EXPERIMENT I.
Ecauſe 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
as to Quantity, or as to Interruption) I hold it 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
by their Colours, and ſeem'd to reflect an almoſt Equal Light.
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 fleck'd Marbl'd Paper being Apply'd as the others, did not caſt any or 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
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
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 White 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
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.
The 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
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;
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 would 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 mention'd particulars may be at one View taken Notice of.
EXPERIMENT V.
|
The Explication of the Scheme. | PPP. An Aequilaterotriangular Cryſtalline Priſm, one of whoſe edges P. is placed directly towards the Sun. A B & α β Two rays from the Sun falling on the Priſm at B β. and thence partly reflected towards C & γ. and partly refracted towards D & δ. B C & β γ. Thoſe reflected Rays. B D & β δ. Thoſe refracted Rays which are partly refracted towards E & ε. and there paint an Iris 1 2 3 4 5. denoting the five conſecutions of colours Red, Yellow, Green, Blew, and Purple; and are partly reflected towards F & ζ. D F & δ ζ. Thoſe Reflected Rays which are partly refracted towards G & η. colourleſs, and partly reflected, towards H & θ. F H & ζ θ. Thoſe reflected Rays which are refracted towards I & ι. and there paint an other fainter Iris, the colours of which are contrary to the former 5 4 3 2 1. ſignifying Purple, Blew, Green, Yellow, Red, ſo that the Priſm in this poſture exhibits four Rainbows. |
I know not whether you will think it Inconſiderable to annex to this Experiment, That we obſerv'd in a Room not 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 througn 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, Prophilus, 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
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 ſomewhat 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 Notorious 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
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 Daylight.
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 Experiments 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 Rod or Cylinder (for thin Peeces would not ſerve the turn) of deep Blew Glaſs, and looking upon the Candles flame at a Convenient diſtance througn 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
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 conctinu'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
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 called 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.
Nobis, ſays he,[a]16] Nova Hiſpania mittit quoddam ligni genus craſſum & enode, cujus uſus jam diu receptus fuit in his Regionibus ad Renum vitia & urinæ difficultates ac arenulas pellendas. Fit autem hac ratione, Lignum aſſulatim & minutim conciſum in limpidiſſima aqua fontana maceratur, inque ea relinquitur, donec aqua à bibentibus abſumpta ſit, dimidia hora post injectum lignum aqua cæruleum colorem contrabit, qui ſenſim intenditur pro temporis diuturnitate, tametſi lignum candidum fit. 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
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 Cæruleous Colour, of which alſo the drops, if any be lying on the outſide 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 Cæruleous, but when it is fallen 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
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 Phænomena 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
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 Cæruleous one.
Theſe and other Phænomena, 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 Phænomena 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
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 Cæruleous, 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
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 Cæruleous 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 Cæruleous Colour, a Sulphureous Salt being of a contrary Nature, would be able to Mortifie the Saline Particles of Vinegar, and Deſtroy their
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 Cæruleous 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 Cæruleous; 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 reſtored Liquor did, as it was Look'd upon againſt or from the Light, exhibit the Same Phænomena 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
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)[a]17] neutiquam omittendum duximus quoddam ligni candidi Mexicani genus, quod Indigenæ Coalle & Tlapazatli vocant, quod etſi experientia hucuſque non niſi Cæruleo aquam 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 eft craſſus, enodis, inſtar piri arboris, folia ciceris foliis, aut rutæ haud abſimilia, flores exigui, oblongi, lutei & ſpicatim digeſti; eſt frigida & humida planta, licet parum recedat à medio temperamento. Hujus itaque deſcriptæ arboris lignum in poculum efformatum, aquam eidem infuſam primo in aquam intenſe Cæruleam, colore floris Bugloſſæ; tingit, & quo diutius in eo ſteterit, tanto intenſiorem colorem acquirit. Hanc igitur aquam si Vitreæ Sphæræ infuderis, lucique expoſueris, ne ullum quidem Cærulei coloris
veſtigium apparebit, ſed inſtar aquæ puræ putæ fontanæ limpidam claramque aspicientibus ſe præbebit. 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, Cæruleum 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
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
then, whereas it has been already ſaid, that the Cæruleous Colour was by Acid Salts aboliſhed, 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 Water, 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 Wood will reſume a Cæruleous Colour, I wiſh he had Inform'd us how he Try'd it.
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 Phænomena, 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
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 Liquors, which have neither of them any Colour at all of their own. And that which deſerves ſome particular wonder, is, that the Cæruleous 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.
A Corollary of the Tenth Experiment.
That this Experiment, Pyrophilus, may be as well Uſefull as Delightfull to You, I muſt mind You, Pyrophilus, that in the newly mention'd Obſervation, I have hinted to You a New and Eaſie way of Diſcovering in many Liquors (for I dare not ſay in all) whether it be an Acid or Sulphureous Salt, that is Predominant; and that ſuch a Diſcovery is oftentimes of great Difficulty, and may frequently be of great Uſe, he that is not a Stranger to the various Properties and Effects of Salts, and of how great moment it is to be able to diſtinguiſh their Tribes, may readily conceive. But to proceed to the way of trying other Liquors by an Infuſion of our Wood, take it briefly thus. Suppoſe I have a mind to try whether I conjecture aright, when I imagine that Allom, though it be plainly a Mixt Body, does abound rather with Acid than Sulphureous Salt. To ſatisfie my ſelf herein, I turn my back to the Light, and holding a ſmall Vial full of the Tincture of Lignum Nephriticum, which look'd upon in that Poſition, appears Cæruleous, I drop into it a little of a ſtrong Solution of Allom made in Fair Water, and finding upon the
Affuſion and ſhaking of this New liquor, that the Blewneſs formerly conſpicuous in our Tincture does preſently vaniſh, I am thereby incited to ſuppoſe, that the Salt Prædominant in Allom belongs to the Family of Sour Salts; but if on the other ſide I have a mind to examine whether or no I rightly conceive that Salt of Urine, or of Harts-horn is rather of a Saline Sulphureous (if I may ſo ſpeak) than of an Acid Nature, I drop a little of the Saline Spirit of either into the Nephritick Tincture, and finding that the Cæruleous Colour is rather thereby Deepned than Deſtroy'd, I collect that the Salts, which conſtitute theſe Spirits, are rather Sulphureous than Acid. And to ſatisfie my ſelf yet farther in this particular, I take a ſmall Vial of freſh Tincture, and placing both it and my ſelf in reference to the Light as formerly, I drop into the Infuſion juſt as much Diſtill'd Vinegar, or other Acid liquor as will ſerve to Deprive it of its Blewneſs (which a few drops, if the Sour Liquor be ſtrong, and the Vial ſmall will ſuffice to do) then without changing my Poſture, I drop and ſhake into the ſame Vial a ſmall proportion of Spirit of Hartſhorn or Urine, and finding that upon this affuſion, the Tincture immediately recovers its Cæruleous Colour, I am thereby confirm'd
firm'd in my former Opinion, of the Sulphureous Nature of theſe Salts. And ſo, whereas it is much doubted by Some Modern Chymiſts to what ſort of Salt, that which is Prædominant in Quick-lime belongs, we have been perſwaded to referr it rather to Lixiviate than Acid Salts, by having obſerv'd, that though an Evaporated Infuſion of it will ſcarce yield ſuch a Salt, as Aſhes and other Alcalizate Bodyes are wont to do, yet if we deprive our Nephritick Tincture of its Blewneſs by juſt ſo much Diſtill'd Vinegar as is requiſite to make that Colour Vaniſh, the Lixivium of Quick-lime will immediately upon its Affuſion recall the Baniſhed Colour; but not ſo Powerfully as either of the Sulphureous Liquors formerly mention'd. And therefore I allow my ſelf to gueſs at the Strength of the Liquors examin'd by this Experiment, by the Quantity of them which is ſufficient to Deſtroy or Reſtore the Cæruleous Colour of our Tincture. But whether concerning Liquors, wherein neither Acid nor Alcaliſate Salts are Eminently Prædominant, our Tincture will enable us to conjecture any thing more than that ſuch Salts are not Prædominant in them, I take not upon me to determine here, but leave to further Tryal; For I find not that Spirit of
Wine, Spirit of Tartar freed from Acidity, or Chymical Oyl of Turpentine, (although Liquors which muſt be conceiv'd very Saline, if Chymiſts have, which is here no place to Diſpute, rightly aſcrib'd taſts to the Saline Principle of Bodyes,) have any Remarkable Power either to deprive our Tincture of its Cæruleous Colour, or reſtore it, when upon the Affuſion of Spirit of Vinegar it has diſappear'd.
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 clear 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 what which may alſo appear ſtrange, is this,
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 Phænomena 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
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
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 Ambiguity, 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)
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
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
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
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
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
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
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.
Calling 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
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,
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 theſe 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,
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 Phænomena 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 delivered, 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 Vapour, the Steam will appear of a Reddiſh or deep Yellow Colour, which will Vaniſh when thoſe Exhalations come to reſume the form of 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
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
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 ſollicitous 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
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.
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
Woud-wax 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.
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 Præcipitating 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,
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 Phænomena 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 mention'd ways of making a Green; for I have ſometimes Conjectur'd, that the mixture
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
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 ton'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 our 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
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
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
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
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 Sphærical 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
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 mentioned 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
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 Feather; the like Phænomenon 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, Imprægnated 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
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.
Annotation upon the twentieth Experiment.
The uſe of what we lately deliver'd concerning the way of turning Syrrup of Violets, Red or Green, may be this; That, though it be a far more common and procurable
Liquor than the Infuſion of Lignum Nephriticum, it may yet be eaſily ſubſtituted in its Room, when we have a mind to examine, whether or no the Salt predominant in a Liquor or other Body, wherein 'tis Looſe and Abundant, belong to the Tribe of Acid Salts or not. For if ſuch a Body turn the Syrrup of a Red or Reddiſh Purple Colour, it does for the moſt part argue the Body (eſpecially if it be a diſtill'd Liquor) to abound with Acid Salt. But if the Syrrup be made Green, that argues the Predominant Salt to be of a Nature repugnant to that of the Tribe of Acids. For, as I find that either Spirit of Salt, or Oyl of Vitriol, or Aqua-fortis, or Spirit of Vinegar, or Juice of Lemmons, or any of the Acid Liquors I have yet had occaſion to try, will turn Syrrup of Violets, of a Red, (or at leaſt, of a Reddiſh Colour, ſo I have found, that not only the Volatile Salts of all Animal Subſtances I have us'd, as Spirit of Harts-horn, of Urine, of Sal-Armoniack, of Blood, &c. but alſo all the Alcalizate Salts I have imploy'd, as the Solution of Salt of Tartar, of Pot-aſhes, of common Wood-aſhes, Lime-water, &c. will immediately change the Blew Syrrup, into a perfect Green. And by the ſame way (to hint that upon
the by) I elſewhere ſhow you, both the changes that Nature and Time produce, in the more Saline parts of ſome Bodies, may be diſcover'd, and alſo how ev'n ſuch Chymically prepar'd Bodies, as belong not either to the Animal Kingdome, or to the Tribe of Alcali's, may have their new and ſuperinduc'd Nature ſucceſsfully Examin'd. In this place I ſhall only add, that not alone the Changing the Colour of the Syrrup, requires, that the Changing Body be more ſtrong, of the Acid, or other ſort of Salt that is Predominant in it, than is requiſite for the working upon the Tincture of Lignum Nephriticum; but that in this is alſo, the Operation of the formerly mention'd Salts upon our Syrrup, differs from their Operation upon our Tinctures, that in this Liquor, if the Cæruleous Colour be Deſtroy'd by an Acid Salt, it may be Restor'd by one that is either Volatile, or Lixiviate; whereas in Syrrup of Violets, though one of theſe contrary Salts will destroy the Action of the other, yet neither of them will reſtore the Syrrup to its native Blew; but each of them will Change it into the Colour which it ſelf doth (if I may ſo ſpeak) affect, as we ſhall have Occaſion to ſhow in the Notes on the twenty fifth Experiment.
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 Corn-weed from their Growing among Corn[a]18]. 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
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.
Annotation upon the one and twentieth Experiment.
But leſt you ſhould be tempted to think (Pyrophilus) that Volatile or Alcalizate
Salts change Blews into Green, rather upon the ſcore of the eaſie Tranſition of the former Colour into the latter, than upon the account of the Texture, wherein moſt Vegetables, that afford a Blew, ſeem, though otherwiſe differing, to be Allied, I will add, that when I purpoſely diſſolv'd Blew Vitriol in fair Water, and thereby imbu'd ſufficiently that Liquor with that Colour, a Lixiviate Liquor, and a Urinous Salt being Copiouſly pour'd upon diſtinct Parcels of it, did each of them, though perhaps with ſome Difference, turn the Liquor not Green, but of a deep Yellowiſh Colour, almoſt like that of Yellow Oker, which Colour the Precipitated Corpuſcles retain'd, when they had Leiſurely ſubſided to the Bottom. What this Precipitated Subſtance is, it is not needfull now to Enquire in this place, and in another, I have ſhown you, that notwithſtanding its Colour, and its being Obtainable from an Acid Menſtruum by the help of Salt of Tartar, it is yet far enough from being the true Sulphur of Vitriol.
EXPERIMENT XXII.
Our next Experiment (Pyrophilus) will perhaps ſeem to be of a contrary Nature
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
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 Cæruleous 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
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,
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.
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 Colour 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
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 far 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
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
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.
Annotation.
After what I have formerly deliver'd to evince, That there are many Inſtances, wherein new Colours are produc'd or acquir'd by Bodies, which Chymiſts are wont to think deſtitute of Salt, or to whoſe change of Colours no new Acceſſion of Saline Particles does appear to contribute, I think we may ſafely enough acknowledge,
that we have taken notice of ſo many Changes made by the Intervention of Salts in the Colours of Mix'd Bodies, that it has leſſen'd our Wonder, That though many Chymiſts are wont to aſcribe the Colours of Such Bodies to their Sulphureous, and the reſt to their Mercurial Principle; yet Paracelſus himſelf directs us in the Indagation of Colours, to have an Eye principally upon Salts, as we find in that paſſage of his, wherein he takes upon him to Oblige his Readers much by Inſtructing them, of what things they are to expect the Knowledge from each of the three diſtinct Principles of Bodies. Alias (ſays he) Colorum ſimilis ratio eſt: De quibus brevem inſtitutionem hanc attendite, quod ſcilicet colores omnes ex Sale prodeant. Sal enim dat colorem, dat Balſamum.[a]19] And a little beneath. Iam natura Ipſa colores protrathit ex ſale, cuique ſpeciei dans illum, qui ipſi competit, &c. After which he concludes; Itaque qui rerum omnium corpora cognoſcere vult, huic opus eſt, ut ante omnia cognoſcat Sulphur, Ab hoc, qui deſiderat noviſſe Colores is ſcientiam iſtorum petat à Sale, Qui ſcire vult Virtutes, is ſcrutetur arcana Mercurii. Sic nimirum fundamentum hauſerit Myſteriorum, in quolibet creſcenti indagandorum,
prout natura cuilibet ſpeciei ea ingeſſit. But though Paracelſus aſcribes to each of his belov'd Hypoſtatical Principles, much more than I fear will be found to belong to it; yet if we pleaſe to conſider Colours, not as Philoſophers, but as Dyers, the concurrence of Salts to the ſtriking and change of Colours, and their Efficacy, will, I ſuppoſe, appear ſo conſiderable, that we ſhall not need to quarrel much with Paracelſus, for aſcribing in this place (for I dare not affirm that he uſes to be ſtill of one Mind) the Colours of Bodies to their Salts, if by Salts he here underſtood, not only Elementary Salts, but ſuch alſo as are commonly taken for Salts, as Allom, Cryſtals of Tartar, Vitriol, &c. becauſe the Saline principle does chiefly abound in them, though indeed they be, as we elſewhere declare, mix'd Bodies, and have moſt of them, beſides what is Saline, both Sulphureous, Aqueous, and Groſs or Earthy parts.
But though (Pyrophilus) I have obſerv'd a Red and Green to be produc'd, the former, by Acid Salts, the later by Salts not Acid, in the expreſs Juices of ſo many differing Vegetable Subſtances, that the Obſervation, if perſued, may prove (as I ſaid) of good Uſe: yet to ſhow you how much e'vn theſe Effects depend upon the
particular Texture of Bodies, I muſt ſubjoyn ſome caſes wherein I (who am ſomewhat backwards to admit Obſervations for Univerſal) had the Curioſity to diſcover, that the Experiments would not Uniformly ſucceed, and of theſe Exceptions, the chief that I now remember, are reducible to the following three.
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 Buckthorn (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,
and Infuſions of the ſame Colour, I have at preſent ſo few at hand, that I muſt leave you to find it out 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
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 Colour effected by Salts, depend upon the particular Texture of the
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.
An admonition touching the four preceding Experiments.
Having thus (Pyrophilus) given you divers Inſtances, to countenance the General obſervation deliver'd in the twenty fifth Experiment, and divers Exceptions whereby it ought to be Limited; I muſt leave the further Inquiry into theſe Matters to your own Induſtry. For not remembring at preſent many of thoſe other Trials, long ſince made to ſatisfie my ſelf about Particulars, and not having now the Opportunity to repeat them, I muſt content my Self to have given you the Hint, and the ways of proſecuting the ſearch your Self; and only declare to you in general, that, As I have made many Trials, unmention'd in this Treatiſe, whoſe Events were agreeable to thoſe mention'd in the twenty fifth Experiment, ſo (to name now no other Inſtances) what I have try'd with Acid and Sulphureous Salts upon the Pulp of Juniper Berries, rubb'd upon White Paper, inclines me to think, That among that vaſt Multitude, and ſtrange Variety of Plants that adorn the face of the Earth, perhaps many other Vegetables may be found, on which ſuch Menſtruums may not
have ſuch Operations, as upon the Juice of Violets, Peaſe-bloſſoms, &c. no nor upon any of thoſe three other ſorts of Vegetables, that I have taken notice of in the three fore-going Experiments. It ſufficiently appearing ev'n by theſe, that the effects of a Salt upon the Juices of particular Vegetables do very much depend upon their particular Textures.
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 apiece of white Paper, with the former, I obſerv'd, that the Juice adhering to it was of adark Reddiſh Colour, full of little
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 miſremember
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 Spice, (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
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 a Purgative faculty,[a]20] 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
in Nicer Experiments you make uſe of. For, it I were not hindred both by haſte and ſome juſtifiable Conſiderations, I could perhaps add conſiderable Inſtances, to thoſe lately deliver'd, for the making out of this Obſervation; but for certain reaſons I ſhall at preſent 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 Leather-dreſſers to Colour Leather, as they uſe alſo to make a Green Colour, call'd Sap-green, taken from the Berries when they are Black, being bruis'd and put into a Braſs or Copper Kettle or Pan, and there ſuffer'd to abide three or four
Days, or a little heated upon the Fire, and ſome beaten Allom put unto them, and afterwards preſs'd forth, the Juice or Liquor is uſually put in great Bladders tied with ſtrong thred at the Head and hung up untill it be Dry, which is diſſolv'd in Water or Wine, but Sack (he affirms) is the beſt to preſerve the Colour from Starving, (as they call it) that is, from Decaying, and make it hold freſh the longer. The third Colour (where of none (ſays he) that I can find have made mention but only Tragus) is a Purpliſh Colour, which is made of the Berries ſuffer'd to grow upon the Buſhes untill the middle or end of November, that they are ready to drop from the Trees.
And, I remember (Pyrophilus) that I try'd, with a ſucceſs that pleas'd me well enough, to make ſuch a kind of Pigment, as Painters call Sap-green, by a way not unlike that, deliver'd here by our Author, but I cannot now find any thing relating to that matter among my looſe Papers. And my Trials were made ſo many years ago, that I dare not truſt my Memory for 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
I ſhall add an Obſervation, which though it does not ſtrictly belong to this place, may well enough be mention'd here, namely, that I find by an account given us by the Learned Cluſius, of Alaternus, that ev'n the Groſſer Parts of the ſame Plant, are ſome of them one Colour, and ſome another; For ſpeaking of that Plant, he tells us, that the Portugalls uſe the Bark to Dye their Nets into a Red Colour, and with the Chips of the Wood, which are Whitiſh, they Dye a Blackiſh Blew.
EXPERIMENT 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)
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
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 in proceſs of time ſo change its Texture, as that the Tranſpoſed parts do Modifie the incident Light otherwiſe, than they did when the Matter appear'd of another Colour.
EXPERIMENT 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
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
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
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
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
be well Drawn, will upon a little Agitation of the Vial firſt unſtop'd (eſpecially if it be held in a Warmer hand) lend forth a copious Fume, not Red, like that of Nitre, but White; And ſometimes this Liquor may be ſo Drawn, that I remember, not long ſince, I took pleaſure to obſerve in a parcel of it, that Ingredients not Red, did not only yield by Diſtillation a Volatile Spirit that was Red, but though that Liquor did upon the bare opening of the Bottle it was kept in, drive us away with the plenty and ſulphureous ſent of a White ſteam which it ſent forth, yet the Liquor it ſelf being touch'd by our Fingers, did immediately Dye them Black.
EXPERIMENT 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,
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;
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 reaſons: The firſt whereof may be fetcht from the newly recited Example of the two Oyls; The next may be, that we have ſometimes obſerv'd
long Window-Curtains of light Colours, to have that part of them, which was expos'd to the Air, when the Window was open, of one Colour, and the lower part, that was ſheltred from the Air by the Wall, of another Colour: And the third Argument may be fetch'd from divers Obſervations, both of others, and our own; For of that Pigment ſo well known in Painters Shops, by the name of Turnſol, our Induſtrious Parkinſon, in the particular account he gives of the Plant that bears it, tells us alſo, That the Berries when they are at their full Maturity, have within them between the outer Skin and the inward Kirnel or Seed, a certain Juice or Moiſture, which being rubb'd upon Paper or Cloath, at the first appears of a freſh and lovely Green Colour, but preſently changeth into a kind of Blewiſh Purple, upon the Cloath or Paper, and the ſame Cloath afterwards wet in Water, and wrung forth, will Colour the Water into a Claret Wine Colour, and theſe (concludes he) are thoſe Raggs of Cloath, which are uſually call'd Turnſol in the Druggiſts or Grocers Shops[a]21]. And to this Obſervation of our Botanist we will add an Experiment of our own, (made before we met with That) which, though in many Circumſtances, very
differing, ſerves to prove the ſame thing; for having taken of the deeply Red Juice of Buckthorn Berries, which I bought of the Man that uſes to ſell it to the Apothecaries, to make their Syrrup de Spina Cervina, I let ſome of it drop upon a piece of White Paper, and having left it there for many hours, till the Paper was grown dry again, I found what I was inclin'd to ſuſpect, namely, That this Juice was degenerated from a deep Red to a dirty kind of Greyiſh Colour, which, in a great part of the ſtain'd Paper ſeem'd not to have ſo much as an Eye of Red: Though a little Spirit of Salt or diſſolv'd Alcaly would turn this unpleaſant Colour (as formerly I told you it would change the not yet alter'd Juice) into a Red or Green. And to ſatisfie my ſelf, that this Degeneration of Colour did not proceed from the Paper, I drop'd ſome of the deep Red or Crimſon Juice upon a White glaz'd Tile, and ſuffering it to dry on there, I found that ev'n in that Body, on which it could not Soak, and by which it could not be Wrought, it nevertheleſs loſt its Colour. And theſe Inſtances (Pyrophilus) I am the more carefull to mention to you, that you may not be much Surpris'd or Diſcourag'd, if you ſhould ſometimes miſs of performing
punctually what I affirm my ſelf to have done in point of changing Colours; ſince in theſe Experiments the over-ſight or neglect of ſuch little 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
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 elſewhere 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
England) a ſort of Pears, which digeſted for ſome time with a little Wine, in a Veſſel exactly clos'd, will in not many hours appear throughout of a deep Red Colour, (as alſo that of the Juice, wherein they are Stew'd, becomes) but ev'n on pure and white Salt of Tartar, pure Spirit of Wine, as clear as Rock-water, will (as we elſewhere declare) by long Digeſtion acquire a Redneſs; Though I ſay ſuch Inſtances might be Multiply'd, and though there be ſome other Obvious changes of Colours, which happen ſo frequently, that they cannot but be as well Conſiderable as Notorious; ſuch as is the Blackneſs of almoſt all Bodies burn'd in the open Air: yet our haſte invites us to reſign you the Exerciſe of enquiring into the Cauſes of theſe Changes. And certainly, the reaſon both why the Soots of ſuch differing Bodies are almoſt all of them all Black, why ſo much the greater part of Vegetables ſhould be rather Green than of any other Colour, and particularly (which more directly concerns this place) why gentle Heats do ſo frequently in Chymical Operations produce rather a Redneſs than another Colour in digeſted Menſtruums, not only Sulphureous, as Spirit of Wine, but Saline, as Spirit of Vinegar, may be very well worth
a ſerious Inquiry; which I ſhall therefore recommend to Pyrophilus and his Ingenious Friends.
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
enough, ſince as Crimſon ſeems to be little elſe than a very deep Red, with (perhaps) an Eye of Blew, ſo ſome kinds of Red ſeem (as I have lately noted) to be little elſe than heightned Yellow. And conſequently in ſuch Bodies, the Yellow ſeems to be but a diluted Red. And accordingly Alcalizate Solutions and Urinous Spirits, which ſeem diſpos'd to Deepen the Colours of the Juices and Liquors of moſt Vegetables, will not only reſtore the Solution of Cochineel and the Infuſion of Brazil to the Crimſon, whence the Spirit of Salt had chang'd them into a truer Red; but will alſo (as I lately told you) not only heighthen the Yellow Juice of Madder into Red, but advance the Red Infuſion of Brazil to a Crimſon. But I know not whether it will not be much ſafer to derive theſe Changes from vary'd Textures, than certain kinds of Bodies; and you will perhaps think it worth while, that I ſhould add on this occaſion, That it may deſerve ſome Speculation, why, notwithſtanding what we have been obſerving, though Blew and Purple ſeem to be deeper Colours than Red, and therefore the Juices of Plants of either of the two former Colours may (congruouſly enough to what has been juſt now noted) be turn'd Red by
Spirit of Salt or Aqua-fortis, yet Blew Syrrup of Violets and ſome Purples ſhould both by Oyl of Tartar and Spirit of Urine be chang'd into Green, which ſeems to be not a deeper but a more diluted Colour than Blew, if not alſo than Purple.
EXPERIMENT 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
with ſuch copious White Fumes, that they ſeem'd to have had their In-ſides waſh'd with Milk. And no leſs obſervable may be, the Diſtill'd Liqours, into which ſuch Fumes convene, (for though we will not deny, that by skill and care a Reddiſh Liqour may be obtain'd from Nitre) yet the common Spirit of it, in the making ev'n of which ſtore of theſe Red Fumes are wont to 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 Liqours I elſewhere obſerve to carry over
the Tincture of the Concrete with them. And as in Diſtillations, ſo in Sublimations, it were worth while to take notice of what comes up, in reference to our preſent ſcope, by purpoſely performing them (as I have in ſome cafes done) in conveniently ſhap'd 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,
ſome of them purely White. And 'tis the Preſcription of ſome Glaſs-men by exquiſitely mingling a convenient proportion of Brimſtone, Sal-Armoniack, and Quickſilver, and Subliming them, together, to make a Sublimate of an excellent Blew; and though having caus'd the Experiment to be made, we found the produc'd Sublimate to be far from being of a lovely Colour, (as was promis'd) that there and there, it ſeem'd Blewiſh, and at leaſt was of a Colour differing enough from either of the Ingredients, which is ſufficient for our preſent purpoſe. But a much finer Colour is promis'd by ſome of the Empiricks, that pretend to Secrets, who tell us, that Orpiment, being Sublim'd, will afford among the Parts of it that fly Upward, ſome little 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
Yellow, but tranſparent almoſt like a Powder. And we have alſo this way obtain'd a Sublimate, the Lower part whereof though it conſiſted not of Rubies, yet the ſmall pieces of it, which were Numerous enough, were of a pleaſant Reddiſh Colour, and Glitter'd very prettily. But to inſiſt on ſuch kind of Trials and Obſervations (where the aſcending Fumes of Bodies differ in Colour from the Bodies themſelves) though it might indeed Inrich the Hiſtory of Colours, would Robb me of too much of the little time I have to diſpatch what I have further to tell you concerning them.
EXPERIMENT 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
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.
Annotation.
This Experiment may bring ſome Light to, and receive ſome from a couple of other Experiments, that I remember I have met with in the ingenious Gaſſendus's Animadverſions upon Epicurus's Philoſophy, whilſt I was turning over the Leaves of thoſe Learned Commentaries; (my Eyes being too weak to let me read ſuch Voluminous Books quite thorough) And I the leſs ſcruple (notwithſtanding my contrary Cuſtom in this Treatiſe) to ſet down theſe Experiments of another, becauſe I ſhall a little improve the latter of them, and becauſe by comparing there with that which I have laſt recited, we may be aſſiſted to Conjecture
upon what account it is, that Oyl of Vitriol heightens the Tincture of Red-roſe Leaves, ſince Spirit of Salt, which is a highly Acid Menſtruum, but otherwiſe differing enough from Oyl of Vitriol, does the ſame thing. Our Authors Experiments then, as we made them, are theſe; We took about a Glaſs-full of luke-warm Water, and in it immerg'd a quantity of the Leaves of Senna, and preſently upon the Immerſion there did not appear any Redneſs in the Water, but dropping into it a little Oyl of Tartar, the Liquor ſoon diſcover'd a Redneſs to the watchfull Eye, whereas by a little of that Acid Liquor of Vitriol, which is like the former, undeſervedly called Oyl, ſuch a Colour would not be extracted from the infuſed Senna. On the other ſide we took ſome Red-roſe Leaves dry'd, and having ſhaken them into a Glaſs of fair Water, they imparted to it no Redneſs, but upon the affuſion of a little Oyl of Vitriol the Water was immediately turn'd Red, which it would not have been, if inſtead of Oyl of Vitriol, we had imployed Oyl of Tartar to produce that Colour: That theſe were Gaſſendus his Experiments, I partly remember, and was aſſur'd by a Friend, who lately Tranſcribed them out of Gaſſendus his Book, which I
therefore add, becauſe I have not now that Book at hand. And the deſign of Gaſſendus in theſe Experiments our Friend affirms to be, to prove, that of things not Red a Redneſs may be made only by Mixture, and the Varied poſition of parts, wherein the Doctrine of that Subtil Philoſopher doth not a little Authorize, what we have formerly delivered concerning the Emergency and Change of Colours. But the inſtances, that we have out of him ſet down, ſeem not to be the moſt Eminent, that may be produced of this truth: For our next Experiment will ſhew the production of ſeveral Colours out of Liquors, which have not any of them any ſuch Colour, nor indeed any diſcernable one at all; and whereas though our Author tells us, that there was no Redneſs either in the Water, or the Leaves of Senna, or the Oyl of Tartar; And though it be true, that the Predominant Colour of the Leaves of Senna be another than Red, yet we have try'd, that by ſteeping that Plant a Night even in Cold water, it would afford a very deep Yellow or Reddiſh Tincture without the help of the Oyl of Tartar, which ſeems to do little more than aſſiſt the Water to extract more nimbly a plenty of that Red Tincture, wherewith the Leaves of Senna
do of themſelves abound, and having taken off the Tincture of Senna, made only with fair Water, before it grew to be Reddiſh, and Decanted it from the Leaves, we could not perceive, that by dropping ſome Oyl of Tartar into it, that Colour was conſiderable, though it were a little heightned into a Redneſs; which might have been expected, if the particles of the Oyl did eminently Co-operate, otherwiſe than we have expreſſed, to the production of this Redneſs.
And as for the Experiment with Red-roſe Leaves, the ſame thing may be alleged, for we found that ſuch Leaves by bare Infuſion for a Night and Day in fair Water, did afford us a Tincture bordering at leaſt upon Redneſs, and that Colour being conſpicuous in the Leaves themſelves, would not by ſome ſeem ſo much to be produc'd as to be extracted by the affuſion of Oyl of Vitriol. And the Experiment try'd with the dry'd Leaves of Damask-roſes ſucceeded but imperfectly, but that is indeed obſervable to our Authors purpoſe, that Oyl of Tartar will not perform in this Experiment what Oyl of Vitriol doth; but becauſe this laſt named Liquor is not ſo eaſily to be had, give me leave to Advertiſe you, that the Experiment will ſucceed,
if inſtead of it you imploy Aqua-fortis. And though ſome Trials of our own formerly made, and others eaſily deducible from what we have already deliver'd, about the different Families and Operations of Salt, might enable us to preſent you an Experiment upon Red-roſe Leaves, more accommodated to our Authors purpoſe, than that which he hath given us; yet our Reverence to ſo Candid a Philoſopher, invites us rather to improve his Experiment, than ſubſtitute another in its place. Take therefore of the Tincture of Red-roſe Leaves, (for with Damask-roſe Leaves the Experiment ſucceedeth not well) made as before hath been taught with a little Oyl of Vitriol, and a good quantity of fair Water, pour off this Liquor into a clear Vial, half fill'd with Limpid water; till the Water held againſt the Light have acquir'd a competent Redneſs, without loſing its Tranſparency, into this Tincture drop leiſurely a little good Spirit of Urine, and ſhaking the Vial, which you muſt ſtill hold againſt the Light, you ſhall ſee the Red Liquor immediately turn'd into a fine Greeniſh Blew, which Colour was not to be found in any of the Bodies, upon whoſe Mixture it emerg'd, and this Change is the more obſervable, becauſe in many Bodies
the Degenerating of Blew into Red is uſual enough, but the turning of Red into Blew is very unfrequent. If at every drop of Spirit of Urine you ſhake the Vial containing the Red Tincture, you may delightfully obſerve a pretty variety of Colours in the paſſage of that Tincture from a Red to a Blew, and ſometimes we have this way hit upon ſuch a Liquor, as being look't upon againſt and from the Light, did ſeem faintly to emulate the above-mention'd Tincture of Lignum Nephriticum. And if you make the Tincture of Red-roſes very high, and without Diluting it with fair Water, pour on the Spirit of Urine, you may have a Blew ſo deep, as to make the Liquor Opacous, but being dropt upon White Paper the Colour will ſoon diſcloſe it ſelf. Alſo having made the Red, and conſequently the Blew Tincture very Tranſparent, and ſuffer'd it to reſt in a ſmall open Vial for a Day or two, we found according to our Conjecture, that not only the Blew but the Red Colour alſo was Vaniſh'd; the clear Liquor being of a bright Amber Colour, at the bottom of which ſubſided a Light, but Copious feculency of almoſt the ſame Colour, which ſeems to be nothing but the Tincted parts of the Roſe Leaves drawn out by the Acid
Spirits of the Oyl of Vitriol, and Precipitated by the Volatile Salt of the Spirit of Urine, which makes it the more probable, that the Redneſs drawn by the Oyl of Vitriol, was at leaſt as well an extraction of the Tinging parts of the Roſes, as a production of Redneſs; and laſtly, if you be deſtitute of Spirit of Urine, you may change the Colour of the Tincture of Roſes with many other Sulphureous Salts, as a ſtrong Solution of Pot-aſhes, Oyl of Tartar, &c. which yet are ſeldome ſo free from Feculency, as the Spirituous parts of Urine becomes by repeated Diſtillation.
Annotation.
On this, occaſion, I call to mind, that I found, a way of producing, though not the ſame kind of Blew, as I have been mentioning, yet a Colour near of Kin to it, namely, a fair Purple, by imploying a Liquor not made Red by Art, inſtead of the Tincture of Red-roſes, made with an Acid Spirit; And my way was only to take Log-wood, (a Wood very well known to Dyers) having by Infuſion the Powder of it a while in fair Water made that Liquor Red, I dropt into it a Tantillum of an Urinous Spirit, as that of Sal-Armoniack,
(and I have done the ſame thing with an Alcali) by which the Colour was in a moment turn'd into a Rich, and lovely Purple. But care muſt be had, that you let not fall into a Spoonfull above two or three Drops, leſt the Colour become ſo deep, as to make the Liquor too Opacous. And (to anſwer the other part of Gaſſendus his Experiment) if inſtead of fair Water, I infus'd the Log-wood in Water made ſomewhat ſowr by the Acid Spirit of Salt, I ſhould obtain neither a Purple Liquor, nor a Red, but only a Yellow one.
EXPERIMENT XL.
The Experiment I am now to mention to you, Pyrophilus, is that which both you, and all the other Virtuoſi that have ſeen it, have been pleas'd to think very ſtrange; and indeed of all the Experiments of Colours, I have yet met with, it ſeems to be the fitteſt to recommend the Doctrine propos'd in this Treatiſe, and to ſhew that we need not ſuppoſe, that all Colours muſt neceſſarily be Inherent Qualities, flowing from the Subſtantial Forms of the Bodies they are ſaid to belong to, ſince by a bare Mechanical change of Texture in the Minute parts of Bodies; two Colours may in
a moment be Generated quite De novo, and utterly Deſtroy'd. For there is this difference betwixt the following Experiment, and moſt of the others deliver'd in theſe Papers, that in this, the Colour that a Body already had, is not chang'd into another, but betwixt two Bodies, each of them apart devoid of Colour, there is in a moment generated a very deep Colour, and which if it were let alone, would be permanent; and yet by a very ſmall Parcel of a third Body, that has no Colour of its own, (leſt ſome may pretend I know not what Antipathy betwixt Colours) this otherwiſe permanent Colour will be in another trice ſo quite Deſtroy'd, that there will remain no foot-ſtepts either of it or of any other Colour in the whole Mixture.
The Experiment is very eaſie, and it is thus perform'd: Take good common Sublimate, and fully ſatiate with it what quantity of Water you pleaſe, Filtre the Solution carefully through clean and cloſe Paper, that it may drop down as Clear and Colourleſs as Fountain water. Then when you'l ſhew the Experiment, put of it about a Spoonfull into a ſmall Wine-glaſs, or any other convenient Veſſel made of clear Glaſs, and droping in three or four
drops of good Oyl of Tartar, per Deliquium; well Filtred that it may likewiſe be without Colour, theſe two Limpid Liquors will in the twinkling of an Eye turn into an Opacous mixture of a deep Orange Colour, which by keeping the Glaſs continually ſhaking in your hand, you muſt preſerve from ſetling too ſoon to the Bottom; And when the Spectators have a little beheld this firſt Change, then you muſt preſently drop in about four or five drops of Oyl of Vitriol, and continuing to ſhake the Glaſs pretty ſtrongly, that it may the Nimbler diffuſe it ſelf, the whole Colour, if you have gone Skilfully to work, will immediately diſappear, and all the Liquor in the Glaſs will be Clear and Colourleſs as before, without ſo much as a Sediment at the Bottom. But for the more gracefull Trial of this Experiment, 'twill not be amiſs to obſerve, Firſt, That there ſhould not be taken too much of the Solution of Sublimate, nor too much of the Oyl of Tartar drop'd in, to avoid the neceſſity of putting in ſo much Oyl of Vitriol as may make an Ebullition, and perhaps run over the Glaſs. Secondly, That 'tis convenient to keep the Glaſs always a little ſhaking, both for the better mixing of the Liquors, and to keep the Yellow Subſtance from Subſiding, which
elſe it would in a ſhort time do, though when 'tis ſubſided it will retain its Colour, and alſo be capable of being depriv'd of it by the Oyl newly mention'd. Thirdly, That if any Yellow matter ſtick at the ſides of the Glaſs, 'tis but inclining the Glaſs, till the clarify'd Liquor can waſh alongſt it, and the Liquor will preſently imbibe it, and deprive it of its Colour.
Many have ſomewhat wondred, how I came to light upon this Experiment, but the Notions or Conjectures I have about the differing Natures of the Several Tribes of Salts, having led me to deviſe the Experiment, it will not be difficult for me to give you the Chymical Reaſon, if I may ſo ſpeak, of the Phænomenon. Having then obſerv'd, that Mercury being diſſolv'd in Some Menſtruums, would yield a dark Yellow Precipitate, and ſuppoſing that, as to this, common Water, and the Salts that ſtick to the Mercury would be equivalent to thoſe Acid Menſtruums, which work upon the Quick-ſilver, upon the account of their Saline particles, I ſubſtituted a Solution of Sublimate in fair Water, inſtead of a Solution of Mercury in Aqua-fortis, or Spirit of Nitre, that ſimple Solution being both clearer and free from that very offenſive Smell, which accompanies the Solutions
of Mercury made with thoſe other corroſive Liquors; then I conſider'd, that That, which makes the Yellow Colour, is indeed but a Precipitate made by the means of the Oyl of Tartar, which we drop in, and which, as Chymiſts know, does generally precipitate Metalline Bodies corroded by Acid Salts; ſo that the Colour in our caſe reſults from the Coalition of the Mercurial particles with the Saline ones, wherewith they were formerly aſſociated, and with the Alcalizate particles of the Salt of Tartar that ſwim up and down in the Oyl. Wherefore conſidering alſo, that very many of the effects of Lixiviate Liquors, upon the Solutions of other Bodies, may be deſtroy'd by Acid Menstruums, as I elſewhere more particularly declare, I concluded, that if I choſe a very potently Acid Liquor, which by its Inciſive power might undo the work of the Oyl of Tartar, and diſperſe again thoſe Particles, which the other had by Precipitation aſſociated, into ſuch minute Corpuſcles as were before ſingly Inconſpicuous, they would become Inconſpicuous again, and conſequently leave the Liquor as Colourleſs as before the Precipitation was made.
This, as I ſaid, Pyrophilus, ſeems to be the Chymical reaſon of this Experiment, that
is ſuch a reaſon, as, ſuppoſing the truth of thoſe Chymical Notions I have elſewhere I hope evinc'd, may give ſuch an account of the Phænomena as Chymical Notions can ſupply us with; but I both here and elſewhere make uſe of this way of ſpeaking, to intimate that I am ſufficiently aware of the difference betwixt a Chymical Explication of a Phænomenon, and one that is truly Philoſophical or Mechanical; as in our preſent caſe, I tell you ſomething, when I tell you that the Yellowneſs of the Mercurial Solution and the Oyl of Tartar is produc'd by the Precipitation occaſion'd by the affuſion of the latter of thoſe Liquors, and that the deſtruction of the Colour proceeds from the Diſſipation of that Curdl'd matter, whoſe Texture is deſtroy'd, and which is diſſolv'd into Minute and Inviſible particles by the potently Acid Menſtruum, which is the reaſon, why there remains no Sediment in the Bottom, becauſe the infuſed Oyl takes it up, and reſolves it into hidden or inviſible Parts, as Water does Salt or Sugar. But when I have told you all this, I am far from thinking I have told all that ſuch an Inquiſitive Perſon as your ſelf would know, for I preſume you would deſire as well as I to learn (at leaſt) why the Particles of the
Mercury, of the Tartar, and of the Acid Salts convening together, ſhould make rather an Orange Colour than a Red, or a Blew, or a Green, for 'tis not enough to ſay what I related a little before, that divers Mercurial Solutions, though otherwiſe made, would yield a Yellow precipitate, becauſe the Queſtion will recurr concerning them; and to give it a ſatisfactory anſwer, is, I freely acknowledge, more than I dare as yet pretend to.
But to confirm my conjecture about the Chymical reaſon of our Experiment, I may add, that as I have (viz. pag. 34th. of this Treatiſe) elſewhere (on another occaſion) told you, with Saline Liquors of another kind and nature than Salt of Tartar, (namely, with Spirit of Urine, and Liquors of kin to that) I can make the Mercury precipitate out of the firſt ſimple Solution quite of another Colour than that hitherto mention'd; Nay, if inſtead of altering the Precipitating liquor, I alter'd the Texture of the Sublimate in ſuch a way as my Notions about Salt requir'd, I could produce the ſame Phænomenon. For having purpoſely Sublim'd together Equal parts (or thereabout) of Sal-Armoniack and Sublimate, firſt diligently Mix'd, the aſcending Flowers being diffolv'd in fair Water,
and Filtred, gave a Solution Limpid and Colourleſs, like that of the other Sublimates, and yet an Akaly drop'd into this Liquor did not turn it Yellow but White. And upon the ſame Grounds we may with Quick-ſilver, without the help of common Sublimate, prepare another ſort of Flowers diſſoluble in Water without Diſcolouring it, with which I could likewiſe do what I newly mention'd; to which I ſhall add, (what poſſibly you'l ſomewhat wonder at) That ſo much does the Colour depend upon the Texture reſulting from the Convention of the ſeveral ſorts of Corpuſcles, that though in out Experiment, Oyl of Vitriol deſtroys the Yellow Colour, yet with Quick-ſilver and fair Water, by the help of Oyl of Vitriol alone, we may eaſily make a kind of Precipitate of a fair and permanent Yellow, as you will e're long (in the forty ſecond Expement of this third Part) be taught. And I may further add, that I choſe Oyl of Vitriol, not ſo much for any other or peculiar Quality, as for its being, when 'tis well rectify'd, (which 'tis ſomewhat hazardous to bring it to be) not only devoid of Colour and in Smells, but extremely Strong and Inciſive; For though common and undephlegmated Aqua-fortis will not perform
the ſame thing well, yet that which is made exceeding Strong by being carefully Dephlegm'd, will do it pretty well, though not ſo well as Oyl of Vitriol which is ſo Strong, that even without Rectification it may for a need be made uſe of. I will not here tell you what I have try'd, that I may be able to deprive at pleaſure the Precipitate that one of the Sulphureous Liquors had made, by the copious Affuſion of the other: Becauſe I found, though this Experiment is too tickliſh to let me give a full account of it in few words, I ſhall therefore tell you, that it is not only for once, that the other above-mention'd Experiment may be made, the ſame Numerical parcels of Liquor being ſtill imploy'd in it; for after I have Clarify'd the Orange Colour'd Liquor, by the addition of as little of the Oyl of Viriol as will ſuffice to perform the effect, I can again at pleaſure re-produce the Opacous Colour, by the dropping in of freſh Oyl of Tartar, and deſtroy it again by the Re-affuſion of more of the Acid Menſtruum; and yet oftner if I pleaſe, can I with theſe two contrariant Liquors recall and diſperſe the Colour, though by reaſon of the addition of ſo much new Liquor, in reference to the Mercurial particles, the Colour will at length appear more dilute and faint.
An improvement of the fortieth Experiment.
And, Pyrophilus, to confirm yet further the Notions that led me to think on the propos'd Experiment, I ſhall acquaint you with another, which when I had conveniency I have ſometimes added to it, and which has to the Spectators appear'd little leſs Odd than the firſt; And though becauſe the Liquor, requiſite to make the Trial ſucceed well, muſt be on purpoſe prepar'd anew a while before, becauſe it will not long retain its fitneſs for this work, I do but ſeldome annex this Experiment to the other, yet I ſhall tell you how I devis'd it, and how I make it. If you boyl Crude Antimony in a ſtrong and clear Lixivium, you ſhall ſeparate a Subſtance from it, which ſome Modern Chymiſts are pleas'd to call its Sulphur, but how deſervedly I ſhall not here examine, having elſewhere done it in an Opportune place; wherefore I ſhall now but need to take notice, that when this ſuppos'd Sulphur (not now to call it rather a kind of Crocus) is let fall by the Liquor upon its Refrigeration, it often ſettles in Flakes, or ſuch like parcels of a Yellow Subſtance, (which being by the precedent
diſſolution reduc'd into Minute parts, may peradventure be made to take Fire much more eaſily than the Groſſer Powder of unprepar'd Antimony would have done.) Conſidering therefore, that common Sulphur boyl'd in a Lixivium may be Precipitated out of it by Rheniſh-wine or White-wine, which are Sowriſh Liquors, and have in them, as I elſewhere ſhew, an Acid Salt; and having found alſo by Trial, that with other Acid Liquors I could Precipitate out of Lixiviate Solvents ſome other Mineral concretions abounding with Sulphureous parts, of which ſort is crude Antimony, I concluded it to be eaſie to Precipitate the Antimony diſſolv'd, as was lately mention'd, with the Acid Oyl of Vitriol; and though common Sulphur yields a White Precipitate, which the Chymiſts call Lac Sulphuris, yet I ſuppos'd the Precipitated Antimony would be of a deep Yellow Colour, as well, if made with Oyl of Vitriol, as if made only by Refrigeration and length of Time. From this 'twas eaſie to deduce this Experiment, that if you put into one Glaſs ſome of the freſhly Impregnated and Filtrated Solution of Antimony, and into another ſome of the Orange-Colour'd Mixture, (which I formerly ſhew'd you how to make with a
Mercurial Solution and Oyl of Tartar) a few drops of Oyl of Vitriol dropp'd into the laſt mention'd Glaſs, would, as I told you before, turn the Deep Yellow mixture into a Cleer Liquor; whereas a little of the ſame Oyl dropp'd out of the ſame Viol into the other Glaſs would preſently (but not without ſome ill ſent) turn the moderately cleer Solution into a Deep Yellow Subſtance, But this, as I Said, ſucceeds not well, unleſs you employ a Lixivium that has but newly diſſolv'd Antimony, and has not yet let it fall. But yet in Summer time, if your Lixivium have been duly Impregnated and well Filtred after it is quite cold, it will for ſome dayes (perhaps much longer than I had occaſion to try) retain Antimony enough to exhibit, upon the Affuſion of the Corroſive Oyl, as much of a good Yellow Subſtance as is neceſſary to ſatisfie the Beholders of the Poſſibility of the Experiment.
Reflections upon the XL. Experiment Compared with the X. and XX.
The Knowledge of the Diſtinction of Salts which we have propos'd, whereby they are diſcriminated into Acid, Volatile,
or Salfuginous (if I may for Diſtinction ſake ſo call the Fugitive Salts of Animal Subſtances) and fix'd or Alcalizate, may poſſibly (by that little part which we have already deliver'd, of what we could ſay of its Applicableneſs) appear of ſo much Uſe in Natural Philoſophy (eſpecially in the Practick part of it) that I doubt not but it will be no Unwelcome Corollary of the Preceding Experiment, if by the help of it I teach you to diſtinguiſh, which of thoſe Salts is Predominant in Chymical Liquors, as well as whether any of them be ſo or not. For though in our Notes upon the X. and XX. Experiments I have ſhown you a way by means of the Tincture of Lignum Nephriticum, or of Syrrup of Violets, to diſcover whether a propounded Salt be Acid or not, yet you can thereby only find in general that ſuch and ſuch Salts belong not to the Tribe of Acids, but cannot determine whether they belong to the Tribe of Urinous Salts (under which for diſtinction ſake I comprehend all thoſe Volatile Salts of Animal or other Subſtances that are contrary to Acids) or to that of Alcalies. For as well the one as the other of theſe Salino-Sulphurous Salts will reſtore the Cæruleous Colour to the Tincture of Lignum Nephriticum, and turn that of Syrrup of Violets
into Green. Wherefore this XL. Experiment does opportunely ſupply the deficiency of thoſe. For being ſollicitous to find out ſome ready wayes of diſcriminating the Tribes of Chymical Salts, I found that all thoſe I thought fit to make Tryal of, would, if they were of a Lixiviate Nature, make with Sublimate diſſolv'd in Fair Water an Orange Tawny Precipitate; whereas if they were of an Urinous Nature the Precipitate would be White and Milky. So that having alwayes by me ſome Syrrup of Violets and ſome Solution of Sublimate, I can by the help of the firſt of thoſe Liquors diſcover in a trice, whether the propounded Salt or Saline Body be of an Acid Nature or no, if it be I need (you know) inquire no further; but if it be not, I can very eaſily, and as readily diſtinguiſh between the other two kinds of Salts, by the White or Orange-Colour that is immediately produc'd, by letting fall a few Drops or Grains of the Salt to be examin'd, into a ſpoonfull of the cleer Solution of Sublimate. For Example, it has been ſuppos'd by ſome eminently Learned, That when Sal Armoniack being mingled with an Alcaly is forc'd from it by the Fire in cloſe Veſſels, the Volatile Salt that will thereby be obtain'd (if the Operation be skilfully perform'd,)
is but a more fine and ſubtile ſort of Sal Armoniack, which, 'tis preſum'd, this Operation do's but more exquiſitely purifie, than common Solutions, Filtrations, and Coagulations. But this Opinion may be eaſily ſhown to be Erroneous, as by other Arguments, ſo particularly by the lately deliver'd Method of diſtinguiſhing the Tribes of Salts. For the Saline Spirit of Sal Armoniack, as it is in many other manifeſt Qualities very like the Spirit of Urine, ſo like, that it will in a trice make Syrrup of Violets of a Lovely Green, turn a Solution of good Verdigreaſe into an Excellent Azure, and make the Solution of a Sublimate yield a White Precipitate, inſomuch that in moſt (for I ſay not all of the Experiments) where I Aim onely at producing a ſudden change of Colour, I ſcruple not to uſe Spirit of Sal Armoniack when it is at hand, inſtead of Spirit of Urine, as indeed it ſeems chiefly to conſiſt (beſides the flegm that helps to make it fluid) of the Volatile Urinous Salt (yet not excluding that of Soot) that abounds in the Sal Armoniack and is ſet at liberty from the Sea Salt wherewith it was formerly aſſociated, and clogg'd, by the Operation of the Alcaly, that divides the Ingredients of Sal Armoniack, and retains that Sea Salt with it ſelf. What uſe may be
made of the like way of exploration in that inquiry which puzzles ſo many Modern Naturaliſts, whether the Rich Pigment (which we have often had occaſion to mention) belongs to the Vegetable or Animal Kingdome, you may find in another place where I give you ſome account of what I try'd about Cocheneel. But I think it needleſs to exemplifie here our Method by any other Inſtances, many ſuch being to be met with in divers parts of this Treatiſe; but I will rather advertiſe you, that, by this way of examining Chymical Liquors, you may not onely in moſt Caſes conclude Affirmatively, but in ſome Caſes Negatively. As ſince Spirit of Wine, and as far as I have try'd, thoſe Chymical Oyles which Artiſts call Eſſential, did not (when I us'd them as I had us'd the ſeveral Families of Salts upon that Syrrup) turn Syrrup of Violets Red or Green, nor the Solution of Sublimate White or Yellow, I inferr'd it may thence be probably argued, that either they are deſtitute of Salt, or have ſuch as belongs not to either of the three Grand families already often mention'd. When I went to examine the Spirit of Oak or of ſuch like Concretes forced over through a Retort, I found by this means amongſt others, that (as I elſewhere ſhow) theſe Chymiſts are
much miſtaken in it, that account it a ſimple Liquor, and one of their Hypoſtatical Principles: for not to mention what flegm it may have, I found that with a few drops of one of this ſort of Spirits mix'd with a good proportion of Syrrup of Violets, I could change the Colour and make it Purpliſh, by the affinity of which Colour to Redneſs, I conjectur'd that this Spirit had ſome Acid Corpuſcles in it, and accordingly I found that as it would deſtroy the Blewneſs of a Tincture of Lignum Nephriticum, ſo being put upon Corals it would Corrode them, as common Spirit of Vinegar, and other Acid Liquors are wont to do. And farther to examine whether there were not a great part of the Liquor that was not of an Acid nature, having ſeparated the Sour or Vinegar-like part from the reſt, which (if I miſtake not) is far the more Copious, we concluded as we had conjectured, the other or remaining part, though it had a ſtrong taſte as well as ſmell, to be of a nature differing from that of either of the three ſorts of Salts above mention'd, ſince it did as little as Spirit of Wine, and Chymical Oyls, alter the Colour either of Syrrup of Violets or Solution of Sublimate, whence we alſo inferr'd that the change that had been made of that Syrrup into a Purple Colour, was
effected by the Vinegar, that was one of the two Ingredients of the Liquor, which was wont to paſs for a Simple or Uncompounded Spirit. And, upon this account, 'twas of the Spirit of Oak (and the like Concretes) freed from it's Vinegar that I elſewhere told you, that I had not then obſerv'd it, (and I have repeated the Tryal but very lately) to deſtroy the Cæruleous Tincture of Lignum Nephriticum. But this onely, en paſsant; for the Chief thing I had to add was this, That by the ſame way may be examin'd and diſcover'd, divers changes that are produc'd in Bodies either by Nature only, or by Art; either of them being able by changing the Texture of ſome Concretes I could name, to qualifie them to Operate after a New manner upon the above mention'd Syrrup, or Solution, or both. And by this means, to tell you that upon the by, I have been able to diſcover, that there may be made Bodies, which though they run per Deliquium, as readily as Salt of Tartar, belong in other reſpects, not to the family of Alcaliz, much leſs to that of Salfuginous, or that of Acid Salts. Perhaps too, I may know a way of making a highly operative Saline Body that ſhall neither change the Colour of Syrrup of Violets, nor Precipitate the Solution of Sublimate; And, I can
likewiſe if I pleaſe conceal by what Liquors I perform ſuch changes of Colour, as I have been mentioning to you, by quite altering the Texture of ſome ordinary Chymical productions, the Exploration of which is the main uſe of the fortieth Experiment, which I think teaches not a little, if it teach us to diſcover the nature of thoſe things (in reference to Salt) that are obtain'd by the ordinary Chymical Analyſis of mix'd Bodyes, though perhaps there may be other Bodyes prepar'd by Chymiſtry which may have the ſame Effects in the change of Colours; and yet be produc'd not from what Chymiſts call the Reſolution of Bodies, but from their Compoſition. But the diſcourſing of things of this nature is more proper for another place. I ſhall now onely add, what might perhaps have been more ſeaſonably told you before; That the Reaſon why the way of Exploration of Salts hitherto deliver'd, ſucceeds in the Solution of Sublimate, depends upon the particular Texture of that Solution, as well as upon the differing Natures of the Saline Liquors imploy'd to Precipitate it. For Gold diſſolv'd in Aqua Regia, whether you Precipitate it with Oyl of Tartar which is an Alcaly, or with Spirit of Urine
, or Sal Armoniack which belongs to the family of
Volatile Salts, will either way afford a Yellow ſubſtance: though with ſuch an Acid Liquor, as, I ſay not Spirit of Salt, the Body that yields it, being upon the matter an Ingredient of Aqua Regis, but Oyl of Vitriol it ſelf, I did not find that I could Precipitate the Metall out of the Solution, or deſtroy the Colour of it, though the ſame Oyl of Vitriol would readily Precipitate Silver diſſolv'd in Aqua-fortis. And if you diſſolve pure Silver in Aqua-fortis, and ſuffer it to ſhoot into Cryſtals, the cleer Solution of theſe made in fair Water, will afford a very White Precipitate, whether it be made with an Alcaly, or an Acid Spirit, as that of Salt, whereas, which may ſeem ſomewhat ſtrange, with Spirit of Sal Armoniack (that I us'd was made of Quicklime) I could obtain no ſuch White Precipitate; that Volatile Spirit, nor (as I remember) that of Urine, ſcarce doing any more than ſtriking down a very ſmall quantity of Matter, which was neither White nor Whitiſh, ſo that the remaining Liquor being ſuffer'd to evaporate till the ſuperfluous Moiſture was gone, the greateſt part of the Metalline Corpuſcles with the Saline ones that had imbib'd them, concoagulated into Salt, as is uſual in ſuch Solutions, wherein the Metall has not been Precipitated.
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.
Annotation.
This Experiment brings into my mind this other, which oftentimes ſuccceds well enough, though not quite ſo well as the former; Namely, that if into about a ſmall ſpoonfull of a Solution of good French Verdigreaſe made in fair Water, I drop't and ſhak'd ſome ſtrong Spirit of Salt, or rather deflegm'd Aqua Fortis, the Greenneſs of the Solution would be made in a trice almoſt
totally to diſappear, & the Liquor held againſt the Light would ſcarce ſeeme other than Cleer or Limpid, to any but an Attentive Eye, which is therefore remarkable; becauſe we know that Aqua-fortis corroding Copper, which is it that gives the Colour to Verdigreaſe, is wont to reduce it to a Green Blew Solution. But if into the other altogether or almoſt Colourleſs Liquor I was ſpeaking of, you drop a juſt quantity either of Oyl of Tartar or Spirit of Urine, you ſhall find that after the Ebullition is ceas'd, the mixture will diſcloſe a lively Colour, though ſomewhat differing from that which the Solution of Verdigreaſe had at firſt.
EXPERIMENT XLII.
That the Colour (Pyrophilus) of a Body may be chang'd by a Liquor which of it ſelf is of no Colour, provided it be Saline, we have already manifeſted by a 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
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,
a more troubleſome way. For Beguinus,[a]22] who calls it Mercurius præcipitatus optimus, takes 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 unnecceſſary 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, wich Oyl'd Colours. And whether this
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 Vitriolate 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 Luciferous a Nature to be fit to be
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 ſwiming 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
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, ſomewhat 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 Phænomena of this Experiment. For the convenienter making whereof, we uſe
inſtead of a Vial, any ſlender Pipe of Glaſs of about 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 ſwimming 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
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 Verdigreaſe) 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
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 clear 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 Greeneſs puts me in mind of a certain thickiſh, but not conſiſtent Pigment I have ſometimes made, and can ſhow you when you pleaſe,
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.
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
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 3d. 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
particulars deliver'd in this Treatiſe, be eaſily induc'd to think that I may have ſet down many Phænomena 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
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
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 Spaw-waters, 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,
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 Phænomenon 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,
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 Urinous 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 foregoing Experiment, for whereas our Eſſence imparts a Greenneſs to Wine, but not to Water, the Induſtrious Olaus Wormius[a]23] in his late Musæum 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 probable 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
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 intervention 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
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.
Annotation I.
It is not unworthy the Admoniſhing you, (Pyrophilus,) and it agrees very well with our Conjectures about the dependence of the change of a Body's Colour upon that of its Texture, that the ſame Metall may by the ſucceſſive operation of the fire receive divers Adventitious Colours, as is evident in Lead, which before it come to ſo deep a Colour as that of Minium, may paſs through divers others.
Annotation II.
Not only the Calces, but the Glaſſes of Metalls, Vitrify'd per ſe, may be of Colours differing from the Natural or Obvious Colour of the Metall; as I have obſerv'd in the Glaſs of Lead, made by long expoſing Crude Lead to a violent fire, and what I have obſerv'd about the Glaſs or Slagg of Copper, (of which I can ſhow you ſome of an odd kind of Texture,) may be elſewhere more conveniently related. I have likewiſe ſeen a piece of very Dark Glaſs, which an Ingenious Artificer that ſhow'd it me profeſs'd himſelf to have made of Silver alone by an extreme Violence (which ſeems to be no more than is needfull) of the fire.
Annotation III.
Minerals alſo by the Action of the Fire may be brought to afford Colours very differing from their own, as I not long ſince noted to you about the variouſly Colour'd Flowers of Antimony, to which we may add the Whitiſh Grey-Colour of its Calx, and the Yellow or Reddiſh Colour of the Glaſs, where into that Calx may be flux'd.
And I remember, that I elſewhere told
you, that Vitriol Calcin'd with a very gentle heat, and afterwards with higher and higher degrees of it, may be made to paſs through ſeveral Colours before it deſcends to a Dark Purpliſh Colour, whereto a ſtrong fire is wont at length to reduce it. But to inſiſt on the Colours produc'd by the Operation of fire upon ſeveral Minerals would take up farr more time than I have now to ſpare.
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
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 Phænomenon 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 elſewhere 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
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
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 ourſelves to inform you, that we have had a Cupreous Body, that was Præcipitated out of a diſtill'd Liquor, that ſeem'd to be the
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 diſſol'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) were 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
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 prædominant, 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) preſent'y ſtain the Steel with a Reddiſh colour, like that of Copper, the reaſon of which, we muſt not now ſtay to inquire.
Annotation I.
I preſume you may have taken notice (Pyrophilus) that I have borrowed ſome of the Inſtances mention'd in this 47th Experiment, from the Laboratories of Chymiſts, and becauſe in ſome (though very few) other paſſages of this Eſſay, I have likewiſe made uſe of Experiments mention'd alſo by ſome Spagyrical Writers, I think it not amiſs to repreſent to you on this Occaſion once for all, ſome things beſides
those which I intimated in the præamble of this preſent Experiment; For beſides, that 'tis very allowable for a Writer to repeat an Experiment which he invented not, in caſe he improve it; And beſides that many Experiments familiar to Chymiſts are unknown to the generality of Learned Men, who either never read Chymical proceſſes, or never underſtood their meaning, or never durſt believe them; beſides theſe things, I ſay, I ſhall repreſent, That, as to the few Experiments I have borrowed from the Chymiſts, if they be very Vulgar, 'twould perhaps be difficult to aſcribe each of them its own Author, and 'tis more than the generality of Chymiſts themſelves can do: and if they be not of very known and familiar practiſe among them, unleſs the Authors wherein I found them had given me cauſe to believe, themſelves had try'd them, I know not why I might not ſet them down, as a part of the Phænomena of Colours which I preſent you; Many things unanimouſly enough deliver'd as matters of fact by (I know not how many Chymical Writers) being not to be rely'd on, upon the ſingle Authority of ſuch Authors: For Inſtance, as ſome Spagyriſts deliver (perhaps amongſt ſeveral deceitful proceſſes) that Saccarum Saturni
with Spirit of Turpentine will afford a Balſom, ſo Beguinus and many more tell us, that the ſame Concrete (Saccarum Saturni) will yield an incomparably fragrant Spirit, and a pretty Quantity of two ſeveral Oyles, and yet ſince many have complain'd, as well as I have done, that they could find no ſuch odoriferous, but rather an ill-ſented Liquor, and ſcarce any oyl in their Diſtillation of that ſweet Vitriol, a wary perſon would as little build any thing on what they ſay of the former Experiment, as upon what they averr of the later, and therefore I ſcrupled not to mention this Red Balſom of which I have not ſeen any, (but what I made) among my other experiments about redneſs.
Annot. II.
We have ſometimes had the Curioſity to try what Colours Minerals, as Tinglaſs, Antimony, Spelter, &c. would yield in ſeveral Menſtruums, nor have we forborn to try the Colours of ſtones, of which that famous one, (which Helmont calls Paracelſus's Ludus) though it be digg'd out of the Earth and ſeem a true ſtone, has afforded in Menſtruums capable to diſſolve ſo ſolid a ſtone, ſometimes a Yellowiſh,
ſometimes a Red ſolution of both which I can ſhow you. But though I have from Minerals obtain'd with ſeveral Menſtruums very differing Colours, and ſome ſuch as perhaps you would be ſurpriz'd to ſee drawn from ſuch Bodies: yet I muſt now paſs by the particulars, being deſirous to put an End to this Treatiſe, before I put an end to your Patience and my own.
Annotation III.
And yet before I paſs to the next Experiment, I muſt put you in mind, that the Colours of Metals may in many caſes be further alter'd by imploying, either præcipitating Salts, or other convenient Subſtances to act upon their Solutions. Of this you may remember, that I have given you ſeveral Inſtances already, to which may be added ſuch as theſe, That if Quickſilver be diſſolv'd in Aqua fortis, and Præcipitated out of the Solution, either with water impregnated with Sea ſalt, or with the ſpirit of that Concrete, it falls to the Bottom in the form of a white powder, whereas if it be Præcipitated with an Alcaly, it will afford a Yellowiſh or tawny powder, and if there be no Præcipitation made, and the Menſtruum be drawn off with a convenient
fire, the corroded Mercury will remain in the bottom, in the form of a ſubſtance that may be made to appear of differing Colours by differing degrees of Heat; As I remember that lately having purpoſely abſtracted Aqua fortis from ſome Quickſilver that we had diſſolv'd in it, ſo that there remain'd a white Calx, expoſing that to ſeveral degrees of Fire, and afterwards to a naked one, we obtain'd ſome new Colours, and at length the greateſt part of the Calx lying at the Bottome of the Vial, and being brought partly to a Deep Yellow, and partly to a Red Colour, the reſt appear'd elevated to the upper part and neck of the Vial, ſome in the form of a Reddiſh, and ſome of an Aſh-Colour Sublimate. But of the differing Colours which by differing wayes and working of Quick Silver with Fire, and Saline Bodies, may be produc'd in Precipitates, I may elſewhere have occaſion to take further notice. I alſo told you not long ſince, that if you corrode Quick-ſilver with Oyl of Vitriol inſtead of Aqua-fortis, and abſtract the Menſtruum, there will remain a White Calx which by the Affuſion of Fair Water preſently turns into a Lemmon Colour. And ev'n the Succedaneum to a Menſtruum may ſometimes ſerve the turn to change the Colours of a Metal. The lovely
Red which Painters call Vermillion, is made of Mercury, which is of the Colour of Silver, and of Brimſtone which is of Kin to that of Gold, Sublim'd up together in a certain proportion, as is vulgarly known to Spagyriſts.
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 powder'd Cryſtal Glaſs, having kept them two or three
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 Glaſsmen do with it, as themſelves inform me, Tinge their Glaſs green. And I remember, that when once we took ſome crude Copper,
and by frequent Ignition quenching it in Water had reduc'd it to a Dark and Ill-colour'd Powder, and afterward 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 Cryſtallo (as the
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 your 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.
Annotation I.
When the Materials of Glaſs being melted with Calcin'd Tin, have compos'd a Maſs Undiaphanous and White, this White Amel is as it were the Baſis of all thoſe fine Concretes that Goldſmiths and ſeveral Artificers imploy in the curious Art of Enamelling. For this White and Fuſible ſubſtance will receive into it ſelf, without ſpoyling them, the Colours of divers other Mineral ſubſtances, which like it will indure the fire.
Annotation II.
So that as by the preſent (XLVIII.) Experiment it appears, that divers Minerals will impart to fuſible Maſſes, Colours differing from their own; ſo by the making and compounding of Amels, it may appear, that divers Bodies will both retain their Colour in the fire, and impart the ſame to ſome others wherewith they were vitrifi'd, and in ſuch Tryals as that mention'd in the 17. Experiment, where I told you, that ev'n in Amels a Blew and Yellow will compound a Green. 'Tis pretty to behold, not only that ſome Colours are of ſo fix'd a Nature, as to be capable of mixture without receiving any detriment by the fire, that do's ſo eaſily deſtroy or ſpoyl thoſe of other Bodies; but Mineral Pigments may be mingled by fire little leſs regularly and ſucceſsfully, than in ordinary Dyeing Fatts, the vulgar Colours are wont to be mingled by the help of Water.
Annotation III.
'Tis not only Metalline, but other Mineral Bodies, that may be imploy'd, to give Tinctures unto Glaſs (and 'tis worth noting
how ſmall a quantity of ſome Mineral ſubſtances, will Tinge a Comparatively vaſt proportion of Glaſs, and we have ſometimes attempted to Colour Glaſs, ev'n with Pretious Stones, and had cauſe to think the Experiment not caſt away. And 'tis known by them that have look'd into the Art of Glaſs, that the Artificers uſe to tinge their Glaſs Blew, with that Dark Mineral Zaffora, (ſome of my Tryals on which I elſewhere acquaint you) which ſome would have to be a Mineral Earth, others a Stone, and others neither the one, nor the other, but which is confeſſedly of a Dark, but not a Blew Colour, though it be not agreed of what particular Colour it is. 'Tis likewiſe though a familiar yet a remarkable practiſe among thoſe that Deal in the making of Glaſs, to imploy (as ſome of themſelves have inform'd me) what they call Manganeſs, and ſome Authors call Magneſia (of which I make particular mention in another Treatiſe) to exhibit in Glaſs not only other Colours than its own, (which is ſo like in Darkneſs or blackiſhneſs to the Load ſtone, that 'tis given by Mineraliſts, for one of the Reaſons of its Latine Name) but Colours differing from one another. For though they uſe it, (which is ſomewhat ſtrange) to Clarifye their Glaſs, and free
it from that Blewiſh Greeniſh Colour, which elſe it would too often be ſubject to, yet they alſo imploy it in certain proportions, to tinge their Glaſs both with a Red colour, and with a Purpliſh or Murry, and putting in a greater Quantity, they alſo make with it that deep obſcure Glaſs which is wont to paſs for Black, which agrees very well with, and may ſerve to confirm what we noted near the beginning of the 44th Experiment, of the ſeeming Blackneſs of thoſe Bodies that are overcharg'd with the Corpuſcles of ſuch Colours, as Red, or Blew, or Green, &c. And as by ſeveral Metals and other Minerals we can give various Colours to Glaſs, ſo on the other ſide, by the differing Colours that Mineral Oars, or other Mineral Powders being melted with Glaſs diſcloſe in it, a good Conjecture may be oftentimes made of the Metall or known Mineral, that the Oar propos'd, either holds, or is moſt of kin to. And this eaſie way of examining Oars, may be in ſome caſes of good uſe, and is not ill deliver'd by Glauber, to whom I ſhall at preſent refer you, for a more particular account of it: unleſs your Curioſity command alſo what I have obſerv'd about theſe matters; only I muſt here advertiſe you, that great circumſpection is
requiſite to keep this way from proving fallacious, upon the account of the variations of Colour that may be produc'd by the differing proportions that may be us'd betwixt the Oar and the Glaſs, by the Richneſs or Poorneſs of the Oar it ſelf, by the Degree of Fire, and (eſpecially) by the Length of Time, during which the matter is kept in fuſion; as you will eaſily gather from what you will quickly meet with in the following Annotation upon this preſent 48th Experiment.
Annotation IV.
There is another way and differing enough from thoſe already mention'd, by which Metalls may be brought to exhibit adventitious Colours: For by This, the Metall do's not ſo much impart a Colour to another Body, as receive a Colour from it, or rather both Bodies do by the new Texture reſulting from their miſtion produce a new Colour. I will not inſiſt to this purpoſe upon the Examples afforded us by yellow Orpiment, and common Sea Salt, from which, ſublim'd together, Chymiſts unanimouſly affirm their White or Cryſtalline Arſenick to be made: But 'tis not unworthy our noting, That though Yellow
Orpiment be acknowledg'd to be the Copiouſeſt by far of the two Ingredients of Arſenick, yet this laſt nam'd Body being duely added to the higheſt Colour'd Metall Copper, when 'tis in fuſion, gives it a whiteneſs both within and without. Thus Lapis Calaminaris changes and improves the Colour of Copper by turning it into Braſs. And I have ſometimes by the help of Zinck duely mix'd after a certain manner, given Copper one of the Richeſt Golden Colours that ever I have ſeen the Beſt true Gold Ennobled with. But pray have a care that ſuch Hints fall not into any hands that may mis-imploy them.
Annotation V.
Upon the Knowledge of the differing wayes of making Minerals and Metalls produce their adventitious Colours in Bodies capable of Vitrification, depends the pretty Art of making what Chymiſts by a Barbarous Word are pleas'd to call Amanſes, that is counterfeit, or factitious Gemms, as Emeralds, Rubies, Saphires, Topazes, and the like. For in the making of theſe, though pure Sand or Calcin'd Cryſtal give the Body, yet 'tis for the moſt part ſome Metalline or Mineral Calx, mingled in a
small proportion that gives the Colour. But though I have many years ſince taken delight, to divert my ſelf with this pleaſing Art, and have ſeen very pretty Productions of it, yet beſides that I fear I have now forgot moſt of the little Skill I had in it, this is no place to entertain you with what would rather take up an intire Diſcourſe, than be comprehended in an Annotation; wherefore the few things which I ſhall here take notice of to you, are only what belong to the preſent Argument, Namely,
Firſt, That I have often obſerv'd that Calcin'd Lead Colliquated with fine White Sand or Cryſtal, reduc'd by ignitions and ſubſequent extinctions in Water to a ſubtile Powder, will of it ſelf be brought by a due Decoction to give a cleer Maſs Colour'd like a German Amethyſt. For though this glaſs of Lead, is look'd upon by them that know no better way of making Amanſes, as the grand Work of them all, yet which is an inconvenience that much blemiſhes this way, the Calcin'd Lead it ſelf does not only afford matter to the Amanſes, but has alſo as well as other Metals a Colour of its own, which as I was ſaying, I have often found to be like that of German (as many call them) not Eaſtern Amethyſts.
Secondly, That nevertheleſs this Colour
may be eaſily over-powr'd by thoſe of divers other Mineral Pigments (if I may ſo call them) ſo that with a glaſs of Lead, you may Emulate (for Inſtance) the freſh and lovely Greenneſs of an Emerald, though in divers caſes the Colour which the Lead it ſelf upon Vitrification tends to, may vitiate that of the Pigment, which you would introduce into the Maſs.
Thirdly, That ſo much ev'n theſe Colours depend upon Texture, that in the Glaſs of Lead it ſelf made of about three parts of Lytharge or Minium Colliquated with one of very finely Powder'd Cryſtal or Sand, we have taken pleaſure to make the mixture paſs through differing Colours, as we kept it more or leſs in the Fuſion. For it was not uſually till after a pretty long Decoction that the Maſs attain'd to the Amethyſtin Colour.
Fourthly and laſtly, That the degrees of Coction and other Circumſtances may ſo vary the Colour produc'd in the ſame maſs, that in a Crucible that was not great I have had fragments of the ſame Maſs, in ſome of which perhaps not ſo big as a Hazel-Nut, you may diſcern four diſtinct Colours.
Annotation VI.
You may remember (Pyrophilus) that when I mention'd the three ſorts of adventitious Colours of Metals, I mention'd them but as the chief, not the only. For there may be other wayes, which though they do not in ſo ſtrict a ſenſe belong to the adventitious Colours of Metals, may not inconveniently be reduc'd to them. And of theſe I ſhall name now a couple, without denying that there may be more.
The firſt may be drawn from the practiſe of thoſe that Dye Scarlet. For the famouſeſt Maſter in that Art, either in England or Holland, has confeſs'd to me, that neither others, nor he can ſtrike that lovely Colour which is now wont to be call'd the Bow-Dye, without their Materials be Boyl'd in Veſſels, either made of, or lin'd with a particular Metall. But of what I have known attempted in this kind, I muſt not as yet for fear of prejudicing or diſpleaſing others give you any particular Account.[a]24]
The other way (Pyrophilus) of making Metals afford unobvious Colours, is by imbuing divers Bodies with Solutions of them made in their proper Menſtruum's, As (for
Inſtance) though Copper plentifully diſſolv'd in Aqua fortis, will imbue ſeveral Bodies with the Colour of the Solution; Yet Some other Metalls will not (as I elſewhere tell you) and have often try'd. Gold diſſolv'd in Aqua Regia, will, (which is not commonly known) Dye the Nails and Skin, and Hafts of Knives, and other things made of Ivory, not with a Golden, but a Purple Colour, which though it manifeſt it ſelf but ſlowly, is very durable, and ſcarce ever to be waſh'd out. And if I miſremember not, I have already told you in this Treatiſe, that the purer Cryſtals of fine Silver made with Aqua fortis, though they appear White, will preſently Dye the Skin and Nails, with a Black, or at leaſt a very Dark Colour, which Water will not waſh off, as it will ordinary Ink from the ſame parts. And divers other Bodies may the Same way be Dy'd, ſome of a Black, and others of a Blackiſh Colour.
And as Metalline, ſo likewiſe Mineral Solutions may produce Colours differing enough from thoſe of the Liquors themſelves. I ſhall not fetch an Example of this, from what we daily ſee happen in the powdring of Beef, which by the Brine imploy'd about it (eſpecially if the fleſh be
over ſalted) do's oftentimes appear at our Tables of a Green, and ſometimes of a Reddiſh Colour, (deep enough) nor ſhall I inſiſt on the practiſe of ſome that deal in Salt Petre, who, (as I ſuſpected, and as themſelves acknowledg'd to me) do, with the mixture of a certain proportion of that; and common Salt, give a fine Redneſs, not only to Neats Tongues, but which is more pretty as well as difficult, to ſuch fleſh, as would otherwiſe be purely White; Theſe Examples, I ſay, I ſhall decline inſiſting on, as chuſing rather to tell you, that I have ſeveral times try'd, that a Solution of the Sulphur of Vitriol, or ev'n of common Sulphur, though the Liquor appear'd clear enough, would immediately tinge a piece of new Coin, or other clean Silver, ſometimes with a Golden, ſometimes with a deeper, and more Reddiſh colour, according to the ſtrength of the Solution, and the quantity of it, that chanc'd to adhere to the Metall; which may take off your wonder that the water of the hot Spring at Bath, abounding with diſſolv'd Subſtances of a very Sulphureous Nature, ſhould for a while, as it were gild, the new or clean pieces of Silver coyn, that are for a due time immers'd in it. And to theſe may be added thoſe formerly mention'd Examples
of the adventitious Colours of Mineral Bodies; which brings into my mind, that, ev'n Vegetable Liquors, whether by degeneration, or by altering the Texture of the Body that imbibes them, may ſtain other Bodies with Colours differing enough, from their own, of which very good Herbariſts have afforded us a notable Example, by affirming that the Juice of Alcanna being green (in which ſtate I could never here procure it) do's yet Dye the Skin and Nails of a Laſting Red. But I ſee this Treatiſe is like to prove too bulky without the addition of further Inſtances of this Nature.
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
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 Potaſhes 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
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 taſteleſs 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
them to imbibe the Moiſture[a]25].
Annotation I.
Whereas it is preſum'd that the Magiſtery of Vegetables obtain'd this way conſiſts but of the more Soluble and Coloured parts of the Plants that afford it, I muſt take the liberty to Queſtion the ſuppoſition. And for my ſo doing, I ſhall give you this account.
According to the Notions (ſuch as they were) that I had concerning Salts; Allom, though to ſenſe a Homogeneous Body, ought not to be reckon'd among true Salts, but to be it ſelf look'd upon as a kind of Magiſtery, in regard that as Native Vitriol (for ſuch I have had) contains both a Saline ſubſtance and a Metall, whether Copper, or Iron, corroded by it, and aſſociated with it; ſo Allom which may be of ſo near a kin to Vitriol, that in ſome places of England (as we are aſſur'd by good Authority the ſame ſtone will
ſometimes afford both) ſeems manifeſtly to contain a peculiar kind of Acid Spirit, generated in the Bowels of the Earth, and ſome kind of ſtony matter diſſolv'd by it. And though in making our ordinary Allom, the Workmen uſe the Aſhes of a Sea Weed (vulgarly call'd Kelp) and Urine: yet thoſe that ſhould know, inform us, that, here in England, there is beſides the factitious Allom, Allom made by Nature Without the help of thoſe Additaments. Now (Pyrophilus) when I conſider'd this compoſition of Allom, and that Alcalizate Salts are wont to Præcipitate what acid Salts have diſſolv'd, I could not but be prone to ſuſpect that the Curdled Matter, which is call'd the Magiſtery of Vegetables, may have in it no inconſiderable proportion of a ſtony ſubſtance Præcipitated out of the Allom by the Lixivium, wherein the Vegetable had been decocted, and to ſhew you, that there is no neceſſity, that all the curdl'd ſubſtance muſt belong to the Vegetable, I ſhall add, that I took a ſtrong Solution of Allom, and having Filtred it, by pouring in a convenient Quantity of a ſtrong Solution of Potaſhes, I preſently, as I expected, turn'd the mixture into a kind of white Curds, which being put to Filtre, the Paper retain'd a ſtony
Calx, copious enough, very White, and which ſeem'd to be of a Mineral Nature, both by ſome other ſignes, and this, that little Bits of it being put upon a live Coal, which was Gently Blown whilſt they were on it, they did neither melt nor fly away, and you may keep a Quantity of this White ſubſtance for a good while, (nay for ought I can gueſs for a very long one) in a red hot Crucible without loſing or ſpoiling it; nor did hot Water wherein I purpoſely kept another parcel of ſuch Calx, ſeem to do any more than waſh away the looſer adhering Salts from the ſtony ſubſtance, which therefore ſeem'd unlikely to be ſeparable by ablutions (though reiterated) from the Præcipitated parts of the Vegetable, whoſe Lake is intended. And to ſhew you, that there is likewiſe in Allom a Body, with which the fix'd Salt of the Alcalizate Solution will concoagulate into a Saline Subſtance differing from either of them, I ſhall add, that I have taken pleaſure to recover out of the ſlowly exhal'd Liquor, that paſs'd through the filtre, and left the foremention'd Calx behind, a Body that at leaſt ſeem'd a Salt very pretty to look on, as being very White, and conſiſting of an innumerable company of exceeding ſlender, and ſhining Particles, which
would in part eaſily melt at the flame of a Candle, and in part flye away with ſome little noiſe. But of this ſubſtance, and its odd Qualities more perhaps elſewhere; for now I ſhall only take notice to you, that I have likewiſe with Urinous Salts, ſuch as the Spirit of Sal Armoniack, as well as with the Spirit of Urine it ſelf, Nay, (if I much miſtake not) ev'n with Stale Urine undiſtil'd, eaſily Precipitated ſuch a White Calx as I was formerly ſpeaking of, out of a Limpid Solution of Allom, ſo that there is need of Circumſpection in judging of the Natures of Liquors by Precipitations wherein Allom intervenes, elſe we may ſometimes miſtakingly imagine that to be Precipitated out of a Liquor by Allom, which is rather Precipitated out of Allom by the Liquor: And this puts me in mind to tell you, that 'tis not unpleaſant to behold how quickly the Solution of Allom (or injected lumps of Allom) do's occaſion the ſevering of the colour'd parts of the Decoction from the Liquor that ſeem'd to have ſo perfectly imbib'd them.
Annot. II.
The above mention'd way of making Lakes we have tryed not only with Turmerick, but alſo with Madder, which yielded us a Red Lake; and with Rue, which afforded us an extract, of (almoſt if not altogether) the ſame Colour with that of the leaves.
But in regard that 'tis Principally the Alcalizate Salt of the Pot-aſhes, which enables the water to Extract ſo powerfully the Tincture of the Decocted Vegetables, I fear that our Author may be miſtaken by ſuppoſing that the Decoction will alwayes be of the very ſame Colour with the Vegetable it is made off. For Lixiviate Salts, to which Pot-aſhes eminently belong, though by peircing and opening the Bodies of Vegetables, they prepare and diſpoſe them to part readily with their Tincture, yet ſome Tinctures they do not only draw out, but likewiſe alter them, as may be eaſily made appear by many of the Experiments already ſet down in this Treatiſe, and though Allom being of an Acid Nature, its Solutions may in ſome Caſes deſtroy the Adventitious Colours produc'd by the Alcaly, and reſtore the former: yet
beſides that Allom is not, as I have lately ſhown, a meer Acid Salt, but a mixt Body, and beſides, that its operations are languid in compariſon of the activity of Salts freed by Diſtillation, or by Incineration and Diſſolution, from the moſt of their Earthy parts, we have ſeen already Examples, that in divers Caſes an Acid Salt will not reſtore a Vegetable ſubſtance to the Colour of which an Alcalizate one had depriv'd it, but makes it aſſume a third very differing from both, as we formerly told you, that if Syrrup of Violets were by an Alcaly turn'd Green, (which Colour, as I have try'd, may be the ſame way produc'd in the Violet-leaves themſelves without any Relation to a Syrrup) an Acid Salt would not make it Blew again, but Red. And though I have by this way of making Lakes, made Magiſteries (for ſuch they ſeem to be) of Brazil, and as I remember of Cochinele it ſelf, and of other things, Red, Yellow or Green which Lakes were enobled with a Rich Colour, and others had no bad one; yet in ſome the colour of the Lake ſeem'd rather inferiour than otherwiſe to that of the Plant, and in others it ſeem'd both very differing, and much worſe; but Writing this in a time and place where I cannot provide my ſelf of Flowres and other Vegetables to proſecute
ſuch Tryals in a competent variety of Subjects, I am content not to be poſitive in delivering a judgment of this way of Lakes, till Experience, or You, Pyrophilus, ſhall have afforded me a fuller and more particular Information.
Annotation III.
And on this occaſion (Pyrophilus) I muſt here (having forgot to do it ſooner) advertiſe you once for all, that having written ſeveral of the foregoing Experiments, not only in haſte but at ſeaſons of the year, and in places wherein I could not furniſh my ſelf with ſuch Inſtruments, and ſuch a variety of Materials, as the deſign of giving you an Introduction into the Hiſtory of Colours requir'd, it can ſcarce be otherwiſe but that divers of the Experiments, that I have ſet down, may afford you ſome matter of new Tryals, if you think fit to ſupply the deficiencies of ſome of them (eſpecially the freſhly mention'd about Lakes, and thoſe that concern Emphatical Colours) which deficiencies for want of being befriended with accommodations I could better diſcern than avoid.
Annotation IV.
The uſe of Allom is very great as well as familiar in the Dyers Trade, and I have not been ill pleas'd with the uſe I have been able to make of it in preparing other pigments than thoſe they imploy with Vegetable Juices. But the Lucriferous practiſes of Dyers and other Tradeſmen, I do, for Reaſons that you may know when you pleaſe, purpoſely forbear in this Eſſay, though not ſtrictly from pointing at, yet from making it a part of my preſent work explicitly and circumſtantially to deliver, eſpecially ſince I now find (though late and not without ſome Bluſhes at my prolixity) that what I intended but for a ſhort Eſſay, is already ſwell'd into almoſt a Volume.
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
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 remembred, that finding the Acidity of Spirit of Vinegar to be wholly deſtroy'd by its working upon Minium (or calcin'd Lead) whereby the Saline 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
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 Præcipitate 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 Præcipitated 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
it would Præcipitate 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 was 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 Præcipitate 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
have done the ſame thing, though perhaps not quite ſo well with Spirit of Salt, and that I could not do it with Aqua-fortis, 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 39th. 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 convenient proportion of Spirit of Salt, would (if the Liquors were well and nimbly ſtirr'd together) preſently
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 Armnoniack, would Precipitate the Corpuſcles of Lead conceal'd in the Solution of Minium, and yet not deſtroy 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
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 ſpecified 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 (50th.) 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
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
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
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.
FINIS.
A SHORT
ACCOUNT
OF SOME
OBSERVATIONS
Made by Mr. BOYLE
About a Diamond that Shines in the Dark.
Firſt encloſed in a Letter written to
a Friend,
And now together with it annexed to the Foregoing
Treatiſe, upon the ſcore of the
Affinity Betwixt
Light and Colours.
LONDON,
Printed for Henry Herringman. 1664
A COPY
OF THE
LETTER
That Mr. Boyle wrote to Sir Robert Morray,
to accompany the Obſervations touching
the Shining Diamond.
SIR,
Hough Sir Robert Morray and Monſieur Zulichem be Perſons that have deſerv'd ſo well of the Commonwealth of Learning, that I ſhould think my ſelf unworthy to be look'd upon as a Member of it, if I declin'd to Obey them, or to Serve them; yet I ſhould not without Reluctancy ſend you the Notes, you deſire for him, if I did not hope that you will tranſmit together with them, ſome Account why they are not leſs unworthy of his peruſal; which, that you may do; I muſt inform you, how
the writing of them was Occaſion'd, which in ſhort was thus. As I was juſt going out of Town, hearing that an Ingenious Gentleman of my Acquaintance, lately return'd from Italy, had a Diamond, that being rubb'd, would ſhine in the Dark, and that he was not far off, I ſnatch'd time from my Occaſions to make him a Viſit, but finding him ready to go abroad, and having in vain try'd to make the Stone yield any Light in the Day time, I borrow'd it of him for that Night, upon condition to reſtore it him within a Day or two at furtheſt, at Greſham College, where we appointed to attend the meeting of the Society, that was then to be at that place. And hereupon I haſted that Evening out of Town, and finding after Supper that the Stone which in the Day time would afford no diſcernable Light, was really Conſpicuous in the Dark, I was ſo taken with the Novelty, and ſo deſirous to make ſome uſe of an opportunity that was like to laſt ſo little a while, that though at that time I had no body to aſſiſt me but a Foot-Boy, yet ſitting up late, I made a ſhift that Night to try a pretty number of ſuch of the things that then came into my thoughts, as were not in that place and time unpracticable. And the next Day being otherwiſe imploy'd,
I was fain to make uſe of a drowſie part of the Night to ſet down haſtily in Writing what I had obſerv'd, and without having the time in the Morning, to ſtay the tranſcribing of it, I order'd the Obſervations to be brought after me to Greſham College, where you may remember, that they were together with the Stone it ſelf ſhown to the Royal Society, by which they had the good Fortune not to be diſlik'd, though ſeveral things were through haſt omitted, ſome of which you will find in the Margin of the incloſed Paper. The ſubſtance of this ſhort Narrative I hope you will let Monſieur Zulichem know, that he may be kept from expecting any thing of finiſh'd in the Obſervations, and be diſpos'd to excuſe the want of it. But ſuch as they are, I hope they will prove (without a Clinch) Luciferous Experiments, by ſetting the Speculations of the Curious on work, in a diligent Inquiry after the Nature of Light, towards the diſcovery of which, perhaps they have not yet met with ſo conſiderable an Experiment, ſince here we ſee Light produc'd in a dead and opacous Body, and that not as in rotten Wood, or in Fiſhes, or as in the Bolonian Stone, by a Natural Corruption, or by a
Violent Deſtruction of the Texture of the Body, but by ſo ſlight a Mechanical operation upon its Texture, as we ſeem to know what it is, and as is immediately perform'd, and that ſeveral wayes without at all prejudicing the Body, or making any ſenſible alterations in its Manifeſt Qualities. And I am the more willing to expoſe my haſty Tryals to Monſieur Zulichem, and to You, becauſe, he being upon the Conſideration of Dioptricks, ſo odd a Phœnomemon relateing to the Subject, as probably he treats of, Light will, I hope, excite a perſon to conſider it, that is wont to conſider things he treats of very well. And for you Sir, I hope you will both recrute and perfect the Obſervations you receive, For you know that I cannot add to them, having a good while ſince reſtor'd to Mr. Clayton the Stone, which though it be now in the hands of a Prince that ſo highly deſerves, by underſtanding them, the greateſt Curioſities; yet he vouchſafes you that acceſs to him as keeps me from doubting, you may eaſily obtain leave to make further Tryals with it, of ſuch a Monarch as ours, that is not more inquiſitive himſelf, than a favourer of them that are ſo. I doubt not but theſe Notes will put you in mind of the Motion you made to the Society, to impoſe upon
me the Task of bringing in, what I had on other occaſions obſerv'd concerning ſhining Bodies. But though I deny not, that I ſometimes made obſervations about the Bolonian Stone, and try'd ſome Experiments about ſome other ſhining Bodies; Yet the ſame Reaſons that reduc'd me then to be unwilling to receive ev'n their commands, muſt now be my Apology for not anſwering your Expectations, Namely the abſtruſe nature of Light, and my being already over-burden'd, and but too much kept imploy'd by the Urgency of the Preſs, as well as by more concerning and diſtracting Occaſions. But yet I will tell you ſome part of what I have met with in reference to the Stone, of which I ſend you an account. Becauſe I find on the one ſide, that a great many think it no Rarity upon a miſtaken perſwaſion, that not only there are ſtore of Carbuncles, of which this is one; but that all Diamonds and other Gliſtering Jewels ſhine in the Dark. Whereas on the other ſide there are very Learn'd Men, who (plauſibly enough) deny that there are any Carbuncles or ſhining Stones at all.
And certainly, thoſe Judicious men have much more to ſay for themſelves, than the others commonly Plead, and therefore did deſervedly look upon Mr. Clayton's Diamond
as a great Rarity. For not only Boetius de Boot, who is judg'd the beſt Author on this Subject, aſcribes no ſuch Virtue to Diamonds, but begins what he delivers of Carbuncles, with this paſſage.[a]26] Magna fama est Carbunculi. Is vulgo putatur in tenebris Carbonis inſtar lucere; fortaſſis quia Pyropus ſeu Anthrax appellatus a veteribus fuit. Verum hactenus nemo nunquam verè aſſerere auſus fuit, ſe gemmam noctu lucentem vidiſſe. Garcias ab Horto proregis Indiæ Medicus, refert ſe allocutum fuiſſe, qui ſe vidiſſe affirmarent. Sed iis fidem non habuit. And a later Author, the Diligent and Judicious Johannes de Laet in his Chapter of Carbuncles and of Rubies, has this paſſage. Quia autem Carbunculi, Pyropi & Anthraces a veteribus nominantur, vulgo creditum fuit, Carbonis instar in tenebris lucere, quod tamen nullâ gemmâ hastenus deprehenſum, licet à quibuſdam temerè jactetur. And the recenteſt Writer I have met with on this Subject, Olaus Wormius, in his Account of his well furniſh'd Musæum, do's, where he treats of Rubies, concurr with the former Writers by theſe Words.[a]27] Sunt qui Rubinum veterum Carbunculum eſſe existimant, ſed deeſt una illa nota, quod
in tenebris inſtar Anthracis non luceat: Aſt talem Carbunculum in rerum naturâ non inveniri major pars Authoram exiſtimant. Licet unum aut alterum in India apud Magnates quoſdam reperiri ſcribant, cum tamen ex aliorum relatione id habeant ſaltem, ſed ipſi non viderint. In confirmation of which I ſhall only add, that hearing of a Rubie, ſo very Vivid, that the Jewellers themſelves have ſeveral times begg'd leave of the fair Lady to whom it belong'd, that they might try their choiceſt Rubies by comparing them with That, I had the Opportunity by the Favour of this Lady and her Huſband, (both which I have the Honour to be acquainted with) to make a Trial of this famous Rubie in the Night, and in a Room well Darkn'd, but not only could not diſcern any thing of Light, by looking on the Stone before any thing had been done to it, but could not by all my Rubbing bring it to afford the leaſt Glimmering of Light.
But, Sir, though I be very backward to admit ſtrange things for truths, yet I am not very forward to reject them as impoſſibilities, and therefore I would not diſcourage any from making further Inquiry, whether or no there be Really in Rerum natura, any ſuch thing as a true Carbuncle or Stone that without Rubbing will ſhine
in the Dark. For if ſuch a thing can be found, it may afford no ſmall Aſſiſtance to the Curious in the Inveſtigation of Light, beſides the Nobleneſs and Rarity of the thing it ſelfe. And though Vartomannus was not an Eye witneſs of what he relates, that the King of Pegu, one of the Chief Kings of the East-Indies, had a true Carbuncle of that Bigneſs and Splendour, that it ſhin'd very Gloriouſly in the Dark, and though Garcias ab Horto, the Indian Vice-Roys Phyſician, ſpeaks of another Carbuncle, only upon the Report of one, that he Diſcours'd with, who affirmed himſelf to have ſeen it; yet as we are not ſure that theſe Men that gave themſelves out to be Eye-witneſſes ſpeak true, yet they may have done ſo for ought we know to the contrary. And I could preſent you with a much conſiderabler Teſtimony to the ſame purpoſe, if I had the permiſſion of a Perſon concern'd, without whoſe leave I muſt not do it. I might tell you that Marcus Paulus Venetus[a]28] (whoſe ſuppos'd Fables, divers of our later Travellours and Navigatours have ſince found to be truths) ſpeaking of the King of Zeilan that then was, tells us, that he was ſaid to have the beſt Rubie in the World, a Palm long and as
big as a mans Arm, without ſpot, ſhining like a Fire, and he ſubjoyns, that the Great Cham, under whom Paulus was a conſiderable Officer, ſent and offer'd the value of a City for it; But the King anſwer'd, he would not give it for the treaſure of the World, nor part with it, having been his Anceſtours. And I could add, that in the Relation made by two Ruſſian Coſſacks of their Journey into Catay[a]29], written to their Emperour, they mention'd their having been told by the people of thoſe parts, that their King had a Stone, which Lights as the Sun both Day and Night, call'd in their Language Sarra, which thoſe Coſſacks interpret a Ruby. But theſe Relations are too uncertain for me to build any thing upon, and therefore I ſhall proceed to tell you, that there came hither about two years ſince out of America, the Governour of one of the Principal Colonies there, an Ancient Virtuoſo, and one that has the Honour to be a member of the Royal Society; this Gentleman finding ſome of the chief Affairs of his Country committed to another and me, made me divers Viſits, and in one of them when I enquir'd what Rare Stones they had in thoſe parts of the Indies he belong'd to, he told me, that the Indians had a Tradition
that in a certain hardly acceſſible Hill, a pretty way up in the Country, there was a Stone which in the Night time ſhin'd very vividly, and to a great diſtance, and he aſſur'd me, that though he thought it not fit to venture himſelf ſo far among thoſe Savages, yet he purpoſely ſent thither a bold Engliſhman, with ſome Natives to be his guides, and that this Meſſenger brought him back word, that at a diſtance from the Hillock he had plainly perceiv'd ſuch a ſhining Subſtance as the Indians Tradition mention'd, and being ſtimulated by Curioſity, had ſlighted thoſe Superſtitious Fears of the Inhabitants, and with much ado by reaſon of the Difficulty of the way, had made a ſhift to clamber up to that part of the Hill, where, by a very heedful Obſervation, he ſuppos'd himſelf to have ſeen the Light: but whether 'twere that he had miſtaken the place, or for ſome other Reaſon, he could not find it there, though when he was return'd to his former Station, he did agen ſee the Light ſhining in the ſame place where it ſhone before. A further Account of this Light I expect from the Gentleman that gave me this, who lately ſent me the news of his being landed in that Country. And though I reſerve to my ſelf a full Liberty of Believing no more
than I ſee cauſe; yet I do the leſs ſcruple to relate this, becauſe a good part of it agrees well enough with another Story that I ſhall in the next place have occaſion to ſubjoyn, in order whereunto I ſhall tell you, that though the Learned Authors I formerly mention'd, tell us, that no Writer has affirm'd his having himſelf ſeen a real Carbuncle, yet, conſidering the Light of Mr. Claytons Diamond, it recall'd into my mind, that ſome years before, when I was Inquiſitive about Stones, I had met with an old Italian Book highly extoll'd to me by very competent Judges, and that though the Book were very ſcarce, I had purchas'd it at a dear Rate, for the ſake of a few conſiderable paſſages I met with in it, and particularly one, which being very remarkable in it ſelf, and pertinent to our preſent Argument, I ſhall put it for you, though not word for word, which I fear I have forgot to do, yet as to the Senſe, into Engliſh.
Having promis'd (Says our Author)[a]30] to ſay ſomething of that moſt precious ſort of Jewels, Carbuncles, becauſe they are very rarely to be met with, we ſhall briefly deliver what we know of them. In Clement the ſeventh's time, I happen'd to ſee one of
them at a certain Raguſian Merchants, nam'd Beigoio di Bona, This was a Carbuncle white, of that kind of whiteneſs which we ſaid was to be found in thoſe Rubies of which we made mention a little above, (where he had ſaid that thoſe Rubies had a kind of Livid Whiteneſs or Paleneſs like that of a Calcidonian) but it had in it a Luſtre ſo pleaſing and ſo marveilous, that it ſhin'd in the Dark, but not as much as colour'd Carbuncles, though it be true, that in an exceeding Dark place I ſaw it ſhine in the manner of fire almoſt gone out. But as for colour'd Carbuncles, it has not been my Fortune to have ſeen any, wherefore I will onely ſet down what I Learn'd about them Diſcourſing in my Youth with a Roman Gentleman of antient Experience in matters of Jewels, who told me, That one Jacopo Cola being by Night in a Vineyard of his, and eſpying ſomething in the midſt of it, that ſhin'd like a little glowing Coal, at the foot of a Vine, went near towards the place where he thought himſelf to have ſeen that fire, but not finding it, he ſaid, that being return'd to the ſame place, whence he had firſt deſcry'd it, and perceiving there the ſame ſplendor as before, he mark'd it ſo heedfully, that he came at length to it, where he took up a very little Stone, which he carry'd away with Tranſports and Joy. And the next
day carrying it about to ſhow it divers of his Friends, whilſt he was relating after what manner he found it, there caſually interven'd a Venetian Embaſſadour, exceedingly expert in Jewels, who preſently knowing it to be a Carbuncle, did craftily before he and the ſaid Jacopo parted (ſo that there was no Body preſent that underſtood the Worth of ſo Precious a Gemm) purchaſe it for the Value of 10. Crowns, and the next day left Rome to ſhun the being neceſſitated to reſtore it, and (as he affirm'd) it was known within ſome while after that the ſaid Venetian Gentleman did in Conſtantinople ſell that Carbuncle to the then Grand Seignior, newly come to the Empire, for a hundred thouſand Crowns. And this is what I can ſay concerning Carbuncles, and this is not a little at leaſt as to the firſt part of this account, where our Cellini affirms himſelf to have ſeen a Real Carbuncle with his own Eyes, eſpecially ſince this Author appears wary in what he delivers, and is inclin'd rather to leſſen, than increaſe the wonder of it. And his Teſtimony is the more conſiderable, becauſe though he were born a Subject neither to the Pope nor the then King of France (that Royal Virtuoſo Francis the firſt) yet both the one and the other of thoſe Princes imploy'd him much
about making of their Nobleſt Jewels. What is now reported concerning a Shining Subſtance to be ſeen in one of the Iſlands about Scotland, were very improper for me to mention to Sr. Robert Morray, to whom the firſt Information was Originally brought, and from whom I expect a farther (for I ſcarce dare expect a convincing) account of it. But I muſt not omit that ſome Virtuoſo queſtioning me the other day at White-Hall about Mr. Claytons Diamond, and meeting amongſt them an Ingenious Dutch Gentleman, whoſe Father was long Embaſſador for the Netherlands in England, I Learn'd of him, that, he is acquainted with a perſon, whoſe Name he told (but I do not well remember it) who was Admiral of the Dutch in the Eaſt-Indies, and who aſſur'd this Gentleman Monſieur Boreel, that at his return from thence he brought back with him into Holland a Stone, which though it look'd but like a Pale Dull Diamond, ſuch as he ſaw Mr. Claytons to be, yet was it a Real Carbuncle, and did without rubbing ſhine ſo much, that when the Admiral had occaſion to open a Cheſt which he kept under Deck in a Dark place, where 'twas forbidden to bring Candles for fear of Miſchances, as ſoon as he open'd the Trunck, the Stone
would by its Native Light, ſhine ſo as to Illuſtrate a great part of it, and this Gentleman having very civilly and readily granted me the requeſt I made him, to Write to the Admiral, who is yet alive in Holland, (and probably may ſtill have the Jewel by him,) for a particular account of this Stone, I hope ere long to receive it, which will be the more welcome to me, not onely becauſe ſo unlikely a thing needs a cleer evidence, but becauſe I have had ſome ſuſpition of that (ſuppoſing the truth of the thing) what may be a ſhining Stone in a very hot Countrey as the Eaſt-Indies, may perhaps ceaſe to be ſo (at leaſt in certain ſeaſons,) in one as cold as Holland. For I obſerv'd in the Diamond I ſend you an account of, that not onely rubbing but a very moderate degree of warmth, though excited by other wayes, would make it ſhine a little. And 'tis not impoſſible that there may be Stones as much more ſuſceptible than that, of the Alterations requiſite to make a Diamond ſhine, as that appeares to be more ſuſceptible of them, than ordinary Diamonds. And I confeſs to you, that this is not the only odd ſuſpition (for they are not ſo much as conjectures) that what I try'd upon this Diamond ſuggeſted to me. For not here to entertain you with the
changes I think may be effected ev'n in harder ſorts of Stones, by wayes not vulgar, nor very promiſing, becauſe I may elſewhere have occaſion to ſpeak of them, and this Letter is but too Prolix already, that which I ſhall now acknowledge to you is, That I began to doubt whether there may not in ſome Caſes be ſome Truth in what is ſaid of the right Turquois, that it often changes Colour as the wearer is Sick or Well, and manifeſtly loſes its ſplendor at his Death. For when I found that ev'n the warmth of an Affriction that laſted not above a quarter of a minute, Nay, that of my Body, (whoſe Conſtitution you know is none of the hotteſt) would make a manifeſt change in the ſolideſt of Stones a Diamond, it ſeem'd not impoſſible, that certain warm and Saline ſteams iſſuing from the Body of a living man, may by their plenty or paucity, or by their peculiar Nature, or by the total abſence of them, diverſifie the Colour, and the ſplendor of ſo ſoft a Stone as the Turquois. And though I admir'd to ſee, that I know not how many Men otherwiſe Learn'd, ſhould confidently aſcribe to Jewels ſuch Virtues as ſeem no way competible to Inanimate Agents, if to any Corporeal ones at all, yet as to what is affirm'd concerning the Turquois's
changing Colour, I know not well how to reject the Affirmation of ſo Learned (and which in this caſe is much more conſiderable) ſo Judicious a Lapidary as Boetius de Boot[a]31], who upon his own particular and repeated Experience delivers ſo memorable
a Narrative of the Turquois's changing Colour, that I cannot but think it worth your Peruſal, eſpecially ſince a much later and very Experienc'd Author, Olaus Wormius,[a]32] where he treats of that Stone, Confirms it with this Teſtimony. Imprimis memorandum exemplum quod Anſhelmus Boetius de ſeipſo refert, tam mutati Coloris, quam à caſu preſervationis. Cui & ipſe haud diſſimile adferre poſsum, niſi ex Anſhelmo petitum quis putaret. I remember that I ſaw two or three years ſince a Turcois (worn in a Ring) wherein there were ſome ſmall ſpots, which the Virtuoſo whoſe it was aſur'd me he had obſerv'd to grow ſometimes greater ſometimes leſs, and to be ſometimes in one part of the Stone, ſometimes in another. And I having encourag'd to make Pictures from time to time of the Stone, and of the Situation of the cloudy parts, thatſo their Motion may be more indiſputable, and better obſerv'd, he came to me about the midle of this very week, and aſſur'd me that he had, as I wiſh'd, made from time to time Schemes or Pictures of the differing parts of the Stone, whereby the ſeveral Removes and motions of the above mentioned Clouds are very manifeſt, though the cauſe ſeem'd to him very occult: theſe Pictures
he has promis'd to ſhow me, and is very ready to put the Stone it ſelf into my hands. But the ring having been the other day caſually broken upon his finger, unleſs it can be taken out, and ſet again without any conſiderable heat, he is loath to have it medled with, for fear its peculiarity ſhould be thereby deſtroy'd. And poſſibly his apprehenſion would have been ſtrengthen'd, if I had had opportunity to tell him what is related by the Learned Wormius[a]33] of an acquaintance of his, that had a Nephritick ſtone, of whoſe eminent Virtues he had often Experience ev'n in himſelf, and for that cauſe wore it ſtill about his Wriſt; and yet going upon a time into a Bath of fair Water only, wherein certain Herbs had been boyl'd, the Stone by being wetted with this decoction, was depriv'd of all his Virtue, whence Wormius takes Occaſion to advertiſe the ſick, to lay by ſuch ſtones whenſoever they make uſe of a Bath. And we might expect to find Turcos likewiſe, eaſily to be wrought upon in point of Colour, if that were true, which the curious Antonio Neri, in his ingenious Arte Vetraria[a]34] teaches of it, namely, That Turcois's diſcolour'd and grown white, will regain and acquire
an excellent Colour, if you but keep them two or three days at moſt cover'd with Oyl of ſweet Almonds kept in a temperate heat by warm aſhes, I ſay if it were true, becauſe I doubt whether it be ſo, and have not as yet had opportunity to ſatisfie my ſelf by Tryals, becauſe I find by the confeſſion of the moſt Skilfull Perſons among whom I have laid out for Turcoiſes, that the true ones are great rarities, though others be not at all ſo. And therefore I ſhall now only mind you of one thing that you know as well as I, namely, that the rare Stone which is called Oculus Mundi, if it be good in its Kind, will have ſo great a change made in its Texture by being barely left a while in the Languideſt of Liquors, common Waters, that from Opacous it will become Tranſparent, and acquire a Luſtre of which it will again be depriv'd, without uſing any other Art or Violence, by leaving it a while in the Air. And before experience had ſatisfy'd us of the truth of this, it ſeem'd as unlikely that common Water or Air, ſhould work ſuch great changes in that Gemm, as it now ſeems that the Effluviums of a human Body ſhould effect leſſer changes in a Turcois, eſpecially if more ſuſceptible of them, than other Stones of the ſame kind. But both my Watch and my Eyes tell me that
'tis now high time to think of going to ſleep, matters of this Nature, will be better, as well as more eaſily, clear'd by Conference, than Writing. And therefore ſince I think you know me too well to make it needfull for me to diſclame Credulity, notwithſtanding my having entertain'd you with all theſe Extravagancies; for you know well, how wide a difference I am wont to put betwixt things that barely may be, and things that are, and between thoſe Relations that are but not unworthy to be inquir'd into, and thoſe that are not worthy to be actually believ'd; without making Apologies for my Ravings, I ſhall readily comply with the drowſineſs that calls upon me to releaſe You, and the rather, becauſe Monſieur Zulichem being concern'd in your deſire to know the few things I have obſerved about the ſhining Stone. To entertain thoſe with Suſpicions that are accuſtomed not to acquieſce but in Demonſtrations, were a thing that cannot be look'd upon as other than very improper by,
SIR,
Your most Affectionate
and
most Faithfull Servant,
RO. BOYLE.
