know of what and of how many Ingredients much less of what kind of Atoms it is made and the proportion and manner wherein they are mingled but the Notice Experience gives him of the power of that admirable Concrete as it is made up and brought to his hands suffices to enable him to perform things with it that nothing but their being common and unheeded can keep from being admir'd The Physitian that has observ'd the Medicinal vertues of Treacle without knowing so much of the names much less the Nature of each of the sixty and odd Ingredients whereof it is compounded may cure many Patients with it And though it must not be deny'd that it is an advantage as well as a satisfaction to know in general how the Qualities of things are deducible from the primitive Affections of the smallest parts of Matter yet whether we know that or no if we know the Qualities of this or that Body they compose and how 't is dispos'd to work upon other Bodies or be brought on by them we may without ascending to the Top in the series of Causes perform things of great Moment and such as without the diligent Examination of particular Bodies would I fear never have been found out à priori ev'n by the most profound Contemplators We see that the Artificers that never dream'd of the Epicurean Philosophy have accommodated Mankind with a Multitude of useful Inventions And Paracelsus who besides that he seems none of the most piercing and speculative Wits sure had little recourse to Atomical Notions if he ever so much as heard of them was able to perform some things that were truly admirable besides those he vainly boasted of as may appear not only by what I elsewhere represent but by what Oporinus himself as severely as he otherwise writes against his deserted Master confesses he saw of the stupendous cures which Paracelsus wrought with his famous Laudanum whatever he made it of But we need not go far to find a noble Example to our present purpose since we see that the bare making of tryals with the Load-stone and Irons touch'd by it though the Experimentors were ignorant as some fear we yet are of the true and first Causes of Magnetical Phaenomena have produc'd Inventions of greater use to Mankind than were ever made by Leucippus or Epicurus or Aristotle or Telesius or Campanella or perhaps any of the speculative Devisers of new Hypotheses whole Contemplations aiming for the most part but at the solving not the encreasing or applying of the Phaenomena of Nature it is no wonder they have been more ingenious than fruitful and have Hitherto more delighted than otherwise benefitted Mankind I say Hitherto because though Experience warrants me so to speak now yet I am not unwilling to think that Hereafter and perhaps in no long time when Physiological Theories shall be better establish'd and built upon a more competent number of Particulars the Deductions that may be made from them may free them from all Imputation of Barrenness But of these things I otherwhere though not as I remember in any of the following Essays more fully discourse And therefore I shall now resume the Subject that occasion'd this long Excursion and add to what I said in excuse of my venturing sometimes to deliver something as my Opinion in difficult or controverted cases that I must declare to you Pyrophilus that as I desire not my Opinions should have more Weight with you than the Proofs brought to countenance them will give them so you must not expect that I should think my self oblig'd to adhere to them any longer than those Considerations that first made me embrace them shall seem of greater Moment than any that I can meet with in opposition to them For Aristotle spoke like a Philosopher when to justifie his Dissent from his Master Plato he said among other things That for the sake of Truth men especially being Philosophers ought to overthrow ev'n their own Tenents 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 And though for a man to change his opinions without seeing more reason to forsake them than he had to assent to them be a Censurable Levity and Inconstancy of mind yet to adhere to whatever he once took for truth though by Accession of more light he discover it to be erroneous is but a proud Obstinacy very injurious to Truth and very ill becoming the sense we ought to have of humane frailties And it ought to be esteem'd much less disgraceful to quit an Error for a Truth than to be guilty of the Vanity and Perverseness of believing a thing still because we once believ'd it And certainly till a Man is sure he is infallible it is not fit for him to be unalterable You will easily discern Pyrophilus that I have purposely in the ensuing Essays refrain'd from swelling my Discourses with solemn and elaborate Confutations of other mens Opinions unless it be in some very few Cases where I judg'd that they might prove great impediments to the Advancement of Experimental Learning and even such Opinions I have been wary of medling with unless I suppos'd I could bring Experimental Objections against them For 't is none of my Design to engage my self with or against any one Sect of Naturalists but barely to invite you to embrace or refuse Opinions as they are consonant to Experiments or clear Reasons deduced thence or at least analogous thereunto without thinking it yet seasonable to contend very earnestly for those other Opinions which seem not yet determinable by such Experiments or Reasons And indeed to allude to our former Comparison I would endeavour to destroy those curious but groundless structures that men have built up of Opinions alone by the same way and with as little Noise by which such fantastical structures as those I mention'd to have seen at Leyden may be demolish'd To destroy which 't were needless to bring battering Engines since nothing is requisite to that effect but an encrease of Light And Experience has shown us that divers very plausible and radicated Opinions such as that of the Unhabitableness of the Torrid Zone of the Solidity of the Celestial part of the World of the Blood 's being convey'd from the Heart by the Veins not the Arteries to the outward parts of the body are generally grown out of request upon the appearing of those new Discoveries with which they are inconsistent and would have been abandon'd by the Generality of Judicious Persons though no man had made it his business purposely to write Confutations of them so true is that Vulgar saying that Rectum est Index sui Obliqui But when at any time Pyrophilus I have been induc'd to oppose others as I have not deny'd my self the freedom that is requisite unto Loyalty to Truth so I have endeavour'd to use that Moderation and Civility that is due to the persons of deserving Men. And therefore you shall find me not only in one Essay oppose an Author whom in
glass Pipe of an indifferent size and open at both ends and if when 't is well fill'd with smoak the lower end be presently stopt and the glass be kept still a while in an erected posture the fumes will settle by degrees to a level superficies like water so that though you gently incline the Pipe any way the upper surface of the smoak will neverthelesse quickly grow parallel to the Horizon And if the glasse be further but slowly made to stoop the smoak will seem to run down in a Body like water whilst it continues in the Pipe though when it is come to the lower end of it instead of dropping down like water it will commonly rather flye upwards and disperse it self into the Aire And as for flame I fore-see I shall ere long have occasion to mention an Experiment whereby I have sometimes endeavour'd to shew that ev'n two contiguous flames as expanded Bodies as they are and as open as their Texture is may like visible Fluids of a differing kind retain distinct surfaces SECT V. But instead of Examining any further how many Bodies are or may be made visibly to appear fluid ones let us now resume the Consideration of what it is that make Bodies fluid especially since having intimated some of the Reasons why we are unwilling to Confine our selves to the Epicurean notion we hope it will the lesse be dislik'd that we thought fit to make such a description of a fluid substance as may intimate that we conceive the conditions of it to be Chiefly these Three The first is the Littlenesse of the Bodies that compose it For in big parcels of matter besides the greater inequalities or roughnesses that are usual upon their surfaces and may hinder the easie sliding of those Bodies along one another and besides that diverse other Affections of a fluid Body cannot well belong to an aggregate of grosse Lumps of matter besides these things I say the bulk it self is apt to make them so heavy that they cannot be agitated by the power of those causes whatever they be that make the minute parts of fluid Bodies move so freely up and down among themselves whereas it would scarce be believ'd how much the smallnesse of parts may facilitate their being easily put into motion and kept in it if we were not able to confirme it by Chymical Experiments But we see that Lead Qâ—ick-silver and ev'n Gold it self though whilst they are of a sensible bulk they will readily sink to the bottom of Aqua Regis or any other such Liquor yet when the Menstruum has corroded them or fretted them asunder into very minute parts those minute Corpuscles grow then so much more capable of agitation than before that quitting the bottom of the Liquor they are carri'd freely every way and to the top with the associated parts of the Liquor without falling back again to the bottom Nay we see that ponderous and mineral Bodies divided into corpuscles small enough may be made so light and voluble as to become Ingredients ev'n of distill'd Liquors as we may learn by what some Chymists call the Butter others simply the Oyle and others the Oleum Glaciale of Antimony which though it be after Rectification a very limpid Liquor yet does in great part consist of the very Body of the Antimony as may appear not to mention its weight by this that 't is most easie to precipitate out of it with fair water store of a ponderous white calx reducible by Art to an Antimonial glasse Nay we make a Menstruum with which we can easily at the first or second Distillation bring over Gold enough to make the distill'd Liquor appear and continue ennobled with a Golden Colour And to show yet more particularly that great Bodies are too unwieldy to constitute fluid ones We may further observe how as well Nature as Art when either of them makes Bodies of considerable bulk fluid is wont in order thereunto to make a Comminution of them as we may observe in divers Examples SECT VI. Thus we see that in the stomacks of Dogs Nature to reduce Bones into those fluid Bodies Chyle and Blood does by some powerful and appropriated juice whether belonging to the Stomack it self or thrown out of the Arteries in the passage of the circulating Blood dissolve them into parts so minute that the acutest Eye would not tempt a man to suspect that such a Liquor had ever been a Bone And that it may not be objected that this dissolution is chiefly performed or at least must always be assisted by the Liquor which Animals take into their Stomachs by drinking I shall represent not only that we find by experience how little common water the only usual drink of Dogs Wolves c. is able to dissolve bones though they be very long not macerated but boil'd in it but that if we may believe Natural Historians and credible Travellers there are some sorts of Animals as particularly Camels that may be brought not to drink once in many days ev'n when they travel in hot Climates And to make you think this the less improbable I shall adde that I am familiarly acquainted with an Ingenious Gentleman who as himself and an ancient Virtuoso in whose house he lives have inform'd me does usually drink but once in several days and then no excessive draught neither And when I askt him how long he had actually abstain'd not barely from drink but from thirsting after it He answer'd that he had once some few years before continued about nine days without either taking or needing any drink and he doubted not but that he might have continued much longer in that state if by distempering himself one night with long and hard study he had not had some light inclination to take a small draught which serv'd him for about four days longer And when I askt him whether in that hot Summers day that preceded the evening wherein he happen'd to tell me this he had not drunk at all he answer'd Negatively And it adds to the strangeness of this Peculiarity that this Gentleman is in the flower of his Youth being but about twenty two years of Age and of a Sanguine and Florid Complexion And to annex that also upon the By I learned by enquiry from him that he sweats freely enough as I remember I saw him do that his Diet is the same with other mens without restraining him from the free use of Salt Meats and that his Urine is in Quantity much like that of ordinary Men of his Age and temperament But to return to what I was saying more generally of the Stomachical Menstruum of Animals I shall adde on this occasion that to make some kind of Imitation of it I prepar'd and do elsewhere mention and teach a certain Liquor that I use whereby I have in a short time and without fire dissociated the parts of rosted or boil'd flesh bread fruit c. and pull'd them asunder into very minute
small grains of this prepar'd Mineral and put them under the wieck of a strong and actually burning Candle whereby as I expected they were with the melted tallow soon carried up to the bottom of the flame and by it so kindl'd that the green not blew flame of the cupreous Body did somewhat to the wonder of the Spectators burn for a good while this combustible matter being marvellously lasting distinct from the yellow flame of the Candle as if there had been some invisible partition between them But to return to the unminglable Liquors we were formerly speaking of the cause why these retain their distinct surfaces my present task does not oblige me to enquire into but this I shall observe in general that it seems to depend very much upon the texture of the particular Liquors and perhaps too upon the peculiar motions of their minute parts For I have observ'd that though pure Spirit of Wine and Salt of Tartar resolv'd into a Liquor by the moisture of the Air will when put together retain distinct surfaces or presently regain them if you shake the Liquors never so strongly together yet by adding a little fair water to either of them the texture being thereby alter'd it will easily incorporate with the other And thus although that as I noted already common Spirit or Oyl of Turpentine will not mingle with Spirit of Wine yet having had the curiosity to make a tryal with Oyl of Turpentine abstracted skilfully and with a very gentle fire for otherwise the Experiment may easily miscarry from melted or at least well decrepitated Sea-Salt we found according to expectation that though there appeared no visible alteration in the Oyl yet we could easily by shaking confound it with pure Spirit of Wine Moreover though lixiviate Liquors and Oyls will not by an ordinary Agitation be permanently joyn'd yet I have try'd that by digesting a good while a solution of Salt of Tartar with Oyl of Almonds I could reduce them to a soft Saponary substance which Experiment makes somewhat more to my present purpose than the common practice of Sope-Boylers because I did not as they boyl away the water wherein the lixiviate Salt is dissolv'd I might adde also that if you put one part of Quick-silver into about four parts of Oyl of Vitriol you will find at least if the Experiment proceed always after the same manner as it has done with me that the two Liquors will remain distinct whilst you keep them in the cold but if by degrees of heat you bring the Oyl of Vitriol to boyl it will pierce the surface of the Quick-silver and by partly incorporating with it reduce it to a substance very differing from what it was But because these two last Experiments may be with less improbability than the two that preceded them refer'd to other causes I shall no farther insist on them but take notice of one thing more concerning the difference of fluid Bodies And it is this SECT XXVI I observe that some of them do not only not mingle with others that are contiguous to them but fashion the surfaces of those others and reduce them to determinate shapes This I have taken pleasure to consider in some Chymical Liquors which I have purposely put together for Instance having pour'd Spirit of Wine upon Oyl of Tartar per Deliquium as Chymists call it I found that the superficies wherein they touch'd each other was flat or as to sense parallel to the Horizon But if this were done in a very slender or narrow glass with the mouth unstop'd though the lower surface of the Spirit of Wine which touch'd the other Liquor appear'd very level yet the upper superficies which was contiguous to the Air was manifestly very concave And if to these two Liquors I did in a broader glass pour Oyl of Almonds that Oyl would sink to the bottom of the Spirit of Wine that being well rectifi'd and floating upon the Oyl of Tartar would separate the two Liquors and both above and below retain a flat or level surface But if instead of Oyl of Almonds or another express'd Oyl I dropt into pure Spirit of Wine swimming upon Oyl of Tartar some common Oyl of Turpentine the Oyl would gather into parcels some of the bigness of hail-shot some as big as small Pistol-bullets and some of other sizes which in case they did swim in the Spirit of Wine and touch'd neither of its surfaces seem'd globulous and continu'd so the glasses being stop'd for many hours But in case they emerg'd to the upper part of the Spirit of Wine as much of them as lay immers'd in the Spirit which was by far the greatest part of them appear'd round and continu'd so long as I pleas'd the upper parts only of thâ—se little globes appearing to have the same surface with the Spirit of Wine And I further observ'd that some small drops would as it were rest constantly upon the superficies of the Oyl of Tartar touching it but as it were in a point and continuing to the Eye Spherical though the surface of the Liquor were purposely now and then somewhat shaken But that which I took special notice of was that having upon design into pure Spirit of Wine for upon common Spirit Oyl will swim let fall some great drops of Oyl of Turpentine they did at first sink to the bottom of it and lie upon the surface of the Oyl of Tartar almost like Hemispheres whose convex part was all above the Oyl of Tartar but after a while they were as I â—xpected press'd on all sides and fashion'd into round Bodies yet a little more protuberant at the sides than the top which seem'd scarce to touch the surface of the Oyl of Tartar on which they lean'd Diverse other Observations of this kind were afforded me by some peculiar mixtures that I made of Chymical Liquors But not having the leisure to set them down much less to enquire into their causes I should scarce have mention'd what I have already deliver'd especially since we found that a light variation of Circumstances would often alter the event of such tryals which we have therefore set down barely historically but that finding that drops of Water Quick-silver and other fluid Bodies seem'd to be fashion'd into a round figure by that every way almost equal pressure of the ambient Air and having likewise try'd that Quick-silver suspended in the Air as it may easily be if the Torricellian Experiment being made in a tube exceeding slender some Air be afterwards dexterously let into divide the long Mercurial Cylinder into diverse short ones has both at the top and bottom where it is expos'd to the Action of the Air a very protuberant surface finding I say these Effects of fluid Bodies upon one another I thought it not amiss to intimate how some Experiments might be made that may possibly facilitate the giving an Account of the figuration of some of the more considerable fluid Bodies which as we noted
touch it as before though whilst the External Air was kept out of the Glass the upper Marble might easily be rais'd without taking up the lower with it yet when the outward Air was let in the Marbles were press'd together and became again strongly coherent But it is now high time to look back to that part of our Discourse which the consideration of our Marbles has so long intic'd us from directly prosecuting Although then it may from the past Discourse be conceiv'd that in Bodies of sensible bulk whose smooth surfaces touch one another the force of the Air does mainly make them cohere yet it seems that generally in Bodies whether greater or smaller it is a sufficient cause of Cohesion that the parts of the Body are at rest by one another though perhaps the entire Concretion be remov'd from place to place For Bodies of sensible bulk being either fluid or consistent and it being as above we have taught the chief requisite of a fluid Body that its small parts be in motion there seems not any thing necessary to keep a Body from being fluid and consequently to keep it a firm Body but that its contiguous parts be in a state of rest I know that almost all Philosophers both ancient and modern require something else than the Rest of the parts of which scarce any of them takes the least notice as of a thing conducive to Firmness to the keeping together the parts of a dry and stable Body But although to engage very far in such a Metaphysical and nice Speculation were unfit for me at least at present when I am but to endeavour to explicate Fluidity and Firmness in the sensible Bodies we converse with yet we dare not quite skip it over lest we be accus'd of Overseeing it The greater number of Contemplators ascribe the effect under Consideration to a certain substantial form to which they assign among other Offices that of keeping all the parts united into one Body But what this form is and by what means it unites the parts so strongly in a Diamond or a Ruby c. and so loosely in Tallow Camphire or the like slight concretions and how the substantial form continuing the same in Water and Ice the same matter may easily and frequently become by turns a hard and a fluid Body how these I say and diverse others things are effected by the forms of solid Bodies is to me I confess at least as difficult to conceive as to imagine without it a cause of Cohesion in the parts of a dry Body Other Learned Men there are among the modern Naturalists who have recourse some of them to a Spirit which penetrating and fastening to each other all substances corporeal unites them into one World but others fancy rather a certain Cement or Glue whereby they conceive the parts of Bodies to be made as it were to stick to each other But as for this last Hypothesis it would be consider'd that though Glue is made use of to joyn together Bodies of sensible bulk yet Glue it self being a Body that is so too it must also it self consist of lesser parts sticking to one another which allows me to demand the cause of the mutual Coherence of those parts And if it be answer'd that they likewise stick together by the Intervention of some more subtil Glue I shall again represent that this Glue also must consist of corporeal parts and therefore I shall further demand how these also stick together and if the like Answer be again made me I shall still renew the like Demand till at length the Answerer be reduc'd to confess that parts of Matter so very small cannot be reasonably suppos'd to be kept together by a Cement And if the Corpuscles that make up the finest Glue imaginable are not kept together by a Cement we may be allow'd to ascribe their Adhesion to the immediate Contact and Rest of the component parts which is a cause intelligible and at least probable till some other sufficient cause be assign'd which I do not take that to be which is taught by the Patrons of the first Hypothesis lately mention'd concerning a Spirit diffus'd through the mass of matter For not to mention that the Agility of a Spirit seems not so proper a Qualification for that which is to fasten Bodies together we may consider that this substance which is called a Spirit is indeed but a subtil Body And why therefore may not the minute parts of other Bodies if they be conveniently shap'd for Adhesion stick to one another as well as stick to this Spirit And I should here also demand how the parts of this Spirit are kept fast to one another If any should answer That this Spirit consists of parts which are inseparable and yet perhaps of a hooked shape which fits them to fasten themselves to the Bodies they take hold of and thereby those to one another this would be to propose such a new Notion of the diffus'd Spirit as I know not whether those whose Opinion I have been examining did ever dream of or would be content to adopt and sure according to this Hypothesis there must be a wonderful plenty of these little Spirits in the grossest Bodies and Ice for example which is thought so destitute of Spirits must be well-nigh half made up of them For these little spirituous parts can fasten no parts of other Bodies together but those they touch since otherwise the parts of other sorts of matter if but contiguous might cohere without these which is against the Hypothesis And since each of these small spirituous Corpuscles if I may so call them being really a natural Body and by consequent necessarily divisible at least by Thought into parts I shall ask the Proposers of this new Notion of Spirit upon what Account this Corpuscle can be indivisible I mean what it is if it be not Rest and immediate Contact that hinders but that the parts or designable parcel of corporeal substance which are divisible by thought should be alwayes kept together and never be actually divided I am not averse indeed from granting that they may almost alwayes escape Dissolution but I am apt to suspect that may be because that by reason of the extreme smallness and the Rest and strict Contact of their parts they can scarce ever meet with an Agent minute and swiftly enough mov'd to be able to shatter them or dissociate the combin'd parts For to say that 't is the Nature of every such Corpuscle to be indivisible is but to give me cause to demand how that appears For so important an Assertion needs more than a bare Affirmation for proof And if two of these Corpuscles that are presum'd to be indivisible should being smooth and of the same figure as for Example Cubical happen to lye upon one another and a third should likewise chance to be fitly plac'd upon the uppermost of the two what should hinder but that this Aggregate may by the
violent knock of some other Corpuscles be broken in the midst of the whole Concretion and consequently in the middlemost body For suppose them as Adamantine as you please yet since Corpuscles as hard as they are can be made very violently to knock against them why may not these grate or break the middlemost Corpuscles or any of the others as we see that Diamonds themselves may be reduc'd to powder by other Diamonds though not as Artificers vers'd in the Trade inform me by Attrition with any other stone To prove that the Cohesion of the middlemost of the three lately-mention'd small Deyes with the other two the one above it the other below is not so strong as that of the parts of that middlemost Corpuscle notwithstanding that the contact between each two adjoyning Bodies is suppos'd to be full for so it must be in such Bodies though not alwayes in others visibly greater in which some subtiler substance may be suppos'd to come in part between them to prove this I say there must be assign'd some better cause of the Cohesion of the matter in one part of the propos'd Body than in the other And it cannot with probability be pretended that a Corpuscle presum'd uncapable to be divided should consist of hooked parts and if that should be pretended yet ev'n these hooks also â—eing true Bodies the Question would recur concerning Them and be still renewable in infinitum If it should be said that these minute Bodies are indissoluble because it is â—heir nature to be so that would not be to render a Reason of the thing propos'd but in effect to decline rendring any And though I know that in every Hypothesis about the principles of things something is allow'd to be assum'd as not being to be explain'd or prov'd by any thing more primary than it self yet I know not whether this excuse be proper in our Case wherein it seems that the entireness and permanency of any parcel of matter how minute soever may be probably enough deduc'd from the immediate Contact the Rest and the extreme littleness of its designable parts And if for a last refuge it should be said that the designable parts of these Corpuscles are therefore unseparable because there is no vacuity at all intercepted between them besides that this is contrary to the supposition formerly made for such extremely minute Deyes as we imagin'd to be one upon another having their surfaces according to our Postulatum flat smooth and exquisitely congruous could no more than the parts of either of the three Corpuscles have any vacuity intercepted between them besides this I say this is both to suppose a Vacuum in all divisible Bodies and that too as the cause of their being such and to decline the former Hypothesis touching the use of this Spirit and take Sanctuary among the Atomists to whose opinion about the account upon which those Bodies they call Atoms are not dissipated although some of the Considerations we have alledg'd against the newly examin'd opinion may in part be appli'd yet diverse of their other opinions do so fairly comport with the generality of our Experiments in these Notes touching Fluidity and Firmness that I am willing to decline clashing with them by not pursuing now any further a Disquisition which as I said a while ago is not necessary to my present design especially since the dim and bounded Intellect of man seldom prosperously adventures to be Dogmatical about things that approach to Infinite whether in vastness or littleness Nor indeed would I have that look'd upon as a resolute Declaration of what I think of so abstruse a Subject which I have rather propos'd to avoid saying nothing where I suppos'd it expected I should say something The other thing then which in our Description of a firm Body we mention'd as capable to make it so is the texture of the parts whether homogeneous or not that constitute it and though the Juxta-position and Rest of these parts may possibly alone suffice to make the Body stable yet this Texture seems to be the most usual cause of stability and sometimes also it may superadde a degree of that quality to that which bodies may have upon the former account only For though whilst the parts of the Body are actually at rest it cannot be fluid yet those parts if they cohere to one another but by rest only may Caeteris paribus be much more easily dissociated and put into motion by any external Body actually mov'd than they could be if they were by little hooks and eyes or other kind of fastenings intangl'd in one another it being often necessary in this case violently to break off these fastenings before the little bodies fasten'd together by them can be disjoyn'd and put into such a separate motion as is requisite to the constituting of a fluid Body We formerly made use of that familiar substance the white of an Egge to illustrate the nature of Fluidity Let us now try whether it will also assist us in our enquiry after the causes of stability When an Egge is made hard by boyling since whether we suppose this Induration to be effected by bare motion or impulse or else by the insinuation of fiery Corpuscles since I say there is nothing that appears to get in at the shell unless perhaps some calorifick Atoms and perchance too some little particles of the fluid water it is boyled in 't is not easie to discover from whence else this change of consistency proceeds than from a change made in the texture of the parts whereby they are connected and dispos'd after a new manner fit to make them reciprocally hinder the freedom of each others motions But if instead of hardning the whites of Eggs by the heat of the fire you beat them very well into froth you may perceive that froth to emulate the nature of a stable Body for not only you may raise it up to a pretty height and make it retain a sharp top almost like a Pyramide but I remember I have for curiosity sake made with a little care a long and proportionably thick Body of these bubbles hang down from my finger without falling like an ice-icle from one of the Reeds of a thatch'd House and yet in this there appears not any alteration to be made in the fluid Body save a meer Mechanical change of the disposition of its parts which may be confirmed by water beaten into froth for there the heaped bubbles will quickly subside and fall back into water of the very same consistence it was of before Now there may be several things whereby a body may be put into such a texture as is convenient to make it firm or stable And of these before we consider of them particularly it will be fit to take notice in general that for the most part 't is not from any of them Single but from two or more of them Concurring that the Stability of Concretions proceeds The first and
the particular opinions wherein the Atomists differ from other modern Naturalists especially since he has on some occasions plainly enough intimated the contrary by proposing together with the Atomical ways of resolving a thing another Explication more agreeable to the Cartesian or some other modern Hypothesis The following Tract was entitl'd a History of Fluidity and Firmness because indeed the having set down Experiments and other matters of fact relating to the Subjects treated of is the Main though not the Only thing the Author dares pretend to have done in it And he stiles the History as it now comes abroad Begun Partly because he would invite abler Pens to contribute their Observations towards the compleating of what he is sensible he has but begun and partly because he may hereafter if God permit do something of that kind himself And lastly the Author though troubl'd that he can do it dares not but Advertise the Reader That some Pages partly a little after the beginning and partly about the middle of the following Treatise having been lost through the negligence or mistake of him to whose Care the sheets whereon it was written were committed he fears he has not been able otherwise than very lamely and imperfectly to repair that loss out of his Memory THE HISTORY OF Fluidity and Firmness The First Part. Of FLUIDITY SECT I. WHether Philosophers might not have done better in making Fluidity and Firmness rather States then Qualities of Bodies we will not now examine But under which soever of the two Notions we look upon them 't is manifest enough that they are to be reckon'd amongst the most general Affections of the Conventions or Associations of several particles of matter into Bodies of any certain denomination there being scarce any distinct portion of matter in the World that is not either Fluid or else Stable or Consistent And therefore I presume it may be well worth while to consider what may be the general causes of these two States Qualities or Affections of Matter and to Try whether by associating Chymical Experiments to Philosophical Notions there may not be given at least a more Intelligible and more Practical of both these Subjects than has been hitherto afforded us by the Doctrine of the Schools which is wont to appear very unsatisfactory to discerning Men many of whom look upon what is wont to be taught by the Peripateticks concerning Fluidity and Firmness as well as other Qualities to be partly too general to teach us much and partly too obscure to be understood And that which at present invites us to this Enquiry is chiefly that some Circumstances of our Authors Experiment touching Salt-Petre may afford us some useful assistance in our designed search For though the chief Phaenomena and Circumstances of the Experiment may be thought principally to respect Fluidity yet since that and Firmness are contrary Qualities and since it is truly as well as commonly said That contraries survey'd together serve to illustrate each other it may reasonably be hop'd That the Light which the circumstances just now related to may give to the Nature of Fluidity may facilitate the knowledge of that of Compactness nevertheless we shall often be oblig'd to treat of these two qualities together because the Experiments we are to produce do many of them relate to both SECT II. A Body then seems to be Fluid chiefly upon this account That it consists of Corpuscles that touching one another in some parts only of their Surfaces and so being incontiguous in the rest and separately Agitated to and fro can by reason of the numerous pores or spaces necessarily left betwixt their incontiguous parts easily glide along each others superficies and by reason of their motion diffuse themselves till they meet with some hard or resisting Body to whose internal surface by virtue of that Motion their Smallness and either their Gravity or something Analogous or Equivalent to it they exquisitely as to sense accommodate themselves SECT III. What notion Epicurus and the Antient Atomists his followers had of fluid Bodies may be learn'd from these Verses of his Paraphrast Lucretius Illa autem debent ex laevibus atque rotundis Esse magis fluido quae corpore liquida constant Nec retinentur enim inter se glomeramina quaeque Et procursus item in proclive volubilis extat And indeed it is probable enough that in divers Liquors the little surfaces of the component particles are smooth and slippery and that their being so does much facilitate the gliding of the Corpuscles among themselves and consequently the Fluidity of the Body they compose Nor is it to be deny'd that the Spherical figure of such Corpuscles may also conduce to their easie rouling upon one another but there are divers other figures which may make the little Bodies indow'd with them voluble enough to constitute a fluid substance And the other qualities to be met with in divers liquid substances and even in water it self and Oyl seem to argue their parts to be otherwise shap'd and those fluid Bodies which are not Liquors as Air and Fire seem to be compos'd of particles not all or most of them round but of very various and sometimes of very irregular figures and yet that such Bodies deserve to be call'd fluid ones will be manifest anon And that they make a much more considerable part of the Universe than those that are wont to be call'd Liquors may be argu'd from hence that except the Earth the Planets and perhaps too the fixt Stars the rest of the World as vast as it is seems to consist chiefly if not only of an Aetherial thin and fluid substance as may appear to omit other arguments by what latter Astronomers have observ'd concerning the free and unresisted motion of such Comets as have by a Trajection through the Aether for a long time wander'd through the Celestial or Interstellar part of the Universe SECT IV. And here let us observe that 't is not necessary to the Fluidity of a Body nay nor to its appearing fluid to the Eye it self That the Corpuscles it consists of be crowded as close together as they are wont to be in water and other bodies that are commonly lookt upon as the only Liquors For though a parcel of matter no bigger than a grain of Corn being rarify'd into smoak will possess an incomparably greater space than it did before and though if a Body be further rarify'd into flame its expansion will be yet much greater yet both smoak and flame may be so order'd as to appear like Liquors We have practis'd divers ways to make the fumes of Bodies acquire a visibly-level superficies like water but the easiest though not perhaps the best is this part of which I remember I have seen perform'd as a kind of trick by a very ingenious Person The mouth being fill'd with the smoak of Rosemary that happening to be at hand when I made the Experiment if this smoak be plentifully blown into a
Bodies whereby I have reduc'd sometimes one sometimes another of them together with the Menstruum which needs not much exceed them in Bulk to the consistence of a fluid Body We see likewise that Fusion makes metalls fluid and in Fusion there is manifestly a comminution of the melted Body the Heat alone of Gold Silver or Iron though encreas'd even to Ignition being not able to make those metalls become fluid whilst they continue in masses of any sensible bulk To which I shall adde anon that even melted Metalls may have their Fluidity encreas'd by a yet further Comminution of their parts SECT VII And to resume here the Consideration of that very difficult Question which we have elsewhere menâ—ion'd it seems well worth Enquiry whence it happens that in the distillation of common Salt and other saline Bodies which not only are not fluid but are hard ev'n to brittleness there will yet be obtain'd a perfect and permanent Liquor and from some of them a very considerable proportion of it In answer to this Question it may indeed be said That in diverse dry Bodies such as Harts-horn Wood and Bones committed to distillation the fire does no more than separate the aqueous or other liquid parts from the others wherewith they were blended in the Concrete and bring them together into the Receiver where they convene into a Liquor But besides that this it self is perhaps more easily said than prov'd it does not reach the propounded Difficulty For with what probability can it be affirm'd of Bodies that have been already calcin'd or melted such as are the red Calx of Vitriol and flux'd Sea Salt c. which yet afford Liquors though their aqueous and other looser parts have been already driven away by a strong fire before their being expos'd to distillation I have sometimes then consider'd whether it may not seem less improbable to conjecture that the vehement agitation produc'd in such Bodies by the violence of Heat does both divide them into minute Corpuscles and drive over swarms of them into the cold Receiver where loosing their former vehemence of agitation they are reduc'd into a Liquor chiefly for I would not exclude concurrent causes by reason that the fire happen'd to rend the Concrete into parts by their extreme littleness or their shape or both so easie to be tumbled up and down that the wonted agitation of the Air propagated by the interpos'd Bodies or Medium or else that the same cause whatever it be that gives the Air its wonted agitation is able to give such minute Corpuscles enough of it to keep them fluid SECT VIII That there is constantly in the Air a various motion of the small parts will be anon declared That also some Bodies will be kept fluid by a much less measure of agitation than is requisite to others seems probable from hence That Wine will continue a Liquor in such a languid warmth of the Air as will not keep the parts of water moving but permit them to rest in the form of Ice And in cold Countries where Wine it self would congeal as I have by Art made it do here in England 't is observ'd that though the more aqueous parts will by the loss of their motion be turn'd into Ice yet the more subtil and spirituous parts remain unfrozen and so do diverse other Liquors especially Chymical of very subtil and voluble parts And the Corpuscles that chiefly compose that Body which is properly call'd the Air though it appears by weather-glasses that Cold may very much contribute to condense it that is to occasion the approach of its parts to one another or reduce them to a closer order have not been observ'd to be frozen by any degree of cold whatsoever which seems to proceed from hence that by reason of their extream littleness not excluding their figure there cannot be so little of agitation about the Earth as not to be sufficient â—o continue a various motion in such very minute Bodies and consequently to keep them fluid Now That likewise it is possible that a saline Spirit should consist at least in great part of very minute grains of Salt we elsewhere declare where 't is taught that a Sal-Armoniack may be made by Spirit of Urine and Spirit of Salt as the common Sal-Armoniack is made with crude Salt and there a way is also shewn how these two Salts the Urinous and the other as strictly as they are united in the compound may be readily divorc'd And agreeably to this I observe that as according to what I elsewhere note a common Aqua fortis may be enabl'd to dissolve Gold on which of it self it will not fasten by the addition of Spirit of Salt so I find that common crude Salt barely dissolv'd in it will give it the like power of working upon Gold Nay I have try'd that crude Nitre dissolv'd in good Spirit of Salt may make it serve for an Aqua Regis And I remember on this occasion that having enquir'd of the most noted Person in Holland for the distilling of corrosive waters what was the greatest proportion of distill'd Liquors that ever he was able to obtain from Sea Salt he though a man not given so much as to boasting affirmed to me that by using instead of the ordinary Caput mortuum as Brick-dust Sand c. that Chymists are wont to mingle with Salt before they distil it a certain whitish clay he had sometimes brought over almost the whole body of Salt into a Liquor insomuch that from a pound of Salt he could draw and that without any extraordinary trouble or degree of fire fourteen Ounces of Liquor And when because I suspected that much of this might be water forc'd from the clay mingled with the Salt I enquired whether he had ever dephlegmed this Liquor He answered me that he had purposely done it and sometimes found no less than about twelve ounces of it to be strong rectify'd Spirit which brought into my mind that almost incredible passage of Beguinus who somewhere teaching the Distillation of another Salt addes to the end of his Directions That if you have wrought well you shall get from a pound of the matter a pound of Spirit But because from all these Liquors distill'd from such kind of Salts 't is possible either by Rectification or some more Philosophical way to obtain a portion of phlegm or water I leave it to further Enquiry whether or no the Fluidity of these distill'd Liquors may not in diverse cases be in part further'd by the mixture of some particleâ— of an aqueous nature such being fit to make Dissolvers and vehicles for Salts which may not absurdly be suspected to have been produc'd by the action of the fire upon the Concrete committed to distillation if we allow with that famous Chymist Helmont That by the Alchahest all gross Bodies may be totally and that without it ev'n Oyle and Salt may in great part and that without Additaments be reduc'd into insipid
water SECT IX We shall anon when we come to treat of Firmness mention our having made a certain substance so dispos'd to Fluidity that it may be made to change the stable consistence for a liquid one by so small an Agitation as only the Surplusage of that which the ambient Air is wont to have about the middle even of a Winters day above what it hath in the first or latter part of it Nay we have made ev'n a Metalline Salt or Vitriol capable of this proclivity to liquefaction of which we have unquestionable witnesses And therefore it need not appear incredible that other heaps or aggregates of Corpuscles much lighter than these though heavier than those of the Air may have all their parts so minute and fitted for motion that the wonted agitation of the Air may not only about noon but at all other times of the day keep them in motion and thereby in the state of Fluidity SECT X. And here I must adde that 't was not altogether without cause that I lately took notice of the shapes as well as the sizes of Bodies in reference to their fitness to constitute fluid ones For though I be not sure but that in those Bodies as Sal-Armoniack Antimony c. which are by the fire sublim'd into flowers rather than distill'd into Liquors the magnitude of the component Corpuscles may not be a hinderance to the Fluidity of the Body they constitute yet this seems as probably referable to their figure unapt for the requisite motion as to their bulk And I have sometimes made to this purpose this Experiment That by slowly distilling Oyl-Olive per se in a glass Retort plac'd in Sand I found as I expected that about the third part of the Oyle which was driven over into the Receiver did there coagulate into a whitish Body almost like Butter So that although it seem'd manifest by the strong smell and very piercing taste of this white substance that the Oyle which afforded it had its particles as it were torn in pieces and though distillation be wont to obtain Liquors ev'n from consistent Bodies yet in our Experiment of a concrete that is naturally fluid the distill'd Liquor it self proves not to be so of which no cause seems more obvious than that the newly-acquired shape of the dissipated parts of the Oyly Corpuscles makes them unfit for motion either Absolutely speaking or at least in Respect of one another by making them less pliant than formerly or giving them a figure more easie to be entangl'd with the neighbouring Corpuscles or else by making their surfaces less smooth and slippery than before SECT XI But to return thither whence we have digress'd and mention some more familiar Examples of the Conduciveness of the smallness of a Bodies disjoyned parts to its Fluidity we may take notice that of Bodies that consist of incoherent parts and are made up as it were by Aggregation those de caeteris partibus in their being pour'd out most resemble Liquors that are the smallest as would appear upon the emptying of several Sacks the one of Apples the other of Walnuts the third of Filberts the fourth of Corn the fifth of Sand and the sixth of Flowre Confectioners also Cooks and others that make much use of whites of Eggs will easily reduce those clammy and viscous Bodies into a thin and fluid substance to which for its affinity with water many give the same name and yet this difference of Fluidity being effected only by long and skilfully beating the mass with a whisk or even with a spoon seems to be produc'd but by pulling asunder the parts which perhaps before were long and somewhat twin'd and breaking them into shorter or lesser and consequently more voluble ones And I remember I have seen a good quantity of that jelly that is sometimes found on the ground and by the Vulgar call'd a Star-shoot as if it remain'd upon the extinction of a falling Star which being brought to an eminent Physician of my acquaintance he lightly digested it in a well-stopt glass for a long time and by that alone resolv'd it into a permanent Liquor which he extols as a specifick to be outwardly apply'd against Wens SECT XII And here we will subjoin an Observation afforded us by the Art of Casting which has sometimes yielded us a not unpleasant Diversion 'T is observ'd then by Gold-smiths well veâ—s'd in that Art and has been recommended to me by an Artificer eminently skilful in it as one of the chief Remarques belonging to it that when any such curious work of Silver is to be cast as requires that the impression of hairs or very slender Lines be taken off by the Metal it is not enough that the Silver be barely melted but it must be kept a considerable while in a strong fusion For if it be too soon pour'd out the figure it will make will be but blunt whereas if it be kept a competent time in Fusion the matter becoming thereby more Liquid as well as hotter will be thin enough to run into the smallest cavities of the Mould and so receive a figuration ev'n from the delicatest of them Whence it may probably be deduc'd that some Bodies already fluid may by a further comminution of their parts be made yet more fluid The like increase of Fluidity may be observ'd in some other fluid Bodies especially unctuous ones as Turpentine Oyle c. when heat begins to break as well as agitate their parts I may elsewhere have occasion to mention how by the operation of the fire the Crystalline Salt of Urine may be reduc'd without Additaments to a strong and ponderous Liquor though in this as perhaps also in some of the former Instances 't is not unlikely that as we may hereafter more particularly declare there may concurre to the prâ—duc'd change of consistence some alteration in the figure of the Corpuscles whereof the firm Body consisted And if that be true which Helmont in several places affirms of his prodigious Liquor Alkahest it is possible to turn Plants Animals Stones Minerals Metals or whatever kind you please of consistent Body here below into a Liquor equiponderant to the resolv'd Concrete which if granted seems to argue That the most solid Body by being divided into parts small enough to be put into motion by the causes that keep those of water and other Liquors in agitation may become fluid Bodies And this Intimation I shall adde for the sake of Philosophers that barely by long Digestions and much more if they be help'd by seasonably-repeated Distillations in exactly stopt Vessels and a due degree of heat there may be made in the parts of many Bodies both Vegetable and Animal so great a change from the state of consistence to that of Fluidity as those that contenting themselves with ordinary courses of Chymistry have not had a peculiar curiosity for tryals of this nature will not be forward to expect SECT XIII The Second of the above-mention'd three
we long since met with as to the main in the shops of Stone-Cutters which though unregarded by them will excellently serve to make out what we mention it for Take then good Alabaster or in defect of this of that white stone which is well known to our Masons by the name of Plaster of Paris beat it very small and put as many pounds as you please of the finely-searc'd powder into any flat-bottom'd and first well heated vessel of Brass or Iron bigger or lesser according to the quantity you intend to burn Encrease the fire by degrees till it grow to be strong and when the calorifick Atoms shall have in sufficient numbers pervaded the heap of powder or if you please when the igneous Corpuscles have by their numerous and brisk strokes upon the vessel communicated by its means their agitation to the enclosed powder and when by either of these ways or both the fire which may also resolve some of the more spirituous and exhalable parts whereof Distillation has shewn me that Alabaster is not destitute into Vapours shall have put the little bodies it consists of into actual motion which will be quickly done you shall see it assume the form of a Liquor and boil with numerous great and confus'd waves just like a seething-pot and if whilst it continues in this state you stir it with a stick it will not like a heap of sand or as it self would do at another time resist the motion thereof but yield thereto like a Liquor and like it will seem to have something of the Nature of a coherent body for by stirring it any thing strongly near one side of the Vessel you may make the waves beat very manifesty against the opposite part of it And besides all this you may observe this further resemblance betwixt this boiling matter and a Liquor that there will flye up out of the Pot great store of steams like smoak but that they are white which will sometimes like smoak ascend for ought can be discern'd to the very top of the Chimney and leave its colour upon the places by which plenty of it hath past Besides those that make this Experiment often as we have taken pleasure to do may have the opportunity to observe that when the Vessel has continued so long over the fire that the contained Alabaster relapses into the form of a heavy moveless powder by keeping it a while longer in the heat it will for once at least resume the form of a fluid body and boil again as before the spirituous steams whose avolation promoted the Ebullition being not yet quite spent And lastly if when it seems most a Liquor you take up a little of it and as nimbly as you can cast it upon a sheet of white Paper it will not at all wet it but immediately discover it self to be a moveless incoherent powder as it was before its being set over the fire whereby it I hope appears that a heap or aggregate of such little bodies as are neither Spherical nor otherwise regularly shap'd nor small enough to be below the discernment of the Eye may without either fusion or being pour'd out be made fluid barely by a sufficiently strong and various agitation from what cause soever that proceed of the particles that make it up and lose its fluidity immediately upon the ceasing of it Thus have we seen how very much it conduces to the making of a Body fluid that its smal parts be actually mov'd But whence this motion proceeds we shall not at present venture to determine For though in the Examples newly mention'd and some others most men will be forward to ascribe the motion produc'd in the parts of the fluid Bodies there mention'd to the action of the fire whereunto they were expos'd yet what it is that puts the parts of fluid Bodies in general into the motion requisite to make them such is a Question of which the true Resolution indeed were very desirable But the full debate of it will not I hope be here expected from me whilst I am writing but Notes since it would engage me to discuss two or three of the difficultest as well as the importantest Controversies belonging to Natural Philosophy For first I should be oblig'd to consider whether Motion or a propensity to it be an inherent Quality belonging to Atoms in general and not losable by them or whether all Motion is communicated by impulse from one Body to another And since those that of late have taught that all visible Liquors as Water Oyl Quick-silver c. owe their fluidity chiefly to the agitation of some thin and restless matter which incessantly permeates them do deduce the necessity of such an Ethereal substance principally from the impossibility that there can be any Vacuum properly so call'd in the Universe wherein yet are very many spaces unpossest by either Air or grosser Bodies than it the Examination of this subtil matter would draw on the Consideration of the nice Controversies that perplex Philosophers concerning Emptiness which 't were more difficult for us to examine in few words than it is necessary for us to meddle with them in this place since not writing of the first Principles of Physiology but of Fluidity which is but a secondary or derivative quality if I may so call it it seems sufficient to give a notion of it that we deduce it not from the unintelligible substantial form of the fluid Bodies but from those simple and general Affections of Matter the Figure Situation and Motion of its small parts SECT XIX Wherefore declining to adde any thing in this place to what we have otherwhere discoursed concerning the Origine of Motion and the possibility or impossibility of a Vacuum we will proceed to take notice that there is one thing more which we may learn from Salt-Petre touching the Nature of Fluidity and that is the distinction betwixt a fluid Body and a wetting Liquor which are wont because they agree in many things to be confounded but inconsiderately enough for though every wetting Liquor be fluid yet every fluid Body does not wet The Air the Aether and ev'n flame it self may be properly call'd Fluid Bodies according to the notion of Fluidity hitherto made out and yet will scarce by any man be call'd Moist Liquors and Salt-Petre whilst in fusion is really a Liquor and so is every melted Metal and yet these wet not the bodies they touch as do Water and other wetting Liquors which are fluid bodies with this peculiar qualification that they stick to and moisten the dry bodies which they touch or at least abound with some parts which being separated from the rest and reduced to a Liquor will do so And according to this notion methinks it may be conceiv'd that the humidity of a body is but a relative thing and depends chiefly upon the congruity or incongruence of the component Particles of the Liquor in reference to the pores of those particular bodies that
blowing the fire without finding that this metalline meal did at all melt though Salt-Petre be a fusible Salt and Tin it self be of exceeding easie fusion Whereas although Copper be a metal which is much harder to melt not only than Tin and Lead but even than Silver as those well know that mix Silver with Copper to make a fusible mixture to sodâ—r upon Copper and Brass yet was this metal that will endâ—re a long and strong Ignition by being joyn'd per Minima with the same kind of Nitrous Corpuscles that had so contrary an effect upon the Tin so strangely dispos'd to fusion that the Vitriol would melt with as small a heat as that of ones hand Nay we have made such a Vitriol either with Spirit of Nitre or with what differ'd little from it a certain Aqua fortis as would even in Winter be made to stand melted for divers hours together by the languid warmth of the Sun though shining on it but through a window where it also stood but in an unstop'd Glass So fit it is that we consider as well the new Texture that mingl'd Bodies obtain by the association of their particles whose size and shape and perhaps motion may be thereby much alter'd as the consistence of the particular Bodies before their being mixt THE HISTORY OF Fluidity and Firmnesse The Second Part. Of FIRMNESSE IT is sufficiently known that the Chymists ascribe the Firmness and Hardness of Bodies to Salt and teach that the Saline Ingredient of them is the Principle of Coagulation in them and the cause of their Compactness and Solidity But though this opinion of the Chymists be embra'cd by so many modern Philosophers and Physitians that some may think it superfluous to make enquiry after other Causes yet others to whom the Explications of Chymists seem not always so much as Intelligible will upon the very account of the Receivedness of the propos'd Opinion think it rather worthy to be examined than to be acquiesc'd in However without making it our business either to side with or oppose any Sect of Naturalists we will apply our selves a while to consider the thing it self in prosecution of the Design already begun And having in the fore-going Part of our little History taken a general view of Fluidity we will now proceed to try what Light it will afford us to discover the nature of Firmness or Compactness And since fluidness and stability being contrary qualities are to be apprehended under contrary notions we may conceive that the firmness or stability of a body consists principally in this that the particles that compose it besides that they are most commonly somewhat Gross either do so rest or are so intangled between themselves that there is among them a mutual cohesion whereby they are rendred unapt to flow or diffuse themselves every way and consequently to be without violence bounded and figur'd by other surfaces than those which their connexion makes themselves constitute In this rude Description of Firmness we have intimated Three principal causes of it namely the Grossness the quiet Contact and the Implication of the component parts The first is Grossness of Parts of which we have in effect almost sufficiently discours'd already for since treating of Fluidity we manifested at large how conducive smalness of Parts was to that Quality 't is easie to deduce that Grossness of parts in a Body must commonly be a great disposition to its being Firm. And bigger Corpuscles being caeteris paribus more difficult than lesser to be put into motion when they are onâ—e at rest it is obvious that a Body consisting of such Particles is less dispos'd to become fluid and consequently more apt to continue firm than if its component parts were smaller and thereby more easie to be displac'd But when I speak of the Grossness of Corpuscles I pretend not to determine whether or no Body or Matter be so perpetually divisible that there is no assignable portion of matter so minute that it may not at least Mentally to borrow a School term be further divided into still lesser and lesser parts For allowing this indefinite Divisibility of corporeal substance 't is plain that it may in some sense be averr'd that there are no firm Bodies whose Parts are not extreamly minute But I understand by the gross parts I here speak of such Corpuscles as actually convening to constitute a Body are scarce dissipable or divisible into lesser by the Agitation of the ambient Air or Aether or by the other causes of the Fluidity of Bodies It is also to be noted that when I spake of the fitness of grosser Corpuscles to make a firm Body I added Caeteris paribus because it may happen that the breaking of the small parts of a Body into minute Particles may make them but the fitter to contribute to the Firmness of the Body they belong to For the parts of the divided Corpuscles may by their comminution acquire a new and perhaps a more irregular shape than before upon whose account they may be more dispos'd to be entangled among the neighbouring Particles or may be better fitted to get into and fill the pores of some kind of Bodies And in in such little Particles not only the minuteness may make them lie closer together and consequently the better exclude the Air but the greatness of the surface in proportion to the bulk of the matter may perhaps in some Cases occasion a fuller contact and so facilitate the constitution of a very firm Body in case these minute parts whose intervals if they intercept any need not be other than very small shall be placed and disposed to the best advantage for a full contact of one another But as I said a while before from what we have already delivered concerning the size of parts when we treated of Fluidity it may easily be understood how much the magnitude of them may conduce to Firmness and therefore we will presently pass on to the mention of the two other things to be considered in reference to consistent Bodies Whereof of the one is the bare Rest of the small and contiguous parts that make up the firm Body and the other the intricate Texture of such parts in the body they make up And either of these two seems alone sufficient to render a body stable though Nature do perhaps oftentimes make some though not equal use of both to fasten the parts of the same body more firmly together Of the former of these Causes I am inform'd that the justly famous Monsiâ—ur Des Cartes has also taken notice but without adding proof from Experiments or Observations But it seems to have been either over-look'd or as incongruous to their Hypothesis of the innate motion of Atoms rejected by the old Atomists and by Lucretius who takes notice that I remember only of the latter for though they did of old make mention of the sudden divulsion of two flat and solid Bodies yet they employ that Observation
in a convenient quantity of Water does upon its recoagulation so dispose of the aqueous Particles among its own Saline ones that if the Experiment be well and carefully made almost the whole mixture will shoot together into fine Chrystals that seem to be of an uniform Substance and are consistent enough to be even brittle and to endure to be pulveriz'd siâ—ted c. though the Concretion may have such a Proportion of Water in it that as I remember when the Experiment succeeded well from three parts of Water and but one of Salt I had about four parts of Crystals I need not tell you that this Salt sâ—ems to have a somewhat more then ordiâ—ary Resâ—mblance of a â—rue Coagulum since it reduces so much water into a stable consiâ—tence yet it does in no contemptible proportion materially concur to the Body produc'd But I may hereafter which I must not do now entertain you about a Salt of a differing kind from this and which put me upon considering whether there may not be a Coagulum more properly so call'd of Common Water which may in a very small proportion operate upon a great quantity of that Liquor as Runnet does on Milk I have not yet examined whether it will be sufficient to refer meerly to the second and third ways lately mention'd of making Bodies become stable in the Phaenomena I am about to speak of or whether it may be reasonably suppos'd and added as a fifth way that the Bodies to be coagulated may in great part be brought to be so by so acting upon the Bodies to which they are put that the Agent Liquor if I may so speak does by its action comâ—unicate to the subject it works on or lose upon some other account some subâ—le parts whose absence fits the dispos'd remaining Fluid for such a Cohesion as may suffice to make a Body be though very soft yet consistent But however 't will not be amiss to take some notice of Effects which what e're the cause be belong to the History of Fluidity and Firmness I some years since prepar'd a Substance of a whitish colour which would not only destroy the Fluidity of some other Liquors but would give a consistency to a notable proportion of Oyl of Vitriol it self though the parâ—s of this Liquor be presum'd upon the score of its corrosiâ—eness and iâ—s aptness to grow very hot with many other Bodies and make them smoke to be very vehemently agitaâ—ed And I remember that I sometimes shew'd the curious a Glass Vial well stopt upon thâ— bottom of which lay a little of this newly mention'd whiâ—ish powder ovâ—r which theâ—e was a considerable propoâ—â—ion of Oyl of Vâ—â—riâ—l in a consistent Form without seeming to have any thing to do with the Powder as indeed it had been only pour'd upon it and suffer'd to stand in the cold for some time which if I mistake not was a day or two at the end of which the above mention'd change was wrought on the Liquor by the powder which did not appear to be dissolv'd thereby Which Phaenomenon seem'd indeed to argue that there happen'd in this Experiment that was not the only one of the kind I then made something like the coagulation formerly mention'd of Quicksilver by the Vapour of Lead some subtle parts of the Coagulator if I may so call it invisibly pervading the Liquor whose Fluidity was to be suspended though it seem not improbable to me that the effect produc'd might depend upon both causes this newly express'd and the other a little abovemention'd where I guess'd that a change of Texture and thereby of Consistence in the Menstruum might be the result of the Operation of the Menstruum and the Body it acts upon And because this powder is not so easie to be prepar'd I shall adde that you may though not so well as by the newly mention'd way see the Coagulation of a Menstruum upon a firm Body which it does not seem to dissolve by the ensuing Experiment Take Crystals of Salt-Petre very well dryed but not powdeâ—'d and gently pouring on it in a Glass Vial some good Oyl of Vitriol till it swim about half an Inch or perhaps more above the Salt leave the Vial clos'd with a cover of Paper in a cool quiet place where it may not be shaken and if the Tryal succeed with you as did it with me the Liquor will though slowly so settle it self about the Nitre that though you incline the Vial to any side or perhaps turn it upside down it will not run out and I have sometimes taken notice of little Saline Bodies and as it were Fibres that seem'd to keep the parts of the mixture united together I made also some other Tryals to coagulate unflegmatick A. F. upon Nitre and some other Bodies the Phaenomena of which Tryals did not oblige me to renounce the lately mention'd Conjectures about the causes of such changes of consistency in Liquors as I have been speaking of For I still think it highly probable that the best Coagulator I have met with acts but as a finer sort of Runnet which in an inconsiderable quantity really disperses material parts of it self through the Liquor to be wrought on though these when the Coagulator is a consistent Body be perchance so few or subtle as not to make any Visible diminution of the Body it parts with A more eminent Example to our present purpose may be afforded us Sometimes for I am sure the Experiment will not Always succeed by the notable way of coagulating Quick-silver and thereby turning it from a fluid into a firm body by the vapour of melted Lead in which when it is taken off the fire but before it be quite grown hard again a little cavity must be made with a pebble or a stick that the Quicksilver tied up in a rag may be nimbly put into that hole and be congeal'd by the permeating stream of the cooling lead Which Effect may be less hopefully expected by the way wont to be prescrib'd by Authors most of whom I doubt never made tryal of it then by another that I have practis'd and may on another occasion shew you And that some metalline steam does really invade the Quicksilver seems probable by the wasting of Lead by fusion and by the operations ascrib'd by Chymists to the fume of Lead upon Gold about which I may elsewhere tell you what is come to my Knowledge And I remember that not long since an ingenious Physician of my acquaintance keeping some Lead long in fusion to reduce it per se into a Calx and holding his head often over rhe melting pot to observe the alterations of the metal was suddenly purg'd diverse times both upwards and downwards which both he and I ascrib'd to the Saturnine exhalations And though I suspected the Congelation formerly-mention'd might proceed from the egress of some subtil substance that formerly agitated but after deserted the Mercuriaâ— Corpuscles yet that the Concretion of
the other to overtake his desired Prey so Nature acts very seriously in all the other things that we make sports with and is in very good earnest whether we Men be so or no. Perhaps you will wonder Pyrophilus that in almost every one of the following Essays I should speak so doubtingly and use so often Perhaps It seems 'T is not improbable and such other expressions as argue a diffidence of the truth of the Opinions I incline to and that I should be so shy of laying down Principles and sometimes of so much as venturing at Explications But I must freely confess to you Pyrophilus that having met with many things of which I could give my self no one probable cause and some things of which several Causes may be assign'd so differing as not to agree in any thing unless in their being all of them probable enough I have often found such Difficulties in searching into the Causes and Manner of things and I am so sensible of my own Disability to surmount those Difficulties that I dare speak confidently and positively of very few things except of Matters of fact And when I venture to deliver any thing by way of Opinion I should if it were not for meer shame speak yet more diffidently than I have been wont to do 'T is not that I at all condemn the Practice of those Inquisitive Wits that take upon them to explicate to us ev'n the abstrusest Phaenomena of Nature For I am so far from censuring them that I admire them when their Endeavours succeed and applaud them ev'n where they do but fairly attempt But I think 't is fit for a man to know his own Abilities and Weaknesses and not to think himself oblig'd to imitate all that he thinks fit to praise I know also that the way to get Reputation is to venture to explicate things and promote Opinions For by that course a Writer shall be sure to be applauded by one sort of men and be mention'd by many others whereas by the way of Writing to which I have condemn'd my self I can hope for little better among the more daring and less considerate sort of men should you shew them these Papers than to pass for a Drudge of greater Industry than Reason and fit for little more than to collect Experiments for more rational and Philosophical heads to explicate and make use of But I am content provided Experimental Learning be â—eally promoted to contribute ev'n in the least plausible Way to the Advancement of it and had rather not only be an Underbuilder but ev'n dig in the Quarries for Materials towards so useful a Structure as a solid body of Natural Philosophy than not do something towards the Erection of it Nor have my thoughts been altogether idle and wanting to themselves in framing Notions and attempting to devise Hypotheses which might avoid the deficiencies observ'd in other mens Theories and Explications but I have hitherto though not always yet not unfrequently found that what pleas'd me for a while as fairly comporting with the Observations on which such Notions were grounded was soon after disgrac'd by some further or new Experiment which at the time of the framing of those Notions was unknown to me or not consulted with And indeed I have the less envy'd Many for I say not All of those Writers who have taken upon them to deliver the Causes of things and explicate the Mysteries of Nature since I have had opportunity to observe how many of their Doctrines after having been for a while applauded and even admir'd have afterwards been confuted by the discovery of some new Phaenomenon in Nature which was either unknown to such Writers or not sufficiently consider'd by them For I have found it happen as well to many others that have publisht their Opinions as to me who have been more private in my Guesses in our Theories built on either too obvious or too few Experiments what is wont to happen to the Falsifiers of Coyn for as Counterfeit pieces of Money will endure some of them One Proof as the Touch-stone others Another as Aqua fortis some a third as the Hammer or the Scales but none of them will endure All proofs so the Notions I mention in which sort I fear too great a part of those hitherto extant may be compriz'd may agree very fairly with this or that or the other Experiment but being made too hastily and without Consulting a competent number of them 't is to be fear'd that there may still after a while be found one or other if not many their Inconsistency with which will betray and discredit them I have notwithstanding all this on some occasions adventur'd to deliver my Opinion not that I am very confident of being less subject to erre in those particulars than in any of the others wherein I have refrain'd from interposing any Conjecture but because I would manifest to You that I scruple not to run the same venture with those incomparably better Naturalists that have thought it no disgrace in difficult matters rather to hazard the being sometimes mistaken than not to afford Inquisitive Persons their best Assistance towards the Discovery of Truth And because Pyrophilus in the Reasons and Explications I offer of Natural Effects I have not for the most part an immediate recourse to the Magnitude Figure and Motion of Atoms or of the least Particles of Bodies I hold it not unfit to give You here some account of this Practice not so much for the sake of those few Passages in my Essays that may be concern'd in it as for that of many Learned men especially Physitians whose useful Writings begin to be undervalu'd and are in danger to be despis'd by an Opinion taken up from the mis-understood Doctrine of some eminent Atomists as if no speculations in Natural Philosophy could be rational wherein any other causes of things are assign'd than Atoms and their Properties I consider then that generally speaking to render a reason of an Effect or Phaenomenon is to deduce it from somthing else in Nature more known than it self and that consequently there may be divers kinds of Degrees of Explication of the same thing For although such Explications be the most satisfactory to the Understanding wherein 't is shewn how the effect is produc'd by the more primitive and Catholick Affection of Matter namely bulk shape and motion yet are not these Explications to be despis'd wherein particular effects are deduc'd from the more obvious and familiar Qualities or states of Bodies such as Heat Cold Weight Fluidity Hardness Fermentation c. Though these themselves do probably depend upon those three universal ones formerly nam'd For in the search after Natural Causes every new measure of Discovery does both instruct and gratifie the Understanding though I readily confess that the nearer the discover'd Causes are to those that are highest in the scale or series of Causes the more is the Intellect both gratify'd and instructed I
think it therefore very fit and highly useful that some speculative Wits well vers'd in Mathematical Principles and Mechanical Contrivances should employ themselves in deducing the chiefest Modes or Qualities of Matter such as are Heat Cold c. and the States or conditions of it if we think fit to distinguish these from its Qualities as fluid firm brittle flexible and the like from the above-mention'd most primitive and simple Affections thereof And I think the Common-wealth of Learning exceedingly beholden to those Heroick Wits that do so much as plausibly perform something in this kind But I think too we are not to despise all those Accounts of particular Effects which are not immediately deduc'd from those primitive Affections of either Atoms or the insensible Particles of Matter but from the familiar though not so universal Qualities of things as cold heat weight hardness and the like And perhaps it would be none of the least advantages which would accrue to Naturalists from a satisfactory explication of such Qualities by the most primitive and simple ones that it would much shorten the explication of particular Phaenomena For though there be many things in Nature that may be readily enough made out by the Size Motion Figure of the small Parts of Matter yet there are many more that cannot be well explain'd without a great deal of Discourse and divers successive Deductions of one thing from another if the purpos'd effect must be deduc'd from such primary and Universal Causes whereas if we be allow'd to take the Notions of Cold Heat and the like Qualities for granted the explications and proofs may be much more compendiously made He gives some Reason why Stones and Iron and all other heavy Bodies will swim in Quick-silver except Gold which will sink in it that teaches that all those other Bodies are in specie as they speak or bulk for bulk lighter than Quick-silver whereas Gold is heavier He I say may be allow'd to have render'd a Reason of the thing propos'd that thus refers the Phaenomenon to that known Affection of almost all Bodies here below which we call Gravity though he do not deduce the Phaenomenon from Atoms nor give us the cause of Gravity as indeed scarce any Philosopher has yet given us a satisfactory Account of it So if it be demanded why if the sides of a blown Bladder be somewhat squeez'd betwixt ones hands they will upon the removal of that which compress'd them fly out again and restore the Bladder to its former figure and dimensions it is not saying nothing to the purpose to say that this happens from the spring of those Aerial Particles wherewith the Bladder is fill'd though he that says this be not perhaps able to declare whence proceeds the Motion of Restitution either in a Particle of compress'd Air or any other bent spring And as for the Reasons of things assign'd by Physitians they must be most of them despis'd unless we will allow of such explications as deduce not things from Atoms or their Affections but only either from secondary Qualities or from the more particular Properties of Mixt Bodies If a Physitian be ask'd why Rhubarb does commonly cure Loosenesses he will probably tell you as a Reason that Rhubarb is available in such Diseases because it hath both a Laxative vertue whereby it evacuates Choler and such other bad humours as are wont in such cases to be the peccant Matter and an astringent Quality whereby it afterwards arrests the Flux But if you further ask him the Reason why Rhubarb purges and why it purges Choler more than any other humour 't is ten to one he will not be able to give you a satisfactory answer And indeed not only the manner whereby Purgative Medicines Work but those other Properties whereby some Bodies are Diuretick others Sudorifick others Sarcotick c. are not I fear so easie to be intelligibly made out as men imagine and yet a skilful Physitian would justly think himself wrong'd if the Reasons he renders of things in his own Profession were deny'd the Name of Reasons because made without recourse to Atomical Principles And indeed there are oftentimes so many subordinate Causes between particular Effects and the most General Causes of things that there is left a large field wherein to exercise Mens Industry and Reason if they will but solidly enough deduce the Properties of things from more general and familiar Qualities and also intermediate Causes if I may so call them from one another And I am the more backward to despise such kind of Reasons because I elsewhere declare that there are Some for I do not say Many things as particularly the Origine of Local Motion of which ev'n by the Atomical Doctrine no Physical Cause can well be render'd since either such things must be ascrib'd to God who is indeed the true but the supernatural Cause of them or else it must be said as it was by the old Epicureans that they did ever belong to Matter which considering that the Notion of Matter may be compleat without them is not to give a Physical efficient cause of the things in Question but in effect to confess that they have no such Causes But of this elsewhere more In the mean time that you may not be drawn away to undervalue such Writers as I have been pleading for nor think you ought to refrain from writing what occurs to you though true and useful unless you deduce it or at least can do so from the Epicurean Notions I shall here briefly represent to you what perhaps you will not hereafter think a despicable suggestion that there are two very distinct Ends that Men may propound to themselves in studying Natural Philosophy For some Men care only to Know Nature others desire to Command Her or to express it otherwise some there are who desire but to Please themselves by the Discovery of the Causes of the known Phaenomena and others would be able to produce new ones and bring Nature to be serviceable to their particular Ends whether of Health or Riches or sensual Delight Now as I shall not deny but that the Atomical the Cartesian or some such Principles are likely to afford the most of satisfaction to those speculative Wits that aim but at the knowledge of Causes so I think that the other sort of men may very delightfully successfully prosecute their ends by collecting and making Variety of Experiments and Observations since thereby learning the Qualities and Properties of those particular Bodies they desire to make use of and observing the power that divers Chymical Operations and other ways of handling Matter have of altering such Bodies and varying their effects upon one another they may by the help of Attention and Industry be able to do many Things some of them very Strange and more of them very Useful in humane life When a Gunner or a Souldier employs Gun-powder it is not necessary that he should consider or so much as
than are essential to the nature of Vitriol or belong ordinarily to it That there is also a difference betwixt those bodies that pass under the general name of common Salt cannot but be obvious to any Chymist that hath occasion to make accurate tryals on that Subject And as for those Concretes that pass under the name of Salt-peter there is probably no small disparity among them for besides the difference which we have observed and which is obvious enough betwixt good English Nitre and that which is brought us over from Barbary which before it is much refin'd abounds very much with an adventitious Salt that tastes much like Sea-salt besides this I say those that do use both good European good East-Indian Salt-peter assure me they find much difference betwixt them and give the preference to the latter and indeed I have often thought I discern'd a considerable difference in the operations of several kinds of Salt-peter even after purification and probably that sort of Salt-peter which near London an ingenious man of my acquaintance does sometimes but cannot always make chiefly out of Sea-salt hath some differing qualities from that which is drawn the common way out of the Earth And indeed Salt-peter being but a kind of Sal terrae generated in very differingly-qualifi'd parcels of Earth may probably receive divers qualities from the particular soyl wherein it grows though these qualities lye concealed and unsuspected under the wonted exterior appearance of Nitre Which consideration brings into my mind what was lately told me by a very ingenious Gentleman concerning one of the eminentest of our London Physitians who was wont as this Confident of his assured me as an excellent secret to imploy in some of his choice Remedies that peculiar Salt-peter which he had drawn out of the Earth digg'd up in Church-yards And such kind of differences would probably in other Mineral bodies be taken notice of if mens prepossessions did not make them ascribe the variations they meet with in their Experiments rather to any other cause than the unsuspected difference of the Materials imploy'd about them Nor is it only Pyrophilus among Mineral Bodies of the same name that such a diversity is to be found but if narrowly look'd into 't is very probable that a greater disparity may be discovered both among Vegetables and Animals reputed of the same nature than hath been yet taken notice of Herbarists indeed have exercis'd a commendable curiosity in subdividing Plants of the same denomination and few Naturalists ignore that there are for instance many sorts of Roses and of Apples which differ widely betwixt themsâ—lves as we see the difference betwixt the Red-rose and the White betwixt the Crab the Pippin and the Peaâ—-main But besides these differences which are obvious enough to be Registred by Botanick Authors there may be more undiscern'd ones which yet may be considerable ones betwixt the Individuals of the same ultimate subdivision of Plants arising partly from the temperature of the air which makes for example Senna growing in England to differ much from that which is denominated from Alexandria partly from the nature of the soyl as is obvious in the change produced in wild Simples transplanted into Gardens and partly from many other causes which we have not now leisure to insist upon But we see oftentimes that one Rose much differs from another of the same kind and one Pear-main from another Pear-main To which we may add that the upper crust or surface of the Earth being impregnated with subterraneal exhalations of several sorts and tempered with variety of Juyces it may very possibly be that some particular Plant may attract some such Juyce out of a determinate spot of ground as may give it Exotick qualities and make it differ even from the neighbouring Plants of the same kind To which purpose I remember that travelling divers years since from Geneva towards Italy I was in my passage through Switzerland by a Gentleman of those parts whose brother had been formerly my Domestick invited to his Castle and entertained among other things with a sort of Wine which was very heady but otherwise seem'd to be Sack and having never met with any such Liquor during my long stay in those parts I was inquisitive to know whence it was brought and being answered that it grew amongst those Mountains I could not believe it till they assur'd me that growing on a little spot of ground whose entrails abounded with Sulphur it had from the soyl acquired its inebriating property and those other qualities which made it so differing from the Wine of the rest of the Vineyards of that Country And now I mention Wine give me leave Pyrophilus to put you in mind of taking notice what a great change is made in that Liquor when upon the recess of the spirits and more volatile sulphureous parts or else the new texture they make with the others it degenerates into Vinegar and yet how little either diminution of quantity or any other alteration doth appear upon this change to the beholders eye And though no body is like to lose an Experiment by mistaking Vinegar for Wine because both those Liquors and the changes of them are so familiar unto us and because we are wont to taste each of them before we imploy it yet who knows what changes there may be in other Bodies with whose alterations we are unacquainted though the Eye which is oftentimes the only Sense employ'd about judging of them discern no change in them as may daily be observed in the superannuated seeds of Plants which after their having been kept long beyond their due time lose all their germinating power without losing any of their obvious qualities And here let me further observe to you that Urine is made much use of not only by Dyers but â—everal other Trades-men in divers operations some of which we may elsewhere have occasion to treat of belonging to their professions Now these men being wont indiscriminately to employ Urine without examining whether it be rich in Salt or not and how long it hath been kept it may not be impertinent to take notice that Chymists who have occasion to distil it often in great quantities assure me that they find a notable disparity betwixt Urines that of healthy and young men abounding much more with volatile Salt than that of sickly or aged persons and that of such as drink Wine freely being much fuller of spiritous and active parts than that of those whose drink is but Beer or Water But because the differing strength of Urines though it be very probable is not so easily to be satisfactorily made out we shall rather insist on this other Observation confirmed to us by Experience which is that though Trades-men are often wont to boil such and such things indifferently in any Urine as if it were all one how new or stale it is they may sometimes thereby commit considerable errors For recent Urine wherein the saline parts
Quantity of matter may be order'd But this is so manifest a truth to those that have dealt much in Experiments that whereas many Chymists would be vastly rich if they could still do in great Quantities what they have sometimes done in little ones many have undone themselves by obstinately attempting to make even real Experiments more gainful I have not been very sollicitous to subjoyn Particulars to the foregoing Observations because that by reason of the Contingency of such Experiments as would be the most for my present purpose you might possibly be tempted to lose toyl and charges upon tryals very likely not only to delude your hopes but perhaps to make you distrust the fidelity of our relations Yet for Illustration sake of what we have delivered I am willing to mention some few contingent Experiments that occur to my thoughts And first it is delivered by the Lord Verulam himself as I remember and other Naturalists that if a Rose-bush be carefully cut as soon as it has done bearing it will again bear Roses in the Autumn Of this many have made unsuccessful tryals and thereupon report the Affirmation to be false and yet I am very apt to think that the Lord Verulam was embolden'd by Experience to write as he did To clear up which difficulty let me tell you that having been particularly sollicitous about the Experiment I find by the relation both of my own and other experienc'd Gardeners that this way of procuring Autumnal Roses will in most Rose-bushes most commonly fail but in some that are good bearers it will succeed and accordingly having this Summer made tryal of it I find that of many bushes that were cut in June in the same Row the greater number by far promise no Autumnal Roses but one that hath manifested it self to be of a vigorous and prolifick nature is at this present indifferently well stor'd with Damask-roses And there may be also a mistake in the kind of Roses for experienc'd Gardeners inform me that the Musk-rose will if it be a lusty Plant bear flowers in Autumn without the help of cutting And therefore that may be misascrib'd to Art which is the bare production of Nature And Cinnamon Rose-bushes do so much better thrive by cutting than several other sorts that I remember this last Spring my Gardener having as he told me about mid April which was as soon as that kind of Rose-bush had done bearing cut many of them in my Garden I saw about the middle of June store of the same bushes plentifully adorn'd both with Buds and with blown Flowers An uncertainty not unlike that which we have newly taken notice of in the Experiment of producing Autumnal Roses has been likewise observed in the attempts that have been made to make diverse sorts of Fruit grow upon the same Tree And as for differing sorts of Fruits of the same denomination as Apples Pears c. though some severe Naturalists are unwilling to believe that they can be made to grow upon the same Tree yet we dare not imitate their severity having lately seen various sorts of Pears fed by the same Tree and elsewhere three and twenty sorts of Apple-Grafts flourishing upon the same old Plant and most of them adorn'd with Fruit. Nay and though the Fruits be not of the same denomination yet if they be of kin in nature they may very possibly be brought to grow on the same Tree for we lately gathered ripe Apricocks and ripe Plums upon one Tree from which we like-wise expect some other sorts of stone-fruit But to make fruits of very differing natures be nourished prosperously by the same stock is so difficult a thing that we can at most but reckon it among contingent Experiments for though Pliny and Baptista Porta relate their having seen each of them an example of the possibility of producing on one Tree great variety of differing fruits and though such a person as the deservedly-famous Astronomer Dr. Ward assures me that he has particularly taken notice of Pears growing upon an Apple-tree and I elsewhere add a resembling Observation of ours yet certainly this Experiment has been for the most part but very improsperously attempted nor have I yet ever seen it succeed above once though try'd with very much care and industry And I remember that this very year in the same Garden where I gather'd the Apricocks and Plums above mention'd I saw the Ciens of a Pear-tree so skilfully grafted upon an Apple-stock that it flourish'd very much with blossoms in the Spring and gave me great hopes that it would bear fruit this newly-past Summer but has deceived my expectation as divers other Plants so grafted in the same Garden have for many years deluded the hopes of the skilful Master of it who assures me that though divers of them did for some years successively afford promising blossoms yet they all decay'd away without bearing any of them any fruit Which yet may seem somewhat strange since not only we have this Summer gather'd Pears upon a graft which a Divine to whom the Garden belongs affirmed to have been grafted upon a Quince-tree and the industrious Kircher tells us that Ex-perientia docet Persicum Moro insitum fructus proferre c. de quo nullum est dubium utpote vulgare penè but experience tells us that as little as a White-thorn and a Pear-tree seem of kin a Ciens of the latter will sometimes prosper well being grafted upon a stock of the former To contingent Experiments Pyrophilus you may if you please refer what is delivered by those learned Writers who affirm That if a Lixivium made of the Ashes or fixt Salt of a burn'd Plant be frozen there will appear in the Ice the Idea of the same Plant For we have divers times purposely made trial of this Experiment without the promised success and I remember that in the last cold season proper for such trials I purposely made a Lixivium of fair Water and Salt of Wormwood and having frozen it with Snow and Salt after the manner of Congelation else-where declar'd I could not discern in the Ice any thing more like to Wormwood than to several other Plants and having about the same time and after the same manner expos'd to congelation a thin Vial full of a strong Decoction of Wormwood from which an Idea of the Plant may be more probably expected thole to whom I shew'd it after it was frozen could discern as little like Wormwood in it as my self 'T is true that in both these Vials the Ice seem'd somewhat odly figur'd but it is true also not only that we have observed that Water wherein a saline body as Salt-peter or Sea-salt or Sugar c. has been dissolv'd has afforded us Ice which seem'd to shoot into several figures but even in ordinary water congealed we have often seen Ice figur'd as if the water had been no Elementary body which needs not be admir'd since to omit other causes which may concur to the
production of this effect many Waters gliding through Earths abounding in saline particles of this or that nature may be easily in their passage impregnated with them whence perhaps it comes to pass that Dyers find some Waters very fit and others very unfit for the dying of Scarlet and some other Colours And therefore we cannot but think that the figures that are oftentimes to be met with in the frozen Lixivium or Decoction of a Plant will afford but uncertain proofs that the Idea of each or so much as of any determinate Plant displays it self constantly in that frozen Liquor And I much fear that most of those that tell us that they have seen such Plants in Ice have in that discovery made as well use of their Imagination as of their Eyes And 't is strange to observe what things some men will fancy rather than be thought to discern less than other men pretend to see As I remember Mr. R. the justly famous maker of Dioptrical Glasses for merriment telling one that came to look upon a great Tube of his of 30 foot long that he saw through it in a Mill six miles off a great Spider in the midst of her Web the credulous man though at first he said he discern'd no such thing at length confessed he saw it very plainly and wonder'd he had discover'd her no sooner But yet Pyrophilus because two or three sober Writers do seriously relate some stories of that nature upon their own observation I am content for their sakes to reckon their Experiments rather among the Contingent than the absolutely false ones for it is not impossible but that among the many figures which frozen Liquors do sometimes put on there may appear something so like this or that Plant that being look'd upon with the favourable eye of a prepossess'd beholder it may seem to exhibit the Picture of the calcin'd Vegetable and we our selves not very long since setting to freeze in Snow and Salt a fine green Solution of good Verdegrease which contains much of the Saline parts of the Grapes coagulated upon the Copper by them corroded obtain'd an Ice of the same colour wherein appear'd divers little figures which were indeed so like to Vines that we were somewhat surpriz'd at the Experiment and that which encreas'd our wonder was that another part of the same Solution being frozen in another Vial by the bare cold of the air afforded us an Ice angularly figur'd as we have observ'd the Ice of saline Liquors oftentimes to be but not at all like that made by the application of Snow and Salt And having for further trial sake suffered that Ice wherein the Vines appear'd to thaw of it self and having then frozen the Liquor a second time in the same Vial and after the same manner as formerly we could not discern in the second Ice any thing like that which we had admir'd in the first And in Wine and Vinegar as much as those Liquors partake of the nature of the Vine we have not after Congelation observed any peculiar resemblance of it in figure The mention we have been making of Ice brings into my memory another Experiment which may perhaps be reckon'd likewise among Contingent ones and that is the Experiment of burning with Ice as with a Glass Lens which though some eminent Modern Writers prescribe to be done without taking notice of any difficulty in it yet both we and others that have industriously enough try'd it have met with such defeating circumstances in it especially from the ununiform Texture wont to be met with in most Ice that the making of such burning-Glasses may be well enough referr'd to those Experiments whose constant success is not to be rely'd on as we else-where more particularly declare In the Trade of Dying there is scarce any tinging Ingredient that is of so great and general use amongst us as Woad or Glastum for though of it self it Dye but a Blew yet it is us'd to prepare the cloath for Green and many other of the sadder Colours when the Dyers have a mind to make them permanent and last without fading but yet in the decocting of Woad to make it yield or strike its colour there are some critical times and other circumstances to be observed the easie mistake of which oftentimes defeats the Dyers expectation to his very great loss which sometimes he knows not to what to impute of which I have heard several of them complain And therefore divers of our less-expert Dyers to avoid those hazards leave off the use of Woad though growing plentifully enough here in England and instead of it employ Indico though it cost them dearer as being brought hither sometimes from Spain sometimes from the Barbadoes and oftentimes even from the East-Indies Our London Refiners when to part Silver and Copper they dissolve those mixed Metals in Aqua fortis are wont afterwards to dilute the glutted Menstruum with store of fair water and then with Copper Plates to strike down the dissolv'd Silver But because by â—his manner of proceeding much Copper is wont after the separation of the Silver to remain in the Menstruum as may appear by its high tincture that this thus impregnated Liquor may be impov'd to the best advantage they are wont to pour it upon what they call Whiting which is said to be a white Chalk or Clay finely powder'd cleans'd and made up into Balls wherewith the tincted parts incorporating themselves will in some hours constitute one sort of Verditer fit for the use of Painters and such other Artificers as deal in Colours leaving the remaining part of the Menstruum an indifferently-clear Liquor whence they afterward by boiling reduce a kind of Salt-peter fit with the addition of Vitriol and some fresh Niter to yield them a new Aqua fortis And these things I mention Pyrophilus that you may know what I mean when I tell you that sometimes the Refiners cannot make this Verditer for a great while together and yet cannot tell whence their disability to make it proceeds Of which Contingency I remember I lately heard one of the eminentest and richest of them sadly complain affirming that neither he nor divers others of his Profession were able not long since to make Verditer for divers months together and that several others were yet at a loss in reference to that particular though for his part he had without knowing the Cause of this Contingency found a Remedy for it namely to warm the Menstruum well before it be poured on the Whiting on which when the Liquor was warm the tincted parts would fasten though they would not whilst according to the custom of Refiners it was poured on cold Making likewise the other day a visit to the chief Copperas work we have in England one of the Overseers of it who went along with me to shew me the contrivance of it assured me that divers times by the mistake or neglect of a circumstance in point of
that in our Case the pressure of the Atmosphere is suppos'd to force the lowermost glass upwards For if we suppose the Air to consist of innumerable little springs as it were bearing upon and supporting one another and whereof the lowermost are bent by the Weight of all that are incumbent on them it will be easie to conceive that neer the surface of the Earth about which the Air must diffuse it self by reason of the Gravity of its small parts and the Resistance of the Earth against their Descent it may press almost equally every way and by a kind of Recoyl though not properly so call'd from the Terrestrial Globe upwards may strongly press any body upon which it can bear against any other which has no such Elastical power to repel from it a body so press'd against it This Difficulty being thus dispatch'd we shall proceed by two or three particulars to confirm our Conjecture at the Cause why smooth Bodies stick â—ogether upon bare juxta-position or contact And firsâ—â— observe that if a piece of flat glass be as we formerlâ— mention'd appended to a Looking-glass held with the unfoliated side downwards parallel to the Horizon though the adhering glass will not drop down yet it will vâ—ry easily be mov'd any way along the level surface and if by inclining the Looking-glass any way you deprive it of its former Level the smaller glass will easily slide downwards upon the surface of the greater Of which the Reason seems to be partly that the Gravity as such of the lower glass does not considerably resist the horizontal motion of it but only the motion upwards whereby it must recede from the Centre of heavy Bodies as might if need were be probably deduc'd from divers Instances obvious enough and partly or rather chiefly that to the edges of the glass the Ambient Air is contiguous as well on the one side as on the other and so the pressure of the Air being equal on every part of the edges the gravity of the smaller glass is not hinder'd by the Air which can as fast succeed on one side as 't is displaced on the other from making it slide down the shelving surface of the greater Glass whereas of the broad and flat sides of the lowermost glass the one is as we said press'd by the spring of the Air whilst the other suffers no such pressure from the Looking-glass to which it was apply'd And so if you take a small open-mouth'd glass and plunge it into a Vessel full of Quick-silver with the mouth upward that the Quick-silver may fill it without leaving any Air in it and if then whilst it is under the Quick-silver you turn the mouth downwards and so keeping it upright lift it up till the mouth be almost come to the top of the Mercury you shall perceive that the glass will remain almost full of Quick-silver in the Vessel And this will continue so though you incline the glass this way or that way provided you keep the mouth of it within the Mercury And this Experiment though more noble when try'd with Quick-silver will succeed also when tryed as it may more easily be with water Of which the Reason seems to be that the glass hinders the Quick-silver in it from the pressure of the incumbent air whereas the Quicksilver in the Vessel being expos'd to it must by it necessarily be forced up against the surface of the inverted bottom of the glass where it meets no Elastical power to repell it downwards For that it is not Natures Abhorrency of a Vacuum that keeps the Quick-silver from descending till some air can come to succeed in its room the famous Experiment invented by Torricellius and found true by many others and our selves touching the descent of Quick-silver in any Tube of above two foot and a half long seems clearly to evince And to confirm what we have said and shew withall that it is not so much the Contact of Bodies according to a large surface as that Contact is considered in it self as by reason of its being ordinarily requisite to the exclusion of Air that at least here below keeps bodies from falling asunder I shall relate that having by a certain Artifice out of a large glass with a narrow mouth caus'd a certain quantity of air to be suck'd we found that by immediately applying a Book which then chanc'd to lie at hand to the Orifice of the Vessel the Book was readily lifted up and sustein'd in the air as long as we pleas'd though the surface of the suspended Body could be touch'd as is evident but by the Ring which incircl'd the Orifice of the Vessel and though the weight taken up besides that it was inconveniently shap'd for such a trial which would probably have succeeded as well with a much greater weight if we had had one fitly shap'd at hand exceeded twenty Ounces Of which event the Cause seems plainly to be this that by reason of the Exsuction of some air out of the glass the Elastical power of the remaining Air was very much debilitated in comparison of the unweaken'd Pressure of the External air which being able to press the Book against the Orifice of the Vessel with greater strength than the internal air can resist thereby it comes to pass that the whole Orifice of the Vessel though there be but part of it of solid body does yet on this occasion perform in some measure the part of an entire surface exactly smooth It may be consider'd also to adde that upon the by whether upon the Principle lately explicated may not in some measure depend the solidity of glass For though its parts seem very little or not at all branched or interwoven one within another and appear very smooth and slippery yet since the fire that brought them to fusion and consequently to be fluid may well be supposd to have sub-divided and reduc'd them into very small Particles and to have thereby assisted them to exclude the air from bâ—twixt them it may seem that it needs not much be wonder'd at if the immediate contact of such small and smooth Corpuscles suffice to make them hold together for that their union is strict enough to keep out the air may appear from this that those that blow glasses and those that distill in them find not the air can traverse the pores even of heated glass and as for any more subtil matter we see by the free passage of Light and Heat or to speak more warily of magnetical Effluvia through glass without injuring its texture that such matter but moderately mov'd will not hinder the little solid parts from cleaving together And on this occasion it might be consider'd how much the juxta-position of their Corpuscles crowded together by fusion may contribute to the consistence and brittleness of Salt-Petre and diverse other bodies which may from an incoherent powder be readily turn'd into one Mass as also how far the sticking together for I speak
not of the figures compos'd by them of the small parts of hanging drops of water and such other Liquors as are not thought to consist of Corpuscles hooked or branch'd may be ascrib'd to the contact of their small parts and the exclusion of air These I say and some other such things might be here consider'd but that we are forbidden to examine them particularly and especially what has been represented touching the solidity of glass which we suspect another cause may have a great Interest in by our haste which calls us to the remaining part of our Discourse Though then it be hence to omit other proofs elsewhere mention'd sufficiently manifest that the Air has a spring and that a strong one yet there appears no great necessity of having recourse to it for the giving an Account why the two smooth glasses above mention'd were able to adhere so closely to each other For a probable Reason of the same Phaenomenon may be rendeâ—'d by the pressure of the Air consider'd as a weight And fiâ—st we must recall to mind what we a little above said of the Recoyling or Rebounding of the Pressure of a Cylinder of Air from the Earth to the suspended piece of glass proceeding from this that the fluid Air which is not without some Gravity being hinder'd by the resisting surface of the terrestrial Globe to fall lower must diffuse it self and consequently press as well upwards as any other way Next we may consider that when the surfaces of two flat Bodies of any notable and for example of equal breadth do immediately touch each other and lye both of them level with the Horizon and one of them directly over the other in this case I say since the Air cannot move in an instant from the edges to the middle of the two surfaces that lye upon each other the lowermost cannot be drawn away downwards in a perpendicular line from the uppermost but that by reason of the stiffness and contact of the two Bodies it must necessarily happen that at the instant of their separation should it be effected the lowermost glass will be press'd upon by the whole Crooked Pillar of Air suppos'd to reach from the top of the Atmosphere and to have for Basis the superficies of the undermost glass For at that instant the Air having not time to get in between the two glasses there is nothing between them during that instant to resist the pressure of that Air which bears against the lower superficies of that undermost glass and consequently such a revulsion of the lower glass cannot be effected but by a weight or force capable to surmount the power of the weight of the abovemention'd Cylinder of the Atmosphere and this as I said because that by reason of the sudden separation the upper surface of the glass has not any air contiguous to it which were it there would according to the nature of Fluid and springy Bodies press as much against the upper surface of the glass as the Pillar of the Atmosphere against the lower and consequently sustain that Endeavour of the Air against the lower side of the glass which in our propos'd case must be surmounted by the weight or force employ'd to draw down the lower glass And hence we may understand to adde that upon the by That it is not necessary that the contiguous surfaces of the two flat glasses we have been treating of be parallel'd to the Horizon For if you should hold them perpendicular to it their divulsion would not cease to be difficult provided it were attempted to be made by suddenly pulling one of the broad surfaces from the other in a level line and not by making one of the surfaces slide upon the other for in the former case the separation of the contiguous Bodies will be hinder'd by the weight or pressure of the lateral Air if I may so speak that bears against the broad sides of the glasses contiguous to it But whereas in these cases we suppose the superficies of the two glasses to be so exactly flat and smooth that no Air at all can come between them Experience has inform'd us that it is extreamly difficult if at all possible to procure from our ordinary Tradesmen either Glasses or Marbles so much as approaching such an Exquisiteness For we could very hardly get either experienc'd Stone-cutters or Persons skill'd at grinding of glasses to make us a pair of round Marbles though of an inch or two only in Diameter that would for so much as two or three minutes hold up one another in the Air by contact though they would easily enough take up each other if the uppermost were drawn up nimbly before the Air could have leisure to insinuate it self betwixt them But this notwithstanding we endeavour'd by the following Expedient not only to manifest that the Power or Pressure of the Air is in these Experiments very great but also to make some Estimate though but an imperfect one how great that Power is Having then provided a pair of Marbles of an inch and half in Diameter and as flat and smooth as we could get and having consider'd that as 't was the getting in of the Air between them that for the reason above declar'd hinder'd them from sticking strongly together so the Access afforded to the Air was for the most part due to that scarcely evitable roughness or inequality of their surfaces that remain'd in spight of the Polish considering these things I say we suppos'd that the intrusion of the Air might be for some while prevented by wetting the surfaces to be joyn'd with pure Spirit of Wine and that yet this Liquor that seems the freest that we know of from tenacity would not otherwise than by keeping out the air prove a Cement to fasten the stones together But because the easie separation of such smooth Bodies as adhere but by contact does in great part as we formerly noted proceed from this That whereas it is very difficult to hold such Bodies exactly level for any considerable space of time and yet the least Inclination any way gives the lower Body opportunity to slide off because of this I say we resolv'd in the first place to see what could be done by fastening to the upper Marble certain Wires and a Button in such manner as that the lower Marble when it was joyn'd might freely fall directly down but noâ— slip much aside being hinder'd by the Wire And in pursuit of this we found that not only the dry Marbles could be made to take up and hold up one another but that once by drawing up the upper Marble nimbly we could take up but not keep up for any time together with the lower Marble a Scale and in it a pound weight of 16 Ounces Troy After this we moisten'd the surfaces of the Marbles with such pure Alkalizate Spirit of Wine as we elsewhere teach to make which was so thin and subtil that not only we burn'd some of it before we
chiefest of these seems to be the fitness of the shapes of the component particles to fasten to each other as if some were figur'd like the handles of Buckets and others like the hooks that are wont to be employ'd to draw them up out of the Well or some like buttons others like loops some like male others like female screws as Mechanicians speak or as if many together were so variously branch'd that their parts may be so interwoven one within another as not to be easily separable as we often see in a well-made dry hedge of which if a man go to pull away one bough he shall often be unable to do it without pulling away with it diverse others whose slender twigs will be intangled with it An eminent example of the power of the bare Texture of many small Bodies even such as each of them apart is not perhaps extraordinarily shap'd for such a purpose to make a stable one is afforded us by Ropes and Cables where only by twisting together and wreathing the slender and flexible threds the Cable is made up of they are so well as it were wedg'd in between and fasten'd to one another that they constitute a Body not to be broken by the weight of an Iron Anchor nor perhaps by the force of a Ship violently driven on by the fury of the Winds and Waves This figuration of the Corpuscles that make up consistent Bodies seems to have been the chief if not only cause of their consistence in the Judgment of the antient Atomists this being the account that is given of it by Lucretius Denique quae nobis durata ac spissa videntur Haec magis hamatis inter sese esse necess ' est Et quasi ramosis alte compacta teneri In quo jam genere imprimis adamantina saxa Prima acie constant ictus contemnere sueta Et validi salices ac duri robora ferri Aeraque quae claustris restantia vociferantur And indeed so innumerable may be the correspondent figures which are fit to fasten bodies to one another that it is very possible that two bodies whereof each a part is fluid may upon their Conjunction immediately intangle their parts in one another and thereupon acquire such a new texture that their parts cannot as formerly dissociate themselves at pleasure and move along one anothers surfaces nor consequently flow after the manner of Liquors but are so connected or intangled that the motion of one of them will be resisted by many and so the whole Body will become firm or stable Something like this may be seen in the Experiment mention'd by our Author where he teaches that the distill'd Liquor of Nitre and that made per Deliquium out of fix'd Nitre will presently upon their mixture in part concoagulate into saline and consequently stable Bodies but this seeming only a re-union of the saline particles that did though invisibly swim up and down in the aqueous parts of the mingled Liquor which after this separation remains both more copious than the saline parts and as fluid as before we will adde a noble instance mention'd to another Purpose by Lully and Hartman to declare how much the firmness of bodies depends upon their tâ—xture If you take then the Alchool or highly-rectify'd Spirit of Wine and exquisitely deflegm'd Spirit of Urine and mix them in a due proportion as I remember the last time I made the Experiment I took about equal parts by guess though two of the former to but one of the latter if This be excellent be a better Proportion you may in and about a minute of an hour turn these two fluid Liquors into a constant Body and â— confess it was not without pleasure that I have immediately upon the shaking of these two Liquors seen them shoot into the likeness of Snow and acquire such a consistence that I could without spilling the mixture turn the vessel that contain'd it upside down But I dare not expect to have this Experiment believ'd ev'n by most of them that shall try it Experience having taught me that it will not succeed unless the Spirits of Urine and of Wine be both of them more exactly deflegm'd than is usual even among Chymists Yet so much more does this coagulation seem to depend upon the Salt of Uâ—ine as of such a texture than barely as Uâ—inous that we will add that As the spirit of fermented Urine is not whatsoever some eminent Chymists may think or say so indispensably requisite but that my curiosity leading me to try whether other Liquors which I suppos'd to be of a resembling nature might not serve the turn I found that sufficiently-rectifyed Spirit of Harts-horn to mention that alone here may be made to supply its place So I endeavour'd to make it probable by this That having try'd a certain method though that may seem strange to most Chymists of so ordering Urine that without staying at all to ferment or putrifie it either forty days or half so many hours I can make the volatile or saline Spirit ascend first in distillation though I use but some such gentle heat as that of a Bath Having I say by this means distill'd a very strong Spirit of unfermented Urine and rectify'd it too I found as I expected that I could not by any means make it coagulate with Spirit of Wine which seem'd to proceed from the differing texture of this Spirit from that of Fermented or rather Putrify'd Urine since I had added nothing to the fresh Urine I distill'd but what was extreamly fix'd and belonging as Chymists speak to the mineral Kingdom Wherâ—upon having had the curiosity to enquire of some of my Chymical acquaintances I found that they complain'd that they had not been able to coagulate Spirit of Wine with the saline Spirit made of meer Urine without any addition at all when they distill'd that Urine without a previous putrefaction which is not wont to be perfâ—cted under six weeks or thereabouts But to return to our Coagulum we will annex That this is further remarkable in this Experiment that this whiâ—e coagulated substance being put into a glass vessel exactly stopt and kept in a gentle heat which yet it self is not peâ—haps necessary though expedient for some weeks or months will at least for the grâ—atest part by much for I have not yet totally seen it do so resume the foâ—m of a limpid Liquor as if eithâ—r all the câ—ooked particlâ—s that connâ—cted the small coalitions of the Vinous and Urinous Corpuscles to one another were by the motion they were put into by the external heat one after another broken off or else the same little concretions for the Menstruum seems to consist chiefly of them being able to perform other matters than either of the single Liquors whereof 't is constituted either afflicted by outward warmth or inabâ—ed thereto by some other cause of mobility did after many and various attempts to clear themselves of each other little by little so
of Amber does by detainiâ—â— some parts which though more gross then the rest may yet be no useless one impair the Remedy and that it does not upon some other score infringe the medicinal vertue of the Oyl the Experiment will not be unuseful For the Liquor that is thus prepared is not only very diaphanous and well colour'd but so pure and subtle that 't will swim not only upon Water but upon Spirit of Wine it self And 't will be no despicable thing it by extending or further applying this Experiment to other indispos'd Bodys many Empyreumatical Oyls distill'd by strong fires in Retorts can be brought to emulate essential Oyls as Chymists call them drawn in Limbicks as to clearness and lightness The additament I last thought fit to make use of for purifying Oyl of Amber was briefly this â„ž Two Pound or somewhat less of good Brandy One Pound of good Sea-Salt and half a Pound of the Oyl to be subtiliz'd mix and distil them together Upon the mention I made above of the white Coagulum of the Spirits of Wine and Urine I remember what I have sometimes observ'd in the essential Oyl of Anniseeds as Chymists speak distill'd with store of water in a Limbick and Refrigeratory namâ—ly that in the heat of Summer it would remain a perfâ—ct Liquor like other Chymical Oyls but during â—he cold of the Winter though they notwithstanding that season continued fluid as before the Oyl of Anniseeds would coagulate into a Body though not of an uniform Texture to the Eye like Butter but rather almost like Camphire yet like it white and consistent not without some kind or degree of Brittleness And on this occasion I will here insert an Experiment which should have been set down in that part of the former History of Fluidity where I mention that the small parts of a Body may be sufficiently agitated to constitute a Liquor by the Air or other Agents not seâ—sibly hot themselves The Experiment take â—hus Casting by chance my Eyes in the Winter time upon a glass of Oyl of Anniseeds which stood coagulated by the cold of the season I presently bethought my self of making a Liquor whose process belongs to another Treatise of which as soon as I had prepar'd it I made this Tryal I melted with a gentle heat the congeled Oyl of Anniseeds to make it flow and then cover'd parâ— of it in another glass wiâ—h a Mixâ—ure I had provided and hâ—ving let thâ—m both rest in the window I found that the meer Oyl being fully refrigerated again coagulated as before but that which was cover'd with the other Liquor continu'd fluid both day and night and in several changes of weather and does still remain at the bottom of the Menstruum a clear Oyl distinct from it though I have purposely shaken them together to confound them And because Pyrophilus I have not discover'd to you the Menstruum I made use of I will here present you with a Succedaneous Experiment made with a common Liquor I took then good clear Venetian Turpentine and having slowly evaporated about a fourth or fifth part of it till the remaining substance being suffer'd to cool would afford me a coherent Body or a fine Colophony I caus'd some of this transparent and very brittle Gum of which I have elsewhere taught you some uses to be reduc'd to fine powder of which I put into pure Spirit of Wine a greater proportion then I judg'd the Liquor was capable of dissolving to the end that when the Spirit had taken up as much of the Powder as it could there might remain at the bottom a pretty quantity of our Colophony On which though the Menstruum being already glutted could not act powerfully enough to dissolve it yet it might give the matter which it had already so far softened as to reduce it into a coherent mass agitation enough to emulate a fluid though somewhat viscous Body And accordingly I obtain'd a sluggish Liquor which continued fluid as long as I pleas'd to continue the Menstruum upon it The like Experiment I try'd with clarify'd Rosin and with fine Colophony though but bought at the Shops and although the Tryal sometimes succeeded not ill yet I found not the success constant and uniform whether because the Bodys to be dissolv'd were not defecated and pure enough or that I did not hit upon the best proportion between the Solvent and them But this circumstance I shall not omit that when the glutinous Liquor was separated from the Menstruum it would by degrees though but slowly harden in the Air. The Application of which property for the preservation of small and very tender Bodies I shall not here more expresly hint then by having barely nam'd it I had forgot to adde that whilst the substance continu'd fluid I could shake it as I lately told you â— could the Oyl of Anniseeds with the supernatant Menstruum without making between them any true or lasting Union Which last circumstance brings into my mind another Experiment that I likewise forgâ—t to adde to that part of the former History of Fluidity where I take notice that the particular Textures of fluid Bodies may be reckon'd among the chief causes of their being dispos'd or indispos'd to mingle with one another For partly to confirm this Conjecture and partly to manifest that 't is not universally true which Chymists are wont to think that Acid Salts and Oyls will not incorporate or mingle I took an arbitrary quantity and as I remember equal weight of common Oyl of Vitriol and common Oyl of Turpentine as I bought them at the Druggists these I put together very slowly for that circumstance should not be omitted and obtain'd according to my desire an opacous and very deep-colour'd mixture whose almost Balsam-like consistence was much thicker than either of the Liquâ—rs that compos'd it The like Experiment also succesfully try'd with some other Chymical Oyls but found none preferable for this purpose to Oyl of Turpentine And to make it probable that the disposition of these Liquors to mingle thus presently together depended much on their Texture we made the mixture be warâ—ly â—â—sâ—ill'd over for else the Experiment will searce sucâ—eed aâ—d thereby obtain'd as we elsewhere menâ—ion to another puâ—pose a certain gross substance which was that which seem'd to mediate the former union betwixt the two Liquors For this substance being separated and thereby the Texture of one of the Liquors or perhaps both being chang'd the Liquors which came over very clear into the Receiver swome upon one another nor have I since been able by shaking them together to confound them for any considerable time but they presently part again and do to this day remain distinct as well as transparent But afâ—er having forgot to set down these things in their proper place I must not forget also that to employ here more words about them were to digress To this then annex we that the Liquor we elsewhere mention
me a Difficulty which though un-mention'd at our meeting may afford an Objection perhaps more difficult than any of not to say all the foregoing namely That 't is scarce imaginable how such solid and hard Bodies should have their internal parts wrought upon by such slight Agents as the air and perhaps some yet minuter matter that is dispersed in it and how it is possible that where there is an actual Motion it should be so slow that a Corpuscle of Iron for instance seated in the internal Part of a Magnetick Needle should spend so long time as our conjecture requires in travelling so little a space as from thence to the next Superficies of the Needle But to this double Objection though some instances which you will meet with in the following part of this Paper may be properly applyed to solve it yet not to make your curiosity wait I will here speak a word or two to each of the members of the Objection SECT IV. And to the first I say That these Intestine Motions of the Corpuscles of hard Bodies need not be solely nor perhaps principally ascribed to those obvious external Agents to which we are wont to refer them since these may but excite or assist the more principal or internal Causes of the Motions we speak of as you may gather from what was but lately mention'd of the connate and unlooseable mobility of the Atoms according to Epicurus and the permeation of the most Solid Bodies by the Cartesian Materia Subtilis and we may see by the sudden effects of the Load-stone in endowing Steel wiâ—h Magnetick Qualities and depriving it of them again both which suppose the intervention of a change of Texture and this a production of Local Motion in the Metal that very minute and insensible Corpuscles of matter are not uncapable of effecting durable changes in the solidest Bodies And as for the other member of the Objection I confess it is not easie for us who are wont perhaps too much to follow our Eyes for Guides in judging of things corporeal and to deny existence to most things to most things whereto Nature has deny'd a visible bulk 't is not easie I say for us to imagine so great a slowness as 't is very possible for Nature to make use of in her Operations though our not being able to discern the motion of a shadow of a Dial-plate or that of the Index upon a Clock or Watch ought to make us sensible of the incompetency of our eyes to discern some motions of natural Bodies which reason tells us ought to be incomparably slower than these But not now to dispute about the existence and Attributes of infinite slowness or at least a slowness in the next possible degree to infinite I consider that it has not that I know of been demonstrated nor attempted to be so that the motion of the Corpuscle for example of the Needle above mention'd must be made in a direct line from the place where 't was first supposed to be to the Superficies of the Needle for it seems more rational and to agree better with the Phaenomena to suppose that the way of this Corpuscle in the Body 't would quit is extreamly crooked and intricate almost like that of a Squib in the air or on the ground for it being on the one hand urg'd on by the Causes whatever they be that make it strive to fly away and on the other hand hindred by the Corpuscles whereto 't is connected and by the occursions of other Corpuscles whose motions may be opposite to or disagreeing with those of our design'd Corpuscle it may probably before it can extricate it self be reduc'd to encounter and wrestle as it were with many other Corpuscles and be by them sometimes thrust or impell'd to the right hand and to the left and sometimes also repell'd inwards even after it is come to the superficial part of the Needle whence it may not presently have the liberty to fly away but may be drawn back by some other Corpuscle wherewith it is yet connected and which happening to be it self thrust inward may draw after it and so entangle again our almost disbanded Corpuscle besides that the gravity of the component Particles of a Body is oftentimes such that 't is easier for the Agent that puts them in motion to continue them in that slow motion among themselves than drive them up into so light a medium as the air as experience shews in those Bodies that are called Fixt as Gold and Glass though in actual fusion But I forget that I promis'd you to decline Speculations and therefore I shall only name to you a couple of Instances which will serve to confirm both what I was lately saying and what I am now in proving SECT V. The first of these I shall take from what is usually granted as matter of Fact namely that if a Spring though made of so hard a Body as Steel be forcibly bent and kept but a moderate while in that posture as soon as the force that kept it bent is removed it will again return to its former Figure but if it be kept too long in that forc't position it will by degrees lose that which they call the motion of Restitution and retain its new crooked Figure though the force that bent â—t be removed which shews both the power of some of the more familiar Agents in Nature and which is that the shewing whereof I here chiefly aim at that where there is a continued endeavour of the parts of a Body to put themselves into another state yet the motion or rather the progress may be much more slow than men seem as yet to have taken notice of since 't was a great while before â—he Texture of the Corpuscles of the Steel were so alter'd as to make them lose their former springiness But I will second this with a more illustrious Experiment which will at once confirm what I have just now said and shew that the Air or the invisible Corpuscles harbour'd in it may have no inconsiderable power to act upon and effect changes in the solidest Bodies To this purpose I shall only observe to you that though if a Bar of Iron having one of its ends held perpendicularly and at a fit distance to the Lilly or North-Point of the Mariners Compass I mean that which points towards the North it will as I elsewhere mention drive it away towards the East or West and if this same lower end of the Bar of Iron be put into a contrary posture it will presently lose its temporary magnetism as I elsewhere declare Yet if this Bar be very long kept upright in a Window or other convenient place then as some late Magnetical Writers will tell you it will have acquired a constant and durable magnetick power Which is a Phaenomenon that makes exceedingly for our present puâ—pose since it hence appears both that the Air together with the magnetical Effluvia of the
three bodies For several if not all of those mineral Ones which Aqua fortis will by corroding dissolve the Solution of fix'd Nitre will precipitate and divers if not all of those Sulphureous and unctuous bodies which the Solution of fixt Nitre will dissolve the acid spirit of Petre will precipitate And we have in a trice re-dissolved with the Spirit a Solution of Sublimate precipitated with the other liquor Thus if into a Scarlet tincture made by an Infusion of Brasil in fair water we pour a little Spirit of Nitre the shaken liquor will in a moment change its Rednesse for a kind of Yellow which by pouring on it a little of the Solution of fix'd Nitre may be again graduated into a somewhat Sanguine colour sometimes paler and somtimes perhaps deeper than the first whereas a Solution of Selt-petre it self pour'd on either of the former tinctures the Red or the Yellow has not been by us discern'd to have produc'd any sensible alteration And whereas Salt-Petre it self is partly fix'd and partly volatile the acid Ingredients of it are altogether volatile the Alkalizate fix'd But having elsewhere occasion to speak to this subject we shall now proceed to tell you that SECT XXIX It may passe for another Observable presented us by our Experiment that it gives us occasion to enquire whether the Air doth not contribute something to the artificial production of Salt-Petre or at least to the figuration of it according to the perfecter shape belonging to that kind of Salt for we formerly observ'd that the Salt which was leisurely permitted to shoot of it self in the liquor expos'd to the open air did shoot into more fair and large Crystalline Stiriae than those that were gain'd out of the remaining part of the same liquor by a more hasty evaporation though made but in a digesting Furnace And we have also observ'd that when once we pour'd Aqua fortis on a strong Solution of Salt of Tartar till no further effervescence was discernable betwixt them though the mixture by a somewhat quick heat afforded a Salt that seem'd to be very Nitrous yet it would not be brought to shoot in so fair and conspicuously-figur'd Crystals of Petre till it had been a good while expos'd to the open air but whether the air its self impregnated with the promiscuous streams of most of the bodies of the terrestrial globe and perhaps with seminal effluvia from some of them do really contribute any thing either to the Production or Figuration of Salt-petre in our Experiment I dare not yet determine for two chief Reasons SECT XXX Whereof the first is because the Figuration seems not improbably ascribable not so much to the proper efficiency of the air as to the conveniency which by quietnesse and a competent vehicle to move in was afforded to the Saline particles to conform themselves or be conform'd by a Concourse of Agents and Circumstances to that figure which is most natural to them For we have observ'd already that the fix'd Nitre which was not dissolv'd in water before the affusion of the acid spirit did not shoot into the wonted form of Cristalls of Petre but remain'd a kind of Nitrous powder the acid and Alkalizate Saline particles not having a convenient vehicle to expand themselves in but being necessitated for want of room to make an unseasonable and over-hasty coalition upon which their own weight made them subside in the figures resulting from their casual concourse and therefore probably differing from those into which the Saline corpuscles would have been dispos'd had they been allowed a competency of vehicle and time SECT XXXI The other reason of my hesitancy about the use of the Air in our experiment is that I inconsiderately forgot to try whether part of that Liquor which shot into Crystals in an open-mouth'd glass expos'd to the air would not have done the like if it had been left quiet as long as the other was though in a vessel accurately stopp'd but whatever the Air hath to do in this experiment I dare invite you to believe that it is so enrich'd with variety of steams from Terrestrial not here to determine whether it receive not some also from Coelestial bodies that the enquiring into the further uses of it for I mean not it's known uses in Respiration Sayling Pneumatical Engines c. may very well deserve your curiosity To encourage which I dare at present only tell you that though I cannot yet pretend to much experience in this particular yet we have known such changes seemingly Chymical made in some Saline Concretes by the help chiefly of the volatilizing operations of the open air as very few save those that have attentively consider'd what Helmont and one or two other Artists have hinted on that subject or have made tryals of that nature themselves will be apt to imagine SECT XXXII And if upon further and exacter tryal it appears that the whole body of the Salt-Petre after it's having been sever'd into very differing parts by distillation may be adequately re-united into Salt-Petre equiponderant to it's first self this Experiment will afford us a noble and for ought we have hitherto met with single instance to make it probable that that which is câ—mmonly called the Form of a Concrete which gives it it's being and denomination and from whence all it's qualities are in the vulgar Philosophy by I know not what inexplicable wayes supposed to flow may be in some bodies but a Modification of the matter they consist of whose parts by being so and so disposed in relation to each other constitute such a determinate kind of body endowed with such and such properties whereas if the same parts were otherwise disposed they would constitute other bodies of very differing natures from that of the Concrete whose parts they formerly were and which may again result or be produc'd after it's dissipation and seeming destruction by the re-union of the same component particles associated according to their former disposition SECT XXXIII The Redintegration or Reproduction of an analyz'd body if it can be accurately and really perform'd may give much light to many particulars in Philosophy and would certainly be very welcome both to the embracers of the Atomical Hypothesis and generally to those other Modern Naturalists who aspire to such Explications of Nature's Phaenomena as may at least be understood all whom I wish that though men cannot perhaps in all things yet at least as far as they can they would accustom themselves to speak and think as Nature does really and sensibly appear to work and not to acquiesce in Notions and Explications of things which strictly examin'd are not inâ—elligible Wherefore I am about to attempt a Reproduction in Vitriol Turpentine and some other Concretes in which it seems not unlikely to be performable and perhaps you may see cause to think that the Experiment of Salt-Petre even as we have already made and proposed it though it be not an exact
and adequate Redintegration is yet not far from being a real one the dissipated parts of the Concrete truly re-uniting into a body of the same nature with the former though not altogether of the same bulk SECT XXXIV And yet I think it requisite to represent to you Pyrophilus that Salt-Petre is a body whose parts are not Organical and which is not so much as very compounded and that therefore bodies that consist of more numerous Ingredients and much more those whose Organical parts require a much more artificial and elaborate disposition or contrivance of their component particles cannot be safely judg'd of by what is possible to be perform'd on a body of so simple and slight a contexture as is Salt-Petre for we see that even wine though no organical body nor so much as the most compounded of inanimate Concretes when it 's spirit is though by the gentlest distillation drawn from it will not by the re-union of it's constituent Liquors be reduc'd to it's pristine Nature because the workmanship of Nature in the disposition of the parts was too elaborate to be imitable or repairable by the bare and inartificial apposition of those divided parts to each other besides that in the dissociating action even of the gentlest fire upon a Concrete there does perhaps vanish though undiscernedly some active and fugitive particles whose presence was requisite to contain the Concrete under such a determinate form as we see in Wine degenerating into Vinegar where the change seems to proceed from this that upon the Avolation or if I may so speak Depression of some subtle sulphureous spirits whose Recesse or degeneration is not to be perceiv'd by any sensible diminution of bulk in the Liquor the remaining parts fall into new leagues or dispositions and constitute an acid Liquor somewhat fix'd and Corrosive and consequently of qualities very differing from those of the Wine whose souring produc'd it as we more fully declare in our Experiments relating to Fermentation SECT XXXV And certainly there is as we formerly said so artificial a contrivance of particles requisite to the constitution of the Organical parts of living bodies that it will be scarce possible for humane Art or Industry to imitate so as to equal those exquisite productions of Nature And therefore I wonder not that the story of the Phoenix's resurrection out of her own ashes should by the best Naturalists be thought a meer fiction And if that relation mention'd by the inquisitive Kircherus as an eye-witness of the Reproduction if I may so call it of Shell-fishes near the brink of a Lake in the Sicilian Promontorie Peloro by the watering of their broken bodies with Salt water in the Spring be strictly true it seems much more improbable that such changes and vicissitudes should be bare Redintegrations of the dissociated parts of such restored bodies than that according to what we elsewhere teach they should be New Productions made by some seminal particles undiscernedly lurking in some part of the destroyed body and afterwards excited and assisted by a Genial and cherishing heat so to act upon the fit and obsequious matter wherein 't was harbor'd as to organize and fashion that disposed matter according to the exigencies of it's own Nature For that in some bodies the Seminal particles may a while survive the seeming destruction of life is not altogether without example as we elsewhere professedly manifest And in Kircher's story it is to be observ'd that the restor'd Animals were but Shell-fish in whose slimy and viscous substance the Spirits and Prolifick parts are probably both more diffused and kept from being easily dissipable to which I know not whether it will be worth while to subjoyn that in such Fishes the Mechanical contrivance is but very plain and as it were slight and obvious in comparison of the exquisitely elaborated parts of more perfect Animals SECT XXXVI The last observable Pyrophilus that we shall at present take notice of in our Experiment shall be this That it may thereby seem probable that some Chymical remedies may be too rashly rejected by Physicians because Oyl or Spirit of Vitriol Aqua Regis or other Corrosive Liquors have been employ'd in their preparation For it is confidently affirm'd by many Physicians and but faintly denied by some Chymists that the Corrosive Menstruums made use of in the preparation of remedies can never be so exquisitely wash'd off from them but that some of the Salts will adhere to the Medicines and perniciously display their Corrosive Nature in the body of him that takes them And it is not to be denied but that many ignorant and venturous Chymists do unskilfully and therefore dangerously enough imploy Corrosives sometimes without any necessity or real advantage to invite them to it and sometimes withouâ— sufficiently freeing their Medicines from the corroding Salts by whose assistance they were prepar'd for 't is not always the frequency of ablutions though with warm water that will suffice to carry off the Salts from some bodies and therefore those great Artists Helmont and Paracelsus prescribe some things to be dulcifi'd by the abstraction of the water of whites of Egges which though it seem insipid hath been found a great disarmer of corrosive Salts and others by the frequent distillation of Spirit of Wine which indeed not to mention the Balsamick parts it may leave behind we have observ'd to have a faculty of carrying up with it the Saline Particles of Spirit of Vinegar adhering to some Chymical remedies But all this notwithstanding Pyrophilus there may be several bodies and perhaps more than are commonly taken notice of which quite alter the nature of the acid Salts employ'd to prepare them by occasioning those Salts to degeneraâ—e into another nature upon the very act of corroding or else by so associating their own Salts with those of the dissolving Menstruum that from the Coalition of both there emerges a third body differing in qualities from either As in our experiment we find that the Spirit of Petre which is much more sharp and corrosive than the strongest distill'd Vinegar and the fix'd Nitre which is Caustick like Salt of Tartar and may I suppose well serve for a Potential Cautery as Surgeons speak do by their mutual action work themselves into Salt-Petre which is far enough from having any eminently fretting Quality and may be safely taken inwardly in a much greater Dose than either of its Ingredients SECT XXXVII How much corrosive Salts may dulcifie themselves by corroding some bodies you may easily try by pouring distill'd Vinegar or moderate Spirit of Vitriol upon a competent proportion of Corals or Crabs Eyes or Pearls or as I suppose almost any testaceous body And for my part though I am very shy of imploying corrosive Liquors in the Preparation of Medicines yet I have lately given a Preparation of refin'd Silver made with Aqua fortis it self or Spirit of Nitre not onely innocently but with such success that a couple of Experienc'd
but to prove a Vacuum without otherwise taking notice that I have met with of those things that are most material in such Observations to our present purpose and without deducing thence what we shall endeavour to do in order to the explication of the causes of Firmness Upon what account then soever the Atomists have omitted to reckon for a cause of Firmness that which we have newly been speaking of yet as we observed above If two bodies be once at rest against one another it seems consonant to the Catholick Laws of Nature that they should continue in that state of rest till some force capable to over-power their resistance puts them out of it And whatever may be said of the unloosable mobility of Atoms strictly so taken yet that diverse parts of Matter may compose bodies that need no other Cement to unite them than the juxta-position which we here presuppose and the resting together of their parts whereby the Air and other fluid Bodies that might dissociate them are excluded I have been inclined to think by what I have observed in grinding of Glasses for sometimes the convex surface of one body being ground upon the concave surface of another the two surfaces will happen to be so closely and exactly fitted to one another their immediate contact in all their parts or at least in innumerable of them hindering the intercurrence of the Air that a man is not able without breaking one or both of them to pull them directly asunder but if you will sever them you must be fain to make one of them to slip along the surface of the other which makes the Glass-Grinders often complain of the trouble they meet with in separating such bodies Nay if you lay two flat Glasses ground very true and well polished upon one another so that their surfaces may almost every where touch each other to which it will be requisite to rub them a little one upon another for the better exclusion of the Air you may by lifting up the uppermost lift up the lowermost though perhaps as we have often try'd two or three times bigger with it as if the two Plates of Glass made but one body Nay we have divers times taken up four or five pieces of Glass at once laid and prest thus one upon another and might perchance have taken up a greater number if we had had more of them at hand And tryal has also informed us that if you hold a Looking-Glass very level with the unfoliated side downward and rub a little against it a piece of other very flat and very smooth Glass you may easily by that way only fasten them to one another so that the lowermost Glass though large will hang between the uppermost and the ground to the wonder of those that behold it and can discern nor imagine nothing capable to keep it from falling and by the same way as we shall recite anon we have often made one considerably thick piece of Marble take and hold up another having purposely caused their flat surfaces to be carefully ground and polished without which the Experiment will not succeed Nor is it requisite that the glasses be flat to make them adhere very closely together provided their immediate contact be made according to a large surface for to what we have already mention'd concerning the cohering of convex and concave Bodies we may adde that having purposely appli'd a long glass-stopple of an almost conical figure and well ground to the mouth of a thick quart Bottle whose neck was made long and of a figure convenient to receive the stopple and ground within fit for it we found that these two glass bodies touching one another in a multitude of parts did adhere together so closely that when the stopple was carefully put in we could easily and divers times one after another lift up the bottle though there was by our guess above a pound of Liquor in it Unless we suppose without much probability that because 't is found that moving them to and fro upon one another and pressing down the stopple promotes their sticking their adhesion may be in part ascrib'd either to some Elastical motion in the parts of the pressed glass or to the exquisite adaptation of the almost numberless though very small asperities of the one to the as numerous little cavities of the other whereby the surfaces do lock in with one another or are as it were clasp'd together For as polish'd as the surfaces may appear to sense we must not deny that there may be such inequalities in them since being wont to be polish'd with Putty or some such powder or heap of grating and irregularly shap'd Corpuscles they must needs make store of little furrows and ridges and other Asperities on them But to insist on these Conjectures were to digress Yet here we must not decline taking notice that at least here below the sticking together of such bodies as are of sensible Bulk and whose smooth surfaces immediately touch one another may possibly not so much proceed from this that their parts as we formerly observ'd are at rest among themselves and by their immediate contact do make up as it were but one body as from the pressure of the Atmosphere proceeding partly from the weight of the ambient Air mixt with the Effluviums of the terrestrial Globe and partly from a kind of Spring by vertue of which the Air continually presses upon the bodies contiguous to it though through accustomance negligence perhaps some other causes not here to be insisted on we neither feel it in our own bodies nor take notice of it in others Now this pressure of the Air every way being suppos'd I think the adhering of the smooth bodies we speak of for we suppose them far greater than the particles of the Air to one another may probably enough be ascrib'd to this That when for instance the smooth surfaces of two pieces of Glass do so exquisitely touch one another that none of the ambient Air is eiâ—her intercepted or admitted between them then the undermost glass will suffer no pressure on that side which touches the uppermost the parts of the uppermost glass having no sensible spring in them so that they can only Resist but not Repell the other but that side of the undermost Glass which is expos'd to the Air will be press'd upon thereby and there being as we said no Elastical pressure on the other side of the glass to balance this it is not to be wonder'd at that the inferiour glass should not fall off from the other in regard the weight that would carry it downwards is much too small to overcome that force of the Air that thrusts it against the uppermost glass As if one should with his hand thrust a plate of Iron broad-wise against the flat cieling of his Chamber the Iron would not fall as long as the force of the hand perseveres to press against it Nor is it material