EXPERIMENT I.

BEcause that, according to the Con­jectures I have above propos'd, one of the most General Causes of the Diversity of Colours in Opacous Bo­dyes, is, that some reflect the Light mingl'd with more, others with less of Shade (either [Page 186] as to Quantity, or as to Interruption) I hold ir not unfit to mention in the first place, the Experiments that I thought upon to exa­mine this Conjecture. And though com­ing to transcribe them out of some Phy­siological Adversaria I had written in loose Papers, I cannot find one of the chief Re­cords I had of my Tryals of this Nature, yet the Papers that scap'd miscarrying, will, I presume, suffice to manifest the main thing for which I now allege them; I find then among my Adversaria, the following Nar­rative.

October the 11. About ten in the Morn­ing in Sun-shiny Weather, (but not with­out fleeting Clouds) we took several sorts of Paper Stain'd, some of one Colour, and some of another; and in a Darken'd Room whose Window look'd Southward, we cast the Beams that came in at a hole about three Inches and a half in Diameter, upon a White wall that was plac'd on one side, about five foot distance from them.

The White gave much the Brightest Reflection.

The Green, Red, and Blew being Com­par'd together, the Red gave much the strongest Reflection, and manifestly enough also threw its Colour upon the Wall; The Green and Blew were scarce Discernable [Page 187] by their Colours, and seem'd to reflect an al­most EqualLight.

The Yellow Compar'd with the two last nam'd, Reflected somewhat more Light.

The Red and Purple being Compar'd to­gether, the former manifestly Reflected a good deal more Light.

The Blew and Purple Compar'd toge­ther, the former seem'd to Reflect a little more Light, though the Purple Colour were more manifestly seen.

A Sheet of very well sleek'd Marbl'd Paper being Apply'd as the others, did not cast any of its Distinct Colours upon the Wall; nor throw its Light upon it with an Equal Diffusion; but threw the Beams Unstain'd and Bright to this and that part of the Wall, as if it's Polish had given it the Nature of a specular Body. But compa­ring it with a sheet of White Paper, we found the Reflection of the latter to be much Stronger, it diffusing almost as much Light to a good Extent as the Marble Paper did to one part of the Wall.

The Green and Purple left us somewhat in suspence which Reflected the most Light; only the Purple seem'd to have some little Advantage over the Green, which was Dark in its kind.

Thus much I find in our above menti­on'd [Page 188] Collections, among which there are also some Notes concerning the Produ­ction of Compounded Colours, by Reflection from Bodyes differingly Colour'd. And these Notes we intended should supply us with what we should mention as our se­cond Experiment: but having lost the Pa­per that contain'd the Particulars, and re­membring onely in General, that if the Ob­jects which Reflected the Light were not Strongly Colour'd and somewhat Glossy, the Reflected Beams would not manifestly make a Compounded Colour upon the Wall, and even then but very Faintly, we shall now say no more of that Matter, on­ly reserving our selves to mention hereafter the Composition of a Green, which we still retain in Memory.

EXPERIMENT II.

We may add, Pyrophilus, on this Occa­sion, that though a Darken'd Room be Ge­nerally thought requisite to make the Co­lour of a Body appear by Reflection from another Body, that is not one of those that are commonly agreed upon to be Specular (as Polish'd Metall, Quick silver, Glass, Wa­ter, &c.) Yet I have often observ'd that when I wore Doublets Lin'd with some sil­ken [Page 189] Stuff that was very Glossy and Vividly Colour'd, especially Red, I could in an In­lightned Room plainly enough Discern the Colour, upon the Pure White Linnen that came out at my Sleeve and reach'd to my Cufs; as if that Fine VVhite Body were more Specular, than Colour'd and Unpo­lish'd Bodyes are thought Capable of be­ing.

EXPERIMENT III.

Whilst we were making the newly men­tion'd Experiments, we thought fit to try also what Composition of Colours might be made by Altering the Light in its Pas­sage to the Eye by the Interposition not of Perfectly Diaphanous Bodies, (that having been already try'd by others as well as by us (as we shall soon have occasion to take notice) but of Semi-opacous Bodyes, and those such as look'd upon in an ordinary Light, and not held betwixt it and the Eye, are not wont to be Discriminated from the rest of Opacous Bodyes; of this Tryal, our mention'd Adversaria present us the fol­lowing Account.

Holding these Sheets, sometimes one sometimes the other of them, before the Hole betwixt the Sun and the Eye, with [Page 190] the Colour'd sides obverted to the Sun; we found them single to be somewhat Trans­parent, and appear of the same Colour as before, onely a little alter'd by the great Light they were plac'd in; but laying two of them one over another and applying them so to the Hole, the Colours were com­pounded as follows.

The Blew and Yellow scarce exhibited any thing but a Darker Yellow, which we ascrib'd to the Coarseness of the Blew Pa­pers, and its Darkness in its Kind. For ap­plying the Blew parts of the Marbl'd Paper with the Yellow Paper after the same man­ner, they exhibited a good Green.

They Yellow and Red look'd upon toge­ther gave us but a Dark Red, somewhat (and but a little,) inclining to an Orange Colour.

The Purple and Red look'd on together appear'd more Scarlet.

The Purple and Yellow made an Orange.

The Green and Red made a Dark O­range Tawny.

The Green and Purple made the Purple appear more Dirty.

The Blew and Purple made the Purple more Lovely, and far more Deep.

The Red parts of the Marbl'd Paper look'd upon with the Yellow appear'd of a [Page 191] Red far more like Scarlet than without it.

But the Fineness or Coarseness of the Papers, their being carefully or slightly Colour'd, and divers other Circumstances, may so vary the Events of such Experi­ments as these, that if, Pyrophilus, you would Build much on them, you must care­fully Repeat them.

EXPERIMENT IV.

The Triangular Prismatical Glass being the Instrument upon whose Effects we may the most Commodiously speculate the Na­ture of Emphatical Colours, (and perhaps that of Others too;) we thought it might be usefull to observe the several Reflections and Refractions which the Incident Beams of Light suffer in Rebounding from it, and Passing through it. And this we thought might be Best done, not (as is usual,) in an ordinary Inlightn'd Room, where (by rea­son of the Difficulty of doing otherwise) ev'n the Curious have left Particulars Unheeded, which may in a convenient place be easily taken notice of; but in a Darken'd Room, where by placing the Glass in a convenient Posture, the Various Reflections and Re­fractions may be Distinctly observ'd; and where it may appear what Beams are Un­ting'd, [Page 192] and which they are, that upon the Bodyes that terminate them, do Paint either the Primary or Secondary Iris. In pursu­ance of this we did in the above mention'd Darken'd Room, make observation of no less than four Reflections, and three Re­fractions that were afforded us by the same Prism, and thought that notwithstanding what was taught us by the Rules of Catop­tricks and Dioptricks, it would not be amiss to find also, by hiding sometimes one part of the Prism, and sometimes another, and observing where the Light or Colour Va­nish'd thereupon, by which Reflection and by which Refraction each of the several places whereon the Light rebounding from, or passing through, the Prism appear'd ei­ther Sincere or Tincted, was produc'd. But because it vvould be Tedious and not so In­telligible to deliver this in Words, I have thought fit to Referr You to the Annexed Scheme where the Newly menrion'd par­ticulars may be at one View taken No­tice of.

EXPERIMENT V.

I know not whether you vvill think it Inconsiderable to annex to this Experi­ment, That vve observ'd in a Room not

[Page 193] Darken'd, that the Prismatical Iris (if I may so call it) might be Reflected without losing any of its several Colours (for we now consider not their Order) not onely from a plain Looking-glass and from the calm Surface of Fair Water, but also from a Concave Looking-glass; and that Re­fraction did as little Destroy those Colours as Reflection. For by the help of a large (double Convex) Burning-glass through which we Refracted the Suns Beams, we found that one part of the Iris might be made to appear either beyond, or on this side of the other Parts of the same Iris; but yet the same Vivid Colours would appear in the Displac'd part (if I may so term it) as in the other. To which I shall add, that having, by hiding the side of the Prism, obverted to the Sun with an Opacous Bo­dy, wherein only one small hole was left for the Light to pass through, reduc'd the Pris­matical Iris (cast upon White Paper) in­to a very narrow compass, and look'd upon it through a Microscope; the Colours ap­pear'd the same as to kind that they did to the naked Eye.

EXPERIMENT VI.

It may afford matter of Speculation to the Inquisitive, such as you, Pyrophilus, that as the Colours of outward Objects brought into a Darken'd Room, do so much depend for their Visibility upon the Dimness of the Light they are there beheld by; that the ordinary Light of the day being freely let in upon them, they immediately disappear: so our Tryals have inform'd us, that as to the Prismatical Iris painted on the Floor by the Beams of the Sun Trajected through a Triangular-glass; though the Colours of it appear very Vivid ev'n at Noon-day, and in Sun shiny Weather, yet by a more Powerfull Light they may be made to dis­appear. For having sometimes, (in pro­secution of some Conjectures of mine not now to be Insisted on,) taken a large. Me­talline Concave Speculum, and with it cast the converging Beams of the Sun upon a Prismatical Iris which I had caus'd to be projected upon the Floor, I found that the over-powerfull Light made the Colours of the Iris disappear. And if I so Reflected the Light as that it cross'd but the middle of the Iris, in that part only the Colours vanish'd or were made Invisible; those [Page 195] parts of the Iris that were on the right and left hand of the Reflected Light (which seem'd to divide them, and cut the Iris asunder) continuing to exhibit the same Colours as before. But upon this we must not now stay to Speculate.

EXPERIMENT VII.

I have sometimes thought it worth while to take notice, whether or no the Colours of Opacous Bodies might not appear to the Eye some what Diversify'd, not only by the Disposition of the Superficial parts of the Bodyes themselves and by the Position of the Eye in Reference to the Object and the Light, (for these things are No orious e­nough;) but according also to the Nature of the Lucid Body that shines upon them. And I remember that in Prosecution of this Curiosity, I observ'd a manifest Difference in some Kinds of Colour'd Bodyes look'd on by Day-light; and afterwards by the light of the Moon; either directly falling on them or Reflected upon them from a Concave Looking-glass. But not finding at present in my Collections about Colours any thing set down of this Kind, I shall, till I have opportunity to repeat them, content my self to add what I find Register'd con­cerning [Page 196] Colours look'd on by Candle-light, in regard that not only the Experiment is more easie to be repeated, but the Objects being the same sorts of Colour'd Paper lastly mention'd, the Collation of the two Experiments may help to make the Con­jectures they will suggest somewhat the less uncertain.

Within a few dayes of the time above mention'd, divers Sheets of Colour'd Paper that had been look'd upon before in the Sun­shine were look'd upon at night by the light of a pretty big Candle, (snuff'd) and the Changes that were observ'd were these.

The Yellow seem'd much fainter than in the Day, and inclinable to a pale Straw Colour.

The Red seem'd little Chang'd; but seem'd to Reflect Light more strongly than any other Colour (for White was none of them.)

A fair Deep Green look'd upon by it self, seem'd to be a Dark Blew: But being look'd upon together with a Dark Blew, appear'd Greenish; and beheld together with a Yellow appear'd more Blew than at first.

The Blew look'd more like a Deep Pur­ple or Murray than it had done in the Day-light.

[Page 197] The Purple seem'd very little alter'd.

The Red look'd upon with the Yellow made the Yellow look almost like Brown Cap-paper.

N. The Caution Subjoyned to the third Experiment, is also Applicable to this.

EXPERIMENT VIII.

But here I must not omit to subjoyn, that to satisfie our Selves, whether or no the Light of a Candle were not made un­sincere, and as it were Ting'd with a Yellow Colour by the Admixtion of the Corpus­cles it assumes from its Fuel; we did not content our selves with what appears to the Naked Eye, but taking a pretty thick Red or Cylinder (for thin Peeces would not serve the turn) of deep Blew Glass, and looking upon the Candles flame at a Con­venient distance through it, we perceiv'd as we expected, the Flame to look Green; which as we often note, is the Colour wont to emerge from the Composition of Opacous Bodies, which were apart one of them Blew, and the other Yellow. And this perchance may be the main Reason of that which some observe, that a sheet of very White Paper being look'd upon by Candle light, 'tis not easie at first to discern it from [Page 198] a light Yellow or Lemon Colour; White Bodyes (as we have elsewhere observ'd) having more than those that are otherwise Colour'd, of a Specular Nature; in regard that though they exhibit not, (unless they be Polish'd,) the shape of the Luminary that shines on them, yet they Reflect its Light more Sincere and Untroubl'd, by either Shades or Refractions, than Bodyes of o­ther Colours (as Blew, or Green, or Yel­low or the like.)

EXPERIMENT IX.

We took a Leaf of such Foliated Gold as Apothecaries are wont to Gild their Pills with; and with the Edge of a Knife, (lightly moysten'd by drawing it over the surface of the Tongue, and afterwards) laid upon the edge of the Gold Leaf; we so fasten'd it to the Knife, that being held a­gainst the light, it continu'd extended like a little Flagg. This Leaf being held very near the Eye, and obverted to the Light, appear'd so full of Pores, that it seem'd to have such a kind of Transparency as that of a Sive, or a piece of Cyprus, or a Love-Hood; but the Light that pass'd by these Pores was in its Passages so Temper'd with Shadow, and Modify'd, that the Eye dis­cern'd [Page 199] no more a Golden Colour, but a Greenish Blew. And for other's satis­faction, we did in the Night look upon a Candle through such a Leaf of Gold; and by trying the Effect of several Proportions of Distance betwixt the Leaf, the Eye and the Light, we quickly hit upon such a Position for the Leaf of Gold, as that the flame, look'd on through it, appear'd of a Greenish Blew, as we have seen in the Day time. The like Experiment try'd with a Leaf of Silver succeeded not well.

EXPERIMENT X.

We have sometimes found in the Shops of our Druggists, a certain Wood, which is there call'd Lignum Nephriticum, because the Inhabitants of the Country where it grows, are wont to use the Infusion of it made in fair Water against the Stone of the Kidneys, and indeed an Eminent Physician of our Acquaintance, who has very Particularly enquir'd into that Disease, assures me, that he has found such an Infu­sion one of the most effectual Remedyes, which he has ever tried against that formi­dable Disease. The ancientest Account I have met: with of this Simple, is given us by the Experienc'd Monardes in these Words. [Page 200] Nobis, says he, Nova Hispania mittit quod­dam ligni genus crassum & enode, cujus usus jam diu receptus fuit in his Regionibus ad Renum vitia & Urinae difficul­tates ac arenulas pellendas. Fit Nicolaus Monar­des lib. simplic. ex India allator. cap. 27. autem hac ratione, Lignum as­sulatim & minutim concisum in limpidissima aqua fontana maceratur, inque earelinquitur, donec aqua à bibentibus absumpta fit, dimidia hora post injectum lignum aqua Coeruleum colorem contrahit, quisensim inten­ditur pro temporis diuturnitate, tametsi lig­num candidum sit. This Wood, Pyrophilus, may afford us an Experiment, which be­sides the singularity of it, may give no small assistance to an attentive Considerer to­wards the detection of the Nature of Co­lours. The Experiment as we made it is this. Take Lignum Nephriticum, and with a Knife cut it into thin Slices, put about a handfull of these Slices into two three or four pound of the purest Spring-water, let them infuse there a night, but if you be in hast, a much shorter time may suffice; de­cant this Impregnated Water into a clear Glass Vial, and if you hold it directly be­tween the Light and your Eye, you shall see it wholly Tincted (excepting the very top of the Liquor, wherein you will some times discern a Sky-colour'd Circle) with [Page 201] an almost Golden Colour, unless your In­fusion have been made too Strong of the Wood, for in that case it will against the Light appear somewhat Dark and Reddish, and requires to be diluted by the addition of a convenient quantity of fair Water. But if you hold this Vial from the Light, so that your Eye be plac'd betwixt the Win­dow and the Vial, the Liquor will appear of a deep and lovely Coeruleous Colour, of which also the drops, if any be lying on the out-side of the Glass, will seem to be very perfectly; And thus far we have try'd the Experiment, and found it to succeed even by the Light of Candles of the larger size. If you so hold the Vial over against your Eyes, that it may have a Window on one side of it, and a Dark part of the Room both before it and on the other side, you shall see the Liquor partly of a Blewish and partly of a Golden Colour. If turning your back to the Window, you powr out some of the Liquor towards the Light and towards your Eyes, it will seem at the comming out of the Glass to be perfectly Coeruleous, but when it is sallen down a little way, the drops may seem Partico­lour'd, according as the Beams of Light do more or less fully Penetrate and Illu­strate them. If you take a Bason about [Page 202] half full of Water, and having plac'd it so in the Sun-beams Shining into a Room, that one part of the Water may be freely Illu­strated by the Beams of Light, and the other part of it Darkned by the shadow of the Brim of the Bason, if then I say you drop of our Tincture, made somewhat strong, both into the Shaded and Illuminated parts of the Water, you may by looking upon it from several places, and by a little Agita­tion of the water, observe divers pleasing Phoenomena which were tedious to parti­cularize. If you powr a little of this Tin­cture upon a sheet of White Paper, so as the Liquor may remain of some depth upon it, you may perceive the Neighbouring drops to be partly of one Colour, and partly of the other, according to the position of your Eye in reference to the Light when it looks upon them, but if you powr off all the Li­quor, the Paper will seem Dy'd of an almost Yellow Colour. And if a sheet of Paper with some of this Liquor in it be plac'd in a window where the Sunbeams may shine freely on it, then if you turn your back to the Sun and take a Pen or some such slender Body, and hold it over-thwart betwixt the Sun and the Liquor, you may perceive that the Shadow projected by the Pen up­on the Liquor, will not all of it be a vulgar [Page 203] and Dark, but in part a curiously Colour'd shadow, that edge of it, which is next the Body that makes it, being almost of a lively Golden Colour, and the remoter verge of a Coeruleous one.

These and other Phoenomena, which I have observ'd in this delightfull Experi­ment, divers of my friends have look'd up­on not without some wonder, and I re­member an excellent Oculist finding by accident in a friends Chamber a fine Vial full of this Liquor, which I had given that friend, and having never heard any thing of the Experiment, nor having any Body near him that could tell him what this strange Liquor might be, was a great while apprehensive, as he presently after told me, that some strange new distemper was in­vading his Eyes. And I confess that the unusualness of the Phoenomena made me very sollicitous to find out the Cause of this Experiment, and though I am far from pretending to have found it, yet my en­quiries have, I suppose, enabled me to give such hints, as may lead your greater sa­gacity to the discovery of the Cause of this wonder. And first finding that this Tincture, if it were too copious in the water, Kept the Colours from being so lively, and their Change from being so discernable, and [Page 204] finding also that the Impregnating Virtue of this Wood did by its being frequently Infus'd in New Water by degrees Decay, I Conjectur'd that the Tincture afforded by the Wood must proceed from some Subtiler parts of it drawn forth by the Water, which swimming too and fro in it did so Modifie the Light, as to exhibit such and such Colours; and because these Subtile parts were so easily Soluble even in Cold water, I concluded that they must abound with Salts, and perhaps contain much of the Essential Salt, as the Chymists call it, of the Wood. And to try whether these Subtile parts were Volatile enough to be Distill'd, without the Dissolution of their Texture, I carefully Distill'd some of the Tincted Liquor in very low Vessels, and the gentle heat of a Lamp Furnace; but found all that came over to be as Limpid and Colourless as Rock-water, and the Liquor remaining in the Vessel to be so deeply Coeruleous, that it requir'd to be oppos'd to a very strong Light to appear of any other Colour. I took likewise a Vial with Spirit of Wine, and a little Salt of Harts-horn, and found that there was a certain proportion to be met with betwixt the Liquor and the Salt, which made the Mixture fit to exhibit some little Variety [Page 205] of Colours not Observable in ordinary Liquors, as it was variously directed in reference to the Light and the Eye, but this Change of Colour was very far short from that which we had admir'd in our Tincture. But however, I suspected that the Tinging Particles did abound with such Salts, whose Texture, and the Colour springing from it, would probably be al­ter'd by peircing Acid Salts, which would in likelihood either make some Dissipation of their Parts, or Associate themselves to the like Bodies, and either way alter the Colour exhibited by them; whereupon Pouring into a small Vial full of Impreg­nated Water, a very little Spirit of Vine­gar, I found that according to my Expe­ctation, the Coeruleous Colour immedi­ately vanish'd, but was deceiv'd in the Expectation I had, that the Golden Colour would do so too; for, which way soever I turned the Vial, either to or from the Light, I found the Liquor to appear al­ways of a Yellowish Colour and no other: Upon this I imagin'd that the Acid Salts of the Vinegar having been able to deprive the Liquor of its Coeruleous Colour, a Sulphureous Salt being of a contrary Na­ture, would be able to Mortifie the Saline Particles of Vinegar, and Destroy their [Page 206] Effects; And accordingly having plac'd my Self betwixt the Window, and the Vial, and into the same Liquor dropt a few drops of Oyl of Tartar per Deliquium, (as Chymists call it) I observ'd with plea­sure, that immediately upon the Diffusion of this Liquor, the Impregnated Water was restor'd to its former Coeruleous Co­lour; And this Liquor of Tartar being very Ponderous, and falling at first to the Bottom of the Vial, it was easie to observe that for a little while the Lower part of the Liquor appear'd deeply Coeruleous, whilst all the Upper part retain'd its former Yel­lowness, which it immediately lost as soon as either Agitation or Time had made a competent Diffusion of the Liquor of Tar­tar through the Body of the former Tin­cture; and this restor'd Liquor did, as it was Look'd upon against or from the Light, exhibit the same Phaenomena as the Tincted Water did, before either of the Adven­titious Liquors was pour'd into it.

Having made, Pyrophilus, divers Tryals upon this Nephritick Wood, we found mention made of it by the Industrious Je­suit Kircherus, who having received a Cup Turned of it from the Mexican Procurator of his Society, has probably receiv'd also from him the Information he gives us con­cerning [Page 207] that Exotick Plant, and therefore partly for that Reason, and partly because what he Writes concerning it, does not perfectly agree with what we have deli­ver'd, we shall not Scruple to acquaint you in his own Words, with as much of what he writes concerning our Wood, as is requisite to our present purpose. Hoc loco (says he) neutiquam omittendum duximus quoddam ligni candidi Mexicani genus, quod Indigenae Coalle & Kircher. Art. Mag. Ducis & umbrae, lib. 1. part. 3. Tlapazatli vocant, quod etsi ex­perientia hucusque non nisi Coe­ruleoaquam colore tingere docuerit, nos tamen continua experientia invenimus id aquam in omne Colorum genus transformare, quod merito cuipiam Paradoxum videri posset; Ligni frutex grandis, ut aiunt, non rarò in molem arboris excrescit, truncus illius est crassus, enodis, instar piri arboris, folia ciceris foliis, aut rutae haud absimilia, flores exigui, oblongi, lutei & spicatim digesti; est frigida & humida planta, licet parum recedat à medio tempera­mento. Hujus itaque descriptae arboris lignum in poculum efformatum, aquam eidem infusam primu in aquam intense Coeruleam, colore floris Baglossae, tingit, & quo diutius in eo steterit, tanto intensiorem colorem acquirit. Hanc igitur aquam si Vitreu Sphaerae infuderis, luci­que exposueris, ne ullum quidem Coerulei co­loris [Page 208] vestigium apparebit, sed instar aquae purae putae fontanae limpidam claramque aspi­cientibus se praebebit. Porro si hanc phialam vitream versus locum magis umbrosum di­rexeris, totus humor gratissimum virorem re­feret; si adhuc umbrosioribus locis, subru­brum, & sic pro rerum objectarum conditione, mirum dictu, colorem mutabit; in tenebris verò vel in vase opaco posita, Coeruleum colo­rem suum resumet.

In this passage we may take notice of the following Particulars. And first, he calls it a White Mexican Wood, whereas (not to mention that Mornardes informs us that it is brought out of Nova Hispania) the Wood that we have met with in several places, and employ'd as Lignum Nephri­ticum, was not White, but for the most part of a much Darker Colour, not unlike that of the Sadder Colour'd Wood of Juniper. 'Tis true, that Monardes himself also says, that the Wood is White; and it is affirm'd, that the Wood which is of a Sadder Colour is Adulterated by being Imbu'd with the Tincture of a Vegetable, in whose Decoction it is steep'd. But ha­ving purposely enquir'd of the Eminentest of our English Druggists, he peremptorily deny'd it. And indeed, having consider'd some of the fairest Round pieces of this [Page 209] Wood that I could meet with in these Parts, I had Opportunity to take notice that in one or two of them it was the Ex­ternal part of the Wood that was White, and the more Inward part that was of the other Colour, the contrary of which would probably have appear'd, if the Wood had been Adulterated after the afore-mention'd manner. And I have at present by me a piece of such Wood, which for about an Inch next the Bark is White, and then as it were abruptly passes to the above-mention'd Colour, and yet this Wood by the Tincture, it afforded us in Water, appears to have its Colour'd part Genuine enough; for as for the White part, it appears upon tryal of both at once, much less enrich'd with the tingent Pro­perty.

Next, whereas our Author tells us, that the Infusion of this Wood expos'd in a Vial to the Light, looks like Spring-water, in which he afterwards adds, that there is no Tincture to be seen in it, our Obser­vation and his agree not, for the Liquor, which opposed to the Darker part of a Room exhibits a Sky-colour, did constant­ly, when held against the Light, appear Yellowish or Reddish, according as its Tincture was more Dilute or Deep; and [Page 210] then, whereas it has been already said, that the Coeruleous Colour was by Acid Salts a bolished, this Yellowish one surviv'd without any considerable Alteration, so that unless our Author's Words be taken in a very Limited Sense, we must conclude, that either his Memory mis-inform'd him, or that his White Nephritick Wood, and the Sadder Colour'd one which we em­ploy'd, were not altogether of the same Nature: What he mentions of the Cup made of Lignum Nephriticum, we have not had Opportunity to try, not having been able to procure pieces of that Wood great enough, and otherwise fit to be turned into Cups; but as for what he says in the Title of his Experiment, that this Wood tinges the Water with all sorts of Co­lours, that is much more than any of those pieces of Nephritick Wood that we have hitherto employ'd, was able to make good; The change of Colours discernable in a Vial full of VVater, Impregnated by any of them, as it is directed towards a place more Lightsome or Obscure, being far from affording a Variety answerable to so pro­mising a Title. And as for what he tells us, that in the Dark the Infusion of our VVood will resume a Coeruleous Colour, I wish he had Inform'd us how he Try'd it.

[Page 211] But this brings into my mind, that ha­ving sometimes for Curiosity sake, brought a round Vial with a long Neck fill'd with the Tincture of Lignum Nephriticum into the Darken'd Room already often menti­on'd, and holding it sometimes in, some­times near the Sun-beams that enter'd at the hole, and sometimes partly in them, and partly out of them, the Glass being held in several postures, and look'd upon from several Neighbouring parts of the Room, disclos'd a much greater Variety of Colours than in ordinary inlightn'd Rooms it is wont to do; exhibiting, besides the usual Colours, a Red in some parts, and a Green in others, besides Intermediate Colours produc'd by the differing Degrees, and odd mixtures of Light and Shade.

By all this You may see, Pyrophilus, the reasonableness of what we elsewhere had occasion to mention, when we have divers times told you, that it is usefull to have New Experiments try'd over again, though they were, at first, made by Knowing and Candid Men, such Reiterations of Expe­riments commonly exhibiting some New Phoenomena, detecting some Mistake or hinting some Truth, in reference to them, that was not formerly taken notice of. And some of our friends have been pleas'd to [Page 212] think, that we have made no unusefull additi­on to this Experiment, by shewing a way, how in a moment our Liquor may be de­priv'd of its Blewness, and restor'd to it a­gain by the affusion of a very few drops of Licuors, which have neither of them any Colour at all of their own. And that which deserves some particular wonder, is, that the Coeruleous Tincture of our Wood is subject by the former Method to be De­stroy'd or Restor'd, the Yellowish or Red­dish Tincture continuing what it was. And that you may see, that Salts are of a consi­derable use in the striking of Colours, let me add to the many Experiments which may be afforded us to this purpose by the Dyers Trade, this Observation; That as far as we have hitherto try'd, those Liquors in general that are strong of Acid Salts have the Power of Destroying the Blew­ness of the Infusion of our Wood, and those Liquors indiscriminatly that abound with Sulphureous Salts, (under which I compre­hend the Urinous and Volatile Salts of Animal Substances, and the Alcalisate or fixed Salts that are made by Incineration) have the vertue of Restoring it.

EXPERIMENT XI.

And here I must not omit, Pyrophilus, to inform You, that we can shew You even in a Mineral Body something that may seem very near of Kin to the Changeable Qua­lity of the Tincture of Lignum Nephriticum, for we have several flat pieces of Glass, of the thickness of ordinary Panes for Win­dows, one of which being interposed be­twixt the Eye and a cleer Light, appears of a Golden Colour, not much unlike that of the moderate Tincture of our Wood, but being so look'd upon as that the Beams of light are not so much Trajected thorough it as Reflected from it to the Eye, that Yel­low seems to degenerate into a pale Blew, somewhat like that of a Turquoise. And that which may also appear strange, is this, [Page 217] that if in a certain posture you hold one of these Plates Perpendicular to the Horizon, so that the Sun-beams shine upon half of it, the other half being Shaded, You may see that the part Shin'd upon will be of a much Diluter Yellow than the Shaded part which will appear much more Richly Colour'd; and if You alter the Posture of the Glass, so that it be not held Perpendicular, but Parallel in reference to the Horizon, You may see, (which perhaps you will admire) the Shaded part look of a Golden Colour, but the other that the Sun shines freely on, will appear considerably Blew, and as you remove any part of the Glass thus held Ho­rizontally into the Sun-beams or Shade, it will in the twinkling of an Eye seem to pass from one of the above mention'd Colours to the other, the Sun-beams Trajected through it upon a sheet of White Paper held near it, do colour it with a Yellow, somewhat bordering upon a Red, but yet the Glass may be so oppos'd to the Sun, that it may upon Paper project a mix'd Colour here and there more inclin'd to Yellow, and here and there more to Blew. The other Phoenomena of this odd Glass, I fear it would be scarce worth while to Record, and therefore I shall rather advertise You, First, that in the trying of these Experi­ments [Page 218] with it, you must take notice that one of the sides has either alone, or at least principally its Superficial parts dispos'd to the Reflection of the Blew Colour above nam'd, and that therefore you must have a care to keep that side nearest to the Eye. And next, that we have our selves made Glasses not unfit to exhibit an Experiment not unlike that I have been speaking of, by laying upon pieces of Glass some very fine­ly foliated Silver, and giving it by degrees a much stronger Fire than is requisite or usual for the Tinging of Glasses of other Colours. And this Experiment, not to men­tion that it was made without a Furnace in which Artificers that Paint Glass are wont to be very Curious, is the more considera­ble, because, that though a Skilfull Painter could not deny to me that 'twas with Sil­ver he Colour'd his Glasses Yellow; yet he told me, that when to Burn them (as they speak) he layes on the plates of Glass no­thing but a Calx of Silver Calcin'd without Corrosive Liquors, and Temper'd with Fair Water, the Plates are Ting'd of a fine Yellow that looks of a Golden Colour, which part soever of it you turn to or from the Light; whereas (whether it be what an Artificer would call Over-doing, or Burning, or else the imploying the Silver [Page 219] Crude that makes the Difference,) we have found more than once, that some Pieces of Glass prepar'd as we have rela­ted, though held against the Light they ap­pear'd of a Transparent Yellow, yet look'd on with ones back turn'd to the Light they exhibited an Untransparent Blew.

EXPERIMENT XII.

If you will allow me, Pyrophilus, for the avoiding of Ambignity, to imploy the Word Pigments, to signifie such prepared materials (as Cochinele, Vermilion, Orpiment,) as Painters, Dyers and other Artificers make use of to impart or imitate particular Colours, I shall be the better understood in divers passages of the follow­ing papers, and particularly when I tell you, That the mixing of Pigments being no inconsiderable part of the Painters Art, it may seem an Incroachment in me to med­dle with it. But I think I may easily be excus'd (though I do not altogether pass it by) if I restrain my self to the making of a Transient mention of some few of their Practices about this matter; and that only so far forth, as may warrant me to observe to you, that there are but few Simple and Primary Colours (if I may so call them) [Page 220] from whose Various Compositions all the rest do as it were Result. For though Pain­ters can imitate the Hues (though not always the Splendor) of those almost Numberless differing Colours that are to be met with in the Works of Nature, and of Art, I have not yet found, that to ex­hibit this strange Variety they need imploy any more than White, and Black, and Red, and Blew, and Yellow; these five, Vari­ously Compounded, and (if I may so speak) Decompounded, being sufficient to exhibit a Variety and Number of Colours, such, as those that are altogether Strangers to the Painters Pallets, can hardly imagine.

Thus (for Instance) Black and White differingly mix'd, make a Vast company of Lighter and Darker Grays.

Blew and Yellow make a huge Variety of Greens.

Red and Yellow make Orange Tawny.

Red with a little White makes a Car­nation.

Red with an Eye of Blew, makes a Pur­ple; and by these simple Compositions again Compounded among themselves, the Skilfull Painter can produce what kind of Colour he pleases, and a great many more than we have yet Names for. But, as I intimated above, 'tis not my De­sign [Page 221] to prosecute this Subject, though I thought it not unfit to take some Notice of it, because we may hereafter have oc­casion to make use of what has been now deliver'd, to illustrate the Generation of Intermediate Colours; concerning which we must yet subjoyn this Caution, that to make the Rules about the Emergency of Colours, fit to be Relied upon, the Cor­puscles whereof the Pigments consist must be such as do not Destroy one anothers Texture, for in case they do, the produced Colour may be very Different from that which would Result from the Mixture of other harmless Pigments of the same Co­lours, as I shall have Occasion to shew ere long.

EXPERIMENT XIII.

It may also give much light to an En­quirer into the Nature of Colours, to know that not only in Green, but in many (if not all) other Colours, the Light of the Sun passing through Diaphanous Bo­dies of differing Hues may be tinged of the same Compound Colour, as if it came from some Painters Colours of the same Denomination, though this later be ex­hibited by Reflection, and be (as the [Page 222] former Experiment declares) manifestly Compounded of material Pigments. Wherefore to try the Composition of Co­lours by Trajection, we provided several Plates of Tinged Glass, which being laid two at a time one on the top of another, the Object look'd upon through them both, appear'd of a Compounded Colour, which agrees well with what we have observ'd in the second Experiment, of Looking against the Light through differingly Colour'd Papers. But we thought the Experiment would be more Satisfactory, if we procur'd the Sun-beams to be so Ting'd in their passage through Plates of Glass, as to ex­hibit the Compounded Colour upon a Sheet of White Paper. And though by reason of the Thickness of the Glasses, the Effect was but Faint, even when the Sun was High and Shin'd forth clear, yet, we easily remedied that by Contracting the Beams we cast on them by means of a Convex Burning-glass, which where it made the Beams much converge Increas'd the Light enough to make the Compounded Colour very manifest upon the Paper. By this means we observ'd, that the Beams trajected through Blew and Yellow com­pos'd a Green, that an intense and mode­rate Red did with Yellow make differing [Page 223] degrees of Saffron, and Orange Tawny Colours, that Green and Blew made a Colour partaking of both, such as that which some Latin Writers call Pavona­ceus, that Red and Blew made a Purple, to which we might add other Colours, that we produc'd by the Combinations of Glasses differingly Ting'd, but that I want proper Words to express them in our Language, and had not when we made the Tryals, the Opportunity of consulting with a Painter, who perchance might have Sup­pli'd me with some of the terms I wanted.

I know not whether it will be requisite to subjoyn on this Occasion, what I tried concerning Reflections from Colour'd Glasses, and other Transparent Bodies, namely, that having expos'd four or five sorts of them to the Sun, and cast the Re­flected Beams upon White Paper held near at hand, the Light appear'd not manifestly Ting'd, but as if it had been Reflected from the Impervious parts of a Colourless Glass, only that Reflected from the Yellow was here and there stain'd with the same Co­lour, as if those Beams were not all Re­flected from the Superficial, but some from the Internal parts of the Glass; upon which Occasion you may take notice, that a Skilfull Tradesman, who makes such Co­lour'd [Page 224] Glass told me, that where as the Red Pigment was but Superficial, the Yellow penetrated to the very midst of the Plate. But for further Satisfaction, not having the Opportunity to Foliate those Plates, and so turn them into Looking-glasses, we Foliated a Plate of Muscovy Glass, and then laying on it a little Transparent Varnish of a Gold Colour, we expos'd it to the Sun-beams, so as to cast them upon a Body fit to receive them, on which the Reflected Light, appearing, as we expected, Yellow, manifested that Rebounding from the Spe­cular part of the Selenitis, it was Ting'd in its return with the Colour of the Trans­parent Varnish through which it pass'd.

EXPERIMENT XIV.

After what we have said of the Com­position of Colours, it will now be season­able to annex some Experiments that we made in favour of those Colours, that are taught in the Schools not to be Real, but only Apparent and Phantastical; For we found by Tryals, that these Colours might be Compounded, both with True and Stable Colours, and with one another, as well as unquestionably Genuine and Lasting Colours, and that the Colours [Page 225] resulting from such Compositions, would respectively deserve the same Denomi­nations.

For first, having by the Trajection of the Sun-beams through a Glass-prism thrown an Iris on the Floor, I found that by pla­cing a Blew Glass at a convenient distance betwixt the Prism and the Iris, that part of the Iris that was before Yellow, might be made to appear Green, though not of a Grass Green, but of one more Dilute and Yellowish. And it seems not improbable, that the narrow Greenish List (if I may so call it) that is wont to be seen between the Yellow and Blew parts of the Iris, is made by the Confusion of those two Bor­dering Colours.

Next, I found, that though the want of a sufficient Liveliness in either of the Com­pounding Colours, or a light Error in the manner of making the following Tryals, was enough to render some of them Un­successfull, yet when all necessary Cir­cumstances were duely observ'd, the Event was answerable to our Expectation and Desire.

And (as I formerly Noted) that Red and Blew compound a Purple, so I could produce this last nam'd Colour, by casting at some Distance from the Glass the Blew [Page 226] part of the Prismatical Iris (as I think it may be call'd for Distinction sake) upon a Lively Red, (for else the Experiment suc­ceeds not so well.) And I remember, that sometimes when I try'd this upon a piece of Red Cloath, that part of the Iris which would have been Blew, (as I try'd by covering that part of the Cloath with a piece of White Paper) and Compoun­ded with the Red, wherewith the Cloath was Imbued before, appear'd of a fair Purple, did, when I came to View it near at hand, look very Odly, as if there were some strange Reflection or Refraction or both made in the Hairs of which that Cloath was composed.

Casting likewise the Prismatical Iris upon a very Vivid Blew, I found that part of it, which would else have been the Yel­low, appear Green. (Another somewhat differing Tryal, and yet fit to confirm this, you will find in the fifteenth Experiment.)

But it may seem somewhat more strange, that though the Prismatical Iris being made by the Refraction of Light through a Body that has no Colour at all, must according to the Doctrine of the Schools consist of as purely Emphatical Colours, as may be, yet even these may be Compounded with one another, as well as Real Colours in [Page 227] the Grossest Pigments. For I took at once two Triangular Glasses, and one of them being kept fixt in the same Posture, that the Iris it projected on the Floor might not Waver, I cast on the same Floor another Iris with the other Prism, and Moving it too and fro to bring what part of the se­cond Iris I pleas'd, to fall upon what part of the first I thought fit, we did some­times (for a small Errour suffices to hinder the Success) obtain by this means a Green Colour in that part of the more Stable Iris, that before was Yellow, or Blew, and fre­quently by casting those Beams, that in one of the Iris's made the Blew upon the Red parts of the other Iris, we were able to produce a lovely Purple, which we can Destroy or Recompose at pleasure, by Se­vering and Reapproaching the Edges of the two Iris's.

EXPERIMENT XV.

On this occasion, Pyrophilus, I shall add, that finding the Glass-prism to be the usefullest Instrument Men have yet imploy'd about the Contemplation of Colours, and considering that Prisms hitherto in use are made of Glass Transparent and Colourless, I thought it would not be amiss to try, [Page 228] what change the Superinduction of a Co­lour, without the Destruction of the Dia­phaneity, would produce in the Colours exhibited by the Prism. But being unable to procure one to be made of Colour'd Glass, and fearing also that if it were not carefully made, the Thickness of it would render it too Opacous, I endeavoured to substitute one made of Clarify'd Rosin, or of Turpentine brought (as I elsewhere teach) to the consistence of a Transparent Gum. But though these Endeavours were not wholly lost, yet we found it so difficult to give these Materials their true Shape, that we chose rather to Varnish over an ordinary Prism with some of those few Pigments that are to be had Transparent; as accordingly we did first with Yellow, and then with Red, or rather Crimson, made with Lake temper'd with a conve­nient Oyl, and the Event was, That for want of good Transparent Colours, (of which you know there are but very few) both the Yellow and the Red made the Glass so Opacous, (though the Pigment were laid on but upon two Sides of the Glass, no more being absolutely necessary) that unless I look'd upon an Inlightned Window, or the Flame of a Candle, or some other Luminous or very Vivid object, [Page 229] I could scarce discern any Colours at all, especially when the Glass was cover'd with Red. But when I did look on such Objects, it appear'd (as I expected) that the Co­lour of the Pigment had Vitiated or Drown'd some of those which the Prism would according to its wont have exhi­bited, and mingling with others, Alter'd them: as I remember, that both to my Eyes, and others to whom I show'd it, when the Prism was cover'd with Yellow, it made those Parts of bright Objects, where the Blew would else have been Con­spicuous, appear of a light Green. But, Pyrophilus, both the Nature of the Colours, and the Degree of Transparency, or of Darkness in the Pigment, besides divers other Circumstances, did so vary the Phae­nomena of these Tryals, that till I can pro­cure small Colour'd Prisms, or Hollow ones that may be filled with Tincted Li­quor, or obtain some better Pigments than those I was reduc'd to imploy, I shall for­bear to Build any thing upon what has been deliver'd, and shall make no other use of it, than to invite you to prosecute the Inquiry further.

EXPERIMENT XVI.

And here, Pyrophilus, since we are treating of Emphatical Colours, we shall add what we think not unworthy your Ob­servation, and not unfit to afford some Ex­ercise to the Speculative. For there are some Liquors, which though Colourless themselves, when they come to be Ele­vated, and Dispers'd into Exhalations, exhibit a conspicuous Colour, which they lose again, when they come to be Recon­joyn'd into a Liquor, as good Spirit of Nitre, or upon its account strong Aqua-fortis, though devoid of all appearance of Redness whilst they continue in the form of a Liquor, if a little Heat chance to turn the Minute parts of them into Vapours, the Steam will appear of a Reddish or deep Yellow Colour, which will Vanish when those Exhalations come to resume the form of a Liquor.

And not only if you look upon a Glass half full of Aqua-fortis, or Spirit of Nitre, and half full of Nitrous steams proceeding from it, you will see the Upper part of the Glass of the Colour freshly mention'd, if through it you look upon the Light. But which is much more considerable, I [Page 231] have tried, that putting Aqua-fortis in a long clear Glass, and adding a little Cop­per or some such open Metall to it, to excite Heat and Fumes, the Light tra­jected through those Fumes, and cast upon a sheet of White Paper, did upon that appear of the Colour that the Fumes did, when directly Look'd upon, as if the Light were as well Ting'd in its passage through these Fumes, as it would have been by passing through some Glass or Liquor in which the same Colour was Inherent.

To which I shall further add, that having sometimes had the Curiosity to observe whether the Beams of the Sun near the Horizon trajected through a very Red Sky, would not (though such Rednesses are taken to be but Emphatical Colours) exhibit the like Colour, I found that the Beams falling within a Room upon a very White Object, plac'd directly opposite to the Sun, disclos'd a manifest Redness, as if they had pass'd through a Colour'd Medium.

EXPERIMENT XVII.

The emergency, Pyrophilus, of Colours upon the Coalition of the Particles of such Bodies as were neither of them of the Co­lour of that Mixture whereof they are the [Page 232] Ingredients, is very well worth our atten­tive Observation, as being of good use both Speculative and Practical; For much of the Mechanical use of Colours among Painters and Dyers, doth depend upon the Knowledge of what Colours may be pro­duc'd by the Mixtures of Pigments so and so Colour'd. And (as we lately inti­mated) 'tis of advantage to the contem­plative Naturalist, to know how many and which Colours are Primitive (if I may so call them) and Simple, because it both eases his Labour by confining his most sol­licitious Enquiry to a small Number of Colours upon which the rest depend, and assists him to judge of the nature of parti­cular compounded Colours, by shewing him from the Mixture of what more Sim­ple ones, and of what Proportions of them to one another, the particular Colour to be consider'd does result. But because to insist on the Proportions, the Manner and the Effects of such Mixtures would oblige me to consider a greater part of the Pain­ters Art and Dyers Trade, than I am well acquainted with, I confin'd my self to make Trial of several ways to produce Green, by the composition of Blew and Yellow. And shall in this place both Recapitulate most of the things I have Dispersedly deli­ver'd [Page 233] already concerning that Subject, and Recruit them.

And first, whereas Painters (as I no­ted above) are wont to make Green by tempering Blew and Yellow, both of them made into a soft Consistence, with either Water or Oyl, or some Liquor of Kin to one of those two, according as the Picture is to be Drawn with those they call Water Colours, or those they term Oyl Colours, I found that by choosing fit Ingredients, and mixing them in the form of Dry Pow­ders, I could do, what I could not if the Ingredients were temper'd up with a Li­quor; But the Blew and Yellow Powders must not only be finely Ground, but such as that the Corpuscles of the one may not be too unequal to those of the other, lest by their Disproportionate Minuteness the Smaller cover and hide the Greater. We us'd with good success a slight Mixture of the fine Powder of Bise, with that of Or­piment, or that of good Yellow Oker, I say a slight Mixture, because we found that an exquisite Mixture did not do so well, but by lightly mingling the two Pigments in several little Parcels, those of them in which the Proportion and Manner of Mix­ture was more Lucky, afforded us a good Green.

[Page 234] 2. We also learn'd in the Dye-houses, that Cloth being Dy'd Blew with Woad, is afterwards by the Yellow Decoction of Luteola or Wood-wax Dy'd into a Green Colour.

3. You may also remember what we above Related, where we intimated, that having in a Darkn'd Room taken two Bo­dies, a Blew and a Yellow, and cast the Light Reflected from the one upon the other, we likewise obtain'd a Green.

4. And you may remember, that we observ'd a Green to be produc'd, when in the same Darkn'd Room we look'd at the Hole at which alone the Light enter'd, through the Green and Yellow parts of a sheet of Marbl'd Paper laid over one ano­ther.

5. We found too, that the Beams of the Sun being trajected through two pieces of Glass, the one Blew and the other Yellow, laid over one another, did upon a sheet of White paper on which they were made to fall, exhibit a lovely Green.

6. I hope also, that you have not already forgot, what was so lately deliver'd, concer­ning the composition of a Green, with a Blew and Yellow; of which most Authors would call the one a Real, and the other an Emphatical.

[Page 235] 7. And I presume, you may have yet fresh in your memory, what the fourteenth Experiment informs you, concerning the exhibiting of a Green, by the help of a Blew and Yellow, that were both of them Emphatical.

8. Wherefore we will proceed to take notice, that we also devis'd a way of trying whether or no Metalline Solutions though one of them at least had its Colour Adven­titious, by the mixture of the Menstruum employ'd to dissolve it, might not be made to compound a Green after the manner of other Bodies. And though this seem'd not easie to be perform'd by reason of the Dif­ficulty of finding Metalline Solutions of the Colour requisite, that would mix without Praecipitating each other; yet after a while having consider'd the matter, the first Tryal afforded me the following Experiment. I took a High Yellow Solution of good Gold in Aqua-Regis, (made of Aqua-fortis, and as I remember half its weight of Spirit of Salt) To this I put a due Proportion of a deep and lovely Blew Solution of Crude Copper, (which I have elsewhere taught to be readily Dissoluble in strong Spirit of Urine) and these two Liquors though at first they seem'd a little to Curdle one ano­ther, yet being throughly mingl'd by Sha­king, [Page 236] they presently, as had been Conje­ctur'd, united into a Transparent Green Liquor, which continu'd so for divers days that I kept it in a small Glass wherein 'twas made, only letting fall a little Blackish Powder to the Bottom. The other Phae­nomena of this Experiment belong not to this place, where it may suffice to take notice of the Production of a Green, and that the Experiment was more than once repeated with Success.

9. And lastly, to try whether this way of compounding Colours would hold ev'n in Ingredients actually melted by the Vio­lence of the Fire, provided their Texture were capable of safely induring Fusion, we caus'd some Blew and Yellow Ammel to be long and well wrought together in the Flame of a Lamp, which being Strong­ly and Incessantly blown on them kept them in some degree of Fusion, and at length (for the Experiment requires some Patience as well as Skil) we obtain'd the expected Ammel of a Green Colour.

I know not, Pyrophilus, whether it be worth while to acquaint you with the ways that came into my Thoughts, whereby in some measure to explicate the first of the ment on'd ways of making a Green; for I have sometimes Conjectur'd, that the mix­ture [Page 237] of the Bise and the Orpiment produc'd a Green by so altering the Superficial As­perity, which each of those Ingredients had apart, that the Light Incident on the mixture was Reflected with differing Shades, as to Quantity, or Order, or both, from those of either of the Ingredients, and such as the Light is wont to be Modi­fy'd with, when it Reflects from Grass, or Leaves, or some of those other Bodies that we are wont to call Green. And some­times too I have doubted, whether the pro­duced Green might not be partly at least deriv'd from this, That the Beams that Rebound from the Corpuscles of the Orpi­ment, giving one kind of stroak upon the Retina, whose Perception we call Yellow, and the Beams Reflected from the Corpus­cles of the Bise, giving another stroak upon the same Retina, like to Objects that are Blew, the Contiguity and Minuteness of these Corpuscles may make the Appulse of the Reflected Light fall upon the Retina within so narrow a Compass, that the part they Beat upon being but as it were a Phy­sical point, they may give a Compounded stroak, which may consequently exhibit a Compounded and new Kind of Sensation, as we see that two Strings of a Musical In­strument being struck together, making two [Page 238] Noises that arrive at the Ear at the same time as to Sense, yield a Sound differing from either of them, and as it were Com­pounded of both; Insomuch that if they be Discordantly tun'd, though each of them struck apart would yield a Pleasing Sound, yet being struck together they make but a Harsh and troublesome Noise. But this not being so fit a place to prosecute Speculations, I shall not insist, neither upon these Conjectures nor any others, which the Experiment we have been mentioning may have suggested to me. And I shall leave it to you, Pyrophilus, to derive what Instru­ction you can from comparing together the Various ways whereby a Yellow and a Blew can be made to Compound a Green. That which I now pretend to, being only to shew that the first of those mention'd ways, (not to take at present notice of the rest) does far better agree with out Con­jectures about Colours, than either with the Doctrine of the Schools, or with that of the Chymists, both which seem to be very much Disfavour'd by it.

For first, since in the Mixture of the two mention'd Powders I could by the help of a very excellent Microscope (for ordinary ones will scarce serve the turn) discover that which seem'd to the naked Eye a Green [Page 239] Body, to be but a heap of Distinct, though very small Grains of Yellow Orpiment and Blew Bise confusedly enough Blended together, it appears that the Colour'd Corpuscles of either kind did each retain its own Nature and Colour; By which it may be guess'd, what meer Transposition and Juxtaposition of Minute and Singly unchang'd Particles of Matter can do to produce a new Colour; For that this Lo­cal Motion and new Disposition of the small parts of the Orpiment did Intervene is much more manifest than it is easie to Explicate how they should produce this new Green otherwise than by the new Manner of their being put together, and consequently by their new Disposition to Modifie the Incident Light by Reflecting it otherwise than they did before they were Mingl'd together.

Secondly, The Green thus made being (if I may so speak) Mechanically produc'd, there is no pretence to derive it from I know not what incomprehensible Substantial Form, from which yet many would have us believe that Colours must flow; Nor does this Green, though a Real and Perma­nent, not a Phantastical and Vanid Colour, seem to be such an Inherent Quality as they would have it, since not only each part of [Page 240] the Mixture remains unalter'd in Colour, and consequently of a differing Colour from the Heap they Compose, but if the Eye be assisted by a Microscope to discern things better and more distinctly than before it could, it sees not a Green Body, but a Heap of Blew and Yellow Corpuscles.

And in the third place, I demand what either Sulphur, or Salt, or Mercury has to do in the Production of this Green; For neither the Bise nor the Orpiment were in­du'd with that Colour before, and the bare Juxtaposition of the Corpuscles of the two Powders that work not upon each other, but might if we had convenient Instruments be separated, unalter'd, cannot with any probability be imagin'd either to Increase or Diminish any of the three Hypostatical Principles, (to which of them soever the Chymists are pleas'd to ascribe Colours) nor does there here Intervene so much as Heat to afford them any colour to pretend, that at least there is made an Extraversion (as the Helmontians speak) of the Sulphur or of any of the two other supposed Princi­ples; But upon this Experiment we have already Reflected enough, if not more than enough for once.

EXPERIMENT XVIII.

But here, Pyrophilus, I must advertise you, that 'tis not every Yellow and every Blew that being mingl'd will afford a Green; For in case one of the Ingredients do not Act only as endow'd with such a Colour, but as having a power to alter the Texture of the Corpuscles of the other, so as to Indispose them to Reflect the Light, as Corpuscles that exhibit a Blew or a Yellow are wont to Reflect it, the emer­gent Colour may be not Green, but such as the change of Texture in the Corpuscles of one or both of the Ingredients qualifies them to shew forth; as for instance, if you let fall a few Drops of Syrrup of Violets upon a piece of White Paper, though the Syrrup being spread will appear Blew, yet mingling with it two or three Drops of the lately mention'd Solution of Gold, I ob­tain'd not a Green but a Reddish mixture, which I expected from the remaining Power of the Acid Salts abounding in the Solution, such Salts or Saline Spirits being wont, as we shall see anon, though weakn'd, so to work upon that Syrrup as to change it into a Red or Reddish Colour. And to confirm that for which I allege the former [Page 242] Experiment, I shall add this other, that having made a very strong and high-co­lour'd Solution of Filings of Copper with Spirit of Urine, though the Menstruum seem'd Glutted with the Metall, because I put in so much Filings that many of them remain'd for divers days Undissolv'd at the Bottom, yet having put three or four Drops of Syrrup of Violets upon White Paper, I found that the deep Blew Solution pro­portionably mingl'd with this other Blew Liquor did not make a Blew mixture, but, as I expected, a fair Green, upon the account of the Urinous Salt that was in the Men­struum.

EXPERIMENT XIX.

To shew the Chymists, that Colours may be made to Appear or Vanish, where there intervenes no Accession or Change either of the Sulphureous, or the Saline, or the Mercurial principle (as they speak) of Bodies: I shall not make use of the Iris afforded by the Glass-prism, nor of the Colours to be seen in a fair Morning in those drops of Dew that do in a convenient manner Reflect and Refract the Beams of Light to the Eye; But I will rather mind them of what they may observe in their [Page 243] own Laboratories, namely, that divers, if not all, Chymical Essential Oyls, as also good Spirit of Wine, being shaken till they have good store of Bubbles, those Bubbles will (if attentively consider'd) appear adorn'd with various and lovely Colours, which all immediately Vanish, upon the relapsing of the Liquor that affords those Bubbles their Skins, into the rest of the Oyl, or Spirit of Wine, so that a Colour­less Liquor may be made in a trice to ex­hibit variety of Colours, and may lose them in a moment without the Accession or Diminution of any of its Hypostatical Principles. And, by the way, 'tis not un­worthy our notice, that some Bodies, as well Colourless, as Colour'd, by being brought to a great Thinness of parts, acquire Co­lours though they had none before, or Co­lours differing from them they were before endued with: For, not to insist on the Variety of Colours, that Water, made somewhat Glutinous by Sope, acquires, when 'tis blown into such Sphaerical Bub­bles as Boys are wont to make and play with; Turpentine (though it have a Co­lour deep enough of its own) may (by being blown into after a certain manner) be brought to afford Bubbles adorn'd with variety of Orient Colours, which though [Page 244] they Vanish after some while upon the breaking of the Bubbles, yet they would in likelihood always exhibit Colours upon their Superfices, (though not always the same in the same Parts of them, but Vary'd according to the Incidence of the Sight, and the Position of the Eye) if their Tex­ture were durable enough: For I have seen one that was Skill'd at fashioning Glasses by the help of a Lamp, blowing some of them so strongly as to burst them, whereupon it was found, that the Tenacity of the Metall was such, that before it broke it suffer'd it self to be reduc'd into Films so extremely thin, that being kept clean they constantly shew'd on their Surfaces (but after the manner newly mention'd) the varying Colours of the Rain-bow, which were exceedingly Vivid, as I had often opportunity to observe in some, that I caus'd purposely to be made, to keep by me.

But lest it should be objected, that the above mention'd Instances are drawn from Transparent Liquors, it may possibly ap­pear, not impertinent to add, what I have sometimes thought upon, and several times tried, when I was considering the Opinions of the Chymists about Colours. I took then a Feather of a convenient Big­ness [Page 245] and Shape, and holding it at a fit di­stance betwixt my Eye and the Sun when he was near the Horizon, me thought there appear'd to me a Variety of little Rain-bows, with differing and very vivid Co­lours, of which none was constantly to be seen in the Feathers; the like Phaenomenon I have at other times (though not with al­together so good success) produc'd, by interposing at a due distance a piece of Black Ribband betwixt the almost setting Sun and my Eye, not to mention the Trials I have made to the same purpose, with other Bodies.

EXPERIMENT XX.

Take good Syrrup of Violets, Impraeg­nated with the Tincture of the flowers, drop a little of it upon a White Paper (for by that means the Change of Colour will be more conspicuous, and the Experiment may be practis'd in smaller Quantities) and on this Liquor let fall two or three drops of Spirit either of Salt or Vinegar, or almost any other eminently Acid Liquor, and upon the Mixture of these you shall find the Syrrup immediatly turn'd Red, and the way of Effecting such a Change has not been unknown to divers Persons [Page 246] who have produc'd the like, by Spirit of Vitriol, or juice of Limmons, but have Groundlessly ascrib'd the Effect to some Peculiar Quality of those two Liquors, whereas, (as we have already intimated) almost any Acid Salt will turn Syrrup of Violets Red. But to improve the Experi­ment, let me add what has not (that I know of) been hitherto observ'd, and has, when we first shew'd it them, appear'd something strange, even to those that have been inquisitive into the Nature of Colours; namely, that if instead of Spirit of Salt, or that of Vinegar, you drop upon the Syrrup of Violets a little Oyl of Tartar per Deliquium, or the like quantity of Solu­tion of Potashes, and rubb them together with your finger, you shall find the Blew Colour of the Syrrup turn'd in a moment into a perfect Green, and the like may be perform'd by divers other Liquors, as we may have occasion elsewhere to Inform you.

EXPERIMENT XXI.

There is a Weed, more known to Plow­men than belov'd by them, whose Flowers from their Colour are com­monly call'd Blew-bottles, and Herbarists are wont to call this Plant Cyanus vul­garis minor. Corn-weed from their Growing among Corn. These Flowers some Ladies do, upon the ac­count of their Lovely Colour, think worth the being Candied, which when they are, they will long retain so fair a Colour, as makes them a very fine Sallad in the Win­ter. But I have try'd, that when they are freshly gather'd, they will afford a Juice, which when newly express'd, (for in some cases 'twill soon enough degenerate) affords a very deep and pleasant Blew. Now, (to draw this to our present Scope) by dropping on this fresh Juice, a little Spirit of Salt, (that being the Acid Spirit I had then at hand) it immediately turn'd (as I predicted) into a Red. And if in­stead of the Sowr Spirit I mingled with it a little strong Solution of an Alcalizate Salt, it did presently disclose a lovely Green; the same Changes being by those differing sorts of Saline Liquors, producible in this Natural juice, that we lately mention'd to [Page 250] have happen'd to that factitious Mixture, the Syrrup of Violets. And I remember, that finding this Blew Liquor, when freshly made, to be capable of serving in a Pen for an Ink of that Colour, I attempted by moistning one part of a piece of White Paper with the Spirit of Salt I have been mentioning, and another with some Al­calizate or Volatile Liquor, to draw a Line on the leisurely dry'd Paper, that should, e'vn before the Ink was dry, ap­pear partly Blew, partly Red, and partly Green: But though the latter part of the Experiment succeeded not well, (whether because Volatile Salts are too Fugitive to be retain'd in the Paper, and Alcalizate ones are too Unctuous, or so apt to draw Moisture from the Air, that they keep the Paper from drying well) yet the former Part succeeded well enough; the Blew and Red being Conspicuous enough to afford a surprizing Spectacle to those, I acquaint not with (what I willingly allow you to call) the Trick.

EXPERIMENT XXII.

Our next Experiment (Pyrophilus) will perhaps seem to be of a contrary Nature [Page 252] to the two former, made upon Syrrup of Violets, and Juice of Blew-bottles. For as in them by the Affusion of Oyl of Tar­tar, a Blewish Liquor is made Green, so in this, by the sole Mixture of the same Oyl, a Greenish Liquor becomes Blew. The hint of this Experiment was given us by the practice of some Italian Painters, who being wont to Counterfeit Ultra-marine Azure (as they call it) by Grinding Ver­digrease with Sal-Armoniack, and some other Saline Ingredients, and letting them Rot (as they imagine) for a good while together in a Dunghill, we suppos'd, that the change of Colour wrought in the Ver­digrease by this way of Preparation, must proceed from the Action of certain Vo­latile and Alcalizate Salts, abounding in some of the mingled Concretes, and brought to make a further Dissolution of the Copper abounding in the Verdigrease, and therefore we Conjectur'd, that if both the Verdigrease, and such Salts were dis­solv'd in fair Water, the small Parts of both being therein more subdivided, and set at liberty, would have better access to each other, and thereby Incorporate much the more suddenly; And accordingly we found, that if upon a strong Solution of good French Verdigrease (for 'tis that we [Page 253] are wont to imploy, as the best) you pour a just quantity of Oyl of Tartar, and shake them well together, you shall immediately see a notable Change of Colour, and the Mixture will grow thick, and not trans­parent, but if you stay a while, till the Grosser part be Precipitated to, and setled in the Bottom, you may obtain a clear Li­quor of a very lovely Colour, and excee­ding delightfull to the Eye. But, you must have a care to drop in a competent Quan­tity of Oyl of Tartar, for else the Colour will not be so Deep, and Rich; and if in­stead of this Oyl you imploy a clear Lixivium of Pot-ashes, you may have an Azure somewhat Lighter or Paler than, and therefore differing from, the former. And if instead of either of these Liquors, you make use of Spirit of Urine, or of Harts-horn, you may according to the Quantity and Quality of the Spirit you pour in, obtain some further Variety (though scarce considerable) of Caeru­leous Liquors. And yet lately by the help of this Urinous Spirit we made a Blew Liquor, which not a few Ingenious Per­sons, and among them, some, whose Pro­fession makes them very Conversant with Colours, have looked upon with some wonder. But these Azure Colour'd Li­quors [Page 254] should be freed from the Subsiding matter, which the Salts of Tartar or Urine precipitate out of them, rather by being Decanted, than by Filtration. For by the latter of these ways we have sometimes found, the Colour of them very much Im­pair'd, and little Superiour to that of the grosser Substance, that it left in the Filtre.

EXPERIMENT XXIII.

That Roses held over the Fume of Sul­phur, may quickly by it be depriv'd of their Colour, and have as much of their Leaves, as the Fume works upon, burn'd pale, is an Experiment, that divers others have tried, as well as I. But (Pyrophilus) it may seem somewhat strange to one that has never consider'd the Compounded na­ture of Brimstone, That, whereas the Fume of Sulphur will, as we have said, Whiten the Leaves of Roses; That Li­quor, which is commonly call'd Oyl of Sulphur per Campanam, because it is sup­pos'd to be made by the Condensation of these Fumes in Glasses shap't like Bells, into a Liquor, does powerfully heighten the Tincture of Red Roses, and make it more Red and Vivid, as we have easily tried by putting some Red-Rose Leaves, [Page 255] that had been long dried, (and so had lost much of their Colour) into a Vial of fair Water. For a while after the Affu­sion of a convenient Quantity of the Li­quor we are speaking of, both the Leaves themselves, and the Water they were Steep'd in, discover'd a very fresh and love­ly Colour.

EXPERIMENT XXIV.

It may (Pyrophilus) somewhat serve to Illustrate, not only the Doctrine of Pig­ments, and of Colours, but divers other Parts of the Corpuscular Philosophy; as that explicates Odours, and many other things, not as the Schools by Aery Qualities, but by Real, though extremely Minute Bodies; to examine, how much of a Colourless Liquor, a very small Parcel of a Pigment may Imbue with a discernable Colour. And though there be scarce any thing of Preciseness to be expected from such Tri­als, yet I presum'd, that (at least) I should be able to show a much further Subdivision of the Parts of Matter into Visible Par­ticles, than I have hitherto found taken notice of, and than most men would ima­gine; no Body, that I know of, having yet attempted to reduce this Matter to any Measure.

[Page 256] The Bodies, the most promising for such a purpose, might seem to be the Me­talls, especially Gold, because of the Mul­titude, and Minuteness of its Parts, which might be argu'd from the incomparable Closeness of its Texture: But though we tried a Solution of Gold made in Aqua Regia first, and then in fair Water; yet in regard we were to determine the Pigment we imploy'd, not by Bulk but Weight, and because also, that the Yellow Colour of Gold is but a faint one in Comparison of the deep Còlour of Cochineel, we rather chose this to make our Trials with. But among divers of these it will suffice to set down one, which was carefully made in Vessels conveniently Shap'd; (and that in the presence of a Witness, and an Assist­ant) the Sum whereof I find among my Adversaria, Registred in the following Words. To which I shall only premise, (to lessen the wonder of so strange a diffu­sion of the Pigment) That Cochineel will be better Dissolv'd, and have its Colour far more heightn'd by Spirit of Urine, than (I say not by common Water, but) by Rectify'd Spirit of Wine it self.

The Note I spoke off is this. [One Grain of Cochineel dissolv'd in a pretty Quantity of Spirit of Urine, and then dis­solv'd [Page 257] further by degrees in fair Water, imparted a discernable, though but a very faint Colour, to about six Glass-fulls of Water, each of them containing about forty three Ounces and an half, which amounts to above a hundred twenty five thousand times its own Weight.]

EXPERIMENT XXV.

It may afford a considerable Hint (Py­rophilus) to him, that would improve the Art of Dying, to know what change of Colours may be produc'd by the three se­veral sorts of Salts already often mention'd, (some or other of which may be procur'd in Quantity at reasonable Rates) in the Juices, Decoctions, Infusions, and (in a word) the more soluble parts of Vege­tables. And, though the design of this Discourse be the Improvement of Know­ledge, not of Trades: yet thus much I shall not scruple to intimate here, That the Blew Liquors, mention'd in the twentieth and one and twentieth Experiments, are fat from being the only Vegetable Substances, upon which Acid, Urinous, and Alcalizate Salts have the like Operations to those recited in those two Experiments. For Ripe Privet Berries (for instance) being crush'd [Page 258] upon White Paper, though they stain it with a Purplish Colour, yet if we let fall on some part of it two or three drops of Spirit of Salt, and on the other part a little more of the strong Solution of Pot-ashes, the former Liquor immediately turn'd that part of the Thick Juice or Pulp, on which it fell, into a lovely Red, and the latter turn'd the other part of it into a delightfull Green. Though I will not undertake, that those Colours in that Substance shall not be much more. Orient, than Lasting; and though (Pyrophilus) this Experiment may seem to be almost the same with those al­ready deliver'd concerning Syrrup of Vio­lets, and the Juice of Blew-bottles, yet I think it not amiss to take this Occasion to inform you, that this Experiment reaches much farther, than perhaps you yet ima­gine, and may be of good Use to those, whom it concerns to know, how Dying Stuffs may be wrought upon by Saline Li­quors. For, I have found this Experiment to succeed in so many Various Berries, Flowers, Blossoms, and other finer Parts of Vegetables, that neither my Memory, nor my Leisure serves me to enumerate them. And it is somewhat surprizing to see, by how Differingly-colour'd Flowers, or Blossoms, (for example) the Paper being [Page 259] stain'd, will by an Acid Spirit be imme­diately turn'd Red, and by any Alcaly or any Urinous Spirit turn'd Green; inso­much that ev'n the crush'd Blossoms of Meserion, (which I gather'd in Winter and frosty Weather) and those of Pease, crush'd upon White Paper, how remote soever their Colours be from Green, would in a moment pass into a deep Degree of that Colour, upon the Touch of an Alca­lizate Liquor. To which let us add, That either of those new Pigments (if I may so call them) may by the Affusion of enough of a contrary Liquor, be presently chang'd from Red into Green, and from Green into Red, which Observation will hold also in Syrrup of Violets; Juices of Blew-bottles, &c.

EXPERIMENT XXVI.

And, (first) I thought fit to try the Operation of Acid Salts upon Vegetable Substances, that are already and by their own Nature Red. And accordingly I made Trial upon Syrrup of Clove-july-flowers, the clear express'd Juice of the succulent Berries of Spina Cervina, or Buck-thorn (which I had long kept by me for the sake of its deep Colour) upon Red Roses, Infusion of Brazil, and divers other Vegetable Substances, on some of which crush'd (as is often mention'd) upon White Paper, (which is also to be under­stood in most of these Experiments, if no Circumstance of them argue otherwise) Spirit of Salt either made no considerable Change, or alter'd the Colour but from a Darker to a Lighter Red. How it will succeed in many other Vegetable Juices, [Page 263] and Infusions of the same Colour, I have at present so few at hand, that I must leave you to find it our your self. But as for the Operation of the other sorts of Salts upon these Red Substances, I found it not very Uniform, some Red, or Reddish Infusions, as of Roses, being turn'd thereby into a dirty Colour, but yet inclining to Green. Nor was the Syrrup of Clove-july-flowers turn'd by the Solution of Pot-ashes to a much better, though somewhat a Greener, Colour. Another sort of Red Infusions was by an Alcaly not turn'd into a Green, but advanc'd into a Crimson, as I shall have occasion to note ere long. But there were other sorts, as particularly the lovely Colour'd juice of Buckthorn Berries, that readily pass'd into a lovely Green.

EXPERIMENT XXVII.

Among other Vegetables, which we thought likely to afford Exceptions to the General Observation about the differing Changes of Colours produc'd by Acid and Sulphureous Salts, we thought fit to make Trial upon the Flowers of Jasmin, they being both White as to Colour, and esteem'd to be of a more Oyly nature than other Flowers. Whereupon having taken [Page 264] the White parts only of the Flowers, and rubb'd them somewhat hard with my Fin­ger upon a piece of clean Paper, it appear'd very little Discolour'd. Nor had Spirit of Salt, wherewith I moisten'd one part of it, any considerable Operation upon it. But Spirit of Urine, and somewhat more effe­ctually a strong Alcalizate Solution, did immediately turn the almost Colourless Paper moisten'd by the Juice of the Jasmin, not as those Liquors are wont to do, when put upon the Juices of other Flowers, of a good Green, but of a Deep, though some­what Greenish Yellow, which Experiment I did afterwards at several times repeat with the like success. But it seems not that a great degree of Unctuousness is necessary to the Production of the like Effects, for when we try'd the Experiment with the Leaves of those purely White Flowers that appear about the end of Winter, and are commonly call'd Snow drops, the event, was not much unlike that, which, we have been newly mentioning.

EXPERIMENT XXVIII.

Another sort of Instances to show, how much changes of Colours effected by Salts, depend upon the particular Texture of the [Page 265] Colour'd Bodies, has been afforded me by several Yellow Flowers, and other Vege­tables, as Mary-gold Leaves, early Prim-roses, fresh Madder, &c. For being rubb'd upon White Paper, till they im­bued it with their Colour, I found not, that by the addition of Alcalizate Liquors, nor yet by that of an Urinous Spirit, they would be turn'd either Green or Red: nor did so Acid a Spirit, as that of Salt, consi­derably alter their Colour, save that it seem'd a little to Dilute it. Only in some early Prim-roses it destroy'd the greatest part of the Colour, and made the Paper almost White agen. And Madder also afforded some thing peculiar, and very differing from what we have newly men­tion'd: For having gather'd some Roots of it, and, (whilst they were recent) ex­press'd upon White Paper the Yellow Juice, an Alcalizate Solution drop'd upon it did not turn it either Green or White, but Red. And the bruis'd Madder it self being drench'd with the like Alcalizate Solution, exchang'd also its Yellowishness for a Redness.

EXPERIMENT XXIX.

It may be of some Use towards the discovery of the nature of these Changes, which the Alimental Juice receives in some Vegetables, according to the differing de­grees of their Maturity, and according to the differing kinds of Plants of the same Denomination, to observe what Opera­tion Acid, Urinous, and Alcalizate Salts will have upon the Juices of the several sorts of the Vegetable Substances I have been mentioning.

To declare my meaning by an Example, I took from the same Cluster, one Black­berry full Ripe, and another that had not yet gone beyond a Redness, and rubbing a piece of White Paper, with the former, I observ'd, that the Juice adhering to it was of a dark Reddish Colour, full of little [Page 268] Black Specks, and that this Juice by a drop of a strong Lixivium, was immediately turn'd into a Greenish Colour deep enough, by as much Urinous Spirit into a Colour much of Kin to the former, though some­what differing, and fainter; and by a drop of Spirit of Salt into a fine and lightsome Red: where as the Red Berry being in like manner rubb'd upon Paper, left on it a Red Colour, which was very little alter'd by the Acid Spirit newly nam'd, and by the Urinous and Lixiviate Salts receiv'd changes of Colour differing from those that had been just before pro­duc'd in the dark Juice of the Ripe Black­berry.

I remember also, that though the Infu­sion of Damask-Roses would as well, though not so much, as that of Red; be heightned by Acid Spirits to an intense degree of Redness, and by Lixiviate Salts be brought to a Darkish Green; yet having for Trials sake taken a Rose, whose Leaves, which were large and numerous, like those of a Province Rose, were perfectly Yellow, though in a Solution of Salt of Tartar, they afforded a Green Blewish Tincture, yet I did not by an Acid Liquor obtain a Red one; all that the Saline Spirit I imploy'd, perform'd, being (if I much mis-remem­ber [Page 269] not) to Dilute somewhat the Yellow­ness of the Leaves. I would also have tried the Tincture of Yellow Violets, but could procure none. And if I were in those Islands of Banda, which are made Famous as well as Rich, by being the almost only places, where Cloves will prosper, I should think it worth my Curiosity to try, what Operation the three differing Kinds of Salts, I have so often mention'd, would have upon the Juice of this Sipce, (ex­press'd at the several Seasons of it) as it grows upon the Tree. Since good Au­thors inform us, (of what is remarkable) that these whether Fruits, or Rudiments of Fruits, are at first white, afterward Green, and then Reddish, before they be beaten off the Tree, after which being Dry'd before they are put up, they grow Blackish as we see them. And one of the recentest Herbarists informs us, that the Flower grows upon the top of the Clove it self, consisting of four small Leaves, like a Cherry Blossom, but of an excellent Blew. But (Pyrophilus) to return to our own Observations, I shall add, that I the rather choose, to mention to you an Example drawn from Roses, because that though I am apt to think, as I elsewhere advertise, that something may be guess'd at about [Page 270] some of the Qualities of the Juices of Ve­getables, by the Resemblance or Disparity that we meet with in the Changes made of their Colours, by the Operation of the same kinds of Salts; yet that those Con­jectures should be very warily made, may appear among other things, by the Instance I have chosen to give in Roses. For though, (as I formerly told you) the Dry'd Leaves, both of the Damask, and of Red ones, give a Red Tincture to Water sharpen'd with Acid Salts, yet the one sort of Leaves is known to have See Parkinson Th. Botan. Trib. 9. cap. 26. a Purgative faculty, and the other are often, and divers ways, imploy'd for Binding.

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 [Page 271] in Nicer Experiments you make use of. For, if 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 substitute a remark­able passage 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 Leather­dressers 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 Brass or Copper Kettle or Pan, and there suffer'd to abide three or four [Page 272] 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 Cir­cumstances, 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 [Page 273] 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 even 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 XXX.

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) [Page 274] of Decoction, run through a great Variety of differing Colours, before it come to that of the Noblest 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 [Page 275] passive 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 improcess 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 XXXI.

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 [Page 276] 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, Guaicum, 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 [Page 277] Sulphur made with Lixiviums, either of Calcin'd Tartar or Pot-ashes, and other Obvious examples, partly by this, that the true Glass 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 XXXII.

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 [Page 278] 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 Glass, where it has a good Thickness, to be of a deep Red, yet if you shake the Glass, 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 Glass, 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 XXXIII.

But to proceed to the Experiments I was about to deliver; First, Oyl or Spirit [Page 279] 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 XXXIV.

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 [Page 280] be well Drawn, will upon a little Agitation of the Vial first unstop'd (especially if it be held in a Warmer hand) send 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 XXXV.

The third and last Experiment I shall now mention to shew, how prone 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, [Page 281] 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 Multi­tude 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 XXXVI.

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; [Page 282] 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 Advertisement, 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 Circum­stance 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 reason: 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 [Page 283] 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 Turnso, 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 Parkinson, Thea, Bot. Trib. 4. cap. 12. 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. 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 Circumstances, very [Page 284] 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 [Page 285] 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 Circumstances, 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 Passives, (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 [Page 286] 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 Mass 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 elswhere show it not to be destitute 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 [Page 287] 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 [Page 288] a serious Inquiry; which I shall therefore recommend to Pyrophilus and his Ingenious Friends.

EXPERIMENT XXXVII.

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 [Page 289] 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 [Page 290] 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 XXXVIII.

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 [Page 291] 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 Liquors, into which such Fumes convene, (for though we will not deny, that by skill and care a Reddish Liquor may be obtain'd from Nitte) yet the common Spirit of it, in the making ev'n of which store of these Red Fumes are wont to pass 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 Liquors I elsewhere observe to carry over [Page 292] 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 cases done) in conveniently shap'd Glasses, 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, [Page 293] some of them purely White. And 'tis the Prescription of some Glass-men by ex­quisitely mingling a convenient proportion of Brimstone, Sal-Armoniack, and Quick-silver, 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 Masses, 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 [Page 294] 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 Glister'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 XXXIX.

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 [Page 295] 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 quantity of the above-mention'd Spirit of Urine.

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 [Page 303] 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 [Page 304] 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 [Page 305] 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 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 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 [Page 306] 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 Corpuseles 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 [Page 307] 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 [Page 308] 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. 34 ^th. 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 dissolv'd in fair Water, [Page 309] and Filtred, gave a Solution Limpid and Colourless, like that of the other Subli­mates, and yet an Alcaly 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 Cor­puseles, that though in our 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 [Page 310] 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.

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 Glass, about a spoonfull of this tincted Liquor, (of which I us'd to keep a Quantity 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.

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 multitude 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 [Page 324] too, should immediately acquire a rich new Colour upon the bare affusion of Spring-Water destitute as well of adventi­tious 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 Glass 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 pour­ing on it a large quantity of fair Water, we did almost in a moment perceive it to pass from a Milky Colour to one of the loveliest Light Yellows that ever we had beheld. Nor is the Turbith Mineral, that Chymists extol for its power to Salivate, and for other vertues, of a Colour much in­feriour to this, though it be often made with a differing proportion of the In­gredients, [Page 325] a more troublesome way. For Beguinus, who calls it Mercu­rius praecipitatus optimus, takes Beguinus. Tyr. Chy. Lib. 2 ^o. Cap. 13 ^o. to one part of Quick-Silver, but two of Liquor, and that is Rectifi'd Oyl of Sulphur, which is (in Eng­land at least) far more scarce and dear than Oyl of Vitriol; he also requires a previous Digestion, two or three Cohobations, and frequent Ablutions with hot Distill'd Wa­ter, with other prescriptions, which though they may conduce to the Goodness of the Medicine, which is that he aims at, are troublesome, and, our Tryals have inform'd you unnecessary to the obtaining the Lemmon Colour which he regards not. But though we have very rarely seen either in Painters Shops, or elsewhere a finer Yellow than that which we have divers times this way produc'd (which is the more considerable, because durable and pleasant Yellows are very hard to be met with, as may appear by the great use which Painters are for its Co­lours sake fain to make of that pernicious and heavy Mineral, Orpiment) yet I fear our Yellow is too costly, to be like to be imploy'd by Painters, unless about Choice pieces of Work, nor do I know how well it will agree with every Pigment, especially, with Oyl'd Colours. And whether this [Page 326] Experiment, though it have seem'd some­what strange to most we have shown it to, be really of another Nature than those wherein Saline Liquors are imploy'd, may, as we formerly also hinted, be so plausibly, doubted, that whether the Water pour'd on the Calx, do barely by imbibing some of its Saline parts alter its Colour by alte­ring its Texture, or whether by dissolving the Concoagulated Salts, it does become a Saline Menstruum, and, as such, work upon the Mercury, I freely leave to you (Pyrophi­lus) to consider. And that I may give you some Assistance in your Enquiry, I will not only tell you, that I have several times with fair Water wash'd from this Calx, good store of strongly tasted Corpuscles, which by the abstraction of the Menstruum, I could reduce into Salt; but I will also subjoyn an Experiment, which I devis'd, to shew among other things, how much a real and permanent Colour may be as it were drawn forth by a Liquor that has neither Colour, nor so much as Saline or other Active parts, provided it can but bring the parts of the Body it imbibes to convene in­to clusters dispos'd after the manner requi­site to the exhibiting of the emergent Co­lour. The Experiment was this.

EXPERIMENT XLIII.

We took good common Vitriol, and ha­ving beaten it to Powder, and put it into a Crucible, we kept it melted in a gentle heat, till by the Evaporation of some parts, and the shuffling of the rest, it had quite lost its former Colour, what remain'd we took out, and found it to be a friable Calx, of a dirty Gray. On this we pour'd fair Water, which it did not Colour Green or Blew, but only seem'd to make a muddy mixture with it, then stopping the Vial wherein the Ingredients were put, we let it stand in a quiet place for some dayes, and after many hours the water having dissolv'd a good part of the imperfectly calcin'd Body, the Yitriolate Corpuscles swiming to and fro in the Liquor, had time by their opportune Occursions to constitute many little Masses of Vitriol, which gave the water they im­pregnated a fair Vitriolate Colour; and this Liquor being pour'd off, the remaining dir­ty Powder did in process of time commu­nicate the like Colour, but not so deep, to a second parcel of cleer Water that we pour'd on it. But this Experiment Pyro­philus is, (to give you that hint by the way) of too Luciferons a Nature to be fit to be [Page 328] fully prosecuted, now that I am in haste, and willing to dispatch what remains. And we have already said of it, as much as is re­quisite to our present purpose.

EXPERIMENT XLIV.

It may (Pyrophilus) somewhat contri­bute towards the shewing how much some Colours depend upon the less or greater mixture, and (as it were,) Contemperation of the Light with shades, to observe, how that sometimes the number of Particles, of the same Colour, receiv'd into the Pores of a Liquor, or swimming up and down in it, do seem much to vary the Colour of it. I could here present you with particular instances to show, how in many (if not most) con­sistent Bodyes, if the Colour be not a Light one, as White, Yellow, or the like, the closeness of parts in the Pigments makes it look Blackish, though when it is display'd and laid on thinly, it will perhaps appear to be either Blew, or Green, or Red. But the Colours of consistent Pigments, not being those which the Preamble of this Experi­ment has lead you to expect Examples in, I shall take the instances I am now to give you, rather from Liquors than Dry Bodyes. If then you put a little fair Water into a [Page 329] cleer and slender Vial, (or rather into one of those pipes of Glass, which we shall by and by mention;) and let fall into it a few drops of a strong Decoction or Infusion of Cochineel, or (for want of that) of Brazil; you may see the tincted drops descend like: little Clouds into the Liquor; through which, if, by shaking the Vial, you diffuse them, they will turn the water either of a Pinck Colour, or like that which is wont to be made by the washing of raw flesh in fair Water; by dropping a little more of the Decoction, you may heighten the Colour into a fine Red, almost like that which en­nobles Rubies; by continuing the affusion, you may bring the Liquor to a kind of a Crimson, and afterwards to a Dark and O­pacous Redness, some what like that of Clotted Blood. And in the passage of the Liquor from one of these Colours to the o­ther, you may observe, if you consider it at­tentively, divers other less noted Colours belonging to Red, to which it is not easie to give Names; especially considering how much the proportion of the Decoction to the fair Water, and the strength of that De­coction, together with that of the trajected Light and other Circumstances, may vary the Phoenomena of this Experiment. For the convenienter making whereof, we use [Page 330] nstead of a Vial, any slender Pipe of Glass ofabout a foot or more in length, and about the thickness of a mans little finger; For, if leaving one end of this Pipe open, you Seal up the other Hermetically, (or at least stop it exquisitely with a Cork well fitted to it, and over-laid with hard Sealing Wax melted, and rubb'd upon it;) you shall have a Glass, wherein may be observ'd the Va­riations of the Colours of Liquors much better than in large Vials, and wherein Ex­periments of this Nature may be well made with very small quantities of Liquor. And if you please, you may in this Pipe produce variety of Colours in the various parts of the Liquor, and keep them swimning upon one another unmix'd for a good while. And some have marveil'd to see, what variety of Colours we have sometimes (but I confess rather by chance than skill) produc'd in those Glasses, by the bare infusion of Bra­zil, variously diluted with fair Water, and alter'd by the Infusion of several Chymical Spirits and other Saline Liquors devoid themselves of Colour, and when the whole Liquor is reduc'd to an Uniform degree of Colour, I have taken pleasure to make that very Liquor seem to be of Colours gradu­ally differing, by filling with it Glasses of a Conical figure, (whether the Glass have [Page 331] its basis in the ordinary position, or turn'd upwards.) And yet you need not Glasses of an extraordinary shape to see an instance of what the vari'd mixture of Light and Shadow can do in the diversifying of the Colour. For if you take but a large round Vial, with a somewhat long and slender Neck, and filling it with our Red Infusion of Brazil, hold it against the Light, you will discern a notable Disparity betwixt the Co­lour of that part of the Liquor which is in the Body of the Vial, and that which is more pervious to the Light in the Neck. Nay, I remember, that I once had a Glass and a Blew Liquor (consisting chiefly (or only, if my memory deceive me not,) of a certain Solution of Verdigreafe) so fitted for my purpose, that though in other Glasses the Experiment would not succeed, yet when that particular Glass was fill'd with that Solution, in the Body of the Vial it ap­pear'd of a Lovely Blew, and in the neck, (where the Light did more dilute the Co­lour,) of a manifest Green; and though I suspected there might be some latent Yel­lowness in the substance of the neck of the Glass, which might with the Blew com­pose that Green, yet was I not satisfi'd my self with my Conjecture, but the thing seem'd odd to me, as well as to divers curi­ous [Page 332] persons to whom it was shown. And I lately had a Broad piece of Glass, which being look'd on against the Light seem'd cleer enough, and held from the Light ap­pear'd very lightly discolour'd, and yet it was a piece knock'd off from a great lump of Glass, to which if we rejoyn'd it, where it had been broken off, the whole Mass was as green as Grass. And I have several times us'd Bottles and stopples that were both made (as those, I had them from assur'd me) of the very same Metall, and yet whilst the bottle appear'd but inclining towards a Green, the Stopple (by reason of its great thickness) was of so deep a Colour that you would hardly believe they could possibly be made of the same materials. But to satis­fie some Ingenious Men, on another occa­sion, I provided my self of a flat Glass (which I yet have by me,) with which if I look against the Light with the Broad side obverted to the Eye, it appeares like a good ordinary window Glass; but if I turn the Edge of it to my Eye, and place my Eye in a convenient posture in reference to the Light, it may contend for deepness of Co­lour with an Emerald. And this Greenness puts me in mind of a certain thickish, but not consistent Pigment I have sometimes made, and can show you when you please, [Page 333] which being dropp'd on a piece of White Paper appears, where any quantity of it is fallen, of a somewhat Crimson Colour, but being with ones finger spread thinly on the Paper does presently exhibit a fair Green, which seems to proceed only from its disclosing its Colour upon the Extenua­tion of its Depth into Superficies, if the change be not somewhat help'd by the Co­lours degenerating upon one or other of the Accounts formerly mention'd. Let me add, that having made divers Tryals with that Blew substance, which in Painters Shops is call'd Litmase, we have sometimes taken Pleasure to observe, that being dissolv'd in a due proportion of fair Water, the Solu­tion either oppos'd to the Light, or dropp'd upon White paper, did appear of a deep Colour betwixt Crimson and Purple; and yet that being spread very thin on the Paper and suffer'd to dry on there, the Paper was wont to appear Stain'd of a Fine Blew. And to satisfie my selfe, that the diversity came not from the Paper, which one might suspect capable of inbibing the Liquor, and altering the Colour, I made the Tryal up­on a flat piece of purely White Glass'd Earth, (which I sometimes make use of a­bout Experiments of Colours) with an Event not unlike the former.

[Page 334] And now I speak of Litmass, I will add, that having this very day taken a piece of it, that I had kept by me these several years, to make Tryals about Colours, and having let fall a few drops of the strong Infusion of it in fair water, into a fine Crystal Glass, shap'd like an inverted Cone, and almost full of fair Water, I had now (as former­ly) the pleasure to see, and to show others, how these few tincted drops variously dis­persing themselves through the Limpid Water, exhibited divers Colours, or va­rieties of Purple and Crimson. And when the Corpuscles of the Pigment seem'd to have equally diffus'd themselves through the whole Liquor, I then by putting two or three drops of Spirit of Salt, first made an odd change in the Colour of the Liquor, as well as a visible commotion among its small parts, and in a short time chang'd it wholly into a very Glorious Yellow, like that of a Topaz. After which if I let fall a few drops of the strong and heavy Solution of Pot-ashes, whose weight would quickly carry it to the sharp bottome of the Glass, there would soon appear four very pleasant and distinct Colours; Namely, a Bright, but Dilute Colour at the picked bottome of the Glass; a Purple, a little higher; a deep and glorious Crimson, (which Crim­son [Page 335] seem'd to terminate the operation of the Salt upward) in the confines betwixt the Purple and the Yellow; and an Excellent Yellow, the same that before enobled the whole Liquor, reaching from thence to the top of the Glass. And if I pleas'd to pour very gently a little Spirit of Sal Armoniack, upon the upper part of this Yellow, there would also be a Purple or a Crimson, or both, generated there, so that the unalter'd part of the Yellow Liquor appear'd in­tercepted betwixt the two Neighbouring Colours.

My scope in this 3 ^d. Experiment (Py­rophilus) is manifold, as first to invite you to be wary in judging of the Colour of Li­quors in such Glasses as are therein recom­mended to you, and consequently as much, if not more, when you imploy other Glasses. Secondly, That you may not think it strange, that I often content my self to rub upon a piece of White paper, the Juice of Bodies I would examine, since not onely I could not easily procure a sufficient Quan­tity of the juices of divers of them; but in several Cases the Tryals of the quantities of such Juices in Glasses would make us more lyable to mistakes, than the way that in those cases I have made use of. Thirdly, I hope you will by these and divers other [Page 336] particulars deliver'd in this Treatise, be ea­sily induc'd to think that I may have set down many Phoenomena. very faithfully, and just as they appear'd to me, and yet by reason of some unheeded circumstance in the conditions of the matter, and in the de­gree of Light, or the manner of trying the Experiment, you may find some things to vary from the Relations I make of them. Lastly, I design'd to give you an opportu­nity to free your self from the amazement which possesses most Men, at the Tricks of those Mountebancks that are commonly call'd Water-drinkers. For though not on­ly the vulgar, but ev'n many persons that are far above that Rank, have so much ad­mir'd to see, a man after having drunk a great deal of fair water, to spurt it out again in the form of Claret Wine, Sack, and Milk, that they have suspected the intervening of Magick, or some forbidden means to effect what they conceived above the power of Art; yet having once by chance had occa­sion to oblige a Wanderer that made pro­fession of that and other Jugling Tricks, I was easily confirm'd by his Ingenious con­fession to me, That this so much Admir'd Art, indeed consisted rather in a few Tricks, than in any great Skill, in altering the Na­ture and Colours of things. And I am easy [Page 337] to be perswaded, that there may be a great deal of Truth in a little Pamphlet Printed divers years ago in English, wherein the Author undertakes to discover, and that (if I mistake not) by the confession of some of the Complices themselves, That a famous Water-drinker then much Admir'd in Eng­land, perform'd his pretended Transmuta­tions of Liquors by the help of two or three inconsiderable preparations and mixtures of not unobvious Liquors, and chiefly of an Infusion of Brazil variously diluted and made Pale or Yellowish, (and otherwise alter'd) with Vinegar, the rest of their work being perform'd by the shape of the Glasses, by Craft and Legerdemane. And for my part, that which I marvel at in this business; is, the Drinkers being able to take down so much Water, and spout it out with that violence; though Custome and a Vomit sea­sonably taken before hand, may in some of them much facilitate the work. But as for the changes made in the Liquors, they were but few and slight in comparison of those, that the being conversant in Chymical Ex­periments, and dextrous in applying them to the Transmuting of Colours; may easily enough enable a man to make, as ev'n what has been newly deliver'd in this, and the foregoing Experiment; especially if we add [Page 338] to it the things contained in the XX, the XXXIX and the XL. Experiments, may perhaps have already perswaded You.

EXPERIMENT XLV.

You may I presume (Pyrophilus) have taken notice, that in this whole Treatise, I purposely decline (as far as I well can) the mentioning of Elaborate Chymical Expe­riments, for fear of frighting you by their tediousness and difficulty; but yet in confir­mation of what I have been newly telling you about the possibility of Varying the Colours of Liquors, better than the Water-drinkers are wont to do, I shall add, that Helmont used to make a preparation of Steel, which a very Ingenious Chymist, his Sons Friend, whom you know, sometimes employes for a succedaneum to the Spaw­waters, by Diluting this Essentia Martis Li­quida (as he calls it) with a due propor­tion of Water. Now that for which I mention to you this preparation, (which as he communicated to me, I know he will not refuse to Pyrophilus) is this, that though the Liquor (as I can shew you when you please) be almost of the Colour of a Ger­man (not an Oriental) Amethyst, and consequently remote enough from Green, [Page 339] yet a very few drops being let fall into a Large proportion of good Rhenish, or (in want of that) White Wine (which yet do's not quite so well) immediately turn'd the Liquor into a lovely Green, as I have not without delight shown several curious Per­sons. By which Phoenomenon you, may learn, among other things, how requisite it is in Experiments about the changes of Colours heedfully to mind the Circumstan­ces of them; for Water will not, as I have purposely try'd, concurr to the production of any such Green, nor did it give that Co­lour to moderate Spirit of Wine, wherein I purposely dissolv'd it, and Wine it self is a Liquor that few would suspect of being able to work suddenly any such change in a Metalline preparation of this Nature; and to satisfie my self that this new Colour proceeds rather from the peculiar Texture of the Wine, than from any greater Acidi­ty, that Rhenish or White-wine (for that may not absurdly be suspected) has in com­parison of Water; I purposely sharpen'd the Solution of this Essence in fair Water, with a good quantity of Spirit of Salt, not­withstanding which, the mixture acquir'd no Greenness. And to vary the Experi­ment a little, I try'd, that if into a Glass of Rhenish Wine made Green by this Essence, [Page 340] I dropp'd an Alcalizate Solution, or Uri­nous Spirit, the Wine would presently grow Turbid, and of an odd Dirty Colour: But if instead of dissolving the Essence in Wine, I dissolv'd it in fair Water sharpen'd per­haps with a little Spirit of Salt, then either the Urinious Spirit of Sal Armoniack, or the Solution of the fix'd Salt of Pot-ashes would immediately turn it of a Yellowish Colour, the fix'd or Urinous Salt Precipi­tating the Vitriolate substance contain'd in the Essence. But here I must not forget to take notice of a circumstance that deserves to be compar'd with some part of the fore-going Experiment, for whereas our Essence imparts a Greenness to Wine, but not to Water, the Industri­ous Libr. 2 ^•o. Cap. 34 ⁰. Olaus Wormius in his late Musaeum tells us of a rare kind of Turn-Sole which he calls Bezetta Rubra given him by an. Apothecary that knew not how it was made, whose lovely Redness would be easily communicated to Water, if it were immers'd in it; but scarce to Wine, and not at all to Spirit of Wine, in which last circumstance it agrees with what I late­ly told you of our Essence, notwithstand­ing their disagreement in other particulars.

EXPERIMENT XLVI.

We have often taken notice, as of a re­markable thing, that Metalls as they appear to the Eye, before they come to be farther alter'd by other Bodyes, do exhibit Co­lours very different from those which the Fire and the Menstruum, either apart, or both together, do produce in them; especially considering that these Metalline Bodyes are after all these disguises reducible not only to their former Metalline Consistence and o­ther more radical properties, but to their Colour too, as if Nature had given divers Metalls to each of them a double Colour, an External, and an Internal; But though upon a more attentive Consideration of this difference of Colours, it seem'd propable to me, that divers (for I say not all) of those Colours which we have just now call'd In­ternal, are rather produc'd by the Coalition of Metalline Particles with those of the Salts, or other Bodyes employ'd to work on them, than by the bare alteration of the parts of the Metalls themselves: and though therefore we may call the obvious Colours, Natural or Common, & the others Adven­titious, yet because such changes of Colours, from whatsoever cause they be resolv'd to [Page 342] proceed may be properly enough taken in to illustrate our present Subject, we shall not scruple to take notice of some of them, especially because there are among them such as are produc'd without the interven­vention of Saline Menstruums. Of the Adven­titious Colours of Metalline Bodies the Chief sorts seem to be these three. The first, such Colours as are produc'd without other Additaments by the Action of the fire upon Metalls. The next such as emerge from the Coalition of Metalline Particles with those of some Menstruum imploy'd to Corrode a Metall or Precipitate it; And the last, The Colours afforded by Metalline Bodyes ei­ther Colliquated with, or otherwise Pene­trating into, other Bodies, especially fusible ones. But these (Pyrophilus,) are only as I told you, the Chief sorts of the adventi­tious Colours of Metalls, for there may o­thers belong to them, of which I shall here­after have occasion to take notice of some, and of which also there possibly may be others that I never took notice of.

And to begin with the first sort of Colours, 'tis well enough known to Chymists, that Tin being Calcin'd by fire alone is wont to afford a White Calx, and Lead Calcin'd by fire alone affords that most Common Red-Powder we call Minium: Copper al­so [Page 343] Calcin'd per se, by a long or violent fire, is wont to yield (as far as I have had occa­sion to take notice of it) a very Dark or Blackish Powder; That Iron likewise may by the Action of Reverberated flames be turn'd into a Colour almost like that of Saffron, may be easily deduc'd from the Preparation of that Powder, which by rea­son of its Colour and of the Metall 'tis made of is by Chymists call'd, Crocus Martis per se. And that Mercury made by the stress of Fire, may be turn'd into a Red Powder, which Chymists call Precipitate per se, I elsewhere more particularly declare.

EXPERIMENT XLVII.

The Adventitious Colours produc'd up­on Metalls, or rather with them, by Saline Liquors, are many of them so well known to Chymists, that I would not here men­tion them, but that besides a not un-need­ed Testimony, I can add something of my own, to what I shall repeat about them, and divers Experiments which are familiar to Chymists, are as yet unknown to the greatest part of Ingenious Men.

That Gold dissolv'd in Aqua Regia en­nobles the Menstruum with its own Colour, is a thing that you cannot (Pyrophilus,) but have often seen. The Solutions of Mercu­ry in Aqua-fortis are not generally taken notice of, to give any notable Tincture to the Menstruum; but sometimes when the [Page 346] Liquor first falls upon the Quick Silver, I have observ'd a very remarkable, though not durable, Greenness, or Blewness to be produc'd, which is a Phoenomenon not un­fit for you to consider, though I have not now the leisure to discourse upon it. Tin Corroded by Aqua-fortis till the Menstru­um will work no farther on it, becomes ex­ceeding White, but as we else where note, does very easily of it self acquire the con­sistence, not of a Metalline Calx, but of a Coagulated matter, which we have observ'd with pleasure to look so like, either to curdled Milk, or curdled Whites of Eggs, that a person unacquainted with such Solu­tions may easily be mistaken in it. But when I purposely prepar'd a Menstruum that would dissolve it as Aqua-fortis dissolves Silver, and not barely Corrode it, and quick­ly let it fall again, I remember not that I took notice of any particular Colour in the Solution, as if the more Whitish Metalls did not much Tinge their Menstruums, though the conspicuously Colour'd Metalls as Gold, and Copper, do. For Lead dissolv'd in Spirit of Vinegar or Aqua-fortis gives a Solution cleer enough, and if the Menstruum be abstracted appears either Diaphanous or White. Of the Colour of Iron we have elsewhere said something: And 'tis worth [Page 347] noting, that, though if that Metall be dis­solv'd in oyl of Vitriol diluted with water, it affords a Salt or Magistery so like in co­lour, as well as some other Qualities, to other green Vitriol, that Chymists do not improperly call it Vitriolum Martis; yet I have purposely try'd, that, by changing the Menstruum, and pouring upon the filings of Steel, instead of oyl of Vitriol, Aqua Fortis, (whereof as I remember, I us'd 4 parts to one of the Metall) I obtain'd not a Green, but a Saffron Colour Solution; or rather a thick Liquor of a deep but yel­lowish Red. Common Silver, such as is to be met with in Coines, being dissolv'd in Aqua fortis, yields a Solution tincted like that of Copper, which is not to be won­dred at, because in the coining of Silver, they are wont (as we elsewhere particular­ly inform you) to give it an Allay of Cop­per, and that which is sold in shops for re­fined silver, is not (so far as we have tryed) so perfectly free from that ignobler Metall, but that a Solution of It in Aqua fortis, will give a Venereal Tincture to the Menstru­um. But we could not observe upon the solution of some Silver, which was perfect­ly refin'd, (such as some that we have, from which 8 or 10 times its weight of Lead has been blown off) that the Men­struum [Page 348] though held against the Light in a Crystal Vial did manifestly disclose any Tincture, only it seem'd sometimes not to be quite destitute of a little, but very faint Blewishness.

But here I must take notice, that of all the Metalls, there is not any which doth so easily and constantly disclose its unobvious colour as Copper doth. For not only in acid Menstruums as Aqua Fortis and Spirit of Vinegar, it gives a Blewish green solu­tion, but if it be almost any way corroded, it appears of one of those two colours, as may be observ'd in Verdigreese made several wayes, in that odd preparation of Venus, which we elsewhere teach you to make with Sublimate, and in the common Vitri­ols of Venus deliver'd by Chymists; and so constant is the disposition of Copper, not­withstanding the disguise Artists put upon it, to disclose the colour we have been men­tioning, that we have by forcing it up with Sal Armoniack obtain'd a Sublimate of a Blewish Colour. Nay a famous Spagyrist affirms, that the very Mercury of it is green, but till he teach us an intelligible way of making such a Mercury, we must content our selves to inform you, that we have had a Cupreous Body, that was Praecipitated out of a distill'd Liquor, that seem'd to be [Page 349] the Sulphur of Venus, and seem'd even when flaming, of a Greenish Colour. And indeed Copper is a Metall so easily wrought upon by Liquors of several kinds; that I should tell you, I know not any Mineral, that will concurr to the production of such a variety of Colours as Copper dissolv'd in several Menstruums, as Spirit of Vinegar, Aqua fortis, Aqua Regis, Spirit of Nitre, of Urine, of Soot, Oyls of several kinds, and I know not how many other Liquors, if the variety of somewhat differing colours (that Copper will be made to assume, as it is wrought upon by several Liquors) where not comprehended within the Li­mits of Greenish Blew, or Blewish Green.

And yet I must advertise you (Pyrophi­lus) that being desirous to try if I could not make with crude Copper a Green Solu­tion without the Blewishness that is wont to accompany its Vulgar Solutions, I be­thought my self of using two Menstruums, which I had not known imploy'd to work on this Metall, and which I had certain Rea­sons to make Tryal of, as I successfully did. The one of these Liquors (if I much misremember not) was Spirit of Sugar distill'd in a Retort, which must be warily done, (if you will avoid breaking your [Page 350] glasses) and the other, Oyl or Spirit of Tur­pentine, which affords a fine Green Solution that is useful to me on several occasions. And yet to shew that the adventitious co­lour may result, as well from the true and permanent Copper it self, as the Salts wherewith 'tis corroded, I shall add, that if you take a piece of good Dantzick Cop­peris, or any other Vitriol wherein Venus is praedominant, and having moistened it in your Mouth, or with fair water, rubb it upon a whetted knife, or any other bright piece of Steel or Iron, it will (as we have formerly told you) presently stain the Steel with a Reddish colour, like that of Copper; the reason of which, we must not now stay to inquire.

EXPERIMENT XLVIII.

The third chief sort of the Adventitious Colours of Metals, is, that which is pro­duc'd by associating them (especially when Calcin'd) with other fusible Bodies, and Principally Venice, and other fine Glass devoid of Colour.

I have formerly given you an Example, whereby it may appear, that a Metal may impart to Glass a Colour much differing from its own, when I told you, how with Silver, I had given Glass a lovely Golden Colour. And I shall now add, that I have Learn'd from one of the Chief Artificers that sells Painted Glass, that those of his Trade Colour it Yellow with a prepara­tion of the Calx of Silver. Though having lately had occasion among other Tryals to mingle a few grains of Shell-silver (such as is imploy'd with the Pensil and Pen) with a convenient proportion of povvder'd Cry­stal Glass, having kept them tvvo or three [Page 356] hours in fusion, I was surpriz'd to find the Colliquated Mass to appear upon breaking the Crucible of a lovely Saphirine Blew, which made me suspect my Servant might have brought me a wrong Crucible, but he constantly affirm'd it to be the same where­in the Silver was put, and considerable Cir­cumstances countenanc'd his Assertion, so that till I have opportunity to make farther Tryal, I cannot but suspect, either that Silver which is not (which is not very probable) brought to a perfect Fusion and Colliqua­tion with Glass, may impart to it other Co­lours than when Neal'd upon it, or else (which is less unlikely) that though Silver Beaters usually chuse the finest Coyn they can get, as that which is most extensive un­der the Hammer, yet the Silver-leaves of which this Shel-silver was made, might re­tain so much Copper as to enable it to give the predominant Tincture to the Glass.

For, I must proceed to tell you (Pyro­philus) as another instance of the Adventi­tious Colours of Metals, that which is something strange, Namely, That though Copper Calcin'd per se affords but a Dark and basely Colour'd Calx, yet the Glas­men do with it, as themselves inform me, Tinge their Glass green. And I remember, that when once we took some crude Cop­per, [Page 357] and by frequent Igintion quenching it in Water had reduc'd it to a Dark and Ill­colour'd Powder, and afterwards kept it in Fusion in about a 100. times its weight of fine Glass, we had, though not a Green, yet a Blew colour'd Mass, which would per­haps have been Green, if we had hit right upon the Proportion of the Materials, and the Degree of Fire, and the Time wherein it ought to be kept in Fusion, so plentifully does that Metal abound in a Venerial Tin­cture, as Artists call it, and in so many wayes does it disclose that Richness. But though Copper do as we have said give somewhat near the like Colour to Glass, which it does to Aqua-fortis, yet it seems worth inquiry, whether those new Colours which Mineral Bodies disclose in melted Glass, proceed from the Coalition of the Corpuscles of the Mineral with the Parti­cles of the Glass as such, or from the Action (excited or actuated by fire) of the Alca­lizate Salt (which is a main Ingredient of Glass,) upon the Mineral Body, or from the concurrence of both these Causes, or else from any other. But to return to that which we were saying, we may observe that Putty made by calcining together a proportion of Tin and Lead, as it is it self a White Calx, so does it turn the Pitta di Crystalio (as the [Page 358] Glassmen call the matter of the Purer sort of Glass, wherewith it is Colliquated into a White Mass, which if it be opacous e­nough is employ'd, as we elsewhere declare, for White Amel. But of the Colours which the other Metals may be made 'to produce in Colourless Glass, and other Vitrifiable Bodies, that have native Colours of their own, I must leave you to inform you self upon Tryal, or at least must forbear to do it till another time, considering how many Annotations are to follow, upon what has in this and the two former Experiments been said already.

EXPERIMENT XLIX.

Meeting the other day, Pyrophilus, in an Italian book, that treats of other matters, with a way of preparing what the Au­thor calls a Lacca of Vegetables, by which the Italians mean a kind of Extract fit for Painting, like that rich Lacca in English commonly call'd Lake, which is imploy'd by Painters as a glorious Red. And finding the Experiment not to be inconsiderable, and very defectively set down, it will not be amiss to acquaint you with what some Tryals have inform'd us, in reference to this [Page 370] Experiment, which both by our Italian Author, and by divers of his Countrymen, is look'd upon as no trifling Secret.

Take then the root call'd in Latin Curcu­ma, and in English Turmerick, (which I made use of, because it was then at hand, and is among Vegetables fit for that pur­pose one of the most easiest to be had) and when it is beaten, put what Quantity of it you please into fair Water, adding to every pound of Water about a spoonfull or better of as strong a Lixivium or Solution of Pot-ashes as you can well make, clarifying it by Filtration before you put it to the Decoct­ing water. Let these things boyl, or rather simper over a soft Fire in a clean glaz'd Earthen Vessel, till you find by the Immer­sion of a sheet of White Paper (or by some other way of Tryal) that the Liquor is suf­ficiently impregnated with the Golden Tincture of the Turmerick, then take the Decoction off the Fire, and Filter or Strain it that it may be clean, and leisurely drop­ping into it a strong Solution of Roch Al­lum, you shall find the Decoction as it were curdl'd, and the tincted part of it either to emerge, to subside, or to swim up and down, like little Yellow flakes; and if you pour this mixture into a Tunnel lin'd with Cap Paper, the Liquor that Filtred former­ly [Page 371] so Yellow, will now pass clean thorow the Filtre, leaving its tincted, and as it were curdled parts in the Filtre, upon which fair Water must be so often pour'd, till you have Dulcifi'd the matter therein contain'd, the sign of which Dulcification is (you know) when the Water that has pass'd through it, comes from it as tastless as it was pour'd on it. And if without Fil­tration you would gather together the flakes of this Vegetable Lake, you must pour a great Quantity of fair Water upon the Decoction after the affusion of the Al­luminous Solution, and you shall find the Liquor to grow clearer, and the Lake to settle together at the bottom, or emerge to the top of the Water, though some­times having not pour'd out a sufficient Quantity of fair Water, we have observ'd the Lake partly to subside, and partly to emerge, leaving all the middle of the Liquor clear. But to make this Lake fit for use, it must by repeated affusions of fresh Water, be Dulcifi'd from the adhering Salts, as well as that separated by Filtration, and be spread and suffer'd to dry lei­surely upon pieces of Cloth, with Brown Paper, or Chalk, or Bricks un­der [Page 372] them to imbibe the Moi­sture The Curious Reader that desires fur­ther Information concerning Lakes, may Resort to the 7th Book of Neri's Art of Glass, Englished (6 or 7 years since the Writing of this 49th Experiment) and Illustrated with Learned Observations, by the Inquisitive and Experienc'd Dr. Charles Merret..

EXPERIMENT L.

Yet here, Pyrophilus, I must take leave to insert an Experiment, though perhaps you'l think its coming in here an Intrusion, For I confess its more proper place would have been among those Experiments, that were brought as proofs and applications of our Notions concerning the differences of [Page 380] Salts; but not having remembred to insert it in its fittest place, I had rather take no­tice of it in this, than leave it quite unmen­tion'd: partly because it doth somewhat differ from the rest of our Experiments about Colours, in the way whereby 'tis made; and partly because the grounds upon which I devis'd it, may hint to you some­what of the Method I use in Designing and Varying Experiments about Colours, and upon this account I shall inform you, not only What I did, but Why I did it.

I consider'd then that the work of the former Experiments was either to change the Colour of a Body into another, or quite to destroy it, without giving it a suc­cessor, but I had a mind to give you also a way, whereby to turn a Body endued with one Colour into two Bodies, of Colours, as well as consistencies, very distinct from each other, and that by the help of a Body that had it self no Colour at all. In order to this, I remembered, that finding the Acidi­ty of Spirit of Vinegar to be wholly de­story'd by its working upon Minium (or calcin'd Lead) whereby the Salin parti­cles of the Menstruum have their Taste and Nature quite alter'd, I had, among other Conjectures I had built upon that change, rightly concluded, that the Solution of Lead [Page 381] in Spirit of Vinegar would alter the Colour of the Juices and Infusions of several Plants, much after the like manner that I had found Oyl of Tartar to do; and according­ly I was quickly satisfied upon Tryal, that the Infusion of Rose-leaves would by a small quantity of this Solution well mingl'd with it, be immediately turn'd into a some­what sad Green.

And further, I had often found, that Oyl of Vitriol, though a potently Acid Menstru­um, will yet Praecipitate many Bodies, both Mineral and others, dissolv'd not onely in Aqua fortis (as some Chymists have ob­serv'd) but particularly in Spirit of Vine­gar, and I have further found, that the Calces or Powders Praecipitated by this Li­quor were usually fair and White.

Laying these things together, 'twas not difficult to conclude, that if upon a good Tincture of Red Rose-leaves made with fair Water, I dropp'd a pretty quantity of a strong and sweet Solution of Minium, the Liquor would be turn'd into the like muddy Green Substance, as I have formerly inti­mated to You, that Oyl of Tartar would reduce it to, and that if then I added a con­venient quantity of good Oyl of Vitriol, this last nam'd Liquor would have two distinct operations upon the Mixture, the one, that [Page 382] it would Praecipitate that resolv'd Lead in the form of a White Powder; the other, that it would Clarifie the muddy Mixture, and both restore, and exceedingly heighten the Redness of the Infusion of Roses, which vvas the most copious Ingredient of the Green composition, and accordingly trying the Experiment in a Wine glass sharp at the bottom (like an inverted Cone) that the subsiding Powder might seem to take up the more room, and be the more con­spicuous, I found that when I had shaken the Green Mixture, that the colour'd Li­quor might be the more equally dispersed, a few drops of the rectifi'd Oyl of Vitriol did presently turn the opacous Liquor into one that was cleer and Red, almost like a Rubie, and threw down good store of a Powder, which when 'twas settl'd, would have appear'd very White, if some inter­spers'd Particles of the red Liquor had not a little Allay'd the Purity, though not ble­mish'd the Beauty of the Colour. And to shew you, Pyrophilus, that these Effects do not flow from the Oyl of Vitriol, as it is such, but as it is a strongly Acid Menstruum, that has the property both to Praecipitate Lead, as well as some other Concretes out of Spirit of Vinegar, and to heighten the Colour of Red Rose-leaves, I add, that I [Page 383] have done the same thing, though perhaps not quite so well with Spirit of Salt, and that I could not do it with Aqua-sortis, because though that potent Menstruum does as well as the others heighthen the Redness of Ro­ses, yet it would not like them Precipitate Lead out of Spirit of Vinegar, but would rather have dissolv'd it, if it had not found it dissolv'd already.

And as by this way we have produc'd a Red Liquor, and a White Precipitate out of a Dirty Green magistery of Rose-leaves, so by the same Method, you may produce a fair Yellow, and sometimes a Red Li­quor, and the like Precipitate, out of an In­fusion of a curious Purple Colour. For you may call to mind, that in the Annotation upon the 39 ^th. Experiment I intimated to you, that I had with a few drops of an Alcaly turn'd the Infusion of Logg-wood into a lovely Purple. Now if instead of this Alcaly I substituted a very strong and well Filtrated Solution of Minium, made with Spirit of Vinegar, and put about half as much of this Liquor as there was of the Infusion of Logg-wood, (that the mixture might afford a pretty deal of Precipitate,) the affusion of a conventent proportion of Spirit of Salt, would (if the Liquors were well and nimbly stirr'd together) presently [Page 384] strike down a Precipitate like that formerly mention'd, and turn the Liquor that swam above it, for the most part into a lovely Yellow.

But for the advancing of this Experiment a little further, I consider'd, that in case I first turn'd a spoonfull of the infusion of Logg-wood Purple, by a convenient pro­portion of the Solution of Minium, the Af­fusion of Spirit of Sal Armoniack, would Precipitate the Corpuscles of Lead con­ceal'd in the Solution of Minium, and yet not destory the Purple colour of the Li­quor; whereupon I thus proceeded; I took about a spoonfull of the fresh Tincture of Logg-wood, (for I found that if it were stale the Experiment would not alwayes succeed,) and having put to it a conveni­ent proportion of the Solution of Minium to turn it into a deep and almost opacous Purple, I then drop'd in as much Spirit of Sal Armoniack, as I guess'd would Preci­pitate about half or more (but not all) of the Lead, and immediately stirring the mix­ture well together, I mingled the Precipi­tated parts with the others, so that they fell to the bottom, partly in the form of a Pow­der, and partly in the form of a Curdled Substance, that (by reason of the Predo­minancy of the Ting'd Corpuscles over [Page 385] the White) retain'd as well as the Super­natant Liquor, a Blewish Purple colour sufficiently Deep, and then instantly (but yet Warily,) pouring on a pretty Quantity of Spirit of Salt, the matter first Precipita­ted, was, by the above specifi'd figure of the bottome of the Glass preserv'd from being reach'd by the Spirituous Salt; which hastily Precipitated upon it a new Bed (if I may so call it) of White Powder, being the remaining Corpuscles of the Lead, that the Urinous Spirit had not struck down: So that there appear'd in the Glass three distinct and very differingly colour'd Sub­stances; a Purple or Violet-colour'd Pre­cipitate at the bottom, a White and Car­nation (sometimes a Variously colour'd) Precipitate over That, and at the Top of all a Transparent Liquor of a lovely Yellow, or Red.

Thus you see, Pyrophilus, that though to some I may have seem'd to have lighted on this (50 ^th.) Experiment by chance, and though others may imagine, that to have excogitated it, must have proceeded from some extraordinary insight into the nature of Colours, yet indeed, the devising of it need not be look'd upon as any great mat­ter, especially to one that is a little vers'd in the notions, I have in these, and other Pa­pers [Page 386] hinted concerning the differences of Salts. And perhaps I might add upon more than conjecture, that these very notions and some particulars scatteringly deliver'd in this Treatise, being skilfully put together, may suggest divers matters (at least) about Colours, that will not be altogether Despi­cable. But those hinted, Pyrophilus, I must now leave such as You to prosecute, having already spent farr more time than I intended to allow my self in acquainting You with particular Experiments and Observations concerning the changes of Colour, to which I might have added many more, but that I hope I may have presented You with a competent number to make out in some measure what I have at the beginning of this Essay either propos'd as my Design in this Tract, or deliver'd as my Conjectures con­cerning these matters. And it not being my present Designe, as I have more than once Declar'd, to deliver any Positive Hypothesis or solemn Theory of Colours, but only to furnish You with some Experiments to­wards the framing of such a Theory; I shall add nothing to what I have said already, but a request that you would not be forward to think I have been mistaken in any thing I have deliver'd as matter of Fact concer­ning the changes of Colours, in case you [Page 387] should not every time you trye it, find it exactly to succeed. For besides the Contin­gencies to which we have elsewhere shewn some other Experiments to be obnoxious, the omission or variation of a seemingly un­considerable circumstance, may hinder the success of an Experiment, wherein no other fault has been committed. Of which truth I shall only give you that single and almost obvious, but yet illustrious instance of the Art of Dying Scarlets, for though you should see every Ingredient that is us'd a­bout it, though I should particularly in­form You of the weight of each, and though you should be present at the kindling of the fire, and at the increasing and remitting of it, when ever the degree of Heat is to be alter'd, and though (in a word) you should see every thing done so particular­ly that you would scarce harbour the least doubt of your comprehending the whole Art: Yet if I should not disclose to You, that the Vessels, that immediately con­tain the Tinging Ingredients, are to be made of or to be lin'd with Tin, You would never be able by all that I could tell you else (at least, if the Famousest and Can­didest Artificers do not strangely delude themselves) to bring your Tincture of [Page 388] Chochinele to Dye a perfect Scarlet. So much depends upon the very Vessel, where­in the Tinging matters are boyl'd, and so great an Influence may an unheeded Circumstance have on the Success of Experiments concerning Colours.