Experiments and Considerations Touching Colours (1664) Part 7

[20] See _Parkinson_ Th. Boran. Trib. 9. cap. 26.

And I also choose (_Pyrophilus_) to subjoyn this twenty ninth Experiment to those that precede it, about the change of the Colours of Vegetables by Salts, for these two reasons: The first, that you may not easily entertain Suspitions, if in the Trials of an Experiment of some of the Kinds formerly mention'd, you should meet with an Event somewhat differing from what my Relations may have made you expect. And the second, That you may hereby be invited to discern, that it may not be amiss to take notice of the particular Seasons wherein you gather the Vegetables which in Nicer Experiments you make use of. For, it I were not hindred both by haste and some justifiable Considerations, I could perhaps add considerable Instances, to those lately deliver'd, for the making out of this Observation; but for certain reasons I shall at present subst.i.tute a remarkable pa.s.sage to be met with in that Laborious Herbarist Mr.

_Parkinson_, where treating of the Virtues of the (already divers times mention'd) Buckthorn Berries, he subjoyns the following account of several Pigments that are made of them, not only according to the several ways of Handling them, but according to the differing Seasons of Maturity, at which they are Gather'd; _Of these Berries_, (says he) _are made three several sorts of Colours as they shall be gather'd, that is, being gather'd while they are Green, and kept Dry, are call'd Sapberries, which being steep'd into some Allom-water, or fresh bruis'd into Allom-water, they give a reasonable fair Yellow Colour which Painters use for their Work, and Book-binders to Colour the edges of Books, and Leather-dressers to Colour Leather, as they use also to make a Green Colour, call'd Sap-green, taken from the Berries when they are Black, being bruis'd and put into a Bra.s.s or Copper Kettle or Pan, and there suffer'd to abide three or four_ _Days, or a little heated upon the Fire, and some beaten Allom put unto them, and afterwards press'd forth, the Juice or Liquor is usually put in great Bladders tied with strong thred at the Head and hung up untill it be Dry, which is dissolv'd in Water or Wine, but Sack_ (he affirms) _is the best to preserve the Colour from Starving, (as they call it) that is, from Decaying, and make it hold fresh the longer. The third Colour (where of none_ (says he) _that I can find have made mention but only_ Tragus_) is a Purplish Colour, which is made of the Berries suffer'd to grow upon the Bushes untill the middle or end of_ November, _that they are ready to drop from the Trees._

And, I remember (_Pyrophilus_) that I try'd, with a success that pleas'd me well enough, to make such a kind of Pigment, as Painters call Sap-green, by a way not unlike that, deliver'd here by our Author, but I cannot now find any thing relating to that matter among my loose Papers. And my Trials were made so many years ago, that I dare not trust my Memory for Circ.u.mstances, but will rather tell you, that in a noted Colour-shop, I brought them by Questions to confess to me, that they made their Sap-green much after the ways by our _Botanist_ here mention'd. And on this occasion I shall add an Observation, which though it does not strictly belong to this place, may well enough be mention'd here, namely, that I find by an account given us by the Learned _Clusius_, of _Alaternus_, that ev'n the Grosser Parts of the same Plant, are some of them one Colour, and some another; For speaking of that Plant, he tells us, that the _Portugalls_ use the Bark to Dye their Nets into a Red Colour, and with the Chips of the Wood, which are Whitish, they Dye a Blackish Blew.

_EXPERIMENT x.x.x._

Among the Experiments that tend to shew that the change of Colours in Bodies may proceed from the Vary'd Texture of their Parts, and the consequent change of their Disposition to Reflect or Refract the Light, that sort of Experiments must not be left unmention'd, which is afforded us by Chymical Digestions. For, if _Chymists_ will believe several famous Writers about what they call the Philosophers Stone, they must acknowledge that the same Matter, seald up Hermetically in a Philosophical Egg, will by the continuance of Digestion, or if they will have it so (for it is not Material in our case which of the two it be) of Decoction, run through a great Variety of differing Colours, before it come to that of the n.o.blest _Elixir_; whether that be Scarlet, or Purple, or what ever other Kind of Red. But without building any thing on so Obtruse and Questionable an Operation, (which yet may be pertinently represented to those that believe the thing) we may observe, that divers Bodies digested in carefully-clos'd Vessels, will in tract of time, change their Colour: As I have elsewhere mention'd my having observ'd ev'n in Rectify'd Spirit of Harts-horn, and as is evident in the Precipitations of Amalgams of Gold, and Mercury, without Addition, where by the continuance of a due Heat the Silver-Colour'd Amalgam is reduc'd into a shining Red Powder. Further Instances of this Kind you may find here and there in divers places of my other Essays. And indeed it has been a thing, that has much contributed to deceive many _Chymists_, that there are more Bodies than one, which by Digestion will be brought to exhibit that Variety and Succession of Colours, which they imagine to be Peculiar to what they call the _True matter of the Philosophers_. But concerning this, I shall referr you to what you may elsewhere find in the Discourse written touching the pa.s.sive Deceptions of _Chymists_, and more about the Production of Colours by Digestion you will meet with presently. Wherefore I shall now make only this Observation from what has been deliver'd, That in these Operations there appears not any cause to attribute the new Colours emergent to the Action of a new Substantial form, nor to any Increase or Decrement of either the Salt, Sulphur, or Mercury of the Matter that acquires new Colours: For the Vessels are clos'd, and these Principles according to the _Chymists_ are Ingenerable and Incorruptible; so that the Effect seems to proceed from hence, that the Heat agitating and shuffling the Corpuscles of the Body expos'd to it, does in process of time so change its Texture, as that the Transposed parts do Modifie the incident Light otherwise, than they did when the Matter appear'd of another Colour.

_EXPERIMENT x.x.xI._

Among the several changes of Colour, which Bodies acquire or disclose by Digestion, it it very remarkable, that _Chymists_ find a Redness rather than any other Colour in most of the Tinctures they Draw, and ev'n in the more Gross Solutions they make of almost all Concretes, that abound either with Mineral or Vegetable Sulphur, though the _Menstruum_ imploy'd about these Solutions or Tinctures be never so Limpid or Colourless.

This we have observ'd in I know not how many Tinctures drawn with Spirit of Wine from _Jalap_, _Guaic.u.m_, and several other Vegetables; and not only in the Solutions of _Amber_, _Benzoin_, and divers other Concretes made with the same _Menstruum_, but also in divers Mineral Tinctures. And, not to urge that familiar Instance of the Ruby of Sulphur, as _Chymists_ upon the score of its Colour, call the Solution of Flowers of Brimstone, made with the Spirit of Turpentine, nor to take notice of other more known Examples of the aptness of Chymical Oyls, to produce a Red Colour with the Sulphur they extract, or dissolve; not to insist (I say) upon Instances of this nature, I shall further represent to you, as a thing remarkable, that, both Acid and Alcalizate Salts, though in most other cases of such contrary Operations, in reference to Colours, will with many Bodies that abound with Sulphureous, or with Oyly parts, produce a Red; as is manifest partly in the more Vulgar Instances of the Tinctures, or Solutions of Sulphur made with _Lixiviums_, either of Calcin'd Tartar or Pot-ashes, and other Obvious examples, partly by this, that the true Gla.s.s of Antimony extracted with some Acid Spirits, with or without Wine, will yield a Red Tincture, and that I know an Acid Liquor, which in a moment will turn Oyl of Turpentine into a deep Red. But among the many Instances I could give you of the easie Production of Redness by the Operation of Saline Spirit, as well as of Spirit of Wine; I remember two or three of those I have tried, which seem remarkable enough to deserve to be mention'd to you apart.

_EXPERIMENT x.x.xII._

But before we set them down, it will not perhaps appear impertinent to premise;

That there seems to be a manifest Disparity betwixt Red Liquors, so that some of them may be said to have a Genuine Redness in comparison of others, that have a Yellowish Redness: For if you take (for example) a good Tincture of _Chochineel_, dilute it never so much with fair Water, you will not (as far as I can judge by what I have tried) be able to make it a Yellow Liquor. Insomuch that a Single drop of a rich Solution of _Cochineel_ in Spirit of Urine, being Diluted with above an Ounce of fair Water, exhibited no Yellowishness at all, but a fair (though somewhat faint) Pinck or Carnation; and even when _Cochineel_ was by degrees Diluted much beyond the newly mention'd Colour, by the way formerly related to you in the twenty fourth Experiment, I remember not, that there appear'd in the whole Trial any Yellow. But if you take Balsom of Sulphur (for Instance) though it may appear in a Gla.s.s, where it has a good Thickness, to be of a deep Red, yet if you shake the Gla.s.s, or pour a few drops on a sheet of White Paper, spreading them on it with your Finger, the Balsom that falls back along the sides of the Gla.s.s, and that which stains the Paper, will appear Yellow, not Red. And there are divers Tinctures, such as that of Amber made with Spirit of Wine, (to name now no more) that will appear either Yellow or Red, according as the Vessels that they fill, are Slender or Broad.

_EXPERIMENT x.x.xIII._

But to proceed to the Experiments I was about to deliver; _First_; Oyl or Spirit of Turpentine, though clear as fair Water, being Digested upon the purely White Sugar of Lead, has, in a short time, afforded us a high Red Tincture, that some Artists are pleas'd to call the Balsom of _Saturn_, which they very much (and probably not altogether without cause) extoll as an excellent Medicine in divers Outward affections.

_EXPERIMENT x.x.xIV._

_Next_, take of common Brimstone finely powdred five Ounces, of Sal-Armoniack likewise pulveriz'd an equal weight, of beaten Quick-lime six Ounces, mix these Powders exquisitely, and Distill them through a Retort plac'd in Sand by degrees of Fire, giving at length as intense a Heat as you well can in Sand, there will come over (if you have wrought well) a Volatile Tincture of Sulphur, which may probably prove an excellent Medicine, and should have been mention'd among the other Preparations of Sulphur, which we have elsewhere imparted to you, but that it is very pertinent to our present Subject, The change of Colours. For though none of the Ingredients be Red, the Distill'd Liquor will be so: and this Liquor if it be well Drawn, will upon a little Agitation of the Vial first unstop'd (especially if it be held in a Warmer hand) lend forth a copious Fume, not Red, like that of Nitre, but White; And sometimes this Liquor may be so Drawn, that I remember, not long since, I took pleasure to observe in a parcel of it, that Ingredients not Red, did not only yield by Distillation a Volatile Spirit that was Red, but though that Liquor did upon the bare opening of the Bottle it was kept in, drive us away with the plenty and sulphureous sent of a White steam which it sent forth, yet the Liquor it self being touch'd by our Fingers, did immediately Dye them Black.

_EXPERIMENT x.x.xV._

The third and _last_ Experiment I shall now mention to shew, how p.r.o.ne Bodies abounding in Sulphureous parts are to afford a Red Colour, is one, wherein by the Operation of a Saline Spirit upon a White or Whitish Body, which according to the _Chymists_ should be altogether Sulphureous, a Redness may be produc'd, not (as in the former Experiments) slowly, but in the twinkling of an Eye. We took then of the Essential Oyl of Anniseeds, which has this Peculiarity, that in Cold weather it loses its Fluidity and the greatest part of its Transparency, and looks like a White or Whitish Oyntment, and near at hand seems to consist of a Mult.i.tude of little soft Scales: Of this Coagulated Stuff we spread a little with a Knife upon a piece of White Paper, and letting fall on it, and mixing with it a drop or two of Oyl of Vitriol, immediately (as we fore-saw) there emerg'd together with some Heat and Smoak, a Blood-Red Colour, which therefore was in a trice produc'd by two Bodies, whereof the one had but a Whitish Colour, and the other (if carefully rectify'd) had no Colour at all.

_EXPERIMENT x.x.xVI._

But on this Occasion (_Pyrophilus_) we must add once for all, that in many of the above-recited Experiments, though the changes of Colour happen'd as we have mention'd them: yet the emergent or produc'd Colour is oft times very subject to Degenerate, both quickly and much. Notwithstanding which, since the Changes, we have set down, do happen presently upon the Operation of the Bodies upon each other, or at the times by us specify'd; _that_ is sufficient both to justifie our Veracity, and to shew what we Intend; it not being Essential to the Genuineness of a Colour to be Durable. For a fading Leaf, that is ready to Rot, and moulder into Dust, may have as true a Yellow, as a Wedge of Gold, which so obstinately resists both Time and Fire. And the reason, why I take occasion from the former Experiment to subjoyn this general Advertis.e.m.e.nt, is, that I have several times observ'd, that the Mixture resulting from the Oyls of Vitriol, and of Anniseeds, though it acquire a thicker consistence than either of the Ingredients had, has quickly lost its Colour, turning in a very short time into a dirty Gray, at least in the Superficial parts, where 'tis expos'd to the Air; which last Circ.u.mstance I therefore mention, because that, though it seem probable, that this Degeneration of Colours may oft times and in divers cases proceed from the further Action of the Saline Corpuscles, and the other Ingredients upon one another, yet in many cases much of the Quick change of Colours seems ascribeable to the Air, as may be made probable by several reasons: The first whereof may be fetcht from the newly recited Example of the two Oyls; The next may be, that we have sometimes observ'd long Window-Curtains of light Colours, to have that part of them, which was expos'd to the Air, when the Window was open, of one Colour, and the lower part, that was sheltred from the Air by the Wall, of another Colour: And the third Argument may be fetch'd from divers Observations, both of others, and our own; For of that Pigment so well known in Painters Shops, by the name of _Turnsol_, our Industrious _Parkinson_, in the particular account he gives of the Plant that bears it, tells us also, That _the Berries when they are at their full Maturity, have within them between the outer Skin and the inward Kirnel or Seed, a certain Juice or Moisture, which being rubb'd upon Paper or Cloath, at the first appears of a fresh and lovely Green Colour, but presently changeth into a kind of Blewish Purple, upon the Cloath or Paper, and the same Cloath afterwards wet in Water, and wrung forth, will Colour the Water into a Claret Wine Colour, and these_ (concludes he) _are those Raggs of Cloath, which are usually call'd_ Turnsol _in the Druggists or Grocers Shops_[21]. And to this Observation of our _Botanist_ we will add an Experiment of our own, (made before we met with That) which, though in many Circ.u.mstances, very differing, serves to prove the same thing; for having taken of the deeply Red Juice of _Buckthorn_ Berries, which I bought of the Man that uses to sell it to the Apothecaries, to make their Syrrup _de Spina Cervina_, I let some of it drop upon a piece of White Paper, and having left it there for many hours, till the Paper was grown dry again, I found what I was inclin'd to suspect, namely, That this Juice was degenerated from a deep Red to a dirty kind of Greyish Colour, which, in a great part of the stain'd Paper seem'd not to have so much as an Eye of Red: Though a little Spirit of Salt or dissolv'd _Alcaly_ would turn this unpleasant Colour (as formerly I told you it would change the not yet alter'd Juice) into a Red or Green. And to satisfie my self, that this Degeneration of Colour did not proceed from the Paper, I drop'd some of the deep Red or Crimson Juice upon a White glaz'd Tile, and suffering it to dry on there, I found that ev'n in that Body, on which it could not Soak, and by which it could not be Wrought, it nevertheless lost its Colour. And these Instances (_Pyrophilus_) I am the more carefull to mention to you, that you may not be much Surpris'd or Discourag'd, if you should sometimes miss of performing punctually what I affirm my self to have done in point of changing Colours; since in these Experiments the over-sight or neglect of such little Circ.u.mstances, as in many others would not be perhaps considerable, may occasion the mis-carrying of a Trial. And I was willing also to take this occasion of Advertising you in the repeating of the Experiments mention'd in this Treatise, to make use of the Juices of Vegetables, and other things prepar'd for your Trials, as soon as ever they are ready, lest one or other of them grow less fit, if not quite unfit by delay; and to estimate the Event of the Trials by the Change, that is produc'd presently upon the due and sufficient Application of Actives to Pa.s.sives, (as they speak) because in many cases the effects of such Mixtures may not be lasting, and the newly produc'd Colour may in a little time degenerate. But, (_Pyrophilus_) I forgot to add to the two former Observations lately made about Vegetables, a third of the same Import, made in Mineral substances, by telling you, That the better to satisfie a Friend or two in this particular, I sometimes made, according to some Conjectures of mine, this Experiment; That having dissolv'd good Silver in _Aqua-fortis_, and Precipitated it with Spirit of Salt, upon the first Decanting of the Liquor, the remaining Matter would be purely White; but after it had lain a while uncover'd, that part of it, that was Contiguous to the Air, would not only lose its Whiteness, but appear of a very Dark and almost Blackish Colour, I say that part that was Contiguous to the Air, because if that were gently taken off, the Subjacent part of the same Ma.s.s would appear very White, till that also, having continu'd a while expos'd to the Air, would likewise Degenerate. Now whether the Air perform these things by the means of a Subtile Salt, which we elsewhere show it not to be dest.i.tute of, or by a peircing Moisture, that is apt easily to insinuate it self into the Pores of some Bodies, and thereby change their Texture, and so their Colour; Or by solliciting the Avolation of certain parts of the Bodies, to which 'tis Contiguous; or by some other way, (which possibly I may elsewhere propose and consider) I have not now the leisure to discourse. And for the same reason, though I could add many other Instances, of what I formerly noted touching the emergency of Redness upon the Digestion of many Bodies, insomuch that I have often seen upon the Borders of _France_ (and probably we may have the like in _England_) a sort of Pears, which digested for some time with a little Wine, in a Vessel exactly clos'd, will in not many hours appear throughout of a deep Red Colour, (as also that of the Juice, wherein they are Stew'd, becomes) but ev'n on pure and white Salt of Tartar, pure Spirit of Wine, as clear as Rock-water, will (as we elsewhere declare) by long Digestion acquire a Redness; Though I say such Instances might be Multiply'd, and though there be some other Obvious changes of Colours, which happen so frequently, that they cannot but be as well Considerable as Notorious; such as is the Blackness of almost all Bodies burn'd in the open Air: yet our haste invites us to resign you the Exercise of enquiring into the Causes of these Changes. And certainly, the reason both _why_ the Soots of such differing Bodies are almost all of them all Black, _why_ so much the greater part of Vegetables should be rather Green than of any other Colour, and particularly (which more directly concerns this place) _why_ gentle Heats do so frequently in Chymical Operations produce rather a Redness than another Colour in digested _Menstruums_, not only Sulphureous, as Spirit of Wine, but Saline, as Spirit of Vinegar, may be very well worth a serious Inquiry; which I shall therefore recommend to _Pyrophilus_ and his Ingenious Friends.

[21] _Parkinson_, Thea. Bot. Trib. 4 cap. 12.

_EXPERIMENT x.x.xVII._

It may seem somewhat strange, that if you take the Crimson Solution of _Cochineel_, or the Juice of Black Cherries, and of some other Vegetables that afford the like Colour, (which because many take but for a deep Red, we do with them sometimes call it so) and let some of it fall upon a piece of Paper, a drop or two of an Acid Spirit, such as Spirit of Salt, or _Aqua-fortis_, will immediately turn it into a fair Red. Whereas if you make an Infusion of Brazil in fair Water, and drop a little Spirit of Salt or _Aqua-fortis_ into it, that will destroy its Redness, and leave the Liquor of a Yellow, (sometimes Pale) I might perhaps plausibly enough say on this occasion, that if we consider the case a little more attentively, we may take notice, that the action of the Acid Spirit seems in both cases, but to weaken the Colour of the Liquor on which it falls. And so though it destroy Redness in the Tincture of Brazil, as well as produce Red in the Tincture of _Chochineel_, its Operations may be Uniform enough, since as Crimson seems to be little else than a very deep Red, with (perhaps) an Eye of Blew, so some kinds of Red seem (as I have lately noted) to be little else than heightned Yellow. And consequently in such Bodies, the Yellow seems to be but a diluted Red. And accordingly Alcalizate Solutions and Urinous Spirits, which seem dispos'd to Deepen the Colours of the Juices and Liquors of most Vegetables, will not only restore the Solution of _Cochineel_ and the Infusion of Brazil to the Crimson, whence the Spirit of Salt had chang'd them into a truer Red; but will also (as I lately told you) not only heighthen the Yellow Juice of Madder into Red, but advance the Red Infusion of Brazil to a Crimson. But I know not whether it will not be much safer to derive these Changes from vary'd Textures, than certain kinds of Bodies; and you will perhaps think it worth while, that I should add on this occasion, That it may deserve some Speculation, why, notwithstanding what we have been observing, though Blew and Purple seem to be deeper Colours than Red, and therefore the Juices of Plants of either of the two former Colours may (congruously enough to what has been just now noted) be turn'd Red by Spirit of Salt or _Aqua-fortis_, yet Blew Syrrup of Violets and some Purples should both by Oyl of Tartar and Spirit of Urine be chang'd into Green, which seems to be not a deeper but a more diluted Colour than Blew, if not also than Purple.

_EXPERIMENT x.x.xVIII._

It would much contribute to the History of Colours, if _Chymists_ would in their Laboratories take a heedfull notice, and give us a faithfull account of the Colours observ'd in the Steams of Bodies either Sublim'd or Distill'd, and of the Colours of those Productions of the Fire, that are made up by the Coalition of those Steams. As (for Instance) we observe in the Distilling of pure Salt peter, that at a certain season of the Operation, the Body, though it seem either Crystalline, or White, affords very Red Fumes: whereas though Vitriol be Green or Blew, the Spirit of it is observ'd to come over in Whitish Fumes. The like Colour I have taken notice of in the Fumes of several other Concretes of differing Colours, and Natures, especially when Distill'd with strong Fires. And we elsewhere note, that ev'n Soot, as Black as it is, has fill'd our Receivers with such copious White Fumes, that they seem'd to have had their In-sides wash'd with Milk. And no less observable may be, the Distill'd Liqours, into which such Fumes convene, (for though we will not deny, that by skill and care a Reddish Liqour may be obtain'd from Nitre) yet the common Spirit of it, in the making ev'n of which store of these Red Fumes are wont to pa.s.s over into the Receiver, appears not to be at all Red. And besides, that neither the Spirit of Vitriol, nor that of Soot is any thing White; And, besides also, that as far as I have observ'd, most (for I say not all) of the Empyreumatical Oyls of Woods, and other Concretes, are either of a deep Red, or of a Colour between Red and Black; besides this, I say, 'tis very remarkable that notwithstanding that great Variety of Colours to be met with in the Herbs, Flowers, and other Bodies wont to be Distill'd in _Balneo_: yet (as far at least as our common Distillers Experience reacheth) all the Waters and Spirits that first come over by that way of Distillation, leave the Colours of their Concretes behind them, though indeed there be one or two Vegetables not commonly taken notice of, whose Distill'd Liqours I elsewhere observe to carry over the Tincture of the Concrete with them. And as in Distillations, so in Sublimations, it were worth while to take notice of what comes up, in reference to our present scope, by purposely performing them (as I have in some cafes done) in conveniently shap'd Gla.s.ses, that the Colour of the ascending Fumes may be discern'd; For it may afford a Naturalist good Information to observe the Congruities or the Differences betwixt the Colours of the ascending Fumes, and those of the _Flowers_, they compose by their Convention. For it is evident, that these _Flowers_, do many of them in point of Colour, much differ, not only from one another, but oft times from the Concretes that afforded them. Thus, (not here to repeat what I formerly noted of the Black Soots of very differingly Colour'd Bodies) though Camphire and Brimstone afford _Flowers_ much of their own Colour, save that those of Brimstone are wont to be a little Paler, than the Lumps that yielded them; yet ev'n of Red _Benzoin_, that sublim'd Substance, which _Chymists_ call its _Flowers_, is wont to be White or Whitish. And to omit other Instances, ev'n one and the same Black Mineral, Antimony, may be made to afford _Flowers_, some of them Red, and some Grey, and, which is more strange, some of them purely White. And 'tis the Prescription of some Gla.s.s-men by exquisitely mingling a convenient proportion of Brimstone, Sal-Armoniack, and Quicksilver, and Subliming them, together, to make a Sublimate of an excellent Blew; and though having caus'd the Experiment to be made, we found the produc'd Sublimate to be far from being of a lovely Colour, (as was promis'd) that there and there, it seem'd Blewish, and at least was of a Colour differing enough from either of the Ingredients, which is sufficient for our present purpose. But a much finer Colour is promis'd by some of the Empiricks, that pretend to Secrets, who tell us, that Orpiment, being Sublim'd, will afford among the Parts of it that fly Upward, some little Ma.s.ses, which, though the Mineral it self be of a good Yellow, will be Red enough to emulate Rubies, both in Colour and Translucency. And this Experiment may, for ought I know, sometimes succeed; for I remember, that having in a small Bolt-head purposely sublim'd some powder'd Orpiment, we could in the Lower part of the Sublimate discern here and there some Reddish Lines, though much of the Upper part of the Sublimate consisted of a matter, which was not alone purely Yellow, but transparent almost like a Powder. And we have also this way obtain'd a Sublimate, the Lower part whereof though it consisted not of Rubies, yet the small pieces of it, which were Numerous enough, were of a pleasant Reddish Colour, and Glitter'd very prettily. But to insist on such kind of Trials and Observations (where the ascending Fumes of Bodies differ in Colour from the Bodies themselves) though it might indeed Inrich the History of Colours, would Robb me of too much of the little time I have to dispatch what I have further to tell you concerning them.

_EXPERIMENT x.x.xIX_

Take the dry'd Buds (or Blossoms) of the Pomegranate Tree, (which are commonly call'd in the Shops _Balaustiums_) pull off the Reddish Leaves, and by a gentle Ebullition of them in fair Water, or by a competent Infusion of them in like Water well heated, extract a faint Reddish Tincture, which if the Liquor be turbid, you may Clarifie it by Filtrating it Into this, if you pour a little good Spirit of Urine, or some other Spirit abounding in the like sort of Volatile Salts, the Mixture will presently turn of a dark Greenish Colour, but if instead of the fore-mention'd Liquor, you drop into the simple Infusion a little rectify'd Spirit of Sea-Salt, the Pale and almost Colourless Liquor will immediately not only grow more Transparent, but acquire a high Redness, like that of Rich Claret Wine, which so suddenly acquir'd Colour, may as quickly be Destroy'd and turn'd into a dirty Blewish Green, by the affusion of a competent quant.i.ty of the above-mention'd Spirit of Urine.

_Annotation._

This Experiment may bring some Light to, and receive some from a couple of other Experiments, that I remember I have met with in the ingenious _Ga.s.sendus_'s Animadversions upon _Epicurus_'s Philosophy, whilst I was turning over the Leaves of those Learned Commentaries; (my Eyes being too weak to let me read such Voluminous Books quite thorough) And I the less scruple (notwithstanding my contrary Custom in this Treatise) to set down these Experiments of another, because I shall a little improve the latter of them, and because by comparing there with that which I have last recited, we may be a.s.sisted to Conjecture upon what account it is, that Oyl of Vitriol heightens the Tincture of Red-rose Leaves, since Spirit of Salt, which is a highly Acid _Menstruum_, but otherwise differing enough from Oyl of Vitriol, does the same thing. Our Authors Experiments then, as we made them, are these; We took about a Gla.s.s-full of luke-warm Water, and in it immerg'd a quant.i.ty of the Leaves of _Senna_, and presently upon the Immersion there did not appear any Redness in the Water, but dropping into it a little Oyl of Tartar, the Liquor soon discover'd a Redness to the watchfull Eye, whereas by a little of that Acid Liquor of Vitriol, which is like the former, undeservedly called Oyl, such a Colour would not be extracted from the infused _Senna_. On the other side we took some Red-rose Leaves dry'd, and having shaken them into a Gla.s.s of fair Water, they imparted to it no Redness, but upon the affusion of a little Oyl of Vitriol the Water was immediately turn'd Red, which it would not have been, if instead of Oyl of Vitriol, we had imployed Oyl of Tartar to produce that Colour: That these were _Ga.s.sendus_ his Experiments, I partly remember, and was a.s.sur'd by a Friend, who lately Transcribed them out of _Ga.s.sendus_ his Book, which I therefore add, because I have not now that Book at hand. And the design of _Ga.s.sendus_ in these Experiments our Friend affirms to be, to prove, that of things not Red a Redness may be made only by Mixture, and the Varied position of parts, wherein the Doctrine of that Subtil Philosopher doth not a little Authorize, what we have formerly delivered concerning the Emergency and Change of Colours. But the instances, that we have out of him set down, seem not to be the most Eminent, that may be produced of this truth: For our next Experiment will shew the production of several Colours out of Liquors, which have not any of them any such Colour, nor indeed any discernable one at all; and whereas though our Author tells us, that there was no Redness either in the Water, or the Leaves of _Senna_, or the Oyl of Tartar; And though it be true, that the Predominant Colour of the Leaves of _Senna_ be another than Red, yet we have try'd, that by steeping that Plant a Night even in Cold water, it would afford a very deep Yellow or Reddish Tincture without the help of the Oyl of Tartar, which seems to do little more than a.s.sist the Water to extract more nimbly a plenty of that Red Tincture, wherewith the Leaves of _Senna_ do of themselves abound, and having taken off the Tincture of _Senna_, made only with fair Water, before it grew to be Reddish, and Decanted it from the Leaves, we could not perceive, that by dropping some Oyl of Tartar into it, that Colour was considerable, though it were a little heightned into a Redness; which might have been expected, if the particles of the Oyl did eminently Co-operate, otherwise than we have expressed, to the production of this Redness.

And as for the Experiment with Red-rose Leaves, the same thing may be alleged, for we found that such Leaves by bare Infusion for a Night and Day in fair Water, did afford us a Tincture bordering at least upon Redness, and that Colour being conspicuous in the Leaves themselves, would not by some seem so much to be produc'd as to be extracted by the affusion of Oyl of Vitriol. And the Experiment try'd with the dry'd Leaves of Damask-roses succeeded but imperfectly, but that is indeed observable to our Authors purpose, that Oyl of Tartar will not perform in this Experiment what Oyl of Vitriol doth; but because this last named Liquor is not so easily to be had, give me leave to Advertise you, that the Experiment will succeed, if instead of it you imploy _Aqua-fortis_. And though some Trials of our own formerly made, and others easily deducible from what we have already deliver'd, about the different Families and Operations of Salt, might enable us to present you an Experiment upon Red-rose Leaves, more accommodated to our Authors purpose, than that which he hath given us; yet our Reverence to so Candid a Philosopher, invites us rather to improve his Experiment, than subst.i.tute another in its place. Take therefore of the Tincture of Red-rose Leaves, (for with Damask-rose Leaves the Experiment succeedeth not well) made as before hath been taught with a little Oyl of Vitriol, and a good quant.i.ty of fair Water, pour off this Liquor into a clear Vial, half fill'd with Limpid water; till the Water held against the Light have acquir'd a competent Redness, without losing its Transparency, into this Tincture drop leisurely a little good Spirit of Urine, and shaking the Vial, which you must still hold against the Light, you shall see the Red Liquor immediately turn'd into a fine Greenish Blew, which Colour was not to be found in any of the Bodies, upon whose Mixture it emerg'd, and this Change is the more observable, because in many Bodies the Degenerating of Blew into Red is usual enough, but the turning of Red into Blew is very unfrequent. If at every drop of Spirit of Urine you shake the Vial containing the Red Tincture, you may delightfully observe a pretty variety of Colours in the pa.s.sage of that Tincture from a Red to a Blew, and sometimes we have this way hit upon such a Liquor, as being look't upon against and from the Light, did seem faintly to emulate the above-mention'd Tincture of _Lignum Nephritic.u.m_. And if you make the Tincture of Red-roses very high, and without Diluting it with fair Water, pour on the Spirit of Urine, you may have a Blew so deep, as to make the Liquor Opacous, but being dropt upon White Paper the Colour will soon disclose it self. Also having made the Red, and consequently the Blew Tincture very Transparent, and suffer'd it to rest in a small open Vial for a Day or two, we found according to our Conjecture, that not only the Blew but the Red Colour also was Vanish'd; the clear Liquor being of a bright Amber Colour, at the bottom of which subsided a Light, but Copious feculency of almost the same Colour, which seems to be nothing but the Tincted parts of the Rose Leaves drawn out by the Acid Spirits of the Oyl of Vitriol, and Precipitated by the Volatile Salt of the Spirit of Urine, which makes it the more probable, that the Redness drawn by the Oyl of Vitriol, was at least as well an extraction of the Tinging parts of the Roses, as a production of Redness; and lastly, if you be dest.i.tute of Spirit of Urine, you may change the Colour of the Tincture of Roses with many other Sulphureous Salts, as a strong Solution of Pot-ashes, Oyl of Tartar, &c. which yet are seldome so free from Feculency, as the Spirituous parts of Urine becomes by repeated Distillation.

_Annotation_.

On this, occasion, I call to mind, that I found, a way of producing, though not the same kind of Blew, as I have been mentioning, yet a Colour near of Kin to it, namely, a fair Purple, by imploying a Liquor not made Red by Art, instead of the Tincture of Red-roses, made with an Acid Spirit; And my way was only to take Log-wood, (a Wood very well known to Dyers) having by Infusion the Powder of it a while in fair Water made that Liquor Red, I dropt into it a _Tantillum_ of an Urinous Spirit, as that of Sal-Armoniack, (and I have done the same thing with an _Alcali_) by which the Colour was in a moment turn'd into a Rich, and lovely Purple. But care must be had, that you let not fall into a Spoonfull above two or three Drops, lest the Colour become so deep, as to make the Liquor too Opacous. And (to answer the other part of _Ga.s.sendus_ his Experiment) if instead of fair Water, I infus'd the Log-wood in Water made somewhat sowr by the Acid Spirit of Salt, I should obtain neither a Purple Liquor, nor a Red, but only a Yellow one.

_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 quant.i.ty 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-gla.s.s, or any other convenient Vessel made of clear Gla.s.s, 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 Gla.s.s 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 Gla.s.s 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 Gla.s.s 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 Gla.s.s.

Secondly, That 'tis convenient to keep the Gla.s.s 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 Gla.s.s, 'tis but inclining the Gla.s.s, 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 _Phaenomenon_. 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 subst.i.tuted 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 a.s.sociated, 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 a.s.sociated, 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 _Phaenomena_ 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 _Phaenomenon_, 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 _Phaenomenon_. 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 Gla.s.s 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 Gla.s.s, 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 Gla.s.s 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 Nephritic.u.m_, 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 Caeruleous Colour to the Tincture of _Lignum Nephritic.u.m_, 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 a.s.sociated, 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 dest.i.tute 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 Nephritic.u.m_, 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 pa.s.s 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 Caeruleous Tincture of _Lignum Nephritic.u.m_. But this onely, _en pa.s.sant_; 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 a.n.a.lysis 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. .h.i.therto 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 quant.i.ty 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.

_EXPERIMENT XLI._

Of Kin to the last or fortieth Experiment is another which I remember I have sometimes shewn to _Virtuosi_ that were pleas'd not to dislike it. I took Spirit of Urine made by Fermentation, and with a due proportion of Copper brought into small parts, I obtain'd a very lovely Azure Solution, and when I saw the Colour was such as was requisite, pouring into a clean Gla.s.s, about a spoonfull of this tincted Liquor, (of which I us'd to keep a Quant.i.ty by me,) I could by shaking into it some drops of Strong Oyl of Vitriol, deprive it in a trice of its Deep Colour, and make it look like Common-water.

_Annotation_.

This Experiment brings into my mind this other, which oftentimes succceds well enough, though not quite so well as the former; Namely, that if into about a small spoonfull of a Solution of good French Verdigrease made in fair Water, I drop't and shak'd some strong Spirit of Salt, or rather deflegm'd _Aqua Fortis_, the Greenness of the Solution would be made in a trice almost totally to disappear, & the Liquor held against the Light would scarce seeme other than Cleer or Limpid, to any but an Attentive Eye, which is therefore remarkable; because we know that _Aqua-fortis_ corroding Copper, which is it that gives the Colour to Verdigrease, is wont to reduce it to a Green Blew Solution. But if into the other altogether or almost Colourless Liquor I was speaking of, you drop a just quant.i.ty either of Oyl of Tartar or Spirit of Urine, you shall find that after the Ebullition is ceas'd, the mixture will disclose a lively Colour, though somewhat differing from that which the Solution of Verdigrease had at first.

_EXPERIMENT XLII._

That the Colour (_Pyrophilus_) of a Body may be chang'd by a Liquor which of it self is of no Colour, provided it be Saline, we have already manifested by a mult.i.tude of instances. Nor doth it seem so strange, because Saline Particles swimming up and down in Liquors, have been by many observ'd to be very operative in the Production and change of Colours. But divers of our Friends that are not acquainted with Chymical Operations have thought it very strange that a White Body, and a Dry one too, should immediately acquire a rich new Colour upon the bare affusion of Spring-Water dest.i.tute as well of advent.i.tious Salt as of Tincture. And yet (_Pyrophilus_) the way of producing such a change of Colours may be easily enough lighted on by those that are conversant in the Solutions of Mercury.

For we have try'd, that though by Evaporating a Solution of Quick-Silver in _Aqua-fortis_, and abstracting the Liquor till the remaining matter began to be well, but not too strongly dryed, fair Water pour'd on the remaining _Calx_ made it but somewhat Yellowish; yet when we took good Quick-Silver, and three or four times its weight of Oyl of Vitriol, in case we in a Gla.s.s Retort plac'd in Sand drew off the Saline _Menstruum_ from the Metalline Liquor, till there remain'd a dry _Calx_ at the bottome, though this Precipitate were a Snow White Body, yet upon