Experiment XL
The Experiment I am now to mention to you, Pyrophilus, is that which both you, and all the other Virtuoſi that have ſeen it, have been pleas’d to think very ſtrange; and indeed of all the Experiments of Colours, I have yet met with, it ſeems to be the fitteſt to recommend the Doctrine propos’d in this Treatiſe, and to ſhew that we need not ſuppoſe, that all Colours muſt neceſſarily be Inherent Qualities, flowing from the Subſtantial Forms of the Bodies they are ſaid to belong to, ſince by a bare Mechanical change of Texture in the Minute parts of Bodies; two Colours may in a moment be Generated quite De novo, and utterly Deſtroy’d. For there is this difference betwixt the following Experiment, and moſt of the others deliver’d in theſe Papers, that in this, the Colour that a Body already had, is not chang’d into another, but betwixt two Bodies, each of them apart devoid of Colour, there is in a moment generated a very deep Colour, and which if it were let alone, would be permanent; and yet by a very ſmall Parcel of a third Body, that has no Colour of its own, (leſt ſome may pretend I know not what Antipathy betwixt Colours) this otherwiſe permanent Colour will be in another trice ſo quite Deſtroy’d, that there will remain no foot-ſtepts either of it or of any other Colour in the whole Mixture.
The Experiment is very eaſie, and it is thus perform’d: Take good common Sublimate, and fully ſatiate with it what quantity of Water you pleaſe, Filtre the Solution carefully through clean and cloſe Paper, that it may drop down as Clear and Colourleſs as Fountain water. Then when you’l ſhew the Experiment, put of it about a Spoonfull into a ſmall Wine-glaſs, or any other convenient Veſſel made of clear Glaſs, and droping in three or four drops of good Oyl of Tartar, per Deliquium; well Filtred that it may likewiſe be without Colour, theſe two Limpid Liquors will in the twinkling of an Eye turn into an Opacous mixture of a deep Orange Colour, which by keeping the Glaſs continually ſhaking in your hand, you muſt preſerve from ſetling too ſoon to the Bottom; And when the Spectators have a little beheld this firſt Change, then you muſt preſently drop in about four or five drops of Oyl of Vitriol, and continuing to ſhake the Glaſs pretty ſtrongly, that it may the Nimbler diffuſe it ſelf, the whole Colour, if you have gone Skilfully to work, will immediately diſappear, and all the Liquor in the Glaſs will be Clear and Colourleſs as before, without ſo much as a Sediment at the Bottom. But for the more gracefull Trial of this Experiment, ’twill not be amiſs to obſerve, Firſt, That there ſhould not be taken too much of the Solution of Sublimate, nor too much of the Oyl of Tartar drop’d in, to avoid the neceſſity of putting in ſo much Oyl of Vitriol as may make an Ebullition, and perhaps run over the Glaſs. Secondly, That ’tis convenient to keep the Glaſs always a little ſhaking, both for the better mixing of the Liquors, and to keep the Yellow Subſtance from Subſiding, which elſe it would in a ſhort time do, though when ’tis ſubſided it will retain its Colour, and alſo be capable of being depriv’d of it by the Oyl newly mention’d. Thirdly, That if any Yellow matter ſtick at the ſides of the Glaſs, ’tis but inclining the Glaſs, till the clarify’d Liquor can waſh alongſt it, and the Liquor will preſently imbibe it, and deprive it of its Colour.
Many have ſomewhat wondred, how I came to light upon this Experiment, but the Notions or Conjectures I have about the differing Natures of the Several Tribes of Salts, having led me to deviſe the Experiment, it will not be difficult for me to give you the Chymical Reaſon, if I may ſo ſpeak, of the Phænomenon. Having then obſerv’d, that Mercury being diſſolv’d in Some Menſtruums, would yield a dark Yellow Precipitate, and ſuppoſing that, as to this, common Water, and the Salts that ſtick to the Mercury would be equivalent to thoſe Acid Menſtruums, which work upon the Quick-ſilver, upon the account of their Saline particles, I ſubſtituted a Solution of Sublimate in fair Water, inſtead of a Solution of Mercury in Aqua-fortis, or Spirit of Nitre, that ſimple Solution being both clearer and free from that very offenſive Smell, which accompanies the Solutions of Mercury made with thoſe other corroſive Liquors; then I conſider’d, that That, which makes the Yellow Colour, is indeed but a Precipitate made by the means of the Oyl of Tartar, which we drop in, and which, as Chymiſts know, does generally precipitate Metalline Bodies corroded by Acid Salts; ſo that the Colour in our caſe reſults from the Coalition of the Mercurial particles with the Saline ones, wherewith they were formerly aſſociated, and with the Alcalizate particles of the Salt of Tartar that ſwim up and down in the Oyl. Wherefore conſidering alſo, that very many of the effects of Lixiviate Liquors, upon the Solutions of other Bodies, may be deſtroy’d by Acid Menstruums, as I elſewhere more particularly declare, I concluded, that if I choſe a very potently Acid Liquor, which by its Inciſive power might undo the work of the Oyl of Tartar, and diſperſe again thoſe Particles, which the other had by Precipitation aſſociated, into ſuch minute Corpuſcles as were before ſingly Inconſpicuous, they would become Inconſpicuous again, and conſequently leave the Liquor as Colourleſs as before the Precipitation was made.
This, as I ſaid, Pyrophilus, ſeems to be the Chymical reaſon of this Experiment, that is ſuch a reaſon, as, ſuppoſing the truth of thoſe Chymical Notions I have elſewhere I hope evinc’d, may give ſuch an account of the Phænomena as Chymical Notions can ſupply us with; but I both here and elſewhere make uſe of this way of ſpeaking, to intimate that I am ſufficiently aware of the difference betwixt a Chymical Explication of a Phænomenon, and one that is truly Philoſophical or Mechanical; as in our preſent caſe, I tell you ſomething, when I tell you that the Yellowneſs of the Mercurial Solution and the Oyl of Tartar is produc’d by the Precipitation occaſion’d by the affuſion of the latter of thoſe Liquors, and that the deſtruction of the Colour proceeds from the Diſſipation of that Curdl’d matter, whoſe Texture is deſtroy’d, and which is diſſolv’d into Minute and Inviſible particles by the potently Acid Menſtruum, which is the reaſon, why there remains no Sediment in the Bottom, becauſe the infuſed Oyl takes it up, and reſolves it into hidden or inviſible Parts, as Water does Salt or Sugar. But when I have told you all this, I am far from thinking I have told all that ſuch an Inquiſitive Perſon as your ſelf would know, for I preſume you would deſire as well as I to learn (at leaſt) why the Particles of the Mercury, of the Tartar, and of the Acid Salts convening together, ſhould make rather an Orange Colour than a Red, or a Blew, or a Green, for ’tis not enough to ſay what I related a little before, that divers Mercurial Solutions, though otherwiſe made, would yield a Yellow precipitate, becauſe the Queſtion will recurr concerning them; and to give it a ſatisfactory anſwer, is, I freely acknowledge, more than I dare as yet pretend to.
But to confirm my conjecture about the Chymical reaſon of our Experiment, I may add, that as I have (viz. pag. 34th. of this Treatiſe) elſewhere (on another occaſion) told you, with Saline Liquors of another kind and nature than Salt of Tartar, (namely, with Spirit of Urine, and Liquors of kin to that) I can make the Mercury precipitate out of the firſt ſimple Solution quite of another Colour than that hitherto mention’d; Nay, if inſtead of altering the Precipitating liquor, I alter’d the Texture of the Sublimate in ſuch a way as my Notions about Salt requir’d, I could produce the ſame Phænomenon. For having purpoſely Sublim’d together Equal parts (or thereabout) of Sal-Armoniack and Sublimate, firſt diligently Mix’d, the aſcending Flowers being diffolv’d in fair Water, and Filtred, gave a Solution Limpid and Colourleſs, like that of the other Sublimates, and yet an Akaly drop’d into this Liquor did not turn it Yellow but White. And upon the ſame Grounds we may with Quick-ſilver, without the help of common Sublimate, prepare another ſort of Flowers diſſoluble in Water without Diſcolouring it, with which I could likewiſe do what I newly mention’d; to which I ſhall add, (what poſſibly you’l ſomewhat wonder at) That ſo much does the Colour depend upon the Texture reſulting from the Convention of the ſeveral ſorts of Corpuſcles, that though in out Experiment, Oyl of Vitriol deſtroys the Yellow Colour, yet with Quick-ſilver and fair Water, by the help of Oyl of Vitriol alone, we may eaſily make a kind of Precipitate of a fair and permanent Yellow, as you will e’re long (in the forty ſecond Expement of this third Part) be taught. And I may further add, that I choſe Oyl of Vitriol, not ſo much for any other or peculiar Quality, as for its being, when ’tis well rectify’d, (which ’tis ſomewhat hazardous to bring it to be) not only devoid of Colour and in Smells, but extremely Strong and Inciſive; For though common and undephlegmated Aqua-fortis will not perform the ſame thing well, yet that which is made exceeding Strong by being carefully Dephlegm’d, will do it pretty well, though not ſo well as Oyl of Vitriol which is ſo Strong, that even without Rectification it may for a need be made uſe of. I will not here tell you what I have try’d, that I may be able to deprive at pleaſure the Precipitate that one of the Sulphureous Liquors had made, by the copious Affuſion of the other: Becauſe I found, though this Experiment is too tickliſh to let me give a full account of it in few words, I ſhall therefore tell you, that it is not only for once, that the other above-mention’d Experiment may be made, the ſame Numerical parcels of Liquor being ſtill imploy’d in it; for after I have Clarify’d the Orange Colour’d Liquor, by the addition of as little of the Oyl of Viriol as will ſuffice to perform the effect, I can again at pleaſure re-produce the Opacous Colour, by the dropping in of freſh Oyl of Tartar, and deſtroy it again by the Re-affuſion of more of the Acid Menſtruum; and yet oftner if I pleaſe, can I with theſe two contrariant Liquors recall and diſperſe the Colour, though by reaſon of the addition of ſo much new Liquor, in reference to the Mercurial particles, the Colour will at length appear more dilute and faint.
An improvement of the fortieth Experiment.
And, Pyrophilus, to confirm yet further the Notions that led me to think on the propos’d Experiment, I ſhall acquaint you with another, which when I had conveniency I have ſometimes added to it, and which has to the Spectators appear’d little leſs Odd than the firſt; And though becauſe the Liquor, requiſite to make the Trial ſucceed well, muſt be on purpoſe prepar’d anew a while before, becauſe it will not long retain its fitneſs for this work, I do but ſeldome annex this Experiment to the other, yet I ſhall tell you how I devis’d it, and how I make it. If you boyl Crude Antimony in a ſtrong and clear Lixivium, you ſhall ſeparate a Subſtance from it, which ſome Modern Chymiſts are pleas’d to call its Sulphur, but how deſervedly I ſhall not here examine, having elſewhere done it in an Opportune place; wherefore I ſhall now but need to take notice, that when this ſuppos’d Sulphur (not now to call it rather a kind of Crocus) is let fall by the Liquor upon its Refrigeration, it often ſettles in Flakes, or ſuch like parcels of a Yellow Subſtance, (which being by the precedent diſſolution reduc’d into Minute parts, may peradventure be made to take Fire much more eaſily than the Groſſer Powder of unprepar’d Antimony would have done.) Conſidering therefore, that common Sulphur boyl’d in a Lixivium may be Precipitated out of it by Rheniſh-wine or White-wine, which are Sowriſh Liquors, and have in them, as I elſewhere ſhew, an Acid Salt; and having found alſo by Trial, that with other Acid Liquors I could Precipitate out of Lixiviate Solvents ſome other Mineral concretions abounding with Sulphureous parts, of which ſort is crude Antimony, I concluded it to be eaſie to Precipitate the Antimony diſſolv’d, as was lately mention’d, with the Acid Oyl of Vitriol; and though common Sulphur yields a White Precipitate, which the Chymiſts call Lac Sulphuris, yet I ſuppos’d the Precipitated Antimony would be of a deep Yellow Colour, as well, if made with Oyl of Vitriol, as if made only by Refrigeration and length of Time. From this ’twas eaſie to deduce this Experiment, that if you put into one Glaſs ſome of the freſhly Impregnated and Filtrated Solution of Antimony, and into another ſome of the Orange-Colour’d Mixture, (which I formerly ſhew’d you how to make with a Mercurial Solution and Oyl of Tartar) a few drops of Oyl of Vitriol dropp’d into the laſt mention’d Glaſs, would, as I told you before, turn the Deep Yellow mixture into a Cleer Liquor; whereas a little of the ſame Oyl dropp’d out of the ſame Viol into the other Glaſs would preſently (but not without ſome ill ſent) turn the moderately cleer Solution into a Deep Yellow Subſtance, But this, as I Said, ſucceeds not well, unleſs you employ a Lixivium that has but newly diſſolv’d Antimony, and has not yet let it fall. But yet in Summer time, if your Lixivium have been duly Impregnated and well Filtred after it is quite cold, it will for ſome dayes (perhaps much longer than I had occaſion to try) retain Antimony enough to exhibit, upon the Affuſion of the Corroſive Oyl, as much of a good Yellow Subſtance as is neceſſary to ſatisfie the Beholders of the Poſſibility of the Experiment.
Reflections upon the XL. Experiment Compared with the X. and XX.
The Knowledge of the Diſtinction of Salts which we have propos’d, whereby they are diſcriminated into Acid, Volatile, or Salfuginous (if I may for Diſtinction ſake ſo call the Fugitive Salts of Animal Subſtances) and fix’d or Alcalizate, may poſſibly (by that little part which we have already deliver’d, of what we could ſay of its Applicableneſs) appear of ſo much Uſe in Natural Philoſophy (eſpecially in the Practick part of it) that I doubt not but it will be no Unwelcome Corollary of the Preceding Experiment, if by the help of it I teach you to diſtinguiſh, which of thoſe Salts is Predominant in Chymical Liquors, as well as whether any of them be ſo or not. For though in our Notes upon the X. and XX. Experiments I have ſhown you a way by means of the Tincture of Lignum Nephriticum, or of Syrrup of Violets, to diſcover whether a propounded Salt be Acid or not, yet you can thereby only find in general that ſuch and ſuch Salts belong not to the Tribe of Acids, but cannot determine whether they belong to the Tribe of Urinous Salts (under which for diſtinction ſake I comprehend all thoſe Volatile Salts of Animal or other Subſtances that are contrary to Acids) or to that of Alcalies. For as well the one as the other of theſe Salino-Sulphurous Salts will reſtore the Cæruleous Colour to the Tincture of Lignum Nephriticum, and turn that of Syrrup of Violets into Green. Wherefore this XL. Experiment does opportunely ſupply the deficiency of thoſe. For being ſollicitous to find out ſome ready wayes of diſcriminating the Tribes of Chymical Salts, I found that all thoſe I thought fit to make Tryal of, would, if they were of a Lixiviate Nature, make with Sublimate diſſolv’d in Fair Water an Orange Tawny Precipitate; whereas if they were of an Urinous Nature the Precipitate would be White and Milky. So that having alwayes by me ſome Syrrup of Violets and ſome Solution of Sublimate, I can by the help of the firſt of thoſe Liquors diſcover in a trice, whether the propounded Salt or Saline Body be of an Acid Nature or no, if it be I need (you know) inquire no further; but if it be not, I can very eaſily, and as readily diſtinguiſh between the other two kinds of Salts, by the White or Orange-Colour that is immediately produc’d, by letting fall a few Drops or Grains of the Salt to be examin’d, into a ſpoonfull of the cleer Solution of Sublimate. For Example, it has been ſuppos’d by ſome eminently Learned, That when Sal Armoniack being mingled with an Alcaly is forc’d from it by the Fire in cloſe Veſſels, the Volatile Salt that will thereby be obtain’d (if the Operation be skilfully perform’d,) is but a more fine and ſubtile ſort of Sal Armoniack, which, ’tis preſum’d, this Operation do’s but more exquiſitely purifie, than common Solutions, Filtrations, and Coagulations. But this Opinion may be eaſily ſhown to be Erroneous, as by other Arguments, ſo particularly by the lately deliver’d Method of diſtinguiſhing the Tribes of Salts. For the Saline Spirit of Sal Armoniack, as it is in many other manifeſt Qualities very like the Spirit of Urine, ſo like, that it will in a trice make Syrrup of Violets of a Lovely Green, turn a Solution of good Verdigreaſe into an Excellent Azure, and make the Solution of a Sublimate yield a White Precipitate, inſomuch that in moſt (for I ſay not all of the Experiments) where I Aim onely at producing a ſudden change of Colour, I ſcruple not to uſe Spirit of Sal Armoniack when it is at hand, inſtead of Spirit of Urine, as indeed it ſeems chiefly to conſiſt (beſides the flegm that helps to make it fluid) of the Volatile Urinous Salt (yet not excluding that of Soot) that abounds in the Sal Armoniack and is ſet at liberty from the Sea Salt wherewith it was formerly aſſociated, and clogg’d, by the Operation of the Alcaly, that divides the Ingredients of Sal Armoniack, and retains that Sea Salt with it ſelf. What uſe may be made of the like way of exploration in that inquiry which puzzles ſo many Modern Naturaliſts, whether the Rich Pigment (which we have often had occaſion to mention) belongs to the Vegetable or Animal Kingdome, you may find in another place where I give you ſome account of what I try’d about Cocheneel. But I think it needleſs to exemplifie here our Method by any other Inſtances, many ſuch being to be met with in divers parts of this Treatiſe; but I will rather advertiſe you, that, by this way of examining Chymical Liquors, you may not onely in moſt Caſes conclude Affirmatively, but in ſome Caſes Negatively. As ſince Spirit of Wine, and as far as I have try’d, thoſe Chymical Oyles which Artiſts call Eſſential, did not (when I us’d them as I had us’d the ſeveral Families of Salts upon that Syrrup) turn Syrrup of Violets Red or Green, nor the Solution of Sublimate White or Yellow, I inferr’d it may thence be probably argued, that either they are deſtitute of Salt, or have ſuch as belongs not to either of the three Grand families already often mention’d. When I went to examine the Spirit of Oak or of ſuch like Concretes forced over through a Retort, I found by this means amongſt others, that (as I elſewhere ſhow) theſe Chymiſts are much miſtaken in it, that account it a ſimple Liquor, and one of their Hypoſtatical Principles: for not to mention what flegm it may have, I found that with a few drops of one of this ſort of Spirits mix’d with a good proportion of Syrrup of Violets, I could change the Colour and make it Purpliſh, by the affinity of which Colour to Redneſs, I conjectur’d that this Spirit had ſome Acid Corpuſcles in it, and accordingly I found that as it would deſtroy the Blewneſs of a Tincture of Lignum Nephriticum, ſo being put upon Corals it would Corrode them, as common Spirit of Vinegar, and other Acid Liquors are wont to do. And farther to examine whether there were not a great part of the Liquor that was not of an Acid nature, having ſeparated the Sour or Vinegar-like part from the reſt, which (if I miſtake not) is far the more Copious, we concluded as we had conjectured, the other or remaining part, though it had a ſtrong taſte as well as ſmell, to be of a nature differing from that of either of the three ſorts of Salts above mention’d, ſince it did as little as Spirit of Wine, and Chymical Oyls, alter the Colour either of Syrrup of Violets or Solution of Sublimate, whence we alſo inferr’d that the change that had been made of that Syrrup into a Purple Colour, was effected by the Vinegar, that was one of the two Ingredients of the Liquor, which was wont to paſs for a Simple or Uncompounded Spirit. And, upon this account, ’twas of the Spirit of Oak (and the like Concretes) freed from it’s Vinegar that I elſewhere told you, that I had not then obſerv’d it, (and I have repeated the Tryal but very lately) to deſtroy the Cæruleous Tincture of Lignum Nephriticum. But this onely, en paſsant; for the Chief thing I had to add was this, That by the ſame way may be examin’d and diſcover’d, divers changes that are produc’d in Bodies either by Nature only, or by Art; either of them being able by changing the Texture of ſome Concretes I could name, to qualifie them to Operate after a New manner upon the above mention’d Syrrup, or Solution, or both. And by this means, to tell you that upon the by, I have been able to diſcover, that there may be made Bodies, which though they run per Deliquium, as readily as Salt of Tartar, belong in other reſpects, not to the family of Alcaliz, much leſs to that of Salfuginous, or that of Acid Salts. Perhaps too, I may know a way of making a highly operative Saline Body that ſhall neither change the Colour of Syrrup of Violets, nor Precipitate the Solution of Sublimate; And, I can likewiſe if I pleaſe conceal by what Liquors I perform ſuch changes of Colour, as I have been mentioning to you, by quite altering the Texture of ſome ordinary Chymical productions, the Exploration of which is the main uſe of the fortieth Experiment, which I think teaches not a little, if it teach us to diſcover the nature of thoſe things (in reference to Salt) that are obtain’d by the ordinary Chymical Analyſis of mix’d Bodyes, though perhaps there may be other Bodyes prepar’d by Chymiſtry which may have the ſame Effects in the change of Colours; and yet be produc’d not from what Chymiſts call the Reſolution of Bodies, but from their Compoſition. But the diſcourſing of things of this nature is more proper for another place. I ſhall now onely add, what might perhaps have been more ſeaſonably told you before; That the Reaſon why the way of Exploration of Salts hitherto deliver’d, ſucceeds in the Solution of Sublimate, depends upon the particular Texture of that Solution, as well as upon the differing Natures of the Saline Liquors imploy’d to Precipitate it. For Gold diſſolv’d in Aqua Regia, whether you Precipitate it with Oyl of Tartar which is an Alcaly, or with Spirit of Urine, or Sal Armoniack which belongs to the family of Volatile Salts, will either way afford a Yellow ſubſtance: though with ſuch an Acid Liquor, as, I ſay not Spirit of Salt, the Body that yields it, being upon the matter an Ingredient of Aqua Regis, but Oyl of Vitriol it ſelf, I did not find that I could Precipitate the Metall out of the Solution, or deſtroy the Colour of it, though the ſame Oyl of Vitriol would readily Precipitate Silver diſſolv’d in Aqua-fortis. And if you diſſolve pure Silver in Aqua-fortis, and ſuffer it to ſhoot into Cryſtals, the cleer Solution of theſe made in fair Water, will afford a very White Precipitate, whether it be made with an Alcaly, or an Acid Spirit, as that of Salt, whereas, which may ſeem ſomewhat ſtrange, with Spirit of Sal Armoniack (that I us’d was made of Quicklime) I could obtain no ſuch White Precipitate; that Volatile Spirit, nor (as I remember) that of Urine, ſcarce doing any more than ſtriking down a very ſmall quantity of Matter, which was neither White nor Whitiſh, ſo that the remaining Liquor being ſuffer’d to evaporate till the ſuperfluous Moiſture was gone, the greateſt part of the Metalline Corpuſcles with the Saline ones that had imbib’d them, concoagulated into Salt, as is uſual in ſuch Solutions, wherein the Metall has not been Precipitated.