Because that, according to the Conjectures I have above propos'd, one of
the most General Causes of the Diversity of Colours in Opacous Bodyes, is,
that some reflect the Light mingl'd with more, others with less of Shade
(either 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.
[Page 191]
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._
[Illustration: _The Explication of the Scheme._]
_PPP_. An Aequilaterotriangular Crystalline Prism, one of whose edges _P_.
is placed directly towards the Sun.
_A B_ & [alpha] [beta] Two rays from the Sun falling on the Prism at _B_
[beta]. and thence partly reflected towards _C_ & [gamma]. and partly
refracted towards _D_ & [delta].
_B C_ & [beta] [gamma]. Those reflected Rays.
_B D_ & [beta] [delta]. Those refracted Rays which are partly refracted
towards _E_ & [epsilon]. 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_ & [zeta].
_D F_ & [delta] [zeta]. Those Reflected Rays which are partly refracted
towards _G_ & [eta]. colourless, and partly reflected, towards _H_ &
[theta].
_F H_ & [zeta] [theta]. Those reflected Rays which are refracted towards
_I_ & [iota]. 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,[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.
[16] _Nicolaus Monardes_ lib _simplic. ex India allatis_, cap. 27.
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)[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._
[17] Kircher. Art. Mag. lucis & umbræ, _lib. 1. part. 3._
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[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_.
[18] _Herbarists_ are wont to call this Plant _Cyanus vulgaris minor_.
_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._[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.
[19] Paracelsus de Mineral. tract. 1. pag. m. 243
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,[20] and the
other are often, and divers ways, imploy'd for Binding.
[20] See _Parkinson_ Th. Boran. Trib. 9. cap. 26.
And I also choose (_Pyrophilus_) to subjoyn this twenty ninth Experiment to
those that precede it, about the change of the Colours of Vegetables by
Salts, for these two reasons: The first, that you may not easily entertain
Suspitions, if in the Trials of an Experiment of some of the Kinds formerly
mention'd, you should meet with an Event somewhat differing from what my
Relations may have made you expect. And the second, That you may hereby be
invited to discern, that it may not be amiss to take notice of the
particular Seasons wherein you gather the Vegetables which in Nicer
Experiments you make use of. For, it I were not hindred both by haste and
some justifiable Considerations, I could perhaps add considerable
Instances, to those lately deliver'd, for the making out of this
Observation; but for certain reasons I shall at present 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._