, I thought fit to make upon Coral a trial, whereof my Memorial gives me this Account.  
[Little bits of good red Coral being Hermetically sealed up in a thin bubble of Glass, after two Drachms of them had been weighed out in a pair of nice Scales, were warily kept at several times over and upon kindled Coals, and at length being taken out for good and all, were found of a very dark Colour, and to have gained in weight three Grains and about a half.]   

EXPER. IX.  
One Experiment there is, which, though it might have come in more properly at another place, is not to be omitted in this because it may invite us to consider, whether in the foregoing Experiments, excepting those made on Lead and Tin in sealed Vessels, there may not be more of the Fire adherent to or incorporated with the Body exposed to it, than one would conclude barely from the recited Increments of their Weight. For having taken very strong fresh Quicklime provided on purpose for choice Experiments, and exposed it, before the Air had time to slake it, upon the Cupel, to a strong fire where it was kept for two hours; I found that it had increased in weight even somewhat beyond my expectation: For being seasonably put into the Balance, the Lumps that weighed, when exposed, but two Drachms, amounted to two Drachms and twenty-nine Grains; which makes this Experiment a pregnant one to our purpose. For by this it appears, that notwithstanding a Body may for many hours, or even for some days, be exposed to a very violent Fire, yet it may be still capable of admitting and retaining fresh Corpuscles; so that, though well made Lime be usually observed to be much lighter than the Stones whereof 'tis made; yet this lightness does not necessarily prove, that, because a burnt Limestone has lost much of its matter by the Fire, it has therefore acquired no matter from the Fire; but only infers, that it has lost far more than it has got. And this may give ground to suspect, that in most of the foregoing trials the accession of the fiery Particles was greater (though in some more, in others less so,) than the Balance discovered; since, for aught we know, divers of the less fixed Particles of the exposed Body might be driven away by the vehemence of the Heat; and consequently the Igneous Corpuscles that fastened themselves to the remaining matter might be numerous enough, not only to bring the accession of Weight that was found by the Scales, but to make amends for all the fugitive Particles, that had been expelled by the violence of the Fire. And since so fixed a Body as Quicklime is capable of being wrought upon by the Igneous Effluvia, so as that they come to be as 'twere incorporated with it, it may perchance be worth considering, whether in other calcined or incinerated Bodies the remaining Calces or Ashes may not retain more than the bare Impression (unless that be stretched to mean some participation of a substance,) of the Fire. Whether these Particles that adhere to or are mingled with the stony ones of the Lime may have any thing to do in the Heat and tumult that is produced upon the slaking of Lime, this is not a fit place to examine. And though by this Experiment and those made in sealed Retorts, which show that what is afforded by Fire may in a Corporeal way invade, adhere and add Weight to even fixed and ponderous Bodies, there is a large Field opened for the Speculative to apply this Discovery to divers Phaenomena of Nature and Chemistry; yet I shall leave this Subject unmedled with in this place.     

A DISCOVERY Of the PERVIOUSNESS OF GLASS TO PONDERABLE PARTS OF FLAME.  
With some Reflections on it by way of COROLLARY.  
Subjoined as an Appendix to his Experiments about Arresting and Weighing of IGNEOUS CORPUSCLES, BY. The Honourable ROBERT boil.  
LONDON: Printed by W. G. for M. Pitt at the sign of the White Hart, over-against the little North Door of St Paul's Church. 1673.   

A DISCOVERY OF The Perviousness of GLASS TO Ponderable Parts of FLAME.  
THAT I might obviate some needless scruples that may be entertained by suspicious Wits upon this Circumstance of our Additional Experiments, That the Glasses employed about them were not exposed to the Action of mere Flame, but were held upon Charcoals, (which to some may seem to contain but a Grosser kind of Fire:) And that also I might, by diversifying the way of trial, render such Experiments both more fit to afford Corollaries, and more serviceable to my other purposes, I attempted to make it succeed with a Body so thin and disengaged from gross matter as mere Flame is allowed to be, knowing, that by going cautiously with it to work, one might handle a Retort without breaking it, in spite of a violent agitation of kindled matter.  

EXPER. I.  
Supposing then that good common Sulphur by reason of its great Inflammability and the vehemency and penetrancy of its Flame, would be a very fit fuel for my purpose, I provided a small double Vessel so contrived, that the one should contain as many Coals as was necessary to keep the Sulphur melted, and that the other, which was much smaller, and shaped like a Pan, should contain the Brimstone requisite for our Trial; and (last,) that these two should be with a convenient Lute so joined to one another, that all being closed at the top, save the orifice of the little Pan, (the fire and smoke of the Coals having their vent another way,) no fire should come at the Retort to be employed, but the flame of the burning Brimstone. Then two ounces of filings of Tin being heedfully weighed out, and put into a Glass-Retort provided for such Trials, and made fit to be easily sealed up at the neck, when the time should be convenient, the Sulphur (which ought to be of the purer sort) was kindled, and the Glass by degrees exposed to it; where it continued, as the Laborant informed me, (the smell of Brimstone, peculiarly offensive to me, forbidding me to be present,) near two hours before the Metal melted; after which he kept the Retort near an hour and half more with the Metal melted in it. Then bringing it me to look upon, I perceived a pretty deal of darkish Calx at the bottom, and partly too upon the surface of the far greater part of the Metal, which now lay in one Lump. The part of the Retort that had been sealed being broken off, we first took out the Calx, and then the Lump, and putting them into the Scales, they had been formerly weighed in, found them to have made a very manifest acquist of weight, which, if both the Laborant and I be not mistaken, (for the paper, which should inform us, is now missing) amounted to four grains and a half, gained by the recited Operation. Afterwards, we being grown more expert in making such Trials, the experiment was repeated with the same quantity of filings of the same Metal: At the end of the Operation, (which in all lasted somewhat above three hours) having broken off the sealed neck of the Retort, we found, that a good proportion of dark-coloured Calx had been produced. This being weighed with the uncalcined part of the Metal, the two ounces we first put in appeared to have acquired no less than eleven grains and a half (and somewhat better.)  
Such Superstructures, both for number and weight, may possibly in time be built on this and the like Experiments, that I shall venture to obviate even such a scruple as is like to be judged too Sceptical. But I remember, that, considering upon occasion of some of the Experiments formerly recited, that though it were very improbable, yet it did not appear impossible, that the increment of Weight, acquired by Bodies exposed in Glass-vessels to the Fire, might proceed, not from the Corpuscles of Fire, but from the Particles of the Glass itself, loosened by the power of so intense a Heat, and forcibly driven into the enclosed Body; I was content to take a couple of Glasses, whereof one was shaped into a little Retort, and having weighed them, and then having kept them for a considerable time upon kindled Coals, and then weighed them again, I could gather little of certainty from the Experiment, (the Retort at one time seeming to have acquired above half a grain in the fire,) save that there was no likelihood at all, that so considerable an increase of weight, as we divers times obtained in close vessels, should proceed from the Glass itself, and not from the Fire.   

EXPER. II.  
Because it seems evident enough, that, whatever Chemists tell us of their Hypostatical Sulphur, common Brimstone is a body Heterogeneous enough, having in it some parts of an oily or inflammable nature, and others acid; and very near of kin to the Spirits of Vitriol; I thought fit to vary our Experiment, by making it with a liquor that is generally reputed to be as Homogeneous as Chemists themselves are wont to render any, I mean with a Spirit of Wine, or some such liquor as will totally flame away without affording Soot, or leaving any drop of Phlegm behind it. In prosecution of this design, we carefully weighed out an ounce of filings of Block-Tin, and put them into a Glass-Retort, fit for the purpose, whose neck was afterwards drawn out to a great slenderness; and we also provided a conveniently shaped metalline Lamp, such as that the flame of this ardent Spirit might commodiously burn in it, and yet not melt nor crack it; which Lamp, though furnished with a Cotton wick, afforded no Soot, because as long as it was supplied with liquor enough, it remained unburnt. These things being in readiness, the Retort was warily approached to the flame, and the Metal was thereby in a short time melted. After which the Glass being kept exposed to the same flame for near two hours in all, the sealed apex of the Retort was broken off, and there appeared to have been produced a not inconsiderable Quantity of Calx, that lay loose about the remaining part of the Tin, which, upon its growing cold, was hardened into a Lump. This, and the Calx, being taken out of the Retort with care, that no little fragment of Glass should at all impose upon us, was weighed in the same Scales as formerly, and found to have gained four grains and a half, besides the Dust that stuck in the inside of the Retort, of which we reckoned enough to make about half a grain more; so that of so fine and pure a flame as of this totally ardent Spirit, enough to amount to five grains was arrested, and in good measure fixed by its operation on the Tin it had wrought upon.   

EXPER. III.  
For confirmation of the former trial, wherein we had employed the Spiritus arden's of Sugar, we made the like experiment with highly Rectified Spirit of Wine, only substituting an ounce of Lead instead of one of Tin. The event, in short, was this; that after the Metal had been for two hours or better kept in the flame, the sealed neck of the Retort being broken off, the external Air rushed in with a noise, (which showed the Vessel to have been very tied,) and we found pretty store of the Lead; for 'twas above seven scruples, turned into a grayish Calx, which together with the rest of the Metal being weighed again, there was very near, if not full, six grains of increase of weight acquired by the Operation.  
1. N. B. The Lump of Lead, that remained after the newly recited Operation, being separated from the Calx, was weighed and cut in pieces, that it might be put into a fresh Retort, wherein it was again exposed to the flame of Spirit of Wine, that I might satisfy myself, whether probably the whole Body of the Lead might not, by repeated Operations, or (perhaps by one continued long enough) be reduced to Calx. And though, after the Retort (whose neck had been drawn out) had been kept in the flame for about two hours, it was, by the negligence of a Footboy, unluckily broken, and some of the Calx lost; yet we made a shift to save about five grains of it, (whose colour was yellowish;) which was enough to make it likely, that, if we had had conveniency to pursue the Operation to the utmost, the whole Metal might have been calcined by the action of the flaming Spirit.  
2. N. B. And lest you should be induced by some Chemical conceits to imagine, that the particles that once belonged to flame, did make more than a Coalition with those of the Lead, and by a perfect Union were Really transmuted into the Metal whose weight they increased; I shall add, that (according to a Method elsewhere delivered) I examined the seven scruples of Calx, mentioned to have been made in the third Experiment, by weighing them in Air and Water, and thereby found, as I expected, that though the absolute Gravity of the Metal had been increased by the particles of Flame that stuck fast to it, yet this Aggregate of Lead and extinguished Flame had lost much of its specific Gravity. For, whereas Lead is wont to be to Water of the same bulk, as about eleven and a half to one, this subtle Calx of Lead was to Water of the same bulk little, if at all, more than as nine to one.  
These are not the only Experiments I made of the Operation of mere Flame upon Bodies enclosed in Glasses; but these, I suppose, are sufficient to allow me to comply with my present haste, and yet make good the Title prefixed to this Paper. For, whence can this increase of absolute weight (for I speak not of specific Gravity,) observed by us in the Metals exposed to the mere flame, be deduced, but from some ponderable parts of that Flame? And how could those parts invade those of the Metal enclosed in a Glass, otherwise than by passing through the pores of that Glass? But, because I judge it unphilosophical, either to more careful that what one writes should appear strange, than be true; or to be forward to advance the repute of Strangeness, to the prejudice of the Interest of Truth, though it be perhaps but a remote one, or a collateral one; I shall deal so impartially, as to subjoin on this occasion two or three short Intimations, that may prove both seasonable for Caution, in reference to the Porousness of Glass, and give a hint or two in relation to other Things.  
I do not then by the foregoing Experiments pretend to make out the Porosity of Glass any farther, than is expressed in the Title of this Paper; namely, in reference to some of the Ponderable parts of Flame. For otherwise I am not at all of their mind, that think Glass is easily penetrable, either, as many do, by Chemical Liquors; or, as some, by Quicksilver; or, as others, at least by our Air: Those opinions not agreeing with the Experiments I made purposely to examine them, as you may find in another Paper.  
Again, if we compare the Increase we observe to be made in the Weight of the Bodies that we expose to the naked Fire, and those of the same or the like kinds that we included in Glasses, or so much as in Crucibles; it may be worth considering, Whether this difference in acquired weight may not give cause to suspect, that the Corpuscles, whereof Fire and Flame consists, are not all of the same size, and equally agitated, but that the interposed Vessel keeps out the grosser Particles like a kind of Strainer, though it gives passage to the minutest and most active?  
I offer it also to Consideration, Whether this perviousness of Glass, even to the minute particles that pervade it, and their adhesion to the Metal they work on, does necessarily imply Pores constantly great enough to transmit such Corpuscles? or, Whether it may not be said, that Glass is generally of a closer Texture, than when in our Experiments the pores are opened by the vehement Heat of the flame that beats upon it, and in that state may let pass Corpuscles too big to permeate Glass in its ordinary state; and that this penetration is much assisted by the vehement agitation of the Igneous parts, which by the rapidness of their motion both force themselves a passage through the narrow pores of the Glass, and pierce deep enough into those of the included Body to stick fast there; (as hailshot thrown with one's hand against a board, will pass off from it, but being shot out of a Gun will pierce it, and lodge themselves in it?) And I know a Menstruum that does not work upon a certain Metal whilst the liquor is cold, or but faintly heated, and yet by intending the Heat would be made to turn it into a powder or Calx, (for it does not properly dissolve it.)  
Perhaps it may not be amiss to add on this occasion, that though Glass be generally acknowledged to have far smaller pores, than any other matter wont to be employed to make vessels, that are to be exposed to the fire; yet till I be farther satisfied, I shall forbear both to determine, whether the rectitude, that some Philosophers suppose in the pores of Glass, as 'tis a transparent body, or rather in their ranks or rows, may facilitate the Perviousness we above observed in Glass, and to conclude from the foregoing Experiments, that ponderable parts of Flame will be able as well to pass through the pores of Metalline vessels as those of Glass. For though, with a silver vessel, made merely of plate without Soder, I made two or three Trials (of which you may command an account) in order to the resolving of these doubts; yet by an accident, which, though it were not a surprising one, was unlucky enough to defeat my endeavours, I was kept, for want of fit Accommodations, from bringing my intended trials to an issue.  
And now having endeavoured by the foregoing Advertisements to prevent the having unsafe Consequences drawn from our Experiments; it remains that I briefly point at three our four Corollaries that may more warily be deduced from them. To which, if I get time, I may subjoin a hint or two about further Inquiries.   

COROLLARY I.  
Confirming this PARADOX, That Flame may act as a Menstruum, and make Coalitions with the Bodies it works on.  
THE Experiments, we have made and recited of the premeating of Flame (as to some of its parts) through Glass-vessels, and of its working on included Metals, may much confirm the Paradox I have elsewhere proposed, That Flame may be a Menstruum, and work on some Bodies at the rate of being so; I mean not only by making a notable Comminution and Dissipation of the parts, but by a Coalition of its own particles with those of the fretted Body, and thereby permanently adding Substance and Weight to them. Nor is it repugnant to Flames, being a Menstruum, that in our experiment the Lead and Tin, exposed to it, were but reduced to powder, and not dissolved in the form of a Liquor, and kept in that state. For, besides that the interposed Glass hindered the Igneous particles from getting through in plenty enough; I consider, that 'tis not necessary, that all Menstruums should be such Solvents, as the objection supposes. For whether it be (as I have sometimes suspected,) that Menstruums, that we think simple, may be compounded of very differing parts, whereof one may precipitate what is dissolved by the other; or for some other Cause, I have not now time to discuss. Certain it is, that some Menstruums corrode Metals and other Bodies without keeping dissolved all, or perhaps any considerable part; as may be seen, if you put Tin in a certain quantity of Aqua fortis, which will in a very short time reduce it almost totally to a very white substance, which, when dry, is a kind of Calx. And so by a due proportion of Oil of Vitriol, abstracted from Quicksilver by a strong fire, we have divers times reduced the main body of the Mercury into a white powder, whereof but an inconsiderable part would be dissoluble in water. And such a white Calx I have had by the action of another fretting Liquor on a Body not Metalline.  
And having thus cleared our Paradox of the opposed Difficulty, my haste would immediately carry me on to the next Corollary, were it not, that there is one Phaenomenon belonging to this place that deserves to be taken notice of. For, whether it be, as seems probable, from the vehement agitation of the permeating particles of Flame, that violently tear asunder the Metalline Corpuscles, or from the nature of the Igneous Menstruum, (which being as 'twere percolated through Glass itself, must be strangely minute,) 'tis worth observing, how small a proportion, in point of weight, of the additional adhering Body may serve to corrode a Metal, in comparison of the Quantity of vulgar Menstruums that is requisite for that purpose. For, whereas we are obliged to employ, to the making the solution of crude Lead, several times its weight of Spirit of Vinegar, and (though not so many times) even of Aqua fortis, 'twas observed in our Experiment, that, though the Lead was increased but six grains in weight, yet above six score of it were fretted into powder, so that the Corrosive Body appeared to be but about the twentieth part of the corroded.   

CORAL. II.  
Proposing a PARADOX about Calcination and Calces.  
Another Consequence, deducible from our discovery of the perviousness of Glass to Flame, may be this; That there is cause to question the Truth of what is generally taken for granted about Calcination, and particularly of the notion, that not only others, but Chemists themselves, have entertained about the Calces of Metals and Minerals. For, whereas 'tis commonly supposed, that in Calcination the greater part of the Body is driven away, and only the Earth, to which Chemists add the Fixed Salt, remains behind; and whereas even Mechanical Philosophers, (for two or three of Them have taken notice of Calcination,) are of opinion, that much is driven away by the violence of the fire; and the remaining parts by being deprived of their more radical and fixed moisture are turned into dry and brittle particles: Whereas these Notions, I say, are entertained about Calcination, it seems, that they are not well framed, and do not universally hold; since, at least they are not applicable to the Metals, our Experiments were made on. For, it does not appear by our Trials, that any proportion, worth regarding, of moist and fugitive parts was expelled in the Calcination; but it does appear very plainly, that by this Operation the Metals gained more weight than they lost; so that the main body of the Metal remained entire, and was far from being, either as a Peripatetic would think, Elementary Earth, or a compound of Earth and Fixed Salt, as Chemists commonly suppose the Calx of Lead to be. From which very erroneous Hypothesis they are wont to infer the sweet Vitriol of Lead, which they call Saccharum Saturni, to be but the sweet Salt of it extracted only by the Spirit of Vinegar, which does indeed plentifully enough concur to compose it. Whence I conclude, that the Calx of a Metal even made (as they speak) per se, that is, by fire without additament, may be, at least in some cases, not the Caput mortuum, or Terra damnata, but a Magistery of it. For, in the sense of the most intelligible of the Chemical Writers, that is properly a Magistery wherein the Principles are not separated, but the bulk of the Body being preserved, it acquires a new and convenient form by the addition of the Menstruum or Solvent employed about the preparation. And, not here to borrow any Argument from my Notes about particular Qualities, you may guests, how true it is, that the greatest part of the Body, or all the radical moisture is expelled in Calcination, which therefore turns the Metal into an arid unfusible powder; by this, That I have several times from Calx of Led reduced corporal Lead. And I remember, that having taken what I guessed to be but about a third or fourth part of the Calx of Lead, produced by the third Experiment; I found by a trial purposely devised, that without any Flux-powder or any additament, but merely by the application of the Flame of highly Rectified Spirit of Wine, there could in a short time be obtained a considerable proportion of malleable Lead; whereof the part I had the Curiosity to examine, was true malleable Lead; so little was the arid powder, whence this was reduced, deprived by the foregoing Calcination of the suppo'sd radical moisture requisite to a Metal. The Consideration of what may be drawn from this Reduction in reference to the Doctrine of Qualities belongs not to this place.   

CORAL. III.  
One use, among the rest, we may make, by way of Corollary, of the foregoing Discovery, which is in reference to a Controversy warmly agitated among the Corpuscular Philosophers themselves. For, some of them, that follow the Epicurean or Atomical Hypothesis, think, that when Bodies are exposed in close vessels to the fire, though the Igneous Corpuscles do not stay with the Bodies they invade, yet they really get through the Pores of the interposed Vessels, and permeate the included Bodies in their passage upwards; whereas others, especially favourers of the Cartesian Doctrine, will not allow the Atomists Igneous Corpuscles, which they take to be but vehemently agitated particles of Terrestrial matter, to penetrate such minute pores as those of Glass; but do suppose the operation of the fire to be performed by the vehement agitation made of the small parts of the Glass, and by them propagated to the included Bodies, whose particles by this violent Commotion are notably altered, and receive new Textures, or other modifications.  
But our Experiments inform us, that, though neither of the two Opinions seems fit to be despised, yet neither seems to have hit the very mark; though the Epicurean Hypothesis comprise somewhat more of the Truth than the other. For, though it be not improbable, that the brisk agitation communicated by the small parts of the Glass to those of the Body contained in it, may contribute much to the effect of the fire; and though, by the small increment of weight, we found in our exposed Metal, 'tis very likely, that far the greater part of the Flame was excluded by the close Texture of the Glass; yet on the other side 'tis plain, that Igneous particles were trajected through the Glass, which agrees with the Epicureans; and they, on the other side, mistake, in thinking that they did but pass through, and divide and agitate the included Bodies; to which nevertheless our Experiments show, that enough of them, to be manifestly ponderable, did permanently adhere.  
Whether these Igneous Corpuscles do stick after the like manner to the parts of meat, dressed by the help of the fire, and especially roast-meat, which is more immediately exposed to the action of the fire, may be a question, which I shall now leave undiscussed, because I think it difficult to be determined, though otherwise it seems worthy to be considered, in regard it may concern men's Health, to know, whether the Coction of meat be made by the fire, only as 'tis a very hot body, or whether it permanently communicates any thing of its substance to the meat exposed to it: In which (last) case it may be suspected, that not only the degree and manner of application of a fire, but the nature of its fuel may be fit to be considered.   

CORAL. IV.  
The Experiments above recited give us this further Information, That Bodies very spirituous, fugitive, and minute, may, by being associated with congruous particles, though of quite another nature, so change their former Qualities, as to be arrested, by a solid and ponderous Body, to that degree, as not to be driven away from it by a fire intense enough to melt and calcine Metals.  
For, the foregoing Trials (taking in what I 
* Exp. III. N. B. 2.  lately delivered of the lessened specific Gravity of calcined Lead) seems plainly enough to discover, that even the agitated parts of flame, minute enough to pass through the pores of Glass itself, were as 'twere entangled among the metalline particles of Tin and Lead, and thereby brought to be fixed enough to endure the Heat that kept those Metals in fusion, and little by little reduced them into calces: Which is a Phaenomenon that one would not easily look for, especially considering how simple a Texture that of Lead or Tin may be supposed to be in comparison of the more elaborate structures of very many other Bodies. And this Phaenomenon, which shows us, what light and fugitive particles of matter may permanently concur to the Composition of Bodies ponderous and fixed enough, may perchance afford useful hints to the Speculative; especially if this strict Combination of spirituous and fugitive substance with such, as being gross or unwieldy, are less fit than organised matter to entangle or detain them, be applied, (as it may be with advantage) to those aggregates of spirituous Corpuscles, and organical Parts, that make up the Bodies of Plants and Animals. And this hint may suggest a main Inference to be drawn from the Operations of the Sunbeams on appropriated subjects, supposing it to prove like that of flame on Tin and Lead.  
And now having dispatched our COROLLARIES, we might here inquire, Whether all the particles of Fire and Flame, that are subtle and agitated enough to penetrate Glass, and fasten themselves to included Bodies, be reduced by Ignition to the same nature, or else retain somewhat of their proper Qualities? Which Inquiry I have some cause not to think so undeterminable, as at first blush it may appear. For, one of the ways, that may be proposed for this Examen, is already intimated at the close of the third Experiment, which shows, that we may compare the specific Gravity of the Calces of the same Metal, made in Glasses by the operation of Flames; whose fuels are of very differing Natures. And I said, one of the ways, because 'tis not the only way I could name, and have partly tried. But though I might say more concerning Expedients of this kind, and could perhaps propound other Inquiries that may reasonably enough be grounded upon the hitherto recited Phaenomena (and those of some other like trials,) yet I must not unseasonably forget, that the pursuit of such Disquisitions would lead me much farther than I have now the leisure to follow it.    

ERRATA.  
Pag. 44. l. 19 r. some Metals work; pag. 1. in the Discourse about the Determinate Nature of Effluviums, add the name of the Author, viz. By the Honourable ROBERT boil.  
FINIS.   

The Printer to the Reader.  
IT hath been thought, it might be the Interest of the Reader, especially Foreiners, to be advertised, That these Essays are already Translating into Latin, and beginning also to be printed in that Language; which that it may duly be done, both as to this and the Author's other Writings, to be published for the future, the greater care will be taken here, because it hath been several times found both at home and elsewhere, that the Versions made of them abroad, and not in the place, where in case of any difficulty the Author may be consulted with by the Latin Interpreters, are often very defective, and not seldom injurious to the sense he hath delivered them in. Which being considered by those that desire to know the genuine sense of the Author, 'tis presumed, they will rather choose those Versions, which are made by persons that have that advantage of comsulting him in any case of doubt, than such as shall mis-inform them; notwithstanding the pretence of a cheaper rate of the Book.  
Which being thus advertised, the Printer taketh this opportunity of farther acquainting the Reader from the Latin Interpreter, that these Essays, to his knowledge, were ready and in the Press several Months before Dr. Thomas Bartholin's Acta Philosophica & Medica appeared in England, in which there are two or three passages that may seem of affinity with some to be met with in the latter part of the Papers about Experiments of Arresting the parts of Flame, and of making them Ponderable.   

A Catalogue of the Writings Published by The Honourable ROBERT boil.  

1. Seraphic Love. London, for Henry Herringman, 1660. in 8ᵒ.  
2. New Experiments Physicomechanical, touching the Spring of the Air, and its Effects. Oxford, for Thomas Robinson, 1660. in 8ᵒ. In Latin: Oxford; for the same, 1661. in 8ᵒ.  
3. Certain Physiological Essays; to which is added, The Physico-Chymical Essay about the Differing parts, and Redintegration of Saltpetre; as also, the History of Fluidity and Firmness. London, for Henry Herringman, 1661. in 4ᵒ. In Latin; London, by the same, 1661. in 4ᵒ.  
4. Some Considerations touching the Style of the H. Scriptures. London, for H. Herringman, 1661. in 8ᵒ.  
5. The Sceptical Chemist. London, for John Crook, 1661. in 8ᵒ. In Latin; London, for the same, in 8ᵒ. 1662.  
6. A Defence of the Doctrine touching the Spring and Weight of the Air, against the Objections of Franciscus Linus. London, for Tho. Robinson, 1662. in 4ᵒ.  
7. An Examen of Mr. Hobbes his Dialologus Physicus de Natura Aeris; with an Appendix touching Mr. Hobbes his Doctrine of Fluidity and Firmness. London, for Tho. Robinson, 1662. in 4ᵒ.  
8. usefulness of Experimental Philosophy. Oxford, for Rich. Davies, 1663. in 4ᵒ.  
9 Experimental History of Colours. London, for H. Herringman, 1664. in 8ᵒ. In Latin: London, for the same, 1665. in 12ᵒ.  
10. History of Cold. To which is added, an Examen of Antiperistasis, and of Mr. Hobbes his Doctrine of Cold. London, for John Crook, 1665. in 8ᵒ.  
11. Hydrostatical Paradoxes. Oxford, for Rich. Davies, 1666. in 8ᵒ. In Latin; Oxford, for the same, 1669. in 12ᵒ.  
12. Origine of Forms and Qualities. Oxford, for Rich. Davies, 1667. in 8ᵒ. In Latin; Oxford, for the same, 1669. in 12ᵒ.  
13. Free Considerations about Subordinate Forms. Oxford, for Rich. Davies, 1667. in 8ᵒ. In Latin; Oxford, 1669.  
14. Continuation of New Experiments Physicomechanical touching the Spring and Weight of the Air, and the Atmosphere of Consistent Bodies. Oxford, for Rich. Davies, 1669. in 4ᵒ.  
15. Of the Absolute Rest of Solid Bodies. London, for H. Herringman, 1669. in 4ᵒ. In Latin; London, for the same, 1672. in 12ᵒ.  
16. Several Tracts; viz. An Introduction to the History of Particular Qualities: Of Cosmical Qualities and Suspicions: Of the Temperature of the Subterraneal and Submarine Regions: Of the bottom of the Sea. Oxford, for Rich. Davies, 1671. in 8ᵒ. In Latin; London, for the same, 1672. in 12ᵒ.  
17. Small Tracts; viz. Of a Discovery of the admirable Rarefaction of the Air, even without Heat: New Observations about the Duration of the Spring of the Air: New Experiments touching the Condensation of the Air by mere Cold, and its Compression without Mechanical Engines: The admirably Differing Extension of the same Quantity of Air rarified and compressed. London, for H. Herringman, 1670. in 4ᵒ. In Latin; London, for the same, 1670. in 12ᵒ.  
18. Of the usefulness of Natural Philosophy, Tom. 2. Oxford, for Rich. Davies, 1671. in 4ᵒ.  
19 An Essay about the Origine and Virtue of Gems. London, for Moses Pitt, 1672. in 8ᵒ. In Latin; London, for the same, 1673. in 12ᵒ.  
20. Several Tracts, containing New Experiments touching the Relation betwixt Flame and Air, and about Explosions: An Hydrostatical Discourse answering some Objections of Dr. Henry More: An Hydrostatical Letter, dilucidating an Experiment about a way of weighing Water in Water: New Experiments of the Positive or Relative Levity of Bodies under Water: Of the Air's Spring on Bodies under Water: About the differing Pressure of Heavy Solids and Fluids. London, for Rich. Davies, 1672. in 8ᵒ.  
21. Essays, of the strange Subtlety, the great Efficacy, and the Determinate Nature of Effluviums. To which are annexed, New Experiments to make Fire and Flame Ponderable; together with a Discovery of the Perviousness of Glass. London, for Moses Pitt, 1673. in 8ᵒ.  
22. A Dialogue concerning the Positive or Privative nature of Cold; by a Member of the R. Society: And a Discourse about the Saltness of the Sea; and another of a Statical Hygroscope; together with some Phaenomena of the force of the Air's Moisture. To which is added a Paradox about the Natural and Preternatural State of Bodies, especially the Air. London, for Rich. Davies, 1673. in 8ᵒ.    

 

 
And some that were published An. 1669. under the Title of The Atmospheres of consistent Bodies.