diff options
| author | Roger Frank <rfrank@pglaf.org> | 2025-10-15 04:44:42 -0700 |
|---|---|---|
| committer | Roger Frank <rfrank@pglaf.org> | 2025-10-15 04:44:42 -0700 |
| commit | 0117250b090077256d0fd923e405573476fba1b8 (patch) | |
| tree | 675a7c3b3f0c83c166a1e1cabd642b8150315dfa /14504-0.txt | |
Diffstat (limited to '14504-0.txt')
| -rw-r--r-- | 14504-0.txt | 8539 |
1 files changed, 8539 insertions, 0 deletions
diff --git a/14504-0.txt b/14504-0.txt new file mode 100644 index 0000000..4b95f7c --- /dev/null +++ b/14504-0.txt @@ -0,0 +1,8539 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 14504 *** + + EXPERIMENTS + AND + CONSIDERATIONS + Touching + COLOURS. + + First occasionally Written, among some other + _Essays_, to a Friend; and now suffer'd to + come abroad as + + THE + BEGINNING + Of An + Experimental History + OF + COLOURS. + + By the Honourable ROBERT BOYLE, + Fellow of the ROYAL SOCIETY. + +_Non fingendum, aut excogitandum, sed inveniendum, +quid Natura faciat, aut ferat._ Bacon. + + _LONDON._ + + Printed for _Henry Herringman_ at the + _Anchor_ on the Lower walk of the _New + Exchange._ MDCLXIV. + + * * * * * + + THE + PREFACE. + +Having in convenient places of the following Treatise, mention'd the +Motives, that induc'd me to write it, and the Scope I propos'd to my self +in it; I think it superfluous to entertain the Reader now, with what he +will meet with hereafter. And I should judge it needless, to trouble +others, or my self, with any thing of Preface: were it not that I can +scarce doubt, but this Book will fall into the hands of some Readers, who +being unacquainted with the difficulty of attempts of this nature, will +think itn strange that I should publish any thing about Colours, without a +particular Theory of them. But I dare expect that Intelligent and Equitable +Readers will consider on my behalf: That the professed Design of this +Treatise is to deliver things rather _Historical_ than _Dogmatical_, and +consequently if I have added divers new _speculative_ Considerations and +hints, which perhaps may afford no despicable Assistance, towards the +framing of a solid and comprehensive Hypothesis, I have done at least as +much as I promis'd, or as the nature of my undertaking exacted. But another +thing there is, which if it should be objected, I fear I should not be able +so easily to answer it, and that is; That in the following treatise +(especially in the Third part of it) the Experiments might have been better +Marshall'd, and some of them deliver'd in fewer words. For I must confess +that this Essay was written to a private Friend, and that too, by snatches, +at several times, and places, and (after my manner) in loose sheets, of +which I oftentimes had not all by me that I had already written, when I was +writing more, so that it needs be no wonder if all the Experiments be not +rang'd to the best Advantage, and if some connections and consecutions of +them might easily have been mended. Especially since having carelessly laid +by the loose Papers, for several years after they were written, when I came +to put them together to dispatch them to the Press, I found some of those I +reckon'd upon, to be very unseasonably wanting. And to make any great +change in the order of the rest, was more than the Printers importunity, +and that, of my own avocations (and perhaps also considerabler +solicitations) would permit. But though some few preambles of the +particular Experiments might have (perchance) been spar'd, or shorten'd, if +I had had all my Papers under my View at once; Yet in the most of those +Introductory passages, the Reader will (I hope) find hints, or +Advertisements, as well as Transitions. If I sometimes seem to insist long +upon the circumstances of a Tryall, I hope I shall be easily excused by +those that both know, how nice divers experiments of Colours are, and +consider that I was not barely to _relate_ them, but so as to teach a young +Gentleman to make them. And if I was not sollicitous, to make a nicer +division of the whole Treatise, than into three parts, whereof the One +contains some Considerations about Colours in general. The Other exhibits a +specimen of an Account of particular Colours, Exemplifi'd in Whiteness and +Blackness. And the Third promiscuous Experiments about the remaining +Colours (especially Red) in order to a Theory of them. If, I say, I +contented my self with this easie Division of my Discourse, it was perhaps +because I did not think it so necessary to be Curious about the Method or +Contrivance of a Treatise, wherein I do not pretend to present my Reader +with a compleat Fabrick, or so much as Modell; but only to bring in +Materials proper for the Building; And if I did not well know how Ingenious +the Curiosity and Civility of Friends makes them, to perswade Men by +specious allegations, to gratifie their desires; I should have been made to +believe by persons very well qualify'd to judge of matters of this nature, +that the following Experiments will not need the addition of accurate +Method and speculative Notions to procure Acceptance for the Treatise that +contains them: For it hath been represented, That in most of them, as the +Novelty will make them surprizing, and the Quickness of performance, keep +them from being tedious; so the sensible changes, that are effected by +them, are so manifest, so great, and so sudden, that scarce any will be +displeased to see them, and those that are any thing Curious will scarce be +able to see them, without finding themselves excited, to make Reflexions +upon Them. But though with me, who love to measure Physical things by +their _use_, not their _strangeness_, or _prettiness_, the partiality of +others prevails not to make me over value these, or look upon them in +themselves as other than Trifles: Yet I confess, that ever since I did +divers years ago shew some of them to a Learned Company of _Virtuosi_: so +many persons of differing Conditions, and ev'n Sexes, have been Curious to +see them, and pleas'd not to Dislike them, that I cannot Despair, but that +by complying with those that urge the Publication of them, I may both +gratifie and excite the Curious, and lay perhaps a Foundation whereon +either others or my self may in time superstruct a substantial theory of +Colours. And if _Aristotle_, after his Master _Plato_, have rightly +observ'd Admiration to be the _Parent of Philosophy_, the wonder, some of +these Trifles have been wont to produce in all sorts of Beholders, and the +access they have sometimes gain'd ev'n to the Closets of Ladies, seem to +promise, that since the subject is so pleasing, that the Speculation +appears as Delightful! as Difficult, such easie and recreative Experiments, +which require but little time, or charge, or trouble in the making, and +when made are sensible and surprizing enough, may contribute more than +others, (far more important but as much more difficult) to recommend those +parts of Learning (Chymistry and Corpuscular Philosophy) by which they have +been produc'd, and to which they give Testimony ev'n to such kind of +persons, as value a pretty Trick more than a true Notion, and would scarce +admit Philosophy, if it approach'd them in another Dress: without the +strangeness or endearments of pleasantness to recommend it. I know that I +do but ill consult my own Advantage in the consenting to the Publication of +the following Treatise: For those things, which, whilst men knew not how +they were perform'd, appear'd so strange, will, when the way of making +them, and the Grounds on which I devis'd them, shall be Publick, quickly +lose all that their being _Rarityes_, and their _being thought Mysteries_, +contributed to recommend them. But 'tis fitter for Mountebancks than +Naturalis to desire to have their discoverys rather admir'd than +understood, and for my part I had much rather deserve the thanks of the +Ingenious, than enjoy the Applause of the Ignorant. And if I can so farr +contribute to the discovery of the nature of Colours, as to help the +Curious to it, I shall have reach'd my End, and sav'd my self some Labour +which else I may chance be tempted to undergo in prosecuting that subect, +and Adding to this Treatise, which I therefore call a _History_, because it +chiefly contains matters of fact, and which History the Title declares me +to look upon but as _Begun_: Because though that above a hundred, not to +say a hundred and fifty Experiments, (some loose, and others interwoven +amongst the discourses themselves) may suffice to give a _Beginning_ to a +History not hitherto, that I know, begun, by any; yet the subject is so +fruitfull, and so worthy, that those that are Curious of these Matters will +be farr more wanting to themselves than I can suspect, if what I now +publish prove any more than a _Beginning_. For, as I hope my Endeavours may +afford them some assistance towards this work, so those Endeavours are much +too Vnfinish'd to give them any discouragement, as if there were little +left for others to do towards the History of Colours. + +For (first) I have been willing to leave unmention'd the _most part_ of +those Phænomena of Colours, that Nature presents us of her own accord, +(that is, without being guided or over-ruld by man) such as the different +Colours that several sorts of Fruites pass through before they are +perfectly ripe, and those that appear upon the fading of flowers and +leaves, and the putrifaction (and its several degrees) of fruits, &c. +together with a thousand other obvious Instances of the changes of colours. +Nor have I _much_ medled with those familiar Phænomena wherein man is not +an Idle spectator; such as the Greenness produc'd by salt in Beef much +powder'd, and the Redness produc'd in the shells of Lobsters upon the +boyling of those fishes; For I was willing to leave the _gathering_ of +_Observations_ to those that have not the Opportunity to _make +Experiments_. And for the same Reasons, among others, I did purposly omit +the Lucriferous practise of Trades-men about colours; as the ways of +making Pigments, of Bleanching wax, of dying Scarlet, &c. though to divers +of them I be not a stranger, and of some I have myself made Tryall. + +Next; I did purposely pass by divers Experiments of other Writers that I +had made Tryall of (and that not without registring some of their Events) +unless I could some way or other improve them, because I wanted leasure to +insert them, and had thoughts of prosecuting the work once begun of laying +together those I had examin'd by themselves in case of my not being +prevented by others diligence. So that there remains not a little, among +the things that are already published, to imploy those that have a mind to +exercise themselves in repeating and examining them. And I will not +undertake, that _none_ of the things deliver'd, ev'n in this Treatise, +though never so faithfully set down, may not prove to be thus farr of this +Sort, as to afford the Curious somewhat to add about them. For I remember +that I have somewhere in the Book it self acknowledged, that having written +it by snatches, partly in the Counntrey, and partly at unseasonable times +of the year, when the want of fit Instruments, and of a competent variety +of flowers, salts, Pigments, and other materials made me leave some of the +following Experiments, (especialy those about Emphatical Colours) far more +unfinish'd than they should have been, if it had been as easie for me to +_supply_ what was wanting to compleat them, as to _discern_. Thirdly to +avoyd discouraging the young Gentleman I call Pyrophilus, whom the less +Familiar, and more Laborious operations of Chymistry would probably have +frighted, I purposely declin'd in what I writ to him, the setting down any +Number of such Chymicall Experiments, as, by being very elaborate or +tedious, would either require much skill, or exercise his patience. And yet +that this sort of Experiments is exceedingly Numerous, and might more than +a little inrich the History of Colours, those that are vers'd in Chymical +processes, will, I presume, easily allow me. + +And (Lastly) for as much as I have occasion more than once in my several +Writings to treat either porposely or incidentally of matters relating to +Colours; I did not, perhaps, conceive my self oblig'd, to deliver in one +Treatise _all_ that I would say concerning that subject. + +But to conclude, by summing up what I would say concerning what I _have_ +and what I _have not_ done, in the following Papers; I shall not (_on the +one side_) deny, that considering that I pretended not to write an accurate +Treatise of Colours, but an Occasional Essay to acquaint a private friend +with what then occurrd to me of the things I had thought or try'd +concerning them; I might presume I did enough for once, if I did clearly +and faithfully set down, though not _all_ the Experiments I could, yet at +least such a variety of them, that an attentive Reader that shall consider +the Grounds on which they have been made, and the hints that are purposely +(though dispersedly) couched in them, may easily _compound_ them, and +otherwise _vary_ them, so as very much to increase their Number. And yet +(_on the other side_) I am so sensible both of how much I have, either out +of necessity or choice, left undone, and of the fruitfullness of the +subject I have begun to handle; that though I had performed far more then +'tis like many Readers will judge I have, I should yet be very free to let +them apply to my Attempts that of _Seneca_, where having spoken of the +Study of Natures Mysteries, and Particularly of the Cause of Earth-Quakes, +he subjoins.[1] _Nulla res consummata est dum incipit. Nec in hac tantum re +omnium maxima ac involutissimá, in quâ etiam cum multum actum erit, omnis +ætas, quod agat inveniet; sed in omni alio Negotio, longè semper à perfecto +fuere Principia._ + + [1] L. Annæ Senecæ Natur. Quest. l. 6. c. 5. + + * * * * * + + _The Publisher to the_ + READER. + +_Friendly Reader,_ + +Here is presented to thy view one of the Abstrusest as well as the +Gentilest Subjects of Natural Philosophy, the _Experimentall History of +Colours_; which though the Noble Author be pleased to think but _Begun_, +yet I must take leave to say, that I think it so well begun, that the work +is more than half dispatcht. Concerning which I cannot but give this +advertisement to the Reader, that I have heard the Author express himself, +that it would not surprise him, if it should happen to be objected, that +some of these Experiments have been already published, partly by Chymists, +and partly by two or three very fresh Writers upon other Subjects. And +though the number of these Experiments be but very small, and though they +be none of the considerablest, yet it may on this occasion be further +represented, that it is easie for our Author to name several men, (of whose +number I can truly name my self) who remember either their having seen him +make, or their having read, his Accounts of the Experiments delivered in +the following Tract several years since, and long before the publication of +the Books, wherein they are mentioned. Nay in divers passages (where he +could do it without any great inconvenience) he hath struck out +Experiments, which he had tryed many years ago, because he since found them +divulged by persons from whom he had not the least hint of them; which yet +is not touched, with design to reflect upon any Ingenious Man, as if he +were a Plagiary: For, though our Generous Author were not reserved enough +in showing his Experiments to those that expressed a Curiosity to see them +(amongst whom a very Learned Man hath been pleased publickly to acknowledge +it several years ago[2]; yet the same thing may be well enough lighted on +by persons that know nothing of one another. And especially Chymical +Laboratories may many times afford the same _Phænomenon_ about Colours to +several persons at the same or differing times. And as for the few +_Phænomena_ mentioned in the same Chymical writers, as well as in the +following Treatise, our Author hath given an account, why he did not +decline rejecting them, in the Anotations upon the 47th Experiment of the +third part. Not here to mention, what he elsewhere saith, to shew what use +may be Justifiably made of Experiments not of his own devising by a writer +of Natural History, if, what he employes of others mens, be well examined +or verified by himself. + + [2] He that desires more instances of this kind and matter, that + according to this doctrine may much help the Theory of colours, and + particularly the force both of Sulphureous and volatile, is likewise of + Alcalizate and Acid Salts, and in what particulars, Colours likely depend + not in the causation from any Salt at all, may beg his information from + M. Boyle who hath some while since honoured me with the sight of his + papers concerning this subject, containing many excellent experiments, + made by him for the Elucidation of this doctrine, &c Dr. R. Sharrock in + his ingenious and usefull History of the Propagation and Improvement of + Vegetables, published in the yeare 1660. + +In the mean time, this Treatise is such, that there needs no other +invitation to peruse it, but that tis composed by one of the Deepest & Most +indefatigable searchers of Nature, which, I think the World, as far as I +know it, affords. For mine own part, I feel a Secret Joy within me, to see +such beginings upon such _Themes_, it being demonstratively true, _Mota +facilius moveri_, which causeth me to entertain strong hopes, that this +Illustrious _Virtuoso_ and Restless Inquirer into Nature's Secrets will not +stop here, but go on and prosper in the Disquisition or the other principal +Colours, _Green, Red_, and _Yellow_. The Reasoning faculty set once afloat, +will be carried on, and that with ease, especially, when the productions +thereof meet, as they do here, with so greedy an Entertainment at home and +abroad. I am confident, that the ROYAL SOCIETY, lately constituted by his +MOST EXCELLENT MAJESTY _for improving Natural knowledge_, will Judge it +their interest to exhort our Author to the prosecution of this Argument, +considering, how much it is their design and business to accumulate a good +stock of such accurate Observations and Experiments, as may afford them and +their Offpring genuine Matter to raise a Masculine Philosophy upon, whereby +the Mind of Man may be enobled with the Knowledge of solid Truths, and the +Life of Man benefited with ampler accommodations, than it hath been +hitherto. + +Our Great Author, one of the Pillars of that Illustrious Corporation, is +constantly furnishing large _Symbola_'s to this work, and is now falln, as +you see, upon so comprehensive and important a theme, as will, if insisted +on and compleated, prove one of the considerablest peeces of that +structure. To which, if he shall please to add his Treatise of _Heat_ and +_Flame_, as he is ready to publish his Experimental Accounts of _Cold_, I +esteem, the World will be obliged to Him for having shewed them both the +_Right_ and _Left Hand_ of Nature, and the Operations thereof. + +The considering Reader will by this very Treatise see abundant cause to +sollicit the Author for more; sure I am, that of whatever of the +Productions of his Ingeny comes into _Forein parts_ (where I am happy in +the acquaintance of many intelligent friends) is highly valued; And to my +knowledge, there are those among the French, that have lately begun to +learn English, on purpose to enable themselves to read his Books, being +impatient of their Traduction into Latin. If I durst say all, I know of the +Elogies received by me from abroad concerning Him, I should perhaps make +this Preamble too prolix, and certainly offend the modesty of our Author. + +Wherefore I shall leave this, and conclude with desiring the Reader, that +if he meet with other faults besides those, that the Errata take notice of +(as I believe he may) he will please to consider both the weakness of the +Authors eyes, for not reviewing, and the manifold Avocations of the +Publisher for not doing his part; who taketh his leave with inviting those, +that have also considered this Nice subject experimentally, to follow the +Example of our Noble Author, and impart such and the like performances to +the now very inquisitive world. _Farewell._ + +_H. O._ + + * * * * * + + THE + CONTENTS. + + * * * * * + +CHAP. I. + +_The Author shews the Reason, first of his Writing on this Subject_ (1.) +_Next of his present manner of Handling it, and why he partly declines a +Methodical way_ (2.) _and why he has partly made use of it in the History +of_ Whiteness _and_ Blackness. (3.) + +Chap. 2. _Some general Considerations are premis'd, first of the +Insignificancy of the Observasion of Colours in many Bodies_ (4, 5.) _and +the Importance of it in others_ (5.) _as particularly in the Tempering of +Steel_ (6, 7, 8.) _The reason why other particular Instances are in that +place omitted_ (9) _A necessary distinction about Colour premis'd_ (10, +11.) _That Colour is not Inherent in the Object_ (11.) _prov'd first by the +Phantasms of Colours to_ Dreaming _men, and_ Lunaticks; _Secondly by the +sensation or apparition of Light upon a Blow given the Eye or the Distemper +of the Brain from internal Vapours_ (12.) _The Author recites a particular +Instance in himself; another that hapn'd to an Excellent Person related to +him_ (13.) _and a third told him by an Ingenious Physician_ (14, 15.) +_Thirdly, from the change of Colours made by the Sensory Disaffected_ (15, +16.) _Some Instances of this are related by the Author, observ'd in +himself_ (16, 17.) _others told him by a Lady of known Veracity_ (18.) _And +others told him by a very Eminent Man_ (19.) _But the strange Instances +afforded by such as are Bit by the_ Tarantula _are omitted, as more +properly deliver'd in another place_. (20.) + +Chap. 3. _That the Colour of Bodies depends chiefly on the disposition of +the Superficial parts, and partly upon the Variety of the Texture of the +Object_ (21.) _The former of these are confirm'd by several Persons_ (22.) +_and two Instances, the first of the Steel mention'd before, the second of +melted Lead_ (23, 24.) _of which last several Observables are noted_ (25.) +_A third Instance is added of the Porousness of the appearing smooth +Surface of Cork_ (26, 27.) _And that the same kind of Porousness may be +also in the other Colour'd Bodies; And of what kind of Figures, the +Superficial reflecting Particles of them may be_ (28.) _and of what Bulks, +and closeness of Position_ (29.) _How much these may conduce to the +Generation of Colour instanc'd in the Whiteness of Froth, and in the +mixtures of Dry colour'd Powders_ (30.) _A further explication of the +Variety that may be in the Superficial parts of Colour'd Bodies, that may +cause that Effect, by an example drawn from the Surface of the Earth_ (31.) +_An Apology for that gross Comparison_ (32.) _That the appearances of the +Superficial asperities may be Varied from the position of the Eye, and +several Instances given of such appearances_ (33, 34, 35.) _That the +appearance of the Superficial particles may be Varied also by their Motion, +confirm'd by an Instance of the smoaking Liquor_ (35.) _especially if the +Superficial parts be of such a Nature as to appear divers in several +Postures, explain'd by the variety of Colours exhibited by the shaken +Leaves of some Plants_ (36.) _and by changeable Taffities_ (37, 38, 39.) +_The Authors wish that the Variety of Colours in Mother of Pearl were +examin'd with a_ Microscope (40.) _And his Conjectures, that possibly good_ +Microscopes _might discover those Superficial inequalities to be Real, +which we now only imagine with his reasons drawn partly from the +Discoveries of the_ Telescope, _and_ Microscope (41.) _And partly also from +the Prodigiously strange example of a Blind man that could feel Colours_ +(42.) _whose History is Related_ (43, 44, 45.) _The Authors conjecture and +thoughts of it_ (46, 47, 48, 49.) _and several Conclusions and Corollaries +drawn from it about the Nature of Blackness and Black Bodies_ (50, 51, 52.) +_and about the Asperities of several other Colour'd Bodies_ (53.) _And from +these, and some premis'd Considerations, are propos'd some Conjectures; +That the reason of the several Phænomena of Colours, afterwards to be met +with, depends upon the Disposition of the Seen parts of the Object_ (54.) +_That Liquors may alter the Colours of each other, and of other Bodies, +first by their Insinuating themselves into the Pores, and filling them, +whence the Asperity of the Surface of a Body becomes alter'd, explicated +with some Instances_ (55, 56.) _Next by removing those Bodies, which before +hindred the appearance of the Genuine Colour, confirm'd by several +examples_ (57) _Thirdly, by making a Fissure or Separation either in the +Contiguous or Continued Particles of a Body_ (58.) _Fourthly, by a Union or +Conjunction of the formerly separated Particles; Illustrated with divers +Instances of precipitated Bodies_ (59.) _Fifthly, by Dislocating the parts, +and putting them both into other Orders and Postures, which is Illustrated +with Instances_ (60, 61.) _Sixthly, by Motion, which is explain'd_ (62.) +_And lastly, and chiefly, by the Union of the Saline Bodies, with the +Superficial parts of another Body, whereby both their Bigness and Shape +must necessarily be alter'd_ (63, 64.) _Explain'd by Experiments_ (65, 66.) +_That the Colour of Bodies may be Chang'd by the concurrence of two or more +of these ways_ (67.) _And besides all these, Eight Reflective causes of +Colours, there may be in Transparent Bodies several Refractive_ (68, 69) +_Why the Author thinks the Nature of Colours deserves yet a further +Inquiry_ (69.) _First for that the little Motes of Dust exhibited very +lovely Colours in a darkned Room, whilst in a convenient posture to the +Eye, which in other Postures and Lights they did not_ (70.) _And that +though the smaller Parts of some Colour'd Bodies are Transparent, yet of +others they are not, so that the first Doubt's, whether the Superficial +parts create those Colours, and the second, whether there be any Refraction +at all in the later_ (71, 72, 73.) _A famous Controversie among +Philosophers, about the Nature of Colour decided_. (74. 75.) + +Chap. 4. _The controversie stated about Real and Emphatical Colours_ (75, +76.) _That the great Disparity between them seems to be, partly their +Duration in the same state, and partly, that Genuine Colours are produc'd +in Opacous Bodies by Reflection, and Emphatical in Transparent by +Refraction_ (78.) _but that this is not to be taken in too large a Sense, +the Cautionary instance of Froth is alleged and insisted on_ (78, 79.) +_That the Duration is not a sufficient Characteristick, exemplify'd by the +duration of Froth, and other Emphatical Colours, and the suddain fading of +Flowers, and other Bodies of Real ones_ (80.) _That the position of the Eye +is not necessary to the discerning Emphatical Colours, shew'd by the seeing +white Froth, or an Iris cast on the Wall by a Prism, in what place of the +Room soever the Eye be_ (81.) _which proceeds from the specular Reflection +of the Wall_ (82.) _that Emphatical Colours may be Compounded, and that the +present Discourse is not much concern'd, whether there be, or be not made a +distinction between Real and Emphatical Colours_. (83.) + +Chap. 5. _Six Hypotheses about Colour recited_ (84, 85) _Why the Author +cannot more fully Speak of any of these_ (86.) _nor Acquiesce in them_ (87, +88.) _What_ Pyrophilus _is to expect in this Treatise_ (88, 89.) _What +Hypothesis of Light and Colour the Author most inclines too_ (90.) _Why he +thinks neither that nor any other sufficient; and what his Difficulties +are, that make him decline all Hypotheses, and to think it very difficult +to stick to any._ (91, 92.) + + * * * * * + +Part the Second. + +_Of the Nature of Whiteness and Blackness,_ + +CHAP. I. + +_The reason why the Author chose the Explication of Whiteness and +Blackness_ (93.) _Wherein_ Democritus _thought amiss of these_ (94.) +Gassendus _his Opinion about them_ (95.) _What the Author approves, and a +more full Explication of White, makinig it a Multiplicity of Light or +Reflections_ (96, 97.) _Confirm'd first by the Whiteness of the_ Meridian +_Sun, observ'd in Water_ (98.) _and of a piece of Iron glowing Hot_ (99.) +_Secondly, by the Offensiveness of Snow to the Travellers eyes, confirm'd +by an example of a Person that has Travell'd much in Russia_ (100.) _and by +an Observation out of_ Olaus Magnus (100.) _and that the Snow does +inlighten and clear the Air in the Night, confirm'd by the Mosco Physician, +and Captain_ James (101.) _But that Snow has no inherent Light, prov'd by +Experience_ (102.) _Thirdly, by the great store of Reflections, from white +Bodies observ'd in a darkned Room, and by their unaptness to be Kindled by +a Burning-glass_ (103.) _Fourthly, the Specularness of White Bodies is +confirm'd by the Reflections in a dark Room from other Bodies_ (104.) _and +by the appearance of a River, which both to the Eye and in a darkned Room +appear'd White_ (105, 106.) _Fifthly, by the Whiteness of distill'd_ +Mercury, _and that of the_ Galaxie (107, 108.) _and by the Whiteness of +Froth, rais'd from whites of Eggs beaten; that this Whiteness comes not +from the Air, shew'd by Experiments_ (109, 110.) _where occasionally the +Whiteness of Distill'd Oyls, Hot water, &c. are shew'd_ (111.) _That it +seems not necessary the Reflecting Surfaces should be Sphærical, confirm'd +by Experiments_ (112, 113.) _Sixthly, by the Whiteness of the Powders of +transparent Bodies_ (114.) _Seventhly, by the Experiment of Whitening and +Burnishing Silver._ (115, 116.) + +Chap. 2. _A Recital of some Opinions about Blackness, and which the Author +inclines to_ (117.) _which he further insists on and explicates_ (118, +119.) _and shews for what reasons he imbrac'd that Hypothesis_ (120.) +_First, from the contrary Nature of Whiteness and Blackness, White +reflecting most Beams outwards, Black should reflect most inward_ (120.) +_Next, from the Black appearance of all Bodies, when Shadow'd; And the +manner how this paucity of Reflection outwards is caus'd, is further +explicated, by shewing that the Superficial parts may be Conical and +Pyramical_ (121.) _This and other Considerations formerly deliver'd, +Illustrated by Experiments with black and white Marble_ (122, 123.) +_Thirdly, from the Black appearance of Holes in white Linnen, and from the +appearance of Velvet stroak'd several ways, and from an Observation of +Carrots_ (124, 125.) _Fourthly, from the small Reflection from Black in a +darkned Room_ (125, 126.) _Fifthly, from the Experiment of a Checker'd Tile +expos'd to the Sun-beams_ (127.) _which is to be preferr'd before a Similar +Experiment try'd in_ Italy, _with black and white Marble_ (128.) _Some +other congruous Observations_ (129.) _Sixthly, from the Roasting black'd +Eggs in the Sun_ (130.) _Seventhly, by the Observation of the Blind man +lately mention'd, and of another mention'd by_ Bartholine (130.) _That +notwithstanding all these Reasons, the Author is not absolutely Positive, +but remains yet a Seeker after the true Nature of Whiteness and Blackness._ +(131, 132.) + +Experiments _in Consort, touching_ Whiteness _and_ Blackness. + +_The first_ Experiment, _with a Solution of Sublimate, made White with +Spirit of Urine_, &c. (133, 134.) + +_The second_ Experiment, _with an Infusion of Galls, made Black with +Vitriol_, &c. (135, 136.) _further Discours'd of_ (137.) + +_The third_ Experiment, _of the Blacking of Hartshorn, and Ivory, and +Tartar, and by a further Calcination making them White_ (138, 139.) + +_The fourth_ Experiment, _limiting the_ Chymist's _principle_, Adusta nigra +sed perusta alba, _by several Instances of Calcin'd Alabaster, Lead, +Antimony, Vitriol, and by the Testimony of_ Bellonius, _about the white +Charcoles of_ Oxy-cædar, _and by that of_ Camphire. (140, 141, 142.) _That +which follows about Inks was misplac'd by an Errour of the Printer, for it +belongs to what has been formerly said of Galls_ (142, 143.) + +_The fifth_ Experiment, _of the black Smoak of Camphire_ (144.) + +_The sixth_ Experiment, _of a black_ Caput Mortuum, _of Oyl of Vitriol, +with Oyl of Worm-word, and also with Oyl of Winter-Savory_ (145.) + +_The seventh_ Experiment, _of whitening Wax_ (146.) + +_The eighth_ Experiment, _with Tin-glass, and Sublimate_ (147, 148.) + +_The ninth_ Experiment, _of a Black powder of Gold in the bottom of_ +Aqua-fortis, _and of the Blacking of Refin'd Gold and Silver_ (148, 149.) + +_The tenth_ Experiment, _of the staining Hair, Skin, Ivory_, &c. _Black, +with Crystals of Silver_ (150, 151.) + +_The eleventh_ Experiment, _about the Blackness of the Skin, and Hair of_ +Negroes, _and Inhabitants of Hot Climates. Several Objections are made, and +the whole Matter more fully discours'd and stated from several notable +Histories and Observations_ (from the 151 to the 167.) + +_The twelfth_ Experiment, _of the white Powders, afforded by Precipitating +several Bodies, as Crabs Eyes, Minium, Coral, Silver, Lead, Tin, +Quick-silver, Tin-glass, Antimony, Benzoin, and Resinous Gumms out of +Spirit of Wine_, &c. _but this is not Universal, since other Bodies, as +Gold, Antimony, Quick-silver_, &c. _may be Precipitated of other Colours_ +(168, 169, 170.) + +_The thirteenth_ Experiment, _of Changing the Blackness of some Bodies into +other Colours_ (171, 172.) _and of Whitening what would be Minium, and +Copper, with Tin, and of Copper with Arsnick, which with Coppilling again +Vanishes; of covering the Colour of that of_ 1/3 _of Gold with_ 2/3 _of +Silver melted in a Mass together_ (173, 174) + +_The fourteenth_ Experiment, _of turning the black Body of Horn into a +White immediately with Scraping, without changing the Substantial form, or +without the Intervention of Salt, Sulphur, or Mercury_ (176.) + +_The fifteenth_ Experiment, _contains several Instances against the Opinion +of the_ Chymists _that Sulphur_ Adust _is the cause of Blackness, and the +whole Matter is fully discuss'd and stated_ (from 176 to 184) + +Part the Third. + +_Concerning Promiscuous Experiments about Colours_. + +Experiment the First. + +_IN confirmation of a former Conjecture about the Generation of Colours +from diversity of Reflections are set down several Observations made in a +Darkned room_ (186, 187.) + +Experiment _the second, That white Linnen seem'd Ting'd with the Red of +Silk plac'd near it in a light Room_ (188,189.) + +Experiment _the third, Of the Trajection of Light through Colour'd Papers_ +(189, 190.) + +Experiment _the fourth, Observations of a Prism in a dark Room_ (191, 192.) + +Experiment _the fifth, Of the Refracting and Reflecting Prismatical Colours +in a light Room_ (193.) + +Experiment _the sixth, On the Vanishing of the_ Iris _of the Prism, upon +the access of a greater adventitious Light_ (194.) + +Experiment _the seventh, Of the appearances of the same Colour'd Papers by +Candle-light_ (195, 196). + +Experiment _the eighth, Of the Yellowness of the Flame of a Candle_ (197). + +Experiment _the ninth, Of the Greenish Blew transparency of Leaf Gold_ +(198). + +Experiment _the tenth, Of the curious Tinctures afforded by_ Lignum +Nephriticum (from 199 to 203). _Several trials for the Investigation of the +Nature of it_ (from 204 to 206.) Kircher's _relation of this Wood set down, +and examin'd_ (from 206 to 212). _A Corollary on this tenth_ Experiment, +_shewing how it may be applicable for the Discovering, whether any Salt be +of an Acid, or a Sulphureous, and Alcalizate Nature_ (from 213 to 216). + +_The eleventh_ Experiment, _Of certain pieces of Glass that afforded this +Variety of Colours; And of the way of so Tinging any Plate of Glass with +Silver_ (from 216 to 219). + +_The twelfth_ Experiment, _Of the Mixing and Tempering of Painters +Pigments_ (219, 220, 221). + +_The thirteenth_ Experiment, _Of compounding several Colours by Trajecting +the Sun-beams through Ting'd Glasses_ (from 221 to 224). + +_The fourteenth_ Experiment, _Of the Compounding of Real and Phantastical +Colours, and the Results_ (224, 225, 226.) _as also the same of +Phantastical Colours_ (226, 227.) + +_The fifteenth_ Experiment, _Of Varying the Trajected_ Iris _by a Colour'd +Prism_ (228, 229.) + +_The sixteenth_ Experiment, _Of the Red fumes of Spirit of_ Nitre, _and, +the resembling Redness of the Horizontal Sun-beams_ (230, 231.) + +_The seventeenth_ Experiment, _Of making a Green by nine Kinds of +Compositions_ (from 231 to 236.) _And some Deductions from them against the +necessity of recurring to Substantial forms and Hypostatical principles for +the production of Colours_ (from 237 to 240.) + +_The eighteenth_ Experiment, _Of several Compositions of Blew and Yellow +which produce not a Green, and of the production of a Green by other +Colours_ (241, 242.) + +_The nineteenth_ Experiment, _contains several instances of producing +Colours, without the alteration of any Hypostatical principle, by the +Prism, Bubbles, and Feathers_ ( from 242 to 245.) + +_The twentieth_ Experiment _Of turning the Blew of Violets into a Red by +Acid Salts, and to a Green by Alcalizate (245, 246.) and the use of it for +Investigating the Nature of Salts_ (247, 248.) + +_The one and twentieth_ Experiment, _of the same Changes effected by the +same means on the Blew Tinctures of Corn-flowers_ (249, 250.) _And some +Restrictions to shew it not to be so general a propriety as one might +imagine_ (251.) + +_The twenty second_ Experiment, _of turning a Solution of Verdigrease into +a Blew, with Alcalizate and Urinous Salts_ (252, 253, 254.) + +_The twenty third_ Experiment, _of taking away the Colour of Roses with the +Steams of Sulphur, and heightning them with the Steams Condens'd into Oyl +of Sulphur_ per Campanam (254, 255.) + +_The twenty fourth_ Experiment, _of Tinging a great quantity of Liquor with +a very little Ting'd Substance, Instanced in_ Cochineel (from 255 to 257.) + +_The twenty fifth_ Experiment, _of the more general use of Alcalizate and +Sulphureous Salts in the Tinctures of Vegetables, further Instanced in the +Tincture of Privet Berries, and of the Flowers of Mesereon and Pease_ (from +257 to 259.) _An_ Annotation, _shewing that of the three Hypostatical +principles, Salt according to_ Paracelsus _is the most active about +Colours_ (from 259 to 261.) _Some things Precursory premis'd to three +several Instances next following, against the fore-mention'd Operations of +Salts_ (261, 262.) + +_The twenty sixth_ Experiment, _containing Trials with Acid and Sulphureous +Salts on the Red Tinctures of Clove-july-flowers, Buckthorn Berries, +Red-Roses, Brasil_, &c. (262, 263.) + +_The twenty seventh_ Experiment, _of the changes of the Colour of Jasmin +flowers, and Snow drops, by Alcalizate and Sulphureous Salts_ (263, 264.) + +_The twenty eighth_ Experiment, _of other differing Effects on Mary-golds, +Prim-roses, and fresh Madder_ (265.) _with an Admonition, that these Salts +may have differing Effects in the changing of the tinctures of divers other +Vegetables_ (266, 267.) + +_The twenty ninth_ Experiment, _of the differing Effects of these Salts on +Ripe and Unripe Juices, instanced in Black-berries, and the Juices of +Roses_ (from 267 to 270.) _Two reasons, why the Author added this twenty +ninth_ Experiment, _the last of which is confirm'd by an Instance of Mr._ +Parkinson, _consonant to the Confession of the Makers of such Colours_ +(272.) + +_The thirtieth_ Experiment, _of several changes in Colours by Digestion, +exemplify'd by an_ Amalgam _of_ Gold _and_ Mercury _and by Spirit of +Harts-horn. And (to such as believe it) by the changes of the_ Elixir. + +_The thirty first_ Experiment, _shewing that most Tinctures drawn by +Digestion Incline to a Red, instanc'd in_ Jalap, Guaicum, _Amber, Benzoin, +Sulphur, Antimony_, &c. (276, 277.) + +_The thirty second_ Experiment, _That some Reds with Diluting turn Yellow, +others not, exemplify'd by the Tincture of_ Cochineel, _and by Balsam of_ +Sulphur, _Tinctures of_ Amber, &c. (277, 278, 279.) + +_The thirty third_ Experiment, _of a Red Tincture of_ Saccarum Saturni _and +Oyl of_ Turpentine _made by Digestion_ (279.) + +_The thirty fourth_ Experiment, _of drawing a Volatile red Tincture of +Mercury_, _whose Steams were white, but it would Tinge the Skin black_ +(279, 280.) + +_The thirty fifth_ Experiment, _of a suddain way of making a Blood red +Colour with Oyl of_ Vitriol, _and Oyl of_ Anniseeds, _two transparent +Liquors_ (280, 281.) + +_The thirty sixth_ Experiment, _of the Degenerating of several Colours +exemplify'd in the last mention'd Blood red, and by Mr._ Parkinsons +_relation of_ Turnsol, _by some Trials with the Juice of Buck-thorn +Berries, and other Vegetables, to which several notable Considerations and +Advertisements back'd with_ Experiments _are adjoyn'd_ (from 281 to 288.) + +_The thirty seventh_ Experiment, _Of Varying the Colour of the Tinctures +of_ Cochineel, _Red-cherries, and Brasil, with Acid and Sulphureous Salts, +and divers Considerations thereon_ (from 288 to 290.) + +_The thirty eighth_ Experiment, _About the Red fumes of some, and White of +other distill'd Bodies, and of their Coalition for the most part into a +transparent Liquor_ (290, 291.) _And of the various Colours of dry +Sublimations, exemplify'd with several_ Experiments (292, 293, 294.) + +_The thirty ninth_ Experiment, _Of Varying the Decoction of_ Balaustiums +_with Acid and Urinous Salts_ (294, 295.) _Some_ Annotations _wherein two_ +Experiments _of_ Gassendus _are Related, Examined, and Improv'd_ (from 295 +to 302.) + +_The fortieth_ Experiment, _Of the no less Strange than Pleasant changes +made with a Solution of Sublimate_ (from 301 to 306.) _The difference +between a Chymical axd Philosophical Solution of a_ Phænomenon (307, 308.) +_The Authors Chymical Explication of the_ Phænomena, _confirm d by several_ +Experiments _made on_ Mercury, _with several Saline Liquors_ (from 308 to +310.) _An Improvement of the fortieth_ Experiment, _by a fresh Decoction +of_ Antimony _in a_ Lixivium (311, 312, 313.) _Reflections on the tenth, +twentieth, and fortieth_ Experiments, _compar'd together, shewing a way +with this Tincture of Sublimate to distinguish whether any Saline Body to +be examin'd be of a Urinous or Alcalizate Nature_ (from 314 to 317.) _The +Examination of Spirit of_ Sal-armoniack, _and Spirit of_ Oak _by these +Principles_ (from 316 to 319.) _That the Author knows ways of making highly +Operative Saline bodies, that produce none of the before mention'd effects_ +(319, 320.) _Some notable_ Experiments _about Solutions and Precipitations +of Gold and Silver_ (320, 321.) + +_The one and fortieth_ Experiment, _Of Depriving a deep Blew Solution of +Copper of its Colour_ (322.) _to which is adjoyn'd the Discolouring or +making Transparent a Solution of Verdigrease, &c. and another of Restoring +or Increasing it_ (322, 323.) + +_The forty second_ Experiment, _Of changing a Milk white Precipitate of_ +Mercury _into a Yellow, by Affusion of fair Water, with several +Considerations thereon_ (from 323 to 326.) + +_The forty third_ Experiment, _Of Extracting a Green Solution with fair +Water out of imperfectly Calcin'd Vitriol_ (327.) + +_The forty fourth_ Experiment, _Of the Deepning and Diluting of several +Tinctures, by the Affusions of Liquors, and by Conical Glasses that +contain'd them, Exemplify'd in the Tinctures of_ Cochineel, Brasil, +Verdigrease, Glass, Litmus, _of which last on this occasion several +pleasant_ Phænomena _are related_ (from 328 to 335.) _To which are adjoyn'd +certain Cautional Corollaries_ (335, 336.) _The Waterdrinker and some of +his Legerdemain tricks related._(337.) + +_The forty fifth_ Experiment, _Of the turning Rhenish and White Wine into a +lovely Green, with a preparation of Steel _(338, 339.) _Some further Trial +made about these Tinctures, and a Similar_ Experiment _of_ Olaus Wormius +(340.) + +_The forty sixth_ Experiment, _Of the Internal Colour of Metalls exhibited +by Calcination_ (341, 342, 343.) Annotation _the first, That several +degrees of Fire may disclose a differing Colour_ (343.) Annotation _the +second, That the Glasses of Metalls may exhibit also other Kinds of +Colours_ (344.) Annotation _the third, That Minerals by several degrees of +Fire may disclose several Colours_(345). + +Experiment _the forty seventh, Of the Internal Colours of Metalls disclos'd +by their Dissolutions in several_ Menstruums (from 345 to 350.) +Annotation _the first, The Authors Apology for Recording some already +known_ Experiments, _without mentioning their Authors_ (from 350 to 352.) +Annotation _the second, That some Minerals also by Dissolutions in_ +Menstruums _may exhibit divers Colours_. Annotation _the third, That +Metalls disclose other Colours by Precipitations, instanc'd in_ Mercury +(from 353 to 355.) + +_The forty eighth_ Experiment, _Of Tinging Glass Blew with Leaf Silver, and +with Calcin'd Copper, and White with Putty_ (from 355 to 358.) Annotation +_the first, That this white Glass is the Basis of Ammels_ (358.) Annotion +_the second, That Colour'd Glasses may be Compounded like Colour'd Liquors +in Dying Fats_ (359.) Annotation _the third, Of Tinging Glass with Minerel +Substances, and of trying what Metalls they contain by this means_ (from +360 to 362.) Annotation _the fourth, That Metalls may be Ting'd by +Mineralls_ (362, 363.) Annotation _the fifth, Of making several Kinds of +Amauses or Counterfeit Stones_ (from 363 to 365.) Annotation _the sixth, Of +the Scarlet Dye, of the Stains of dissolv'd Gold and Silver_ (366, 367) _Of +the Greenness of Salt Beef, and Redness of Neats Tongues from Salts; of +Gilding Silver with Bathe Water_ (368, 369.) _And Tinging the Nails and +Skin with_ Alcanna (369) + +_The forty ninth_ Experiment, _Of making Lakes_ (369.) _A particular +example in Turmerick_ (370, 371.) Annotation _the first, That in +Precipitations wherein Allum is a Coefficient, a great part of them may +consist of the Stony particles of that Compound Body_ (from 372 to 375.) +Annotation _the second, That Lakes may be made of other Substances, as +Madder, Rue,_ &c. _but that Alcalizate Salts do not Always Extract the same +Colour of which the Vegetable appears_ (from 376 to 378.) Annotation _the +third, That the_ Experiments _related may Hint divers others_ (378) +Annotation _the fourth, That Alum is usefull for the preparing other than +Vegetable Pigments_ (379.) + +_The fiftieth_ Experiment, _Of the Similar effects of_ Saccarum Saturni +_and_ Alkalies, _of Precipitating with Oyl of_ Vitriol _out of_ +Aqua-fortis, _and Spirit of_ Vinegar; _and of divers Varyings of the +Colours, with these Compounded_ (from 380 to 384.) _Another very pretty_ +Experiment, _with a Solution of_ Minium (384, 385.) _That these_ +Experiments _Skilfully digested may hint divers matters about Colours_ +(386.) _The Authors Apologetick conclusion, in which is Cursorily hinted +the Bow or Scarlet Dye_ (387.) _The Authors Letter to Sir_ Robert Moray, +_concerning his Observations on the Shining Diamond_ (391. &c.) _And the +Observations themselves_. + + * * * * * + +Errata. + +Pag. 142. l. 20. These words, _And to manifest_, with the rest of what is +by a mistake further printed in this fourth Experiment, belongeth, and is +to be referred to the end of the second Eperiment, p.137. pag. 145. l. 1. +leg. _matter_. 146. l. 4. leg. _Bolts-head_. pag 161. in the marginal note +l. 2. dele _de_ ib. l. 3. lege lib 1. p 163. l. ult. insert _where_ between +the words _places_ and _the_. p. 164 l. 1. dele _that_. ibid, l. 8. leg +_Epidermis_. ibid. l. 19 leg. 300. for 200. p. 169. l. 22. leg. _into it_. +p. 170. l. 23. & 24. leg. _Some Solutions hereafter to be mentioned_, for +_the Solutions of Potashes_, and other _Lixiviate Salts_. p. 171. l. 6. +insert _part of_ between the words _most_ and _dissolved_ p. 176. l. ult. +insert the participle _it_ between the words _Judged_ and _not_ p. 234. l. +4. leg. _Woud-wax_ or _Wood-wax_. p. 320 l. 29. leg. _urine_ for _urne_. + + * * * * * + + _THE_ + _EXPERIMENTAL HISTORY_ + _OF COLOURS BEGUN._ + + THE FIRST PART. + +CHAP. I. + +1 I have seen you so passionately addicted, _Pyrophilus_ to the delightful +Art of Limning and Painting, that I cannot but think my self obliged to +acquaint you with some of those things that have occurred to mee concerning +the changes of Colours. And I may expect that I shall as well serve the +_Virtuosi_ in general, as gratifie you in particular, by furnishing a +person, who, I hope, will both improve my Communications, and communicate +his Improvements, with such Experiments and Observations as may both invite +you to enquire seriously into the Nature of Colours, and assist you in the +Investigation of it. This being the principal scope of the following Tract, +I should do that which might prevent my own design, if I should here +attempt to deliver you an accurate and particular Theory of Colours; for +that were to present you with what I desire to receive from you; and, as +farr as in mee lay, to make that study needless, to which I would engage +you. + +2 Wherefore my present work shall be but to divert and recreate, as well as +excite you by the delivery of matters of fact, such as you may for the most +part try with much _ease_, and possibly not without some _delight_: And +lest you should expect any thing of Elaborate or Methodical in what you +will meet with here, I must confess to you before-hand, that the seasons I +was wont to chuse to devise and try Experiments about Colours, were those +daies, wherein having taken Physick, and finding my self as unfit to +speculate, as unwilling to be altogether idle, I chose this diversion, as a +kind of Mean betwixt the one and the other. And I have the less scrupled to +set down the following Experiments, as some of them came to my mind, and as +the Notes wherein I had set down the rest, occurr'd to my hands, that by +declining a Methodical way of delivering them, I might leave you and my +self the greater liberty and convenience to add to them, and transpose them +as shall appear expedient. + +3 Yea, that you may not think mee too reserv'd, or look upon an Enquiry +made up of meer Narratives, as somewhat jejune, am content to _premise_ a +few considerations, that now offer themselves to my thoughts, which relate +in a more general way, either to the Nature of Colours, or to the study of +it. And I shall _insert_ an _Essay_, as well Speculative as Historical, of +the Nature of Whiteness and Blackness, that you may have a _Specimen_ of +the History of Colours, I have sometimes had thoughts of; and if you +dislike not the Method I have made use of, I hope, you, and some of the +_Virtuosi_, your friends, may be thereby invited to go thorow with _Red, +Blew, Yellow_, and the rest of the particular Colours, as I have done with +_White_ and _Black_, but with farr more sagacity and success. And if I can +invite Ingenious men to undertake such Tasks, I doubt not but the Curious +will quickly obtain a better Account of Colours, than as yet we have, since +in our Method the Theorical part of the Enquiry being attended, and as it +were interwoven with the Historical, whatever becomes of the disputable +Conjectures, the Philosophy of Colours will be promoted by the indisputable +Experiments. + + * * * * * + +CHAP. II. + +1 To come then in the first place to our more general Considerations, I +shall begin with saying something as to the Importance of examining the +Colours of Bodies. For there are some, especially _Chymists_, who think, +that a considerable diversity of Colours does constantly argue an equal +diversity of Nature, in the Bodies wherein it is conspicuous; but I confess +I am not altogether of their mind; for not to mention changeable Taffaties, +the blew and golden necks of Pidgeons, and divers Water-fowl, Rainbows +Natural and Artificial, and other Bodies, whose Colours the Philosophers +have been pleased to call not Real, but Apparent and Phantastical; not to +insist on these, I say, (for fear of needlesly engaging in a Controversie) +we see in Parrots, Goldfinches, and divers other Birds, not only that the +contiguous feathers which are probably as near in properties as place, are +some of them Red, and others White, some of them Blew, & others Yellow, +_&c._ but that in the several parts of the self-same feather there may +often be seen the greatest disparity of Colours; and so in the leaves of +Tulips, July-flowers, and some other Vegetables the several leaves, and +even the several parts of the same leaf, although no difference have been +observed in their other properties, are frequently found painted with very +different Colours. And such a variety we have much more admired in that +lovely plant which is commonly, and not unjustly call'd the _Marvayl of +Peru_; for of divers scores of fine Flowers, which in its season that gaudy +Plant does almost daily produce, I have scarce taken notice of any two that +were dyed perfectly alike. But though _Pyro_: such things as these, among +others, keep mee from daring to affirm, that the Diversity and change of +Colours does _alwaies_ argue any great difference or alteration, betwixt, +or in, the Bodies, wherein it is to be discerned, yet that _oftentimes_ the +Alteration of Colours does signifie considerable Alterations in the +disposition of parts of Bodies, may appear in the Extraction of Tinctures, +and divers other Chymical Operations, wherein the change of Colours is the +chief, and sometimes the only thing, by which the Artist regulates his +proceeding, and is taught to know when 'tis seasonable for him to leave +off. Instances of this sort are more obvious in divers sorts of fruits, as +Cherries, Plums, &c. wherein, according as the Vegetable sap is sweetned, +or otherwise ripened, by passing from one degree to another of Maturation, +the external part of the fruit passes likewise from one to another Colour. +But one of the noblest Instances I have met with of this kind, is not so +obvious; and that is the way of tempering Steel to make Gravers, Drills, +Springs, and other Mechanical Instruments, which we have divers times both +made Artificers practise in our presence, and tryed our selves, after the +following manner, First, the slender Steel to be tempered is to be hardened +by heating as much of it as is requisite among glowing Coals, till it be +glowing hot, but it must not be quenched assoon as it is taken from the +fire (for that would make it too brittle, and spoil it) but must be held +over a bason of water, till it descend from a White heat to a Red one, +which assoon as ever you perceive, you must immediately quench as much as +you desire to harden in the cold water. The Steel thus hardened, will, if +it be good, look somewhat White and must be made bright at the end, that +its change of Colours may be there conspicuous; and then holding it so in +the flame of a Candle, that the bright end may be, for about half an inch, +or more, out of the flame, that the smoak do not stain or sully the +brightness of it, you shall after a while see that clean end, which is +almost contiguous to the flame, pass very nimbly from one Colour to +another, as from a brighter Yellow, to a deeper and reddish Yellow, which +Artificers call a _sanguine_, and from that to a fainter first, and then a +a deeper Blew. And to bring home this Experiment to our present purpose, it +is found by daily Experience, that each of these succeeding Colours argue +such a change made in the texture of the Steel, that if it be taken from +the flame, and immediately quenched in the tallow (whereby it is setled in +whatever temper it had before) when it is Yellow, it is of such a hardness +as makes it fit for Gravers Drills, and such like tools; but if it be kept +a few minutes longer in the flame till it grow Blew, it becomes much +softer, and unfit to make Gravers for Metalls, but fit to make Springs for +Watches, and such like Instruments, which are therefore commonly of that +Colour; and if the Steel be kept in the flame, after that this deep Blew +hath disclosed it self, it will grow so soft, as to need to be new hardened +again, before it can be brought to a temper, fit for Drills or Penknives. +And I confess _Pyro._ I have taken much pleasure to see the Colours run +along from the parts of the Steel contiguous to the flame, to the end of +the Instrument, and succeed one another so fast, that if a man be not +vigilant, to thrust the Steel into the tallow at the very nick of time, at +which it has attain'd its due Colour, he shall miss of giving his tool the +right temper. But because the flame of a Candle is offensive to my weak +eyes, and because it is apt to either black or sully the contiguous part of +the Steel which is held in it, and thereby hinder the change of Colours +from being so long and clearly discern'd, I have sometimes made this +Experiment by laying the Steel to be tempered upon a heated bar of Iron, +which we finde also to be employ'd by some Artificers in the tempering of +such great Instruments, as are too big to be soon heated sufficiently by +the flame of a Candle. And you may easily satisfie your self _Pyro_: of the +differing hardness and toughness, which is ascribed to Steel temper'd at +different Colours, if you break but some slender wires of Steel so +temper'd, and observe how they differ in brittleness, and if with a file +you also make tryal of their various degrees of hardness. + +2 But _Pyrophilus_, I must not at present any further prosecute the +Consideration of the importance of Experiments about Colours, not only +because you will in the following papers finde some instances, that would +here be presented you out of their due place, of the use that may be made +of such Experiments, in discovering in divers bodies, what kind the salt +is, that is predominant in them; but also because a speculative Naturalist +might justly enough allege, that as Light is so pleasing an object, as to +be well worth our looking on, though it discover'd to us nothing but its +self; so modifi'd Light called Colour, were worth our contemplation, though +by understanding its Nature we should be taught nothing else. And however, +I need not make either you or my self excuses for entertaining you on the +subject I am now about to treat of, since the pleasure _Pyro_: takes in +mixing and laying on of Colours, will I presume keep him, and will (I am +sure) keep mee from thinking it troublesome to set down, especially after +the tedious processes (about other matters) wherewith I fear I may have +tyr'd him, some easie, and not unpleasant Experiments relating to that +subject. + +3 But, before we descend to the more particular considerations, we are to +present you concerning Colours, I presume it will be seasonable to propose +at the very entrance a Distinction; the ignorance or neglect of which, +seems to mee to have frequently enough occasioned either mistakes or +confusion in the Writings of divers Modern Philosophers; for Colour may be +considered, either as it is a quality residing in the body that is said to +be coloured, or to modifie the light after such or such a manner; or else +as the Light it self, which so modifi'd, strikes upon the organ of sight, +and so causes that Sensation which we call Colour; and that this latter may +be look'd upon as the more proper, though not the usual acception of the +word Colour, will be made probable by divers passages in the insuing part +of our discourse; and indeed it is the Light it self, which after a certain +manner, either mingled with shades, or some other waies troubled, strikes +our eyes, that does more immediately produce that motion in the organ, upon +whose account men say they see such or such a Colour in the object; yet, +because there is in the body that is said to be coloured, a certain +disposition of the superficial particles, whereby it sends the Light +reflected, or refracted, to our eyes thus and thus alter'd, and not +otherwise, it may also in some sense be said, that Colour depends upon the +visible body; and therefore we shall not be against that way of speaking of +Colours that is most used among the Modern Naturalists, provided we be +allowed to have recourse when occasion shall require to the premis'd +distinction, and to take the more immediate cause of Colour to be the +modifi'd Light it self, as it affects the Sensory; though the disposition +also of the colour'd body, as that modifies the Light, may be call'd by +that name Metonimically (to borrow a School term) or Efficiently, that is +in regard of its turning the Light, that rebounds from it, or passes thorow +it, into this or that particular Colour. + +4 I know not whether I may not on this occasion add, that Colour is so far +from being an Inherent quality of the object in the sense that is wont to +be declar'd by the Schools, or even in the sense of some Modern Atomists, +that, if we consider the matter more attentively, we shall see cause to +suspect, if not to conclude, that though Light do more immediately affect +the organ of sight, than do the bodies that send it thither, yet Light it +self produces the sensation of a Colour, but as it produces such a +determinate kind of local motion in some part of the brain; which, though +it happen most commonly from the motion whereinto the slender strings of +the _Retina_ are put, by the appulse of Light, yet if the like motion +happen to be produc'd by any other cause, wherein the Light concurrs not at +all, a man shall think he sees the same Colour. For proof of this, I might +put you in mind, that 'tis usual for dreaming men to think they see the +Images that appear to them in their sleep, adorn'd some with this, and some +with that lively Colour, whilst yet, both the curtains of their bed, and +those of their eyes are close drawn. And I might add the confidence with +which distracted persons do oftentimes, when they are awake, think, they +see black fiends in places, where there is no black object in sight without +them. But I will rather observe, that not only when a man receives a great +stroak upon his eye, or a very great one upon some other part of his head, +he is wont to see, as it were, flashes of lightning, and little vivid, but +vanishing flames, though perhaps his eyes be shut: But the like apparitions +may happen, when the motion proceeds not from something without, but from +something within the body, provided the unwonted fumes that wander up and +down in the head, or the propagated concussion of any internal part in the +body, do cause about the inward extremities of the Optick Nerve, such a +motion as is wont to be there produc'd, when the stroak of the Light upon +the _Retina_ makes us conclude, that we see either Light, or such and such +a Colour: This the most ingenious _Des Cartes_ hath very well observ'd, but +because he seems not to have exemplifi'd it by any unobvious or peculiar +observation, I shall indeavour to illustrate this doctrine by a few +Instances. + +5 And first, I remember, that having, through Gods goodness, been free for +several years, from troublesome Coughs, being afterwards, by an accident, +suddenly cast into a violent one, I did often, when I was awaked in the +night by my distempers, observe, that upon coughing strongly, it would seem +to mee, that I saw very vivid, but immediately disappearing flames, which I +took particular notice of, because of the conjecture I am now mentioning. + +6 An excellent and very discreet person, very near ally'd both to you and +mee, was relating to mee, that some time since, whilst she was talking with +some other Ladies, upon a sudden, all the objects, she looked upon, +appeared to her dyed with unusual Colours, some of one kind, and some of +another, but all so bright and vivid, that she should have been as much +delighted, as surpriz'd with them, but that finding the apparition to +continue, she fear'd it portended some very great alteration as to her +health: As indeed the day after she was assaulted with such violence by +Hysterical and Hypocondrical Distempers, as both made her rave for some +daies, and gave her, during that time, a Bastard Palsey. + +7 Being a while since in a Town, where the Plague had made great havock, +and inquiring of an ingenious man, that was so bold, as without much +scruple to visit those that were sick of it, about the odd symptomes of a +Disease that had swept away so many there; he told mee, among other things, +that he was able to tell divers Patients, to whom he was called, before +they took their beds, or had any evident symptomes of the Plague, that they +were indeed infected upon peculiar observations, that being asked, they +would tell him that the neighbouring objects, and particularly his cloths, +appear'd to them beautifi'd with most glorious Colours, like those of the +Rainbow, oftentimes succeeding one another; and this he affirm'd to be one +of the most usual, as well as the most early symptomes, by which this odd +Pestilence disclos'd it self: And when I asked how long the Patients were +wont to be thus affected, he answered, that it was most commonly for about +a day; and when I further inquired whether or no Vomits, which in that +Pestilence were usually given, did not remove this symptome (For some used +the taking of a Vomit, when they came ashore, to cure themselves of the +obstinate and troublesome giddiness caus'd by the motion of the ship) +reply'd, that generally, upon the evacuation made by the Vomit, that +strange apparition of Colours ceased, though the other symptomes were not +so soon abated, yet he added (to take notice of that upon the by, because +the observation may perchance do good) that an excellent Physician, in +whose company he was wont to visit the sick, did give to almost all those +to whom he was called, in the beginning before Nature was much weakened, a +pretty odd Vomit consisting of eight or ten dramms of Infusion of _Crocus +Metallorum_, and about half a dramm, or much more, of White Vitriol, with +such success, that scarce one of ten to whom it was seasonably administred, +miscarried. + +8 But to return to the consideration of Colours: As an apparition of them +may be produced by motions from within, without the assistance of an +outward object, so I have observed, that 'tis sometimes possible that the +Colour that would otherwise be produced by an outward object, may be +chang'd by some motion, or new texture already produced in the Sensory, as +long as that unusual motion, or new disposition lasts; for I have divers +times try'd, that after I have through a Telescope look'd upon the Sun, +though thorow a thick, red, or blew glass, to make its splendor supportable +to the eye, the impression upon the _Retina_, would be not only so vivid, +but so permanent, that if afterwards I turned my eye towards a flame, it +would appear to mee of a Colour very differing from its usual one. And if I +did divers times successively shut and open the same eye, I should see the +adventitious Colour, (if I may so call it) changed or impair'd by degrees, +till at length (for this unusual motion of the eye would not presently +cease) the flame would appear to mee, of the same hew that it did to other +beholders; a not unlike effect I found by looking upon the Moon, when she +was near full, thorow an excellent Telescope, without colour'd Glass to +screen my eye with; But that which I desire may be taken notice of, because +we may elsewhere have occasion to reflect upon it, and because it seems not +agreeable to what Anatomists and Optical Writers deliver, touching the +relation of the two eyes to each other, is this circumstance, that though +my Right eye, with which I looked thorow the Telescope, were thus affected +by the over-strong impression of the light, yet when the flame of a Candle, +or some other bright object appear'd to me of a very unusual Colour, whilst +look'd upon with the Discompos'd Eye, or (though not so notably) with both +eyes at once; yet if I shut that Eye, and looked upon the same object with +the other, it would appear with no other than its usual Colour, though if I +again opened, and made use of the Dazled eye, the vivid adventitious Colour +would again appear. And on this occasion I must not pretermit an +Observation which may perswade us, that an over-vehement stroak upon the +Sensory, especially if it be naturally of a weak constitution, may make a +more lasting impression than one would imagine, which impression may in +some cases, as it were, mingle with, and vitiate the action of vivid +objects for a long time after. + +For I know a Lady of unquestionable Veracity, who having lately, by a +desperate fall, receiv'd several hurts, and particularly a considerable one +upon a part of her face near her Eye, had her sight so troubl'd and +disorder'd, that, as she hath more than once related to me, not only when +the next morning one of her servants came to her bed side, to ask how she +did, his cloaths appear'd adorn'd with such variety of dazling Colours, +that she was fain presently to command him to withdraw, but the Images in +her Hangings, did, for many daies after, appear to her, if the Room were +not extraordinarily darken'd, embellish'd with several offensively vivid +Colours, which no body else could see in them; And when I enquir'd whether +or no White Objects did not appear to her adorn'd with more luminous +Colours than others, and whether she saw not some which she could not now +well describe to any, whose eyes had never been distemper'd, she answer'd +mee, that sometimes she thought she saw Colours so new and glorious, that +they were of a peculiar kind, and such as she could not describe by their +likeness to any she had beheld either before or since, and that White +Objects did so much disorder her sight, that if several daies after her +fall, she look'd upon the inside of a Book, she fanci'd she saw there +Colours like those of the Rain-bow, and even when she thought her self +pretty well recover'd, and made bold to leave her Chamber, the coming into +a place where the Walls and Ceeling were whited over, made those Objects +appear to her cloath'd with such glorious and dazling Colours, as much +offended her sight, and made her repent her venturousness, and she added, +that this Distemper of her Eyes lasted no less than five or six weeks, +though, since that, she hath been able to read and write much without +finding the least Inconvenience in doing so. I would gladly have known, +whether if she had shut the Injur'd Eye, the _Phænomena_ would have been +the same, when she employ'd only the other, but I heard not of this +accident early enough to satisfie that Enquiry. + +9 Wherefore, I shall now add, that some years before, a person exceedingly +eminent for his profound Skil in almost all kinds of Philological Learning, +coming to advise with mee about a Distemper in his Eyes, told me, among +other Circumstances of it, that, having upon a time looked too fixedly upon +the Sun, thorow a Telescope, without any coloured Glass, to take off from +the dazling splendour of the Object, the excess of Light did so strongly +affect his Eye, that ever since, when he turns it towards a Window, or any +White Object, he fancies, he seeth a Globe of Light, of about the bigness +the Sun then appeared of to him, to pass before his Eyes: And having +Inquir'd of him, how long he had been troubled with this Indisposition, he +reply'd, that it was already nine or ten years, since the Accident, that +occasioned it, first befel him. + +I could here subjoyn, _Pyrophilus_, some memorable Relations that I have +met with in the Account given us by the experienc'd _Epiphanius +Ferdinandus_, of the Symptomes he observ'd to be incident to those that are +bitten with the Tarantula, by which (Relations) I could probably shew, that +without any change in the Object, a change in the Instruments of Vision may +for a great while make some Colours appear Charming, and make others +Provoking, and both to a high degree, though neither of them produc'd any +such Effects before. These things, I say, I could here subjoyn in +confirmation of what I have been saying, to shew, that the Disposition of +the Organ is of great Importance in the Dijudications we make of Colours, +were it not that these strange Stories belonging more properly to another +Discourse, I had rather, (contenting my self to have given you an +Intimation of them here) that you should meet with them fully deliver'd +there. + + * * * * * + +CHAP. III. + +But, _Pyrophilus_, I would not by all that I have hitherto discours'd, be +thought to have forgotten the Distinction (of Colour) that I mentioned to +you about the beginning of the third Section of the former Chapter; and +therefore, after all I have said of Colour, as it is modifi'd Light, and +immediately affects the Sensory, I shall now re-mind you, that I did not +deny, but that Colour might in some sense be consider'd as a Quality +residing in the body that is said to be Colour'd, and indeed the greatest +part of the following Experiments referr to Colour principally under that +Notion, for there is in the bodyes we call Colour'd, and chiefly in their +Superficial parts, a certain disposition, whereby they do so trouble the +Light that comes from them to our Eye, as that it there makes that distinct +Impression, upon whose Account we say, that the Seen body is either White +or Black, or Red or Yellow, or of any one determinate Colour. But because +we shall (God permiting) by the Experiments that are to follow some Pages +hence, more fully and particularly shew, that the Changes, and consequently +in divers places the Production and the appearance of Colours depends upon +the continuing or alter'd Texture of the Object, we shall in this place +intimate (and that too but as by the way) two or three things about this +Matter. + +2. And first it is not without some Reason, that I ascribe Colour (in the +sense formerly explan'd) _chiefly_ to the Superficial parts of Bodies, for +not to question how much Opacous Corpuscles may abound even in those Bodies +we call Diaphanous, it seems plain that of Opacous bodies we do indeed see +little else than the Superficies, for if we found the beams of Light that +rebound from the Object to the Eye, to peirce deep into the Colour'd body, +we should not judge it Opacous, but either Translucid, or at least +Semi-diaphanous, and though the Schools seem to teach us that Colour is a +Penetrative Quality, that reaches to the Innermost parts of the Object, as +if a piece of Sealing-wax be broken into never so many pieces, the Internal +fragments will be as Red as the External surface did appear, yet that is +but a Particular Example that will not overthrow the Reason lately offer'd, +especially since I can alleage other Examples of a contrary Import, and two +or three Negative Instances are sufficient to overthrow the Generality of a +Positive Rule, especially if that be built but upon One or a Few Examples. +Not (then) to mention Cherries, Plums, and I know not how many other +Bodies, wherein the skin is of one Colour, and what it hides of another, I +shall name a couple of Instances drawn from the Colours of Durable bodies +that are thought far more Homogeneous, and have not parts that are either +Organical, or of a Nature approaching thereunto. + +3 To give you the first Instance, I shall need but to remind you of what I +told you a little after the beginning of this Essay, touching the Blew and +Red and Yellow, that may be produc'd upon a piece of temper'd Steel, for +these Colours though they be very Vivid, yet if you break the Steel they +adorn, they will appear to be but Superficial; not only the innermost parts +of the Metall, but those that are within a hairs breadth of the +Superficies, having not any of these Colours, but retaining that of the +Steel it self. Besides that, we may as well confirm this Observation, as +some other particulars we elsewhere deliver concerning Colours, by the +following Experiment which we purposely made. + +4 We took a good quantity of clean Lead, and melted it with a strong Fire, +and then immediately pouring it out into a clean Vessel of a convenient +shape and matter, (we us'd one of Iron, that the great and sudden Heat +might not injure it) and then carefully and nimbly taking off the Scum that +floated on the top, we perceiv'd, as we expected, the smooth and glossie +Surface of the melted matter, to be adorn'd with a very glorious Colour, +which being as Transitory as Delightfull, did almost immediately give place +to another vivid Colour, and that was as quickly succeeded by a third, and +this as it were chas'd away by a fourth, and so these wonderfully vivid +Colours successively appear'd and vanish'd, (yet the same now and then +appearing the second time) till the Metall ceasing to be hot enough to +afford any longer this pleasing Spectacle, the Colours that chanc'd to +adorn the Surface, when the Lead thus began to cool, remain'd upon it; but +were so Superficial, that how little soever we scrap'd off the Surface of +the Lead, we did in such places scrape off all the Colour, and discover +only that which is natural to the Metall it self, which receiving its +adventitious Colours, only when the heat was very Intense, and in that part +which was expos'd to the comparatively very cold Air, (which by other +Experiments seems to abound with subtil Saline parts, perhaps not uncapable +of working upon Lead so dispos'd:) These things I say, together with my +observing that whatever parts of the so strongly melted Lead were expos'd a +while to the Air, turn'd into a kind of Scum or Litharge, how bright and +clean soever they appear'd before, suggested to me some Thoughts or +Ravings, which I have not now time to acquaint You with. One that did not +know me, _Pyrophilus_, would perchance think I endeavour'd to impose upon +You by relating this Experiment, which I have several times try'd, but the +Reason why the _Phænomena_ mention'd have not been taken notice of, may be, +that unless Lead be brought to a much higher degree of Fusion or Fluidity +than is usual, or than is indeed requisite to make it melt, the _Phænomena_ +I mention'd will scarce at all disclose themselves; And we have also +observ'd that this successive appearing and vanishing of vivid Colours, was +wont to be impair'd or determin'd whilst the Metal expos'd to the Air +remain'd yet hotter than one would readily suspect. And one thing I must +further Note, of which I leave You to search after the Reason, namely, that +the same Colours did not always and regularly succeed one another, as is +usually in Steel, but in the diversify'd Order mention'd in this following +Note, which I was scarce able to write down, the succession of the Colours +was so very quick, whether that proceeded from the differing degrees of +Heat in the Lead expos'd to the cool Air, or from some other Reason, I +leave you to examine. + + [_Blew, Yellow, Purple, Blew; Green, Purple, Blew, Yellow, Red; Purple, + Blew, Yellow and Blew, Yellow, Blew, Purple, Green mixt, Yellow, Red, + Blew, Green, Yellow, Red, Purple, Green_.] + +5. The _Atomists_ of Old, and some Learned men of late, have attempted to +explicate the variety of Colours in Opacous bodies from the various Figures +of their Superficial parts; the attempt is Ingenious, and the Doctrine +seems partly True, but I confess I think there are divers other things that +must be taken in as concurrent to produce those differing forms of +Asperity, whereon the Colours of Opacous bodies seem to depend. To declare +this a little, we must assume, that the Surfaces of all such Bodies how +Smooth or polite soever they may appear to our Dull Sight and Touch, are +exactly smooth only in a popular, or at most in a Physical sense, but not +in a strict and rigid sense. + +6. This, excellent _Microscopes_ shew us in many Bodies, that seem Smooth +to our naked Eyes; and this not only as to the little Hillocks or +Protuberancies that swell above that which may be conceiv'd to be the Plain +or Level of the consider'd Surface, for it is obvious enough to those that +are any thing conversant with such Glasses, but as to numerous Depressions +beneath that Level, of which sort of Cavities by the help of a +_Microscope_, which the greatest Artificer that makes them, judges to be +the greatest Magnifying Glass in _Europe_, except one that equals it, we +have on the Surface of a thin piece of Cork that appear'd smooth to the +Eye, observ'd about sixty in a Row, within the length of less then an 31 +and 32 part of an Inch, (for the Glass takes in no longer a space at one +view) and these Cavities (which made that little piece of Cork look almost +like an empty Honey-comb) were not only very distinct, and figur'd like one +another, but of a considerable bigness, and a scarce credible depth; +insomuch that their distinct shadows as well as sides were plainly +discern'd and easiy to be reckon'd, and might have been well distinguish'd, +though they had been ten times lesser than they were; which I thought it +not amiss to mention to you _Pyrophilus_ upon the by, that you may thence +make some Estimate, what a strange Inequality, and what a multitude of +little Shades, there may really be, in a scarce sensible part of the +Physical superficies, though the naked Eye sees no such matter. And as +Excellent _Microscopes_ shew us this Ruggedness in many Bodies that pass +for Smooth, so there are divers Experiments, though we must not now stay to +urge them, which seem to perswade us of the same thing as to the rest of +such Bodies as we are now treating off; So, that there is no sensible part +of an Opacous body, that may not be conceiv'd to be made up of a multitude +of singly insensible Corpuscles, but in the giving these surfaces that +disposition, which makes them alter the Light that reflects thence to the +Eye after the manner requisite to make the Object appear Green, Blew, &c. +the Figures of these Particles have _a great_, but not _the only_ stroak. +'Tis true indeed that the protuberant Particles may be of very great +variety of Figures, Sphærical, Elliptical, Conical, Cylindrical, +Polyedrical, and some very irregular, and that according to the Nature of +these, and the situation of the Lucid body, the Light must be variously +affected, after one manner from Surfaces (I now speak of Physical Surfaces) +consisting of Sphaerical, and in another from those that are made up of +Conical or Cylindrical Corpuscles; some being fitted to reflect more of the +incident Beams of Light, others less, and some towards one part, others +towards another. But besides this difference of Shape, there may be divers +other things that may eminently concurr to vary the forms of Asperity that +Colours so much depend on. For, willingly allowing the Figure of the +Particles in the first place, I consider secondly, that the superficial +Corpuscles, if I may so call them, may be bigger in one Body, and less in +another, and consequently fitted to allay the Light falling on them with +greater shades. Next, the protuberant Particles may be set more or less +close together, that is, there may be a greater or a smaller number of them +within the compass of one, than within the compass of another small part of +the Surface of the same Extent, and how much these Qualities may serve to +produce Colour may be somewhat guess'd at, by that which happens in the +Agitation of Water; for if the Bubbles that are thereby made be Great, and +but Few, the Water will scarce acquire a sensible Colour, but if it be +reduc'd to a Froth, consisting of Bubbles, which being very Minute and +Contiguous to each other, are a multitude of them crowded into a narrow +Room, the Water (turned to Froth) does then exhibit a very manifest White +Colour,[3] (to which these last nam'd Conditions of the Bubbles do as well +as their Convex figure contribute) and that for Reasons to be mention'd +anon. Besides, it is not necessary that the Superficial particles that +exhibit one Colour, should be all of them Round, or all Conical, or all of +any one Shape, but Corpuscles of differing Figures may be mingled on the +Surface of the Opacous Body, as when the Corpuscles that make a Blew +colour, and those that make a Yellow, come to be Accurately and Skilfully +mix'd, they make up a Green, which though it seem one simple Colour, yet in +this case appears to be made by Corpuscles of very differing Kinds, duely +commix'd. Moreover the Figure and Bigness of the little Depressions, +Cavities, Furrows or Pores intercepted betwixt these protuberant +Corpuscles, are as well to be consider'd as the Sizes and Shapes of the +Corpuscles themselves: For we may conceive the Physical superficies of a +Body, where (as we said) its Colour does as it were reside, to be cut +Transversly by a Mathematical plain, which you know is conceiv'd to be +without any Depth or Thickness at all, and then as some parts of the +Physical Superficies will be Protuberant; or swell above this last plain, +so others may be depress'd beneath it; as (to explane my self by a gross +Comparison) in divers places of the Surface of the Earth, there are not +only Neighbouring Hills, Trees, &c. that are rais'd above the Horizontal +Level of the Valley, but Rivers, Wells, Pits and other Cavities that are +depress'd beneath it, and that such Protuberant and Concave parts of a +Surface may remit the Light so differingly, as much to vary a Colour, some +examples and other things, that we shall hereafter have occasion to take +notice off in this Tract, will sufficiently declare, till when, it may +suffice to put you in mind, that of two Flat-sides of the same piece of, +for example, red Marble, the one being diligently Polished, and the other +left to its former Roughness, the differing degrees or sorts of Asperity, +for the side that is smooth to the Touch wants not its Roughness, will so +diversifie the Light reflected from the several Plains to the Eye, that a +Painter would employ two differing Colours to represent them. + + [3] _See the Discourse of the Nature of Whiteness and Blackness._ + +7. And I hope, _Pyrophilus_, you will not think it strange or impertinent, +that I employ in divers passages of these Papers, examples drawn from +Bodies and Shadows far more Gross, than those minute Protuberances and +shady Pores on which in most cases the Colour of a Body as 'tis an Inherent +Quality or Disposition of its Surface, seems to depend. For sometimes I +employ such Examples, rather to declare my Meaning, than prove my +Conjecture; things, whom their Smallness makes Insensible, being better +represented to the Imagination by such familiar Objects, as being like them +enough in other respects, are of a Visible bulk. And next, though the Beams +of Light are such subtil Bodies, that in respect of them, even Surfaces +that are sensibly Smooth, are not exactly so, but have their own degree of +Roughness, consisting of little Protuberances and Depressions; and though +consequently such Inequalities may suffice to give Bodies differing +Colours, as we see in Marble that appears White or Black, or Red or Blew, +even when the most carefully Polish'd, yet 'tis plain by the late Instance +of Red Marble, and many others, that even bigger Protuberances and greater +Shades may likewise so Diversifie the Roughness of a Bodies Superficies, as +manifestly to concurr to the varying of its Colour, whereby such Examples +appear to be proper enough to be employ'd in such a Subject as we have now +in hand. And having hinted thus much on this Occasion, I now proceed. + +8. The Situation also of the Superficial particles is considerable, which I +distinguish into the Posture of the single Corpuscles, in respect of the +Light, and of the Eye, and the Order of them in reference also to one +another; for a Body may otherwise reflect the Light, when its Superficial +particles are more erected upon the Plain that may be conceiv'd to pass +along their Basis, and when the Points or Extremes of such Particles are +Obverted to the Eye, than when those Particles are so Inclin'd, that their +Sides are in great part Discernable, as the Colour of Plush or Velvet will +appear Vary'd to you, if you carefully stroak part of it one way, and part +of it another, the posture of the particular Thrids, in reference to the +Light, or the Eye, becoming thereby different. And you may observe in a +Field of ripe Corn blown upon by the Wind, that there will appear as it +were Waves of a Colour (at least Gradually) differing from that of the rest +of the Field, the Wind by Depressing some of the Ears, and not at the same +time others, making the one Reflect more from the Lateral and Strawy parts, +than do the rest. And so, when Doggs are so angry, as to Erect the Hairs +upon their Necks, and upon some other parts of their Bodies, those Parts +seem to acquire a Colour vary'd from that which the same Hairs made, when +in their usual Posture they did farr more stoop. And that the Order wherein +the Superficial Corpuscles are Rang'd is not to be neglected, we may guess +by turning of Water into Froth, the beating of Glass, and the scraping of +Horns, in which cases the Corpuscles that were before so marshall'd as to +be Perspicuous, do by the troubling of that Order become Dispos'd to +terminate and reflect more Light, and thereby to appear Whitish. And there +are other ways in which the Order of the Protuberant parts, in reference to +the Eye, may much contribute to the appearing of a particular Colour, for I +have often observ'd, that when Pease are Planted, or Set in Parallel Lines, +and are Shot up about half a Foot above the Surface of the Ground, by +looking on the Field or Plot of Ground from that part towards which the +Parallel Lines tended, the greater part of the Ground by farr would appear +of its own dirty Colour, but if I look'd upon it Transversly, the Plot +would appear very Green, the upper parts of the Pease hindering the +intercepted parts of the Ground, which as I said retain'd their wonted +Colour, from being discover'd by the Eye. And I know not, _Pyrophilus_, +whether I might not add, that even the Motion of the Small Parts of a +Visible Object may in some cases contribute, though it be not so easie to +say how, to the Producing or the Varying of a Colour; for I have several +times made a Liquor, which when it has well settled in a close Vial, is +Transparent and Colourless, but as soon as the Glass is unstopp'd, begins +to fly away very plentifully in a White and Opacous fume; and there are +other Bodies, whose Fumes, when they fill a Receiver, would make one +suspect it contains Milk, and yet when these Fumes settle into a Liquor, +that Liquor is not White, but Transparent; And such White Fumes I have seen +afforded by unstopping a Liquor I know, which yet is it self Diaphanous and +Red; Nor are these the only Instances of this Kind, that our Tryals can +supply us with. And if the Superficial Corpuscles be of the Grosser sort, +and be so Framed, that their differing Sides or Faces may exhibit differing +Colours, then the Motion or Rest of those Corpuscles may be considerable, +as to the Colour of the Superficies they compose, upon this account, that +sometimes more, sometimes fewer of the Sides dispos'd to exhibit such a +Colour may by this means become or continue more Obverted to the Eye than +the rest, and compose a Physical Surface, that will be more or less +sensibly interrupted; As, to explane my meaning, by proposing a gross +Example, I remember, that in some sorts of Leavy Plants thick set by one +another, the two sides of whose Leaves were of somewhat differing Colours, +there would be a notable Disparity as to Colour, if you look'd upon them +both when the Leaves being at Rest had their upper and commonly expos'd +sides Obverted to the Eye, and when a breath of Wind passing thorow them, +made great Numbers of the usually Hidden sides of the Leaves become +conspicuous. And though the Little Bodies, we were lately speaking of, may +Singly and Apart seem almost Colourless, yet when Many of them are plac'd +by one another, so near, that the Eye does not easily discern an +Interruption, within a sensible space, they may exhibit a Colour; as we +see, that though a Slenderest Thrid of Dy'd Silk do's, whilst look'd on +Single, seem almost quite Devoyd of Redness, (for instance) yet when +numbers of these Thrids are brought together into one Skein, their Colour +becomes notorious. + +9. But the same Occasion that invited me to say what I have mention'd +concerning the Leaves of Trees, invites me also to give you some account of +what happens in Changeable Taffities, where we see differing Colours, as it +were, Emerge and Vanish upon the Ruffling of the same piece of Silk: As I +have divers times with Pleasure observ'd, by the help of such a +_Microscope_, as, though it do not very much Magnifie the Object, has in +recompence this great Conveniency, that you may easily, as fast as you +please, remove it from one part to another of a Large Object, of which the +Glass taking a great part at once, you may thereby presently Survey the +Whole. Now by the help of such a _Microscope_ I could easily (as I began to +say) discern, that in a piece of Changeable Taffity, (that appear'd, for +Instance, sometimes Red, and sometimes Green) the Stuff was compos'd of Red +thrids and Green, passing under and over each other, and crossing one +another in almost innumerable points; and if I look'd through the Glass +upon any considerable portion of the Stuff, that (for example sake) to the +naked Eye appear'd to be Red, I could plainly see, that in that Position, +the Red thrids were Conspicuous, and reflected a vivid Light; and though I +could also perceive, that there were Green ones, yet by reason of their +disadvantagious Position in the _Physical Surface_ of the Taffity, they +were in part hid by the more Protuberant Thrids of the other Colour; and +for the same cause, the Reflection from as much of the Green as was +discover'd, was comparatively but Dim and Faint. And if, on the contrary, I +look'd through the _Microscope_ upon any part that appear'd Green, I could +plainly see that the Red thrids were less fully expos'd to the Eye, and +obscur'd by the Green ones, which therefore made up the Predominant Colour. +And by observing the Texture of the Silken Stuff, I could easisy so expose +the Thrids either of the one Colour or of the other to my Eye, as at +pleasure to exhibit an apparition of Red or Green, or make those Colours +succeed one another: So that, when I observ'd their Succession by the help +of the Glass, I could mark how the Predominant Colour did as it were start +out, when the Thrids that exhibited it came to be advanagiously plac'd; And +by making little Folds in the Stuff after a certain manner, the Sides that +met and terminated in those Folds, would appear to the naked Eye, one of +them Red, and the other Green. When Thrids of more than two differing +Colours chance to be Interwoven, the resulting changeableness of the +Taffity may be also somewhat different. But I choose to give an Instance in +the Stuff I have been speaking off, because the mixture being more Simple, +the way whereby the Changeableness is produc'd, may be the more easily +apprehended: and though Reason alone might readily enough lead a +considering Man to guess at the Explication, in case he knew how Changeable +Taffities are made: yet I thought it not impertinent to mention it, because +both Scholars and Gentlemen are wont to look upon the Inquiry into +Manufactures, as a _Mechanick_ imployment, and consequently below Them; and +because also with such a _Microscope_ as I have been mentioning, the +discovery is as well Pleasant as Satisfactory, and may afford Hints of the +Solution of other _Phænomena_ of Colours. And it were not amiss, that some +diligent Inquiry were made, whether the _Microscope_ would give us an +account of the Variableness of Colour, that is so Conspicuous and so +Delightfull in Mother of Pearl, in Opalls, and some other resembling +Bodies: For though I remember I did formerly attempt something of that Kind +(fruitlesly enough) upon Mother of Pearl, yet not having then the advantage +of my best _Microscope_, nor some Conveniences that might have been wish'd, +I leave it to you, who have better Eyes, to try what you can do further; +since 'twill be _Some_ discovery to find, that, in this case, the best Eyes +and _Microscopes_ themselves can make _None_. + +10. I confess, _Pyrophilus_, that a great part of what I have deliver'd, +(or propos'd rather) concerning the differing forms of Asperity in Bodies, +by which Differences the incident Light either comes to be Reflected with +more or less of Shade, and with that Shade more or less Interrupted, or +else happens to be also otherwise Modify'd or Troubl'd, is but Conjectural. +But I am not sure, that if it were not for the Dullness of our Senses, +either these or some other Notions of Kin to them, might be better +Countenanc'd; for I am apt to suspect, that if we were Sharp sighted +enough, or had such perfect _Microscopes_, as I fear are more to be wish'd +than hop'd for, our promoted Sense might discern in the Physical Surfaces +of Bodies, both a great many latent Ruggidnesses, and the particular Sizes, +Shapes, and Situations of the extremely little Bodies that cause them, and +perhaps might perceive among other Varieties that we now can but imagine, +how those little Protuberances and Cavities do Interrupt and Dilate the +Light, by mingling with it a multitude of little and singly undiscernable +Shades, though some of them more, and some of them less Minute, some less, +and some more Numerous; according to the Nature and Degree of the +particular Colour we attribute to the Visible Object; as we see, that in +the Moon we can with Excellent _Telescopes_ discern many Hills and Vallies, +and as it were Pits and other Parts, whereof some are more, and some less +Vividly illustrated, and others have a fainter, others a deeper Shade, +though the naked Eye can discern no such matter in that Planet. And with an +Excellent _Microscope_, where the _Naked_ Eye did see but a Green powder, +the _Assisted_ Eye as we noted above, could discern particular Granules, +some of them of a Blew, and some of them of a Yellow colour, which +Corpuscles we had beforehand caus'd to be exquisitly mix'd to compound the +Green. + +11. And, _Pyrophilus_, that you may not think me altogether extravagant in +what I have said of the Possibility, (for I speak of no more) of discerning +the differing forms of Asperity in the Surfaces of Bodies of several +Colours, I'l here set down a Memorable particular that chanc'd to come to +my Knowledge, since I writ a good part of this _Essay_; and it is this. +Meeting casually the other Day with the deservedly Famous[4] Dr. _J. +Finch_, Extraordinary _Anatomist_ to that Great Patron of the _Virtuosi_, +the now Great Duke of _Toscany_, and enquiring of this Ingenious Person, +what might be the chief Rarity he had seen in his late return out of +_Italy_ into _England_, he told me, it was a Man at _Maestricht_ in the +Low-Countrys, who at certain times can discern and _distinguish Colours by +the Touch_ with his Fingers. You'l easily Conclude, that this is farr more +strange, than what I propos'd but as _not Impossible_; since the Sense of +the _Retina_ seeming to be much more Tender and quick than that of those +Grosser Filaments, Nerves or Membranes of our Fingers, wherewith we use to +handle Gross and Hard Bodies, it seems scarce credible, that any +Accustomance, or Diet, or peculiarity of Constitution, should enable a Man +to distinguish with such Gross and Unsuitable Organs, such Nice and Subtile +Differences as those of the forms of Asperity, that belong to differing +Colours, to receive whose Languid and Delicate Impressions by the +Intervention of Light, Nature seems to have appointed and contexed into the +_Retina_ the tender and delicate Pith of the Optick Nerve. Wherefore I +confess, I propos'd divers Scruples, and particularly whether the Doctor +had taken care to bind a Napkin or Hankerchief over his Eyes so carefully, +as to be sure he could make no use of his Sight, though he had but +Counterfeited the want of it, to which I added divers other Questions, to +satisfie my Self, whether there were any Likelihood of Collusion or other +Tricks. But I found that the Judicious Doctor having gone farr out of his +way, purposely to satisfie Himself and his Learned Prince about this +Wonder, had been very Watchfull and Circumspect to keep _Himself_ from +being Impos'd upon. And that he might not through any mistake in point of +Memory mis-inform _Me_, he did me the Favour at my Request, to look out the +Notes he had Written for his Own and his Princes Information, the summ of +which Memorials, as far as we shall mention them here, was this, That the +Doctor having been inform'd at _Utrecht_, that there Lived one at some +Miles distance from _Maestricht_, who could distinguish Colours by the +Touch, when he came to the last nam'd Town, he sent a Messenger for him, +and having Examin'd him, was told upon Enquiry these Particulars: + + [4] Since for his eminent Qualities and Loyalty Grac'd, by his Majesty, + with the Honour of Knighthood. + +That the Man's name was _John Vermaasen_, at that time about 33 Years of +Age; that when he was but two years Old, he had the Small Pox, which +rendred him absolutely Blind: That at this present he is an _Organist_, and +serves that Office in a publick Quire. + +That the Doctor discoursing with him over Night, the Blind man affirm'd, +that he could distinguish Colours by the Touch, but that he could not do +it, unless he were Fasting; Any quantity of Drink taking from him that +Exquisitness of Touch, which is requisite to so Nice a Sensation. + +That hereupon the Doctor provided against the next Morning seven pieces of +Ribbon, of these seven Colours, Black, White, Red, Blew, Green, Yellow, and +Gray, but as for _mingled_ Colours, this _Vermaasen_ would not undertake to +discern them, though if offer'd, he would tell that they were _Mix'd_. + +That to discern the Colour of the Ribbon, he places it betwixt the Thumb +and the Fore-finger, but his most exquisite perception was in his Thumb, +and much better in the right Thumb than in the left. + +That after the Blind man had four or five times told the Doctor the several +Colours, (though Blinded with a Napkin for fear he might have some Sight) +the Doctor found he was twice mistaken, for he call'd the White Black, and +the Red Blew, but still, he, before his Errour, would lay them by in Pairs, +saying, that though he could easily distinguish them from all others, yet +those two Pairs were not easily distinguish'd amongst themselves, whereupon +the Doctor desir'd to be told by him what kind of Discrimination he had of +Colours by his Touch, to which he gave a reply, for whose sake chiefly I +insert all this Narrative in this place, namely, That all the difference +was more or less Asperity, for says he, (I give you the Doctor's own words) +Black feels as if you were feeling Needles points, or some harsh Sand, and +Red feels very Smooth. + +That the Doctor having desir'd him to tell in Order the difference of +Colours to his Touch, he did as follows; + +Black and White are the most asperous or unequal of all Colours, and so +like, that 'tis very hard to distinguish them, but Black is the most Rough +of the two, Green is next in Asperity, Gray next to Green in Asperity, +Yellow is the fifth in degree of Asperity, Red and Blew are so like, that +they are as hard to distinguish as Black and White, but Red is somewhat +more Asperous than Blew, so that Red has the sixth place, and Blew the +seventh in Asperity. + +12. To these Informations the Obliging Doctor was pleas'd to add the +welcome present of three of those very pieces of Ribbon, whose Colours in +his presence the Blind man had distinguished, pronouncing the one Gray, the +other Red, and the third Green, which I keep by me as Rarities, and the +rather, because he fear'd the rest were miscarry'd. + +13. Before I saw the Notes that afforded me the precedent Narrative, I +confess I suspected this man might have thus discriminated Colours, rather +by the Smell than by the Touch; for some of the Ingredients imployed by +Dyers to Colour things, have Sents, that are not so Languid, nor so near of +Kin, but that I thought it not impossible that a very Critical Nose might +distinguish them, and this I the rather suspected, because he requir'd, +that the Ribbons, whose Colours he was to Name, should be offer'd him +Fasting in the morning; for I have observ'd in Setting Doggs, that the +feeding of them (especially with some sorts of Aliments) does very much +impair the exquisite sent of their Noses. And though some of the foregoing +particulars would have prevented that Conjecture, yet I confess to you +(_Pyrophilus_) that I would gladly have had the Opportunity of Examining +this Man my self, and of Questioning him about divers particulars which I +do not find to have been yet thought upon. And though it be not incredible +to me, that since the Liquors that Dyers imploy to tinge, are qualifi'd to +do so by multitudes of little Corpuscles of the Pigment or Dying stuff, +which are dissolved and extracted by the Liquor, and swim to and fro in it, +those Corpuscles of Colour (as the _Atomists_ call them) insinuating +themselves into, and filling all the Pores of the Body to be Dyed, may +Asperate its Superficies more or less according to the Bigness and Texture +of the Corpuscles of the Pigment; yet I can scarce believe, that our Blind +man could distinguish all the Colours he did, meerly by the Ribbons having +more or less of Asperity, so that I cannot but think, notwithstanding this +History, that the Blind man distinguish'd Colours not only by the _Degrees_ +of Asperity in the Bodies offer'd to him, but by _Forms_ of it, though this +(latter) would perhaps have been very difficult for him to make an +Intelligible mention of, because those Minute disparities having not been +taken notice of by men for want of touch as Exquisite as our Blind Mans, +are things he could not have Intelligibly express'd, which will easily seem +Probable, if you consider, that under the name of Sharp, and Sweet, and +Sour, there are abundance of, as it were, immediate peculiar Relishes or +Tasts in differing sorts of Wine, which though Critical and Experienc'd +Palats can easily discern themselves cannot make them be understood by +others, such Minute differences not having hitherto any Distinct names +assign'd them. And it seems that there was somthing in the Forms of +Asperity that was requisite to the Distinction of Colours, besides the +Degree of it, since he found it so difficult to distingush Black and White +from one another, though not from other Colours. For I might urge, that he +seems not consonant to himself about the _Red_, which as you have seen in +one place, he represents as somewhat more Asperous than the _Blew_; and in +another, very Smooth: But because he speaks of this Smoothness in that +place, where he mentions the Roughness of _Black_, we may favourably +presume that he might mean but a _comparative Smoothness_; and therefore I +shall not Insist on this, but rather Countenance my Conjecture by this, +that he found it so Difficult, not only, to Discriminate Red and Blew, +(though the first of our promiscuous Experiments will inform you, that the +Red reflects by great Odds more Light than the other) but also to +distinguish Black and White from one another, though not from other +Colours. And indeed, though in the Ribbonds that were offer'd him, they +might be almost equally Rough, yet in such slender Corpuscles as those of +Colour, there may easily enough be Conceiv'd, not only a greater Closeness +of Parts, or else Paucity of Protuberant Corpuscles, and the little extant +Particles may be otherwise Figur'd, and Rang'd in the White than in the +Black, but the Cavities may be much Deeper in the one than the other. + +14. And perhaps, (_Pyrophilus_) it may prove some _Illustration of what I +mean_, and help you to conceive how _this may_ be, if I Represent, that +where the Particles are so exceeding Slender, we may allow the Parts +expos'd to the Sight and Touch to be a little Convex in comparison of the +Erected Particle of Black Bodies, as if there were Wyres I know not how +many times Slenderer than a Hair: whether you suppose them to be Figur'd +like Needles, or Cylindrically, like the Hairs of a Brush, with +Hemisphærical (or at least Convex) Tops, they will be so very Slender, and +consequently the Points both of the one sort and the other so very Sharp, +that even an exquisite Touch will be able to distinguish no greater +Difference between them, than that which our Blind man allow'd, when +comparing Black and White Bodies, he said, that the latter was the less +Rough of the two. Nor is every Kind of Roughness, though Sensible enough, +Inconsistent with Whiteness, there being Cases, wherein the Physical +Superficies of a Body is made by the same Operation both _Rough_ and +_white_, as when the Level Surface of clear Water being by agitation +Asperated with a multitude of Unequal Bubbles, do's thereby acquire a +Whiteness; and as a Smooth piece of Glass, by being Scratch'd with a +Diamond, do's in the Asperated part of its Surface disclose the same +Colour. But more (perchance) of this elsewhere. + +15. And therefore, we shall here pass by the Question, whether any thing +might be consider'd about the Opacity of the Corpuscles of Black Pigments, +and the _Comparative_ Diaphaneity of those of many White Bodies, apply'd to +our present Case; and proceed, to represent, That the newly mention'd +Exiguity and Shape of the extant Particles being suppos'd, it will then be +considerable what we lately but Hinted, (and therefore must now somewhat +Explane) That the Depth of the little Cavities, intercepted between the +extant Particles, without being so much greater in Black Bodies than in +White ones, as to be perceptibly so to the Gross Organs of Touch, may be +very much greater in reference to their Disposition of Reflecting the +imaginary subtile Beams of Light. For in Black Bodies, those Little +intercepted Cavities, and other Depressions, may be so Figur'd, so Narrow +and so Deep, that the incident Beams of Light, which the more extant Parts +of the Physical Superficies are dispos'd to Reflect inwards, may be +Detain'd there, and prove unable to Emerge; whilst in a White Body, the +Slender Particles may not only by their Figure be fitted to Reflect the +Light copiously outwards, but the intercepted Cavities being not Deep, nor +perhaps very Narrow, the Bottoms of them may be so Constituted, as to be +fit to Reflect outwards much of the Light that falls even upon Them; as you +may possibly better apprehend, when we shall come to treat of Whiteness and +Blackness. In the mean time it may suffice, that you take Notice with me, +that the Blind mans Relations import no necessity of Concluding, that, +though, because, according to the Judgment of his Touch, Black was the +Roughest, as it is the Darkest of Colours, therefore White, which +(according to us) is the Lightest, should be also the Smoothest: since I +observe, that he makes Yellow to be two Degrees more Asperous than Blew, +and as much less Asperous than Green; whereas indeed, Yellow do's not only +appear to the Eye a Lighter Colour than Blew, but (by our first Experiment +hereafter to be mention'd) it will appear, that Yellow reflected much more +Light than Blew, and manifestly more than Green, (which we need not much +wonder at, since in this Colour and the two others (Blew and Yellow) 'tis +not _only_ the _Reflected Light_ that is to be considered, since to produce +both these, _Refraction_ seems to Intervene, which by its Varieties may +much alter the Case:) which both seems to strengthen the Conjecture I was +formerly proposing, that there was something else in the _Kinds_ of +Asperity, as well as in the _Degrees_ of it, which enabled our Blind man to +Discriminate Colours, and do's at least show, that we cannot in all Cases +from the bare Difference in the Degrees of Asperity betwixt Colours, safely +conclude, that the Rougher of any two always Reflects the least Light. + +16. But this notwithstanding, (_Pyrophilus_) and what ever Curiosity I may +have had to move some Questions to our Sagacious Blind man, yet thus much I +think you will admit us to have gain'd by his Testimony, that since many +Colours may be felt with the Circumstances above related, the Surfaces of +such Coloured Bodies must certainly have differing _Degrees_, and in all +probability have differing _Forms_ or Kinds of Asperity belonging to them, +which is all the Use that my present attempt obliges me to make of the +History above deliver'd, that being sufficient to prove, _that_ Colour do's +much depend upon the Disposition of the Superficial parts of Bodies, and to +shew in general, _wherein_ 'tis probable that such a Disposition do's +(principally at least) consist. + +17. But to return to what I was saying before I began to make mention of +our Blind _Organist_, what we have deliver'd touching the causes of the +several Forms or Asperity that may Diversifie the Surfaces of Colour'd +Bodies, may perchance somewhat assist us to make some Conjectures in the +general, at several of the ways whereby 'tis possible for the Experiments +hereafter to be mention'd, to produce the suddain changes of Colours that +are wont to be Consequent upon them; for most of these _Phænomena_ being +produc'd by the Intervention of Liquors, and these for the most part +abounding with very Minute, Active, and Variously Figur'd Saline +Corpuscles, Liquors so Qualify'd may well enough very Nimbly after the +Texture of the Body they are imploy'd to Work upon, and so may change the +form of Asperity, and thereby make them Remit to the Eye the Light that +falls on them, after another manner than they did before, and by that means +Vary the Colour, so farr forth as it depends upon the Texture or +Disposition of the Seen Parts of the Object, which I say, _Pyrophilus_, +that you may not think I would absolutely exclude all other ways of +Modifying the Beams of Light between their Parting from the Lucid Body, and +their Reception into the common Sensory. + +18. Now there seem to me divers ways, by which we may conceive that Liquors +may Nimbly alter the Colour of one another, and of other Bodies, upon which +they Act, but my present haste will allow me to mention but some of them, +without Insisting so much as upon those I shall name. + +19. And first, the Minute Corpuscles that compose a Liquor may early +insinuate themselves into those Pores of Bodies, whereto their Size and +Figure makes them Congruous, and these Pores they may either exactly Fill, +or but Inadequately, and in this latter Case they will for the most part +alter the Number and Figure, and always the Bigness of the former Pores. +And in what capacity soever these Corpuscles of a Liquor come to be Lodg'd +or Harbour'd in the Pores that admit them, the Surface of the Body will for +the most part have its Asperity alter'd, and the Incident Light that meets +with a Grosser Liquor in the little Cavities that before contain'd nothing +but Air, or some yet Subtiler Fluid, will have its Beams either Refracted, +or Imbib'd, or else Reflected more or less Interruptedly, than they would +be, if the Body had been Unmoistned, as we see, that even fair Water +falling on white Paper, or Linnen, and divers other Bodies apt to soak it +in, will for some such Reasons as those newly mention'd, immediately alter +the Colour of them, and for the most part make it Sadder than that of the +Unwetted Parts of the same Bodies. And so you may see, that when in the +Summer the High-ways are Dry and Dusty, if there falls store of Rain, they +will quickly appear of a much Darker Colour than they did before, and if a +Drop of Oyl be let fall upon a Sheet of White Paper, that part of it, which +by the Imbibition of the Liquor acquires a greater Continuity, and some +Transparency, will appear much Darker than the rest, many of the Incident +Beams of Light being now Transmitted, that otherwise would be Reflected +towards the Beholders Eyes. + +20. Secondly, A Liquor may alter the Colour of a Body by freeing it from +those things that hindred it from appearing in its Genuine Colour; and +though this may be said to be rather a Restauration of a Body to its own +Colour, or a Retection of its native Colour, than a Change, yet still there +Intervenes in it a change of the Colour which the Body appear'd to be of +before this Operation. And such a change a Liquor may work, either by +Dissolving, or Corroding, or by some such way of carrying off that Matter, +which either Veil'd or Disguis'd the Colour that afterwards appears. Thus +we restore Old pieces of Dirty Gold to a clean and nitid Yellow, by putting +them into the Fire, and into _Aqua-fortis_, which take off the adventitious +Filth that made that pure Metall look of a Dirty Colour. And there is also +an easie way to restore Silver Coyns to their due Lustre, by fetching off +that which Discolour'd them. And I know a _Chymical_ Liquor, which I +employ'd to restore pieces of Cloath spotted with Grease to their proper +Colour, by Imbibing the Spotted part with this Liquor, which Incorporating +with the Grease, and yet being of a very Volatile Nature, does easily carry +it away with it Self. And I have sometimes try'd, that by Rubbing upon a +good Touch-stone a certain _Metalline_ mixture so Compounded, that the +Impression it left upon the Stone appear'd of a very differing Colour from +that of Gold, yet a little of _Aqua-fortis_ would in a Trice make the +Golden Colour disclose it self, by Dissolving the other _Metalline_ +Corpuscles that conceal'd those of the Gold, which you know that +_Menstruum_ will leave Untouch'd. + +21. Thirdly, A Liquor may alter the Colour of a Body by making a +Comminution of its Parts, and that principally two ways, the first by +Disjoyning and Dissipating those Clusters of Particles, if I may so call +them, which stuck more Loosely together, being fastned only by some more +easily Dissoluble Ciment, which seems to be the Case of some of the +following Experiments, where you'l find the Colour of many Corpuscles +brought to cohere by having been Precipitated together, Destroy'd by the +Affusion of very peircing and incisive Liquors. The other of the two ways I +was speaking of, is, by Dividing the Grosser and more Solid Particles into +Minute ones, which will be always Lesser, and for the most part otherwise +Shap'd than the Entire Corpuscle so Divided, as it will happen in a piece +of Wood reduc'd into Splinters or Chips, or as when a piece of Chrystal +heated red Hot and quench'd in Cold water is crack'd into a multitude of +little Fragments, which though they fall not asunder, alter the Disposition +of the Body of the Chrystal, as to its manner of Reflecting the Light, as +we shall have Occasion to shew hereafter. + +22. There is a fourth way contrary to the third, whereby a Liquor may +change the Colour of another Body, especially of another Fluid, and that +is, by procuring the Coalition of several Particles that before lay too +Scatter'd and Dispers'd to exhibit the Colour that afterwards appears. Thus +sometimes when I have had a Solution of Gold so Dilated, that I doubted +whether the Liquor had really Imbib'd any true Gold or no, by pouring in a +little _Mercury_, I have been quickly able to satisfie my Self, that the +Liquor contain'd Gold, that Mettall after a little while Cloathing the +Surface of the _Quick-silver_, with a Thin Film of its own Livery. And +chiefly, though not only by this way of bringing the Minute parts of Bodies +together in such Numbers as to make them become Notorious to the Eye, many +of these Colours seem to be Generated which are produc'd by Precipitations, +especially by such as are wont to be made with fair Water, as when Resinous +Gumms dissolv'd in Spirit of Wine, are let fall again, if the Spirit be +Copiously diluted with that weakning Liquor. And so out of the Rectify'd +and Transparent Butter of _Antimony_, by the bare Mixture of fair Water, +there will be plentifully Precipitated that Milk-white Substance, which by +having its Looser Salts well wash'd off, is turn'd into that Medicine, +which Vulgar _Chymists_ are pleas'd to call _Mercurius Vitæ._ + +23. A fifth way, by which a Liquor may change the Colour of a Body, is, by +Dislocating the Parts, and putting them out of their former Order into +another, and perhaps also altering the Posture of the single Corpuscles as +well as their Order or Situation in respect of one another. What certain +Kinds of Commotion or Dislocation of the Parts of a Body may do towards the +Changing its Colour, is not only evident in the Mutations of Colour +observable in _Quick-silver_, and some other Concretes long kept by +_Chymists_ in a Convenient Heat, though in close Vessels, but in the +Obvious Degenerations of Colour, which every Body may take notice of in +Bruis'd Cherries, and other Fruit, by comparing after a while the Colour of +the Injur'd with that of the Sound part of the same Fruit. And that also +such Liquors, as we have been speaking of, may greatly Discompose the +Textures of many Bodies, and thereby alter the Disposition of their +Superficial parts, the great Commotion made in Metalls, and several other +Bodies by _Aqua-fortis_, Oyl of _Vitriol_, and other Saline _Menstruums_, +may easily perswade us, and what such Vary'd Situations of Parts may do +towards the Diversifying of the manner of their Reflecting the Light, may +be Guess'd in some Measure by the Beating of Transparent Glass into a White +Powder, but farr better by the Experiments lately Pointed at, and hereafter +Deliver'd, as the Producing and Destroying Colours by the means of subtil +Saline Liquors, by whose Affusion the Parts of other Liquors are manifestly +both Agitated, and likewise Dispos'd after another manner than they were +before such Affusion. And in some _Chymical_ Oyls, as particularly that of +Lemmon Pills, by barely Shaking the Glass, that holds it, into Bubbles, +that Transposition of the Parts which is consequent to the Shaking, will +shew you on the Surfaces of the Bubbles exceeding Orient and Lively +Colours, which when the Bubbles relapse into the rest of the Oyl, do +immediately Vanish. + +24. I know not, _Pyrophilus_, whether I should mention as a Distinct way, +because it is of a somewhat more General Nature, that Power, whereby a +Liquor may alter the Colour of another Body, by putting the Parts of it +into Motion; For though possibly the Motion so produc'd, does, as such, +seldome suddenly change the Colour of the Body whose Parts are Agitated, +yet this seems to be one of the most General, however not Immediate causes +of the Quick change of Colours in Bodies. For the Parts being put into +Motion by the adventitious Liquor, divers of them that were before United, +may become thereby Disjoyn'd, and when that Motion ceases or decays others +of them may stick together, and that in a new Order, by which means the +Motion may sometimes produce Permanent changes of Colours, as in the +Experiment you will meet with hereafter, of presently turning a Snowy White +Body into a Yellow, by the bare Affusion of fair Water, which probably so +Dissolves the Saline Corpuscles that remain'd in the _Calx_, and sets them +at Liberty to Act upon one another, and the Metall, far more Powerfully +than the Water without the Assistance of such Saline Corpuscles could do. +And though you rubb Blew _Vitriol_, how Venereal and Unsophisticated soever +it be, upon the Whetted Blade of a Knife, it will not impart to the Iron +its Latent Colour, but if you moisten the _Vitriol_ with your Spittle, or +common Water, the Particles of the Liquor disjoyning those of the +_Vitriol_, and thereby giving them the Various Agitation requisite to Fluid +Bodies, the Metalline Corpuscles of the thus Dissolv'd _Vitriol_ will Lodge +themselves in Throngs in the Small and Congruous Pores of the Iron they are +Rubb'd on, and so give the Surface of it the Genuine Colour of the Copper. + +25. There remains yet a way, _Pyrophilus_ to be mention'd, by which a +Liquor may alter the Colour of another Body, and this seems the most +Important of all, because though it be nam'd but as One, yet it may indeed +comprehend Many, and that is, by Associating the Saline Corpuscles, or any +other Sort of the more Rigid ones of the Liquor, with the Particles of the +Body that it is employ'd to Work upon. For these Adventitious Corpuscles +Associating themselves with the Protuberant Particles of the Surface of a +Colour'd Body, must necessarily alter their Bigness, and will most commonly +alter their Shape. And how much the Colours of Bodies depend upon the Bulk +and Figure of their Superficial Particles, you may Guess by this, that +eminent antient _Philosophers_ and divers _Moderns_, have thought that all +Colours might in a general way be made out by these two; whose being +Diversify'd, will in our Case be attended with these two Circumstances, the +One, that the Protuberant Particles being Increas'd in Bulk, they will +oftentimes be Vary'd as to the Closness or Laxity of their Order, fewer of +them being contain'd within the same Sensible (though Minute) space than +before; or else by approaching to one another, they must Straighten the +Pores, and it may be too, they will by their manner of Associating +themselves with the Protuberant Particles, intercept new Pores. And this +invites me to consider farther, that the Adventitious Corpuscles, I have +been speaking of, may likewise produce a great Change as well in the Little +Cavities or Pores as in the Protuberances of a Colour'd Body; for besides +what we have just now taken notice of, they may by Lodging themselves in +those little Cavities, fill them up, and it may well happen, that they may +not only fill the Pores they Insinuate themselves into, but likewise have +their Upper Parts extant above them; and partly by these new Protuberances, +partly by Increasing the Bulk of the former, these Extraneous Corpuscles +may much alter the Number and Bigness of the Surfaces Pores, changing the +Old and Intercepting new ones. And then 'tis Odds, but the Order of the +Little Extancies, and consequently that of the Little Depressions in point +of Situation will be alter'd likewise: as if you dissolve _Quick-silver_ in +some kind of _Aqua-fortis_, the Saline Particles of the _Menstruum_ +Associating themselves with the Mercurial Corpuscles, will make a Green +Solution, which afterwards easily enough Degenerates. And Red Lead or +_Minium_ being Dissolv'd in Spirit of Vinegar, yields not a Red, but a +Clear Solution, the Redness of the Lead being by the Liquor Destroy'd. But +a better Instance may be taken from Copper, for I have try'd, that if upon +a Copper-plate you let some Drops of weak _Aqua-fortis_ rest for a while, +the Corpuscles of the _Menstruum_, joyning with those of the Metall, will +produce a very sensible Asperity upon the Surface of the Plate, and will +Concoagulate that way into very minute Grains of a Pale Blew _Vitriol_; +whereas if upon another part of the same Plate you suffer a little strong +Spirit of Urine to rest a competent time, you shall find the Asperated +Surface adorn'd with a Deeper and Richer Blew. And the same _Aqua-fortis_, +that will quickly change the Redness of Red Lead into a Darker Colour, +will, being put upon Crude Lead, produce a Whitish Substance, as with +Copper it did a Blewish. And as with Iron it will produce a Reddish, and on +White Quills a Yellowish, so much may the Coalition of the Parts of the +same Liquor, with the differingly Figur'd Particles of Stable Bodies, +divers ways Asperate the differingly Dispos'd Surfaces, and to Diversifie +the Colour of those Bodies. And you'l easily believe, that in many changes +of Colour, that happen upon the Dissolutions of Metalls, and Precipitations +made with Oyl of _Tartar_, and the like Fix'd Salts, there may Intervene a +Coalition of Saline Corpuscles with the Particles of the Body Dissolv'd or +Precipitated, if you examine how much the _Vitriol_ of a Metall may be +Heavier than the Metalline part of it alone, upon the Score of the Saline +parts Concoagulated therewith, and, that in Several Precipitations the +weight of the _Calx_ does for the same Reason much exceed that of the +Metall, when it was first put in to be Dissolv'd. + +26. But, _Pyrophilus_, to consider these Matters more particularly would be +to forget that I declar'd against Adventuring, at least for this time, at +particular Theories of Colours, and that accordingly you may justly expect +from me rather Experiments than Speculations, and therefore I shall Dismiss +this Subject of the Forms of Superficial Asperity in Colour'd Bodies, as +soon as I shall but have nam'd to you by way of Supplement to what we have +hitherto Discours'd in this Section, a Couple of Particulars, (which you'l +easily grant me) The one, That there are divers other ways for the speedy +Production even of True and Permanent Colours in Bodies, besides those +Practicable by the help of Liquors; for proof of which Advertisement, +though several Examples might be alleged, yet I shall need but Re-mind you +of what I mention'd to you above, touching the change of Colours suddenly +made on Temper'd Steel, and on Lead, by the Operation of Heat, without the +Intervention of a Liquor. But the other particular I am to observe to you +is of more Importance to our present Subject and it is, That though Nature +and Art may in some cases so change the Asperity of the Superficial parts +of a Body, as to change its Colour by either of the ways I have propos'd +Single or Unassisted, yet for the most part 'tis by two or three, or +perhaps by more of the fore-mention'd ways Associated together, that the +Effect is produc'd, and if you consider how Variously those several ways +and some others Ally'd unto them, which I have left unmention'd, may be +Compounded and Apply'd, you will not much wonder that such fruitfull, +whether Principles (or Manners of Diversification) should be fitted to +Change or Generate no small store of Differing Colours. + +27. Hitherto, _Pyrophilus_, we have in discoursing of the Asperity of +Bodies consider'd the little Protuberances of other Superficial particles +which make up that Roughness, as if we took it for granted, that they must +be perfectly Opacous and Impenetrable by the Beams of Light, and so, must +contribute to the Variety of Colours as they terminate more or less Light, +and reflect it to the Eye mix'd with more or less of thus or thus mingl'd +Shades. But to deal Ingenuously with you, _Pyrophilus_, before I proceed +any further, I must not conceal from you, that I have often thought it +worth a Serious Enquiry, whether or no Particles of Matter, each of them +sing'y Insensible, and therefore small enough to be capable of being such +Minute Particles as the _Atomists_ both of old and of late have (not +absurdly) called _Corpuscula Coloris_, may not yet consist each of them of +divers yet Minuter Particles, betwixt which we may conceive little +Commissures where they Adhere to one another, and, however, may not be +Porous enough to be, at least in some degree, Pervious to the unimaginably +subtile Corpuscles that make up the Beams of Light, and consequently to be +in such a degree Diaphanous. For, _Pyrophilus_, that the proposed Enquiry +may be of moment to him that searches after the Nature of Colour, you'l +easily grant, if you consider, that whereas Perfectly Opacous bodies can +but reflect the incident Beams of Light, those that are Diaphanous are +qualified to refract them too, and that Refraction has such a stroak in the +Production of Colours, as you cannot but have taken notice of, and perhaps +admir'd in the Colours generated by the Trajection of Light through Drops +of Water that exhibit a Rain-bow, through Prismatical glasses, and through +divers other Transparent bodies. But 'tis like, _Pyrophilus_, you'l more +easily allow that about this matter 'tis rather Important to have a +Certainty, than that 'tis Rational to entertain a Doubt; wherefore I must +mention to you some of the Reasons that make me think it may need a further +Enquiry, for I find that in a Darkned Room, where the Light is permitted to +enter but at One hole, the little wandering Particles of Dust, that are +commonly called Motes, and, unless in the Sunbeams, are not taken notice of +by the unassisted Sight, I have, I say, often observ'd, that these roving +Corpuscles being look'd on by an Eye plac'd on one side of the Beams that +enter'd the Little hole, and by the Darkness having its Pupill much +Enlarg'd, I could discern that these Motes as soon as they came within the +compass of the Luminous, whether Cylinder or Inverted Cone, if I may so +call it, that was made up by the Unclouded Beams of the Sun, did in certain +positions appear adorn'd with very vivid Colours, like those of the +Rain-bow, or rather like those of very Minute, but Sparkling fragments of +Diamonds; and as soon as the Continuance of their Motion had brought them +to an Inconvenient position in reference to the Light and the Eye, they +were only visible without Darting any lively Colours as before, which seems +to argue that these little Motes, or minute Fragments, of several sorts of +bodies reputed Opacous, and only crumbled as to their Exteriour and Looser +parts into Dust, did not barely Reflect the Beams that fell upon them, but +remit them to the Eye Refracted too. We may also observe, that several +Bodies, (as well some of a Vegetable, as others of an Animal nature) which +are wont to pass for Opacous, appear in great part Transparent, when they +are reduc'd into Thin parts, and held against a powerful Light. This I have +not only taken notice of in pieces of Ivory reduc'd but into Thick leaves, +as also in divers considerable Thick shells of Fishes, and in shaving of +Wood, but I have also found that a piece of Deal, far thicker than one +would easily imagine, being purposly interposed betwixt my Eye plac'd in a +Room, and the clear Daylight, was not only somewhat Transparent, but +(perhaps by reason of its Gummous nature) appear'd quite through of a +lovely Red. And in the Darkned Room above mention'd, Bodies held against +the hole at which the Light enter'd, appear'd far less Opacous then they +would elsewhere have done, insomuch that I could easily and plainly see +through the whole Thickness of my Hand, the Motions of a Body plac'd (at a +very near distance indeed, but yet) beyond it. And even in Minerals, the +Opacity is not always so great as many think, if the Body be made Thin, for +White Marble though of a pretty Thickness, being within a Due distance +plac'd betwixt the Eye and a Convenient Light, will Suffer the Motions of +ones Finger to be well discern'd through it, and so will pieces, Thick +enough, of many common Flints. But above all, that Instance is remarkable, +that is afforded us by _Muscovie_ glass, (which some call _Selenites_, +others _Lapis Specularis_) for though plates of this Mineral, though but of +a moderate Thickness, do often appear Opacous, yet if one of these be +Dextrously split into the thinnest Leaves 'tis made up of, it will yield +such a number of them, as scarce any thing but Experience could have +perswaded me, and these Leaves will afford the most Transparent sort of +consistent Bodies, that, for ought I have observ'd, are yet known; and a +single Leaf or Plate will be so far from being Opacous, that 'twill scarce +be so much as Visible. And multitudes of Bodies there are, whose Fragments +seem Opacous to the naked Eye, which yet, when I have included them in good +_Microscopes_, appear'd Transparent; but, _Pyrophilus_, on the other side I +am not yet sure that there are no Bodies, whose Minute Particles even in +such a _Microscope_ as that of mine, which I was lately mentioning, will +not appear Diaphanous. For having consider'd _Mercury_ Precipitated _per +se_, the little Granules that made up the powder, look'd like little +fragments of Coral beheld by the naked Eye at a Distance (for very Near at +hand Coral will sometimes, especially if it be Good, shew some +Transparency.) Filings likewise of Steel and Copper, though in an excellent +_Microscope_, and a fair Day, they show'd like pretty Big Fragments of +those Metalls, and had considerable Brightness on some of their Surfaces, +yet I was not satisfi'd, that I perceiv'd any Reflection from the Inner +parts of any of the Filings. Nay, having look'd in my best _Microscope_ +upon the Red _Calx_ of Lead, (commonly call'd _Minium_) neither I, nor any +I shew'd it to, could discern it to be other than Opacous, though the Day +were Clear, and the Object strongly Enlightned. And the deeply Red Colour +of _Vitriol_ appear'd in the same _Microscope_ (notwithstanding the great +Comminution effected by the Fire) but like Grossy beaten Brick. So that, +_Pyrophilus_, I shall willingly resign you the care of making some further +Enquiries into the Subject we have now been considering; for I confess, as +I told you before, that I think that the Matter may need a further +Scrutiny, nor would I be forward to Determine how far or in what cases the +Transparency or Semi-diaphaniety of the Superficial Corpuscles of Bigger +Bodies, may have an Interest in the Production of their Colours, especially +because that even in divers White bodies, as Beaten Glass, Snow and Froth, +where it seems manifest that the Superficial parts are singly Diaphanous, +(being either Water, or Air, or Glass) we see not that such Variety of +Colours are produc'd as usually are by the Refraction of Light, even in +those Bodies, when by their Bigness, Shape, &c. they are conveniently +qualify'd to exhibit such Various and Lively Colours as those of the +Rain-bow, and of Prismatical Glasses. + +28. By what has been hitherto discours'd, _Pyrophilus_, we may be assisted +to judge of that famous Controversie which was of Old disputed betwixt the +_Epicureans_ and other _Atomists_ on the one side, and most other +_Philosophers_ on the other side. The former Denying Bodies to be Colour'd +in the Dark, and the Latter making Colour to be an Inherent quality, as +well as Figure, Hardness; Weight, or the like. For though this Controversie +be Reviv'd, and hotly Agitated among the _Moderns_, yet I doubt whether it +be not in great part a Nominal dispute, and therefore let us, according to +the Doctrine formerly deliver'd, Distinguish the Acceptions of the word +Colour, and say, that if it be taken in the Stricter Sense, the +_Epicureans_ seem to be in the Right, for if Colour be indeed, though not +according to them, but Light Modify'd, how can we conceive that it can +Subsist in the Dark, that is, where it must be suppos'd there is no Light; +but on the other side, if Colour be consider'd as a certain Constant +Disposition of the Superficial parts of the Object to Trouble the Light +they Reflect after such and such a Determinate manner, this Constant, and, +if I may so speak, Modifying disposition persevering in the Object, whether +it be Shin'd upon or no, there seems no just reason to deny, but that in +this Sense, Bodies retain their Colour as well in the Night as Day; or, to +Speak a little otherwise, it may be said, that Bodies are Potentially +Colour'd in the Dark, and Actually in the Light. But of this Matter +discoursing more fully elsewhere, as 'tis a difficulty that concerns +Qualities in general, I shall forbear to insist on it here. + + * * * * * + +CHAP. IV + +1. Of greater Moment in the Investigation of the Nature of Colours is the +Controversie, Whether those of the Rain-bow, and those that are often seen +in Clouds, before the Rising, or after the Setting of the Sun; and in a +word, Whether those other Colours, that are wont to be call'd Emphatical, +ought or ought not to be accounted True Colours. I need not tell you that +the Negative is the Common Opinion, especially in the Schools, as may +appear by that Vulgar distinction of Colours, whereby these under +Consideration are term'd Apparent, by way of Opposition to those that in +the other Member of the Distinction are call'd True or Genuine. This +question I say seems to me of Importance, upon this Account, that it being +commonly Granted, (or however, easie enough to be Prov'd) that Emphatical +Colours are Light it self Modify'd by Refractions chiefly, with a +concurrence sometimes of Reflections, and perhaps some other Accidents +depending on these two; if these Emphatical Colours be resolv'd to be +Genuine, it will seem consequent, that Colours, or at least divers of them, +are but Diversify'd Light, and not such Real and Inherent qualities as they +are commonly thought to be. + +2. Now since we are wont to esteem the Echoes and other Sounds of Bodies, +to be True Sounds, all their Odours to be True Odours, and (to be short) +since we judge other Sensible Qualities to be True ones, because they are +the proper Objects of some or other of our Senses, I see not why Emphatical +Colours, being the proper and peculiar Objects of the Organ of Sight, and +capable to Affect it as Truly and as Powerfully as other Colours, should be +reputed but Imaginary ones. + +And if we have (which perchance you'l allow) formerly evinc'd Colour, (when +the word is taken in its more Proper sense) to be but Modify'd Light, there +will be small Reason to deny these to be true Colours, which more +manifestly than others disclose themselves to be produc'd by +Diversifications of the Light. + +3. There is indeed taken notice of a Difference betwixt these Apparent +colours, and those that are wont to be esteem'd Genuine, as to the +Duration, which has induc'd some Learned Men to call the former rather +Evanid than Fantastical. But as the Ingenious _Gassendus_ does somewhere +Judiciously observe, if this way of Arguing were Good, the Greeness of a +Leaf ought to pass for Apparent, because, soon Fading into a Yellow, it +Scarce lasts at all, in comparison of the Greeness of an Emerauld. I shall +add, that if the Sun-beams be in a convenient manner trajected through a +Glass-prism, and thrown upon some well-shaded Object within a Room, the +Rain-bow thereby Painted on the Surface of the Body that Terminates the +Beams, may oftentimes last longer than Some Colours I have produc'd in +certain Bodies, which would justly, and without scruple be accounted +Genuine Colours, and yet suddenly Degenerate, and lose their Nature. + +4. A greater Disparity betwixt Emphatical Colours, and others, may perhaps +be taken from this, that Genuine Colours seem to be produc'd in Opacous +Bodies by Reflection, but Apparent ones in Diaphanous Bodies, and +principally by Refraction, I say Principally rather than Solely, because in +some cases Reflection also may concurr, but still this seems not to +conclude these Latter Colours not to be True ones. Nor must what has been +newly said of the Differences of True and Apparent Colours, be interpreted +in too Unlimited a Sense, and therefore it may perhaps somewhat Assist you, +both to Reflect upon the two fore-going Objections, and to judge of some +other Passages which you'l meet with in this Tract, if I take this Occasion +to observe to you, that if Water be Agitated into Froth, it exhibits you +know a White colour, which soon after it Loses upon the Resolution of the +Bubbles into Air and Water, now in this case either the Whiteness of the +Froth is a True Colour or not, if it be, then True Colours, supposing the +Water pure and free from Mixtures of any thing Tenacious, may be as +Short-liv'd as those of the Rain-bow; also the Matter, wherein the +Whiteness did Reside, may in a few moments perfectly Lose all foot-steps or +remains of it. And besides, even Diaphanous Bodies may be capable of +exhibiting True Colours by Reflection, for that Whiteness is so produc'd, +we shall anon make it probable. But if on the other side it be said, that +the Whiteness of Froth is an Emphatical Colour, then it must no longer be +said, that Fantastical Colours require a certain Position of the Luminary +and the Eye, and must be Vary'd or Destroy'd by the Change thereof, since +Froth appears White, whether the Sun be Rising or Setting, or in the +Meridian, or any where between it and the Horizon, and from what +(Neighbouring) place soever the Beholders Eye looks upon it. And since by +making a Liquor Tenacious enough, yet without Destroying its Transparency, +or Staining it with any Colour, you may give the Little Films, whereof the +Bubbles consist, such a Texture, as may make the Froth last very many +Hours, if not some Days, or even Weeks, it will render it somewhat Improper +to assign Duration for the Distinguishing Character to Discriminate Genuine +from Fantastical Colours. For such Froth may much outlast the Undoubtedly +true Colours of some of Nature's Productions, as in that Gaudy Plant not +undeservedly call'd the Mervail of _Peru_, the Flowers do often Fade, the +same Day they are Blown; And I have often seen a _Virginian_ Flower, which +usually Withers within the compass of a Day; and I am credibly Inform'd, +that not far from hence a curious Herborist has a Plant, whose Flowers +perish in about an Hour. But if the Whiteness of Water turn'd into Froth +must therefore be reputed Emphatical, because it appears not that the +Nature of the Body is Alter'd, but only that the Disposition of its Parts +in reference to the Incident Light is Chang'd, why may not the Whiteness be +accounted Emphatical too, which I shall shew anon to be Producible, barely +by such another change in Black Horn? and yet this so easily acquir'd +Whiteness seems to be as truly its Colour as the Blackness was before, and +at least is more Permanent than the Greenness of Leaves, the Redness of +Roses, and, in short, than the Genuine Colours of the most part of Nature's +Productions. It may indeed be further Objected, that according as the Sun +or other Luminous Body changes place, these Emphatical Colours alter or +vanish. But not to repeat what I have just now said, I shall add, that if a +piece of Cloath in a Drapers Shop (in such the Light being seldome Primary) +be variously Folded, it will appear of differing Colours, as the Parts +happen to be more Illuminated or more Shaded, and if you stretch it Flat, +it will commonly exhibit some one Uniform Colour, and yet these are not +wont to be reputed Emphatical, so that the Difference seems to be chiefly +this, that in the Case of the Rain-bow, and the like, the Position of the +Luminary Varies the Colour, and in the Cloath I have been mentioning, the +Position of the Object does it. Nor am I forward to allow that in all Cases +the Apparition of Emphatical Colours requires a Determinate position of the +Eye, for if Men will have the Whiteness of Froth Emphatical, you know what +we have already Inferr'd from thence. Besides, the Sun-beams trajected +through a Triangular Glass, after the manner lately mention'd, will, upon +the Body that Terminates them, Paint a Rain-bow, that may be seen whether +the Eye be plac'd on the Right Hand of it or the Left, or Above or Beneath +it, or Before or Behind it; and though there may appear some Little +Variation in the Colours of the Rain-bow, beheld from Differing parts of +the Room, yet such a Diversity may be also observ'd by an Attentive Eye in +Real Colours, look'd upon under the like Circumstances, Nor will it follow, +that because there remains no Footsteps of the Colour upon the Object, when +the Prism is Remov'd, that therefore the Colour was not Real, since the +Light was truly Modify'd by the Refraction and Reflection it Suffer'd in +its Trajection through the Prism; and the Object in our case serv'd for a +Specular Body, to Reflect that Colour to the Eye. And that you may not be +Startled, _Pyrophilus_, that I should Venture to say, that a Rough and +Coiour'd Object may serve for a _Speculum_ to Reflect the Artificial +Rain-bow I have been mentioning, consider what usually happens in Darkned +Rooms, where a Wall, or other Body conveniently Situated within, may so +Reflect the Colours of Bodies, without the Room, that they may very clearly +be Discern'd and Distinguish'd, and yet 'tis taken for granted, that the +Colours seen in a Darkned Room, though they leave no Traces of themselves +upon the Wall or Body that Receives them, are the True Colours of the +External Objects, together with which the Colours of the Images are Mov'd +or do Rest. And the Errour is not in the Eye, whose Office is only to +perceive the Appearances of things, and which does Truly so, but in the +Judging or Estimative faculty, which Mistakingly concludes that Colour to +belong to the Wall, which does indeed belong to the Object, because the +Wall is that from whence the Beams of Light that carry the Visible +_Species_, do come in Straight Lines directly to the Eye, as for the same +Reason we are wont at a certain Distance from Concave Sphærical Glasses, to +perswade our Selves that we see the Image come forth to Meet us, and Hang +in the Air betwixt the Glass and Us, because the Reflected Beams that +Compose the image cross in that place, where the Image seems to be, and +thence, and not from the Glass, do in Direct Lines take their Course to the +Eye, and upon the like Cause it is, that divers Deceptions in Sounds and +other Sensible Objects do depend, as we elsewhere declare. + +5. I know not, whether I need add, that I have purposely Try'd, (as you'l +find some Pages hence, and will perhaps think somewhat strange) that +Colours that are call'd Emphatical, because not Inherent in, the Bodies in +which they Appear, may be Compounded with one another, as those that are +confessedly Genuine may. But when all this is said, _Pyrophilus_, I must +Advertise you, that it is but Problematically Spoken, and that though I +think the Opinion I have endeavour'd to fortifie Probable, yet a great part +of our Discourse concerning Colours may be True, whether that Opinion be so +or not. + + * * * * * + +CHAP. V. + +1. There are you know, _Pyrophilus_, besides those Obsolete Opinions about +Colours which have been long since Rejected, very Various Theories that +have each of them, even at this day, Eminent Men for its Abetters; for the +Peripatetick Schools, though they dispute amongst themselves divers +particulars concerning Colours, yet in this they seem Unanimously enough to +Agree, that Colours are Inherent and Real Qualities, which the Light doth +but Disclose, and not concurr to Produce. Besides there are _Moderns_, who +with a slight Variation adopt the Opinion of _Plato_, and as he would have +Colour to be nothing but a Kind of Flame consisting of Minute Corpuscles as +it were Darted by the Object against the Eye, to whose Pores their +Littleness and Figure made them congruous, so these would have Colour to be +an Internal Light of the more Lucid parts of the Object, Darkned and +consequently Alter'd by the Various Mixtures of the less Luminous parts. +There are also others, who in imitation of some of the Ancient _Atomists_, +make Colour not to be Lucid steam, but yet a Corporeal _Effluvium_ issuing +out of the Colour'd Body, but the Knowingst of these have of late Reform'd +their Hypothesis, by acknowledging and adding that some External Light is +necessary to Excite, and as _they_ speak, Sollicit these Corpuscles of +Colour as _they_ call them, and Bring them to the Eye. Another and more +principal Opinion of the _Modern_ Philosophers, to which this last nam'd +may by a Favourable explication be reconcil'd, is that which derives +Colours from the Mixture of Light and Darkness, or rather Light and +Shadows. And as for the _Chymists_ 'tis known, that the generality of them +ascribes the Origine of Colours to the Sulphureous Principle in Bodies, +though I find, as I elsewhere largely shew, that some of the Chiefest of +them derive Colours rather from Salt than Sulphur, and others, from the +third Hypostatical Principle, _Mercury_. And as for the _Cartesians_ I need +not tell you, that they, supposing the Sensation of Light to bee produc'd +by the Impulse made upon the Organs of Sight, by certain extremely Minute +and Solid Globules, to which the Pores of the Air and other Diaphanous +bodies are pervious, endeavour to derive the Varieties of Colours from the +Various Proportion of the Direct Progress or Motion of these Globules to +their Circumvolution or Motion about their own Centre, by which Varying +Proportion they are by this Hypothesis suppos'd qualify'd to strike the +Optick Nerve after several Distinct manners, so to produce the perception +of Differing Colours. + +2. Besides these six principal Hypotheses, _Pyrophilus_, there may be some +others, which though Less known, may perhaps as well as thesc deserve to be +taken into consideration by you; but that I should copiously debate any of +them at present, I presume you will not expect, if you consider the Scope +of these Papers, and the Brevity I have design'd in them, and therefore I +shall at this time only take notice to you in the general of two or three +things that do more peculiarly concern the Treatise you have now in your +hands. + +3. And first, though the Embracers of the Several Hypotheses I have been +naming to you, by undertaking each Sect of them to explicate Colours +indefinitely, by the particular Hypotheses they maintain, seem to hold it +forth as the only Needful Theory about that Subject, yet for my part I +doubt whether any one of all these Hypotheses have a right to be admitted +Exclusively to all others, for I think it Probable, that Whiteness and +Blackness may be explicated by Reflection alone without Refraction, as +you'l find endeavour'd in the Discourse you'l meet with e're long Of the +Origine of Whiteness and Blackness, and on the other side, since I have not +found that by any Mixture of White and True Black, (for there is a Blewish +Black which many mistake for a Genuine) there can be a Blew, a Yellow, or a +Red, to name no other Colours, produced, and since we do find that these +Colours may be produc'd in the Glass-prism and other Transparent bodies, by +the help of Refractions, it seems that Refraction is to be taken in into +the Explication of some Colours, to whose Generation they seem to concurr, +either by making a further or other Commixture of Shades with the Refracted +Light, or by some other way not now to be discours'd. And as it seems not +improbable, that in case the Pores of the Air, and other Diaphanous bodies +be every where almost fill'd with such _Globuli_ as the _Cartesians_ +suppose, the Various kind of Motion of these _Globuli_, may in many cases +have no small stroak in Varying our Perception of Colour, so without the +Supposition of these _Globuli_, which 'tis not so easie to evince, I think +we may probably enough conceive in general, that the Eye may be Variously +affected, not only by the Entire Beams of Light that fall upon it as they +are such, but by the Order, and by the Degree of Swiftness, and in a word +by the Manner according to which the Particles that compose each Particular +Beam arrive at the Sensory, so that whatever be the Figure of the Little +Corpuscles, of which the Beams of Light consist, not only the Celerity or +Slowness of their Revolution or Rotation in reference to their Progressive +Motion, but their more Absolute Celerity, their Direct or Undulating +Motion, and other Accidents, which may attend their Appulse to the Eye, may +fit them to make Differing Impressions on it. + +4. Secondly, For these and the like Considerations, _Pyrophilus_, I must +desire that you would look upon this little Treatise, not as a Discourse +written Principally to maintain any of the fore-mention'd Theories, +Exclusively to all others, or substitute a New one of my Own, but as the +beginning of a History of Colours, upon which, when you and your Ingenious +friends shall have Enrich'd it, a Solid Theory may be safely built. But yet +because this History is not meant barely for a Register of the things +recorded in it, but for an _Apparatus_ to a sound and comprehensitive +Hypothesis, I thought fit, so to temper the whole Discourse, as to make it +as conducible, as conveniently I can to that End, and therefore I have not +scrupled to let you see that I was willing, as to save you the labour of +Cultivating some Theories that I thought would never enable you to reach +the Ends you aim at, so to contract your Enquiries into a Narrow compass, +for both which purposes I thought it requisite to do these two things, the +_One_, to set down some Experiments which by the help of the Reflections +and Insinuations that attend them, may assist you to discover the +Infirmness and Insufficiency both of the common Peripatetick Doctrine, and +of the now more applauded Theory of the _Chymists_ about Colour, because +those two Doctrines having Possess'd themselves, the one of the most part +of the Schools, and the other of the Esteem of the Generality ef Physicians +and other Learned Men, whose Professions and Ways of Study do not exact +that they should Scrupulously examine the very First and Simplest +Principles of Nature, I fear'd it would be to little purpose, without doing +something to discover the Insufficiency of these Hypotheses, that I should, +(which was the _Other_ thing I thought requisite for me to do) set down +among my other Experiments those in the greatest Number, that may let you +see, that, till I shall be Better Inform'd, I encline to take Colour to be +a Modification of Light, and would invite you chiefly to Cultivate that +Hypothesis, and Improve it to the making out of the Generation of +Particular Colours, as I have Endeavour'd to apply it to the Explication of +Whiteness and Blackness. + +5. Thirdly. But, _Pyrophilus_, though this be at present the Hypothesis I +preferr, yet I propose it but in a General Sense, teaching only that the +Beams of Light, Modify'd by the Bodies whence they are sent (Reflected or +Refracted) to the Eye, produce there that Kind of Sensation, Men commonly +call Colour; But whether I think this Modification of the Light to be +perform'd by Mixing it with Shades, or by Varying the Proportion of the +Progress and Rotation of the _Cartesian Globuli Cælestes_, or by some other +way which I am not now to mention, I pretend not here to Declare. Much less +do I pretend to Determine, or scarce so much as to Hope to know all that +were requisite to be Known, to give You, or even my Self, a perfect account +of the Theory of Vision and Colours, for in Order to such an undertaking I +would first Know what Light is, and if it be a Body (as a Body or the +Motion of a Body it seems to be) what Kind of Corpuscles for Size and Shape +it consists of, with what Swiftness they move Forwards, and Whirl about +their own Centres. Then I would Know the Nature of Refraction, which I take +to be one of the Abstrusest things (not to explicate Plausibly, but to +explicate Satisfactorily) that I have met with in Physicks; I would further +Know what Kind and what Degree of Commixture of Darkness or Shades is made +by Refractions or Reflections, or both, in the Superficial particles of +those Bodies, that being Shin'd upon, constantly exhibit the one, for +Instance, a Blew, the other a Yellow, the third a Red Colour; I would +further Know why this Contemperation of Light and Shade, that is made, for +Example, by the Skin of a Ripe Cherry, should exhibit a Red, and not a +Green, and the Leaf of the same Tree should exhibit a Green rather than a +Red; and indeed, Lastly, why since the Light that is Modify'd into these +Colours consists but of Corpuscles moved against the _Retina_ or Pith of +the Optick Nerve, it should there not barely give a Stroak, but produce a +Colour, whereas a Needle wounding likewise the Eye, would not produce +Colour but Pain. These, and perhaps other things I should think requisite +to be Known, before I should judge my Self to have fully Comprehended the +True and Whole Nature of Colours; and therefore, though by making the +Experiments and Reflections deliver'd in this Paper, I have endeavour'd +somewhat to Lessen my Ignorance in this Matter, and think it far more +Desireable to discover a Little, than to discover Nothing, yet I pretend +but to make it Probable by the Experiments I mention, that some Colours may +be Plausibly enough Explicated in the General by the Doctrine here +propos'd; For whensoever I would Descend to the Minute and Accurate +Explication of Particulars, I find my Self very Sensible of the great +Obscurity of things, without excepting those which we never see but when +they are Enlightned, and confess with _Scaliger_[5], _Latet natura hæc_, +(says he, Speaking of that of Colour) _& sicut aliarum rerum species in +profundissima caligine inscitiæ humanæ._ + + [5] Exercitat. 325 Parag. 4 + + * * * * * + + _THE_ + _EXPERIMENTAL HISTORY_ + _OF COLOURS._ + + * * * * * + + PART. II. + + _Of the Nature of Whiteness and_ + _Blackness._ + +CHAP. I. + +1. Though after what I have acknowledged, _Pyrophilus_, of the Abstruse +Nature of Colours in _particular_, you will easily believe, that I pretend +not to give you a Satisfactory account of Whiteness and Blackness; Yet not +wholly to frustrate your Expectation of my offering something by way of +Specimen towards the Explication of some Colours in particular, I shall +make choice of These as the most Simple Ones, (and by reason of their +mutual Opposition the Least hardly explicable) about which to present you +my Thoughts, upon condition you will take them at most to be my +Conjectures, not my Opinions. + +2. When I apply'd my Self to consider, how the cause of Whiteness might be +explan'd by Intelligible and Mechanical Principles, I remembred not to have +met with any thing among the Antient _Corpuscularian_ Philosophers, +touching the Quality we call Whiteness, save that _Democritus_ is by +_Aristotle_ said to have ascrib'd the Whiteness of Bodies to their +Smoothness, and on the contrary their Blackness to their Asperity.[6] But +though about the Latter of those Qualities his Opinion be allowable, as we +shall see anon, yet that he heeds a Favourable Interpretation in what is +Deliver'd concerning the First, (at least if his Doctrine be not +Mis-represented in this point, as it has been in many others) we shall +quickly have Occasion to manifest. But amongst the _Moderns_, the most +Learned _Gassendus_ in his Ingenious Epistle publish'd in the Year 1642. +_De apparente Magnitudine solis humilis & sublimis_, reviving the +_Atomical_ Philosophy, has, though but Incidentally, deliver'd something +towards the Explication of Whiteness upon Mechanical Principles: And +because no Man that I know of, has done so before him, I shall, to be sure +to do him Right, give you his Sense in his own Words:[7] _Cogites velim_ +(says he) _lucem quidem in Diaphano nullius coloris videri, sed in Opaco +tamen terminante Candicare, ac tantò magis, quantò densior seu collectior +fuerit. Deinde aquam non esse quidem coloris ex se candidi & radium tamen +ex eâ reflexum versus oculum candicare. Rursus cum plana aquæ Superficies +non nisi ex una parte eam reflexionem faciat: si contigerit tamen illam in +aliquot bullas intumescere, bullam unamquamque reflectionem facere, & +candoris speciem creare certa Superficiei parte. Ad hæc Spumam ex aqua pura +non alia ratione videri candescere & albescerere quam quod sit congeries +confertissima minutissimarum bullarum, quarum unaquæque suum radium +reflectit, unde continens candor alborve apparet. Denique Nivem nihil aliud +videri quam speciem purissimæ spumæ ex bullulis quam minutissimis & +confertissimis cohærentis. Sed ridiculam me exhibeam, si tales meas nugas +uberius proponem._ + + [6] _Album quippe & agrum, hoc quidem asperum esse dicit, hoc vero læve. + de Sensu & Sensib. 3. 3._ + + [7] Epist. 2. pag. 45. + +3. But though in this passage, that very Ingenous Person has Anticipated +part of what I should say; Yet I presume you will for all that expect, that +I should give you a fuller Account of that Notion of Whiteness, which I +have the least Exceptions to, and of the Particulars whence I deduce it, +which to do, I must mention to you the following Experiments and +Observations. + +Whiteness then consider'd as a Quality in the Object, seems chiefly to +depend upon this, That the Superficies of the Body that is call'd White, is +Asperated by almost innumerable Small Surfaces, which being of an almost +Specular Nature, are also so Plac'd, that some Looking this way, and some +that way, they yet Reflect the Rays of Light that fall on them, not towards +one another, but outwards towards the Spectators Eye. In this Rude and +General account of Whiteness, it seems that besides those Qualities, which +are common to Bodies of other Colours, as for instance the Minuteness and +Number of the Superficial parts, the two chief things attributed to Bodies +as White are made to be, First, that its Little Protuberances and +Superficial parts be of somewhat a Specular Nature, that they may as little +Looking-glasses each of them Reflect the Beams it receives, (or the little +Picture of the Sun made on it) without otherwise considerably Altering +them; whereas in most other Colours, they are wont to be much Chang'd, by +being also Refracted, or by being Return'd to the Eye, mixt with Shades or +otherwise. And next, that its Superficial parts be so Situated, that they +Retain not the Incident Rays of Light by Reflecting them Inwards, but Send +them almost all Back, so that the Outermost Corpuscles of a White Body, +having their Various Little Surfaces of a Specular Nature, a Man can from +no place Behold the Body, but that there will be among those Innumerable +_Superficieculæ_, that Look some one way, and some another, enough of them +Obverted to his Eye, to afford like a broken Looking-glass, a confused +Idæa, or Representation of Light, and make such an Impression on the Organ, +as that for which Men are wont to call a Body White. But this Notion will +perhaps be best Explan'd by the same Experiments and Observations, on which +it is Built, And therefore I shall now advance to _Them_. + +4. And in the first place I consider, that the Sun and other Powerfully +Lucid Bodies, are not only wont to Offend, which we call to Dazle our Eyes, +but that if any Colour be to be Ascrib'd to them as they are Lucid, it +seems it should be Whiteness: For the Sun at Noon-day, and in Clear +weather, and when his Face is less Troubled, and as it were Stained by the +Steams of Sublunary Bodies, and when his Beams have much less of the +Atmosphere to Traject in their Passage to our Eyes, appears of a Colour +more approaching to White, than when nearer the Horizon, the Interposition +of certain Sorts of Fumes and Vapours make him oftentimes appear either +Red, or at least more Yellow. And when the Sun Shines upon that Natural +Looking-glass, a Smooth water, that part of it, which appears to this or +that particular Beholder, the most Shin'd on, does to his Eye seem far +Whiter than the rest. And here I shall add, that I have sometimes had the +Opportunity to observe a thing, that may make to my present purpose, +namely, that when the Sun was Veil'd over as it were, with a Thin White +Cloud, and yet was too Bright to be Look'd upon Directly without Dazling, +by casting my Eyes upon a Smooth water, as we sometimes do to observe +Eclipses without prejudice to our Eyes, the Sun then not far from the +Meridian, appear'd to me not Red, but so White, that 'twas not without some +Wonder, that I made the Observation. Besides, though we in _English_ are +wont to say, a thing is Red hot, as an Expression of its being +Superlatively _Ignitum_, (if I may so Speak for want of a proper _English_ +word) yet in the Forges of Smiths, and the Furnaces of other Artificers, by +that which they call a White heat, they mean a further Degree of +_Ignition_, than by that which both they and we call a Red heat. + +5. Secondly, I consider, that common Experience informs us, that as much +Light Over-powers the Eye, so when the Ground is covered with Snow, (a Body +extremely White) those that have Weak Eyes are wont to complain of too much +Light: And even those that have not, are generally Sensible of an +Extraordinary measure of Light in the Air; and if they are fain to Look +very long upon the Snow, find their Sight Offended by it. On which occasion +we may call to mind what _Xenophon_ relates, that his _Cyrus_ marching his +Army for divers days through Mountains covered with Snow, the Dazling +splendor of its Whiteness prejudic'd the Sight of very many of his +Souldiers, and Blinded some of them; and other Stories of that Nature be +met with in Writers of good Note. And the like has been affirm'd to me by +credible Persons of my own Acquaintance, and especially by one who though +Skill'd in Physick and not Ancient confess'd to me when I purposely ask'd +him, that not only during his stay in _Muscovy_, he found his Eyes much +Impair'd, by being reduc'd frequently to Travel in the Snow, but that the +Weakness of his Eyes did not Leave him when he left that Country, but has +follow'd him into these Parts, and yet continues to Trouble him. And to +this doth agree what I as well as others have observ'd, namely, that when I +Travell'd by Night, when the Ground was all cover'd with Snow, though the +Night otherwise would not have been Lightsome, yet I could very well see to +Choose my way. But much more Remarkable to my present purpose is that, +which I have met with in _Olaus Magnus_,[8] concerning the way of +Travelling in Winter in the _Northern_ Regions, where the Days of that +Season are so very Short; for after other things not needfull to be here +Transcribed: _Iter_, says he, _Diurnum duo scilicet montana milliaria (quæ +12 Italica sunt) consiciunt. Nocte verò sub splendissima luna, duplatum +iter consumunt aut triplatum. Neque id incommodè fit, cum nivium +reverberatione lunaris splendoris sublimes & declives campos illustret, ac +etiam montium præcipitia ac noxias feras à lorgè prospiciant evitandas_. +Which Testimony I the less Scruple to allege, because that it agrees very +well with what has been Affirm'd to me by a Physician of _Mosco_, whom the +Notion I have been Treating of concerning Whiteness invited me to ask +whether he could not See much farther when he Travell'd by Night in +_Russia_ than he could do in _England_, or elsewhere, when there was no +Snow upon the Ground; For this Ingenious Person inform'd me, that he could +See Things at a farr greater Distance, and with more Clearness, when he +Travell'd by Night on the _Russian_ Snow, though without the Assistance of +Moon-shine, than we in these Parts would easily be perswaded. Though it +seems not unlikely to me, that the Intenseness of the Cold may contribute +something to the considerableness of the Effect, by much Clearing the Air +of Darkish Steams, which in these more Temperate Climates are wont to +Thicken it in Snowy weather: For having purposely inquir'd of this Doctor, +and consulted that Ingenious Navigator Captain _James_'s Voyage hereafter +to be further mention'd, I find both their Relations agree in this, that in +Dark Frosty Nights they could Discover more Stars, and See the rest Clearer +than we in _England_ are wont to do. + + [8] Gent. Septen. Histor. lib. 4 cap. 13. + +6. I know indeed that divers Learned Men think, that Snow so strongly +Affects our Eye, not by a Borrow'd, but a Native Light; But I venture to +give it as a Proof, that White Bodies reflect more Light than Others, +because having once purposely plac'd a parcel of Snow in a Room carefully +Darkned, that no Celestial Light might come to fall upon it; neither I, nor +an ingenous Person, (Skill'd in Opticks) whom I desir'd for a Witness, +could find, that it had any other Light than what it receiv'd. And however, +'tis usual among those that Travel in Dark Nights, that the Guides wear +something of White to be Discern'd by, there being scarce any Night so +Dark, but that in the Free Air there remains some Light, though Broken and +Debilitated perhaps by a thousand Reflections from the Opacous Corpuscles +that Swim in the Air, and lend it to one another before it comes to arrive +at the Eye. + +7. Thirdly, And the better to shew that White Bodies reflect store of +Light, in comparson of those that are otherwise Colour'd, I did in the +Darkn'd Room, formerly mention'd, hold not far from the Hole, at which the +Light was admitted, a Sheet only of White Paper, from whence casting the +Sun-beams upon a White Wall, whereunto it was Obverted, it manifestly +appear'd both to Me, and to the Person I took for a Witness of the +Experiment, that it Reflected a far greater Light, than any of the other +Colours formerly mention'd, the Light so thrown upon one Wall notably +Enlightning it, and by it a good part of the Room. And yet further to show +you, that White Bodies Reflect the Beams From them, and not Towards +themselves, Let me add, that Ordinary Burning-glasses, such as are wont to +be employ'd to light Tobacco, will not in a great while Burn, or so much as +Discolour a Sheet of White Paper. Insomuch that even when I was a Boy, and +Lov'd to make Tryals with Burning-glasses, I could not but wonder at this +Odd _Phænomenon_, which set me very Early upon Guessing at the Nature of +Whiteness, especially because I took notice, that the Image of the Sun upon +a White Paper was not so well Defin'd (the Light seeming too Diffus'd) as +upon Black, and because I try'd, that Blacking over the Paper with Ink, not +only the Ink would be quickly Dry'd up, but the Paper that I could not Burn +before, would be quickly set on Fire. I have also try'd, that by exposing +my Hand with a Thin Black Glove over it to the Warm Sun, it was thereby +very quickly and considerably more Heated, than if I took off the Glove, +and held my Hand Naked, or put on it another Glove of Thin but White +Leather. And having thus shewn you, _Pyrophilus_, that White Bodies reflect +the most Light of any, let us now proceed, to consider what is further to +be taken notice of in them, in order to our present Enquiry. + +8. And Fourthly, whereas among the Dispositions we attributed to White +Bodies, we also intimated this, That such Bodies are apt, like _Speculums_, +though but Imperfect ones, to Reflect the Light that falls on them +Untroubled or Unstain'd, we shall besides other particulars to be met with +in these Papers, offer you this in favour of the Conjecture; That in the +Darkned Room several times mention'd in this Treatse, we try'd that the +Sun-beams being cast from a Coloured Body upon a neighbouring White Wall, +the Determinate Colour of the Body was from the Wall reflected to the Eye; +whereas we could in divers cases manifestly Alter the Colour arriving at +the Eye, by Substituting at a convenient Distance, a (conveniently) +Colour'd (and Glossy) Body instead of the White Wall. As by throwing the +Beams from a Yellow Body upon a Blew, there would be Exhibited a kind of +Green, as in the Experiments about Colours is more fully Declar'd. + +9. I know not whether I should on this Occasion take notice, that when, as +when looking upon the Calm and Smooth Surface of a River betwixt my Eye and +the Sun, it appear'd to be a natural _Speculum_, wherein that Part which +Reflected to my Eye the Entire and defin'd Image of the Sun, and the Beams +less remote from those which exhibited That Image, appear'd indeed of a +great and Whitish Brightness, but the rest Comparatively Dark enough: if +afterwards the Superficies chanc'd to be a little, but not much troubled, +by a gentle Breath of Wind, and thereby reduc'd into a Multitude of Small +and Smooth _Speculums_, the Surface of the River would suitably to the +Doctrine lately deliver'd, at a Distance appear very much of Kin to White, +though it would lose that Brightness or Whiteness upon the Return of the +Surface to Calmness and an Uniform Level. And I have sometimes for Tryals +sake brought in by a Lenticular Glass, the Image of a River, Shin'd upon by +the Sun, into an Upper Room Darkn'd, and Distant about a Quarter of a Mile +from the River, by which means the Numerous Declining Surfaces of the Water +appear'd so Contracted, that upon the Body that receiv'd the Images, the +whole River appear'd a very White Object at two or three paces distance. +But if we drew Near it, this Whiteness appear'd to proceed from an +Innumerable company of Lucid Reflections, from the several Gently wav'd +Superficies of the Water, which look'd Near at hand like a Multitude of +very Little, but Shining Scales of Fish, of which many did every moment +Disappear, and as many were by the Sun, Wind and River generated anew. But +though this Observation seem'd Sufficiently to discover, how the Appearing +Whiteness in that case was Produc'd, yet in some other cases Water may have +the Same, though not so Vivid a Colour upon other Accounts; for oftentimes +it happens that the Smooth Surface of the Water does appear Bright or +Whitish, by reason of the Reflection not immediatly of the Images of the +Sun, but of the Brightness of the Sky; and in such cases a Convenient Wind +may where it passes along make the Surface look Black, by causing many such +Furrows and Cavities, as may make the Inflected Superficies of the Water +reflect the Brightness of the Sky rather Inward than Outward. And again if +the Wind increase into a Storm, the Water may appear White, especially near +the Shore and the Ship, namely because the Rude Agitation Breaks it into +Fome or Froth. So much do Whiteness and Blackness depend upon the +Disposition of the Superficial parts of a Body to Reflect the Beams of +Light Inward or Outward. But that as White Bodies reflect the most Light of +any, so there Superficial Particles are, in the Sense newly Deliver'd, of a +Specular Nature, I shall now further endeavour to shew both by the making +of Specular bodies White, and the making of a White body Specular. + +10. In the Fifth place then, I will inform You, that (not to repeat what +_Gassendus_ observes concerning Water) I have for Curiosity sake Distill'd +Quicksilver in a Cucurbit, fitted with a Capacious Glass-head, and observ'd +that when the Operation was perform'd by the Degrees of Fire requisite for +my purpose, there would stick to the Inside of the Alembick a multitude of +Little round drops of _Mercury_. And as you know that _Mercury_ is a +Specular Body, so each of these Little drops was a small round +Looking-glass, and a Multitude of them lying Thick and Near one another, +they did both in my Judgment, and that of those I Invited to see it, make +the Glass they were fastened to, appear manifestly a White Body. And yet as +I said, this Whiteness depended upon the Minuteness and Nearness of the +Little Mercurial _Globuli_, the Convexity of whose Surfaces fitted them to +represent in a Narrow compass a Multitude of Little Lucid Images to +differingly situated Beholders. And here let me observe a thing that seems +much to countenance the Notion I have been recommending: namely, that +whereas divers parts of the Sky, and especially the Milky-way, do to the +naked Eye appear White, (as the name it self imports) yet the Galaxie +look'd upon through the Telescope, does not shew White, but appears to be +made up of a Vast multitude of Little Starrs; so that a Multitude of Lucid +Bodies, if they be so Small that they cannot Singly or apart be discern'd +by the Eye, and if they be sufficiently Thick set by one another, may by +their confus'd beams appear to the Eye One White Body. And why it is not +possible, that the like may be done, when a Multitude of Bright and Little +Corpuscles being crowded together, are made to send together Vivid beams to +the Eye, though they Shine but as the Planets by a Borrow'd Light? + + +11. But to return to our Experiments. We may take notice, That the White of +an Egg, though in part Transparent, yet by its power of Reflecting some +Incident Rays of Light, is in some measure a Natural _Speculum_, being long +agitated with a Whisk or Spoon, loses its Transparency, and becomes very +White, by being turn'd into Froth, that is into an Aggregate of Numerous +small Bubbles, whose Convex Superficies fits them to Reflect the Light +every way Outwards. And 'tis worth Noting, that when Water, for instance, +is Agitated into Froth, if the Bubbles be Great and Few, the Whiteness will +be but Faint, because the number of _Specula_ within a Narrow compass is +but Small, and they are not Thick set enough to Reflect so Many Little +Images or Beams of the Lucid Body, as are requisite to produce a Vigorous +sensation of Whiteness: And partly least it should be said, that the +Whiteness of such Globulous Particles proceeds from the Air Included in the +Froth; (which to make good, it should be prov'd that the Air it self is +White) and partly to illustrate the better the Notion we have propos'd of +Whiteness, I shall add, that I purposely made this Experiment, I took a +quantity Fair water, & put to it in a clear Glass phial, a convenient +quantity of Oyl or Spirit of Turpentine, because that Liquor will not +incorporate with Water, and yet is almost as Clear and Colourless as it; +these being Gently Shaken together, the Agitation breaks the Oyl (which as +I said, is Indispos'd to Mix like Wine or Milk _per minima_ with the Water) +into a Multitude of Little Globes, which each of them Reflecting Outwards a +Lucid Image, make the Imperfect Mixture of the two Liquors appear Whitish; +but if by Vehemently Shaking the Glass for a competent time you make a +further Comminution of the Oyl into far more Numerous and Smaller +_Globuli_, and thereby confound it also better with the Water, the Mixture +will appear of a Much greater Whiteness, and almost like Milk; whereas if +the Glass be a while let alone, the Colour will by degrees Impair, as the +Oyly globes grow Fewer and Bigger, and at length will quite Vanish, leaving +both the Liquors Distinct and Diaphanous as before. And such a Tryal hath +not ill succeeded, when insteed of the Colourless Oyl of Turpentine I took +a Yellow Mixture made of a good Proportion of Crude Turpentine dissolv'd in +that Liquor; and (if I mis-remember not) it also Succeeded better than one +would expect, when I employ'd an Oyl brought by Filings of Copper infused +in it, to a deep Green. And this (by the way) may be the Reason, why often +times when the Oyls of some Spices and of Anniseeds &c. are Distilled in a +Limbec with Water, the Water (as I have several times observ'd) comes over +Whitish, and will perhaps continue so for a good while, because if the Fire +be made too Strong, the subtile Chymical Oyl is thereby much Agitated and +Broken, and Blended with the Water in such Numerous and Minute Globules, as +cannot easily in a short time Emerge to the Top of the Water, and whilst +they Remain in it, make it, for the Reason newly intimated, look Whitish; +and perhaps upon the same Ground a cause may be rendred, why Hot water is +observ'd to be usually more Opacous and Whitish, than the same Water Cold, +the Agitation turning the more Spirituous or otherwise Conveniently +Dispos'd Particles of the Water into Vapours, thereby Producing in the Body +of the Liquor a Multitude of Small Bubbles, which interrupt the Free +passage, that the Beams of Light would else have Every way, and from the +Innermost parts of the Water Reflect many of them Outwards. These and the +like Examples, _Pyrophilus_, have induc'd me to Suspect, that the +Superficial Particles of White bodies, may for the Most part be as well +Convex as Smooth; I content my self to say _Suspect_ and _for the most +part_, because it seems not Easie to prove, that when Diaphanous bodies, as +we shall see by and by, are reduc'd into White Powders, each Corpuscle must +needs be of a Convex Superficies, since perhaps it may Suffice that +Specular Surfaces look severally ways. For (as we have seen) when a +Diaphanous Body comes to be reduc'd to very Minute parts, it thereby +requires a Multitude of Little Surfaces within a Narrow compass. And though +each of these should not be of a Figure Convenient to Reflect a Round Image +of the Sun, yet even from such an Inconveniently Figur'd body, there may be +Reflected some (either Streight or Crooked) Physical Line of Light, which +Line I call Physical, because it has some Breadth in it, and in which Line +in many cases some Refraction of the Light falling upon the Body it depends +on, may contribute to the Brightness, as if a Slender Wire, or Solid +Cylinder of Glass be expos'd to the Light, you shall see in some part of it +a vivid Line of Light, and if we were able to draw out and lay together a +Multitude of these Little Wires or Thrids of Glass, so Slender, that the +Eye could not discern a Distance betwixt the Luminous Lines, there is +little doubt (as far as I can guess by a Tryal purposely made with very +Slender, but far less Slender Thrids of Glass, whose Aggregate was Look'd +upon one way White) but the whole Physical Superficies compos'd of them, +would to the Eye appear White, and if so, it will not be always necessary +that the Figure of those Corpuscles, that make a Body appear White, should +be _Globulous_. And as for Snow it self, though the Learned _Gassendus_ (as +we have seen above) makes it to seem nothing else but a pure Frozen Froth, +consisting of exceedingly Minute and Thickset Bubbles; yet I see no +necessity of Admitting that, since not only by the Variously and Curiously +Figur'd Snow, that I have divers times had the Opportunity with Pleasure to +observe, but also by the Common Snow, it rather doth appear both to the +Naked Eye, and in a _Microscope_, often, if not most commonly, to consist +principally of Little Slender Icicles of several Shapes, which afford such +Numerous Lines of Light, as we have been newly Speaking of. + +12. Sixthly, If you take a Diaphanous Body, as for instance a Piece of +Glass, and reduce it to Powder, the same Body, which when it was Entire, +freely Transmitted the Beams of Light, acquiring by Contusion a multitude +of Minute Surfaces, each of which is as it were a Little, but Imperfect +_Speculum_, is qualify'd to Reflect in a Confus'd manner, so many either +Beams, or Little and Singly Unobservable Images of the Lucid Body, that +from a Diaphanous it Degenerates into a White Body. And I remember, I have +for Trials sake taken Lumps of Rock Crystal, and Heating them Red hot in a +Crucible, I found according to my Expectation, that being Quench'd in Fair +water, even those that remain'd in seemingly entire Lumps exchang'd their +Translucency for Whiteness, the Ignition and Extinction having as it were +Crack'd each Lump into a multitude of Minute Bodies, and thereby given it a +great multitude of new Surfaces. And ev'n with Diaphanous Bodies, that are +Colour'd, there may be this way a Greater Degree of Whiteness produced, +than one would lightly think; as I remember, I have by Contusion obtain'd +Whitish Powders of _Granates_, Glass of _Antimony_, and _Emeralds_ finely +Beaten, and you may more easily make the Experiment, by taking Good +Venereal _Vitriol_ of a Deep Blew, and comparing with some of the Entire +Crystalls purposely reserv'd, some of the Subtile Powder of the same Salt, +which will Comparatively exhibit a very considerable degree of Whitishness. + +13. Seventhly, And as by a Change of Position in the Parts, a Body that is +not White, may be made White, so by a Slight change of the Texture of its +Surface, a White Body may be Depriv'd of its Whiteness. For if, (as I have +try'd in Gold-smiths Shops) you take a piece of Silver that has been +freshly Boyl'd, as the Artificers call it, (which is done by, first +Brushing, and then Decocting it with Salt and Tartar, and perhaps some +other Ingredients) you shall find it to be of a Lovely White. But if you +take a piece of Smooth Steel, and therewith Burnish a part of it, which may +be presently done, you shall find that Part will Lose its Whiteness, and +turn a _Speculum_, looking almost every where Dark, as other +Looking-glasses do, which may not a little confirm our Doctrine. For by +this we may guess, what it is chiefly that made the Body White before, by +considering that all that was done to deprive it of that Whiteness, was +only to Depress the Little Protuberances that were before on the Surface of +the Silver into one Continu'd Superficies, and thereby effect this, that +now the Image of the Lucid Body, and consequently a Kind of Whiteness shall +appear to your Eye, but in some place of the greater Silver Looking-glass +(whence the Beams reflected at an Angle Equal to that wherewith they fall +on it, may reach your Eye) whilst the Asperity remain'd Undestroy'd, the +Light falling on innumerable Little _Specula_ Obverted some one way, and +some another, did from all Sensibly Distinguishable parts of the +Superficies reflect confus'd Beams or Representations of Light to the +Beholders Eye, from whence soever he chance to Look upon it. And among the +Experiments annex'd to this Discourse, you will find One, wherein by the +Change of Texture in Bodies, Whiteness is in a Trice both Generated and +Destroy'd. + + * * * * * + +CHAP. II. + +1. What we have Discours'd of Whiteness, may somewhat Assist us to form a +Notion of Blackness, those two Qualities being Contrary enough to +Illustrate each other. Yet among the Antient _Philosophers_ I find less +Assistance to form a Notion of Blackness than of Whiteness, only +_Democritus_ in the passage above Recited out of _Aristotle_ has given a +General Hint of the Cause of this Colour, by referring the Blackness of +Bodies to their Asperity. But this I call but a General Hint, because those +Bodies that are Green, and Purple, and Blew, seem to be so as well as Black +ones, upon the Account of their Superficial Asperity. But among the +_Moderns_, the formerly mention'd _Gassendus_, perhaps invited by this Hint +of _Democritus_, has Incidentally in another Epistle given us, though a +very Short, yet a somewhat Clearer account of the Nature of Blackness in +these words: _Existimare par est corpora suâpte Naturâ nigra constare ex +particulis, quarum Superficieculæ scabræ sint, nec facilè lucem extrorsum +reflectant._ I wish this Ingenious Man had enlarg'd himself upon this +Subject; For indeed it seems, that as that which makes a Body White, is +chiefly such a Disposition of its Parts, that it Reflects (I mean without +much Interruption) more of the Light that falls on it, than Bodies of any +other Colour do, so that which makes a Body Black is principally a Peculiar +kind of Texture, chiefly of its Superficial Particle, whereby it does as it +were Dead the Light that falls on it, so that very little is Reflected +Outwards to the Eye. + +2. And this Texture may be Explicated two, and perhaps more than two +several ways, whereof the first is by Supposing in the Superficies of the +Black Body a Particular kind of Asperity, whereby the Superficial Particles +reflect but Few of the Incident Beams Outwards, and the rest Inwards +towards the Body it self. As if for Instance, we should conceive the +Surface of a Black Body to be Asperated by an almost Numberless throng of +Little Cylinders, Pyramids, Cones, and other such Corpuscles, which by +their being Thick Set and _Erected_, reflect the Beams of Light from one to +another Inwards, and send them too and fro so often, that at length they +are Lost before they can come to Rebound out again to the Eye. And this is +the first of the two mention'd ways of Explicating Blackness. The other way +is by Supposing the Texture of Black Bodies to be such, that either by +their Yielding to the Beams of Light, or upon some other Account, they do +as it were Dead the Beams of Light, and keep them from being Reflected in +any Plenty, or with any Considerable Vigour of Motion, Outwards. According +to this Notion it may be said, that the Corpuscles that make up the Beams +of Light, whether they be Solary _Effluviums_, or Minute Particles of some +Ætherial Substance, Thrusting on one another from the Lucid Body, do, +falling on Black Bodies, meet with such a Texture, that such Bodies receive +Into themselves, and Retain almost all the Motion communicated to them by +the Corpuscles that make up the Beams of Light, and consequently Reflect +but Few of them, or those but Languidly, towards the Eye, it happening here +almost in like manner as to a ball, which thrown against a Stone or Floor, +would Rebound a great way Upwards, but Rebounds very Little or not at all, +when it is thrown against Water, or Mud, or a Loose Net, because the Parts +yield, and receive into themselves the Motion, on whose Account the Ball +should be Reflected Outwards. But this Last way of Explicating Blackness, I +shall content my Self to have Propos'd, without either Adopting it, or +absolutely Rejecting it. For the Hardness of Touchstones, Black Marble and +other Bodies, that being Black are Solid, seem to make it somewhat +Improbable, that such Bodies should be of so Yielding a Texture, unless we +should say, that some Bodies may be more Dispos'd to Yield to the Impulses +of the Corpuscles of Light by reason of a Peculiar Texture, than other +Bodies, that in other Tryals appear to be Softer than they. But though the +Former of these two Explications of Blackness be that, by which we shall +Endeavour to give an Account of it, yet as we said, we shall not Absolutely +Reject this Latter, partly because they both Agree in this, that Black +Bodies Reflect but Little of the Light that falls on them, and partly +because it is not Impossible, that in some Cases both the Disposition of +the Superficial particles, as to Figure and Position, and the Yielding of +the Body, or some of its Parts, may joyntly, though not in an Equal measure +concurr to the rendring of a Body Black. The Considerations that induc'd me +to propose this Notion of Blackness, as I Explan'd it, are principally +these: + +3. First, That as I lately said, Whiteness and Blackness being generally +reputed to be Contrary Qualities, Whiteness depending as I said upon the +Disposition of the Parts of a Body to Reflect much Light, it seems likely, +that Blackness may depend upon a Contrary Disposition of the Black Bodies +Surface; But upon this I shall not Insist. + +4. Next then we see, that if a Body of One and the same Colour be plac'd, +part in the Sun-beams, and part in the Shade, that part which is not Shin'd +on will appear more of Kin to Blackness than the other, from which more +Light Rebounds to the Eye; And Dark Colours seem the Blacker, the less +Light they are Look'd upon in, and we think all Things Black in the Dark, +when they send no Beams to make Impressions on our Organs of Sight, so that +Shadows and Darkness are near of Kin, and Shaddow we know is but a +Privation of Light; and accordingly Blackness seems to proceed from the +Paucity of Beams Reflected from the Black Body to the Eye, I say the +Paucity of Beams, because those Bodies that we call Black, as Marble, Jeat, +&c. are Short of being perfectly so, else we should not See them at all. +But though the Beams that fall on the Sides of those Erected Particles that +we have been mentioning, do Few of them return Outwards, yet those that +fall upon the Points of those Cylinders, Cones, or Pyramids, may thence +Rebound to the Eye, though they make there but a Faint Impression, because +they Arrive not there, but Mingl'd with a great Proportion of Little +Shades. This may be Confirm'd by my having procur'd a Large piece of Black +Marble well Polish'd, and brought to the Form of a Large Sphærical and +Concave _Speculum_; For on the Inside this Marble being well Polish'd, was +a kind of Dark Looking-glass, wherein I could plainly see a Little Image of +the Sun, when that Shin'd upon it. But this Image was very far from +Offending and Dazling my Eyes, as it would have done from another +_Speculum_; Nor, though the _Speculum_ were Large, could I in a Long time, +or in a Hot Sun set a piece of Wood on Fire, though a far less _Speculum_ +of the same Form, and of a more Reflecting Matter, would have made it Flame +in a Trice. + +5. And on this Occasion we may as well in Reference to something formerly +deliver'd concerning Whiteness, as in Reference to what has been newly +said, Subjoyn what we further observ'd touching the Differing Reflections +of Light from White and Black Marble, namely, that having taking a pretty +Large Mortar of White Marble, New and Polish'd in the Inside, and Expos'd +it to the Sun, we found that it Reflected a great deal of Glaring Light, +but so Dispers'd, that we could not make the Reflected Beams concurr in any +such Conspicuous _Focus_, as that newly taken notice of in the Black +Marble, though perhaps there may enough of them be made to meet near the +Bottom, to make some Kind of _Focus_, especially since by holding in the +Night-time a Candle at a convenient Distance, we were able to procure a +Concourse of some, though not many of the Reflected Beams, at about two +Inches distant from the Bottom of the Mortar: But we found the Heat even of +the Sunbeams so Dispersedly Reflected to be very Languid, even in +Comparison of the Black Marbles _Focus_. And the Little Picture of the Sun, +that appear'd upon the White Marble as a _Speculum_, was but very Faint and +exceeding ill Defin'd. Secondly, That taking two pieces of Plain and +Polish'd Surfaces, and casting on them Successively the Beams of the Same +Candle, In such manner, as that the Neighbouring Superficies being Shaded +by an Opacous and Perforated Body, the Incident Beams were permitted to +pass but through a Round Hole of about Half an Inch Diameter, the Circle of +Light that appear'd on the White Marble was in Comparison very Bright, but +very ill Defin'd; whereas that on the Black Marble was far less Luminous, +but much more precisely Defin'd. + +6. Thirdly, When you Look upon a piece of Linnen that has Small Holes in +it, those Holes appear very Black, and Men are often deceiv'd in taking +Holes for Spots of Ink; And Painters to represent Holes, make use of Black, +the Reason of which seems to be, that the Beams that fall on those Holes, +fall into them So Deep, that none of them is Reflected back to the Eye. And +in narrow Wells part of the Mouth seems Black, because the Incident Beams +are Reflected Downwards from one side to another, till they can no more +Rebound to the Eye. + +We may consider too, that if Differing parts of the same piece of Black +Velvet be stroak'd Opposite ways, the piece of Velvet will appear of two +Distinct kinds of Blackness, the one far Darker than the other, of which +Disparity the Reason Seems to be, that in the Less obscure part of the +Velvet, the Little Silken Piles whereof 'tis made up, being Inclin'd, there +is a Greater part of each of them Obverted to the Eye, whereas in the other +part the Piles of Silk being more Erected, there are far Fewer Beams +Reflected Outwards from the Lateral parts of each Pile, So that most of +those that Rebound to the Eye, come from the Tops of the Piles, which make +but a small part of the whole Superficies, that may be cover'd by the piece +of Velvet. Which Explication I propose, not that I think the Blackness of +the Velvet proceeds from the Cause assign'd, since each Single Pile of Silk +is Black by reason of its Texture, in what Position soever you Look upon +it; But that the Greater Blackness of one of these Tuffts seems to proceed +from the Greater Paucity of Beams Reflected from it, and that from the +Fewness of those Parts of a Surface that Reflect Beams, and the Multitude +of those Shaded Parts that Reflect none. And I remember, that I have +oftentimes observ'd, that the Position of Particular Bodies far greater +than Piles of Silk in reference to the Eye, may notwithstanding their +having each of them a Colour of its own, make one part of their Aggregate +appear far Darker than the other; For I have near Great Towns often taken +notice, that a Cart-load of Carrots pack'd up, appear'd of a much Darker +Colour when Look'd upon, where the Points of the Carrots were Obverted to +the Eye, than where the Sides of them were so. + +7. Fourthly, In a Darkned Room, I purposely observ'd, that if the +Sun-beams, which came in at the Hole were receiv'd upon White or any other +Colour, and directed to a Convenient place of the Room, they would +Manifestly, though not all Equally, Encrease the Light of that Part; +whereas if we Substituted, either a piece of Black Cloth or Black Velvet, +it would so Dead the Incident Beams, that the place (newly mention'd) +whereto I Obverted the Black Body, would be Less Enlightned than it was +before, when it received its Light but from the Weak and Oblique +Reflections of the Floor and Walls of a pretty Large Room, through which +the Beams that came in at the Hole were Confusedly and Brokenly Dispers'd. + +8. Fifthly, And to shew that the Beams that fall on Black Bodies, as they +do not Rebound Outwards to the Eye, so they are Reflected towards the Body +it self, as the Nature of those Erected Particles to which we have imputed +Blackness, requires, we will add an Experiment that will also confirm our +Doctrine touching Whiteness; Namely, that we took a Broad and Large Tile, +and having Whitened over one half of the Superficies of it, and Black'd the +other, we expos'd it to the Summer Sun; And having let it lye there a +convenient time (for the Difference is more Apparent, if it have not lain +there too long) we found, as we expected, that whilst the Whited part of +the Tile remained Cool enough, the Black'd part of the same Tile was grown +not only Sensible, but very Hot, (sometimes to a strong Degree.) And to +satisfie some of our Friends the more, we have sometimes left upon the +Surface of the Tile, besides the White and Black parts thereof, a part that +Retain'd the native Red of the Tile it self, and Exposing them to the Sun, +we observ'd this Last mention'd to have Contracted a Heat in comparison of +the White, but a Heat Inferiour to that of the Black, of which the Reason +seems to be, that the Superficial Particles of Black Bodies, being, as we +said, more Erected, than those of White or Red ones, the Corpuscles of +Light falling on their sides, being for the most part Reflected Inwards +from one Particle to another, and thereby engag'd as it were and kept from +Rebounding Upwards, they communicate their brisk Motion, wherewith they +were impell'd against the Black Body, (upon whose account had they fallen +upon a White Body, they would have been Reflected Outwards) to the Small +parts of the Black Body, and thereby Produce in those Small parts such an +Agitation, as (when we feel it) we are wont to call Heat. I have been +lately inform'd, that an Observation near of Kin to Ours, has been made by +some Learned Men in _France_ and _Italy_, by long Exposing to a very Hot +Sun, two pieces of Marble, the one White, the other Black; But though the +Observation be worthy of them, and may confirm the same Truth with Our +Experiment, yet besides that our Tryal needs not the Summer, nor any Great +Heat to succeed, It seems to have this Advantage above the other, that +whereas Bodies more Solid, and of a Closer Texture, though they use to be +more Slowly Heated, are wont to receive a Greater Degree of Heat from the +Sun or Fire, than (_Cæteris paribus_) Bodies of a Slightest Texture; I have +found by the Information of Stone-cutters, and by other ways of Enquiry, +that Black Marble is much Solider and Harder than White, so that possibly +the Difference betwixt the Degrees of Heat they receive from the Sunbeams +will by many be ascrib'd to the Difference of their Texture, rather than to +that of their Colour, though I think our Experiment will make it Probable +enough that the greater part of that Difference may well be ascrib'd to +that Disposition of Parts, which makes the one Reflect the Sunbeams Inward; +and the other Outwards. And with this Doctrine accords very well, that +Rooms hung with Black, are not only Darker than else they would be, but are +wont to be Warmer too; Insomuch that I have known a great Lady, whose +Constitution was somewhat Tender, complain that she was wont to catch Cold, +when she went out into the Air, after having made any long Visits to +Persons, whose Rooms were hung with Black. And this is not the only Lady I +have heard complain of the Warmth of such Rooms, which though perhaps it +may be partly imputed to the _Effluvia_ of those Materials wherewith the +hangings were Dy'd, yet probably the Warmth of such Rooms depends chiefly +upon the same Cause that the Darkness does; As (not to repeat what I +formerly Noted touching my Gloves,) to satisfie some Curious Persons of +that Sex, I have convinc'd them, by Tryall, that of two Pieces of Silken +Stuff given me by themselves, and expos'd in their Presence, to the same +Window, Shin'd on by that Sun, the White was _considerably_ Heated, when +the Black was not so much as _Sensibly_ so. + +9. Sixthly, I remember, that Acquainting one Day a _Virtuoso_ of +Unsuspected Credit, that had Visited Hot Countries, with part of what I +have here Deliver'd concerning Blackness, he Related to me by way of +Confirmation of it, a very notable Experiment, which he had both others +make, and Made himself in a Warm Climate, namely, that having carefully +Black'd over Eggs, and Expos'd them to the Hot Sun, they were thereby in no +very Long time well Roasted, to which Effect I conceive the Heat of the +Climate must have Concurr'd with the Disposition of the Black Surface to +Reflect the Sunbeams Inward, for I remember, that having made that among +other Tryals in _England_, though in Summer-time, the Eggs I Expos'd, +acquir'd indeed a considerable Degree of Heat, but yet not so Intense a +One, as prov'd Sufficient to Roast them. + +10. Seventhly, and Lastly, Our Conjectures at the Nature of Blackness may +be somewhat Confirm'd by the (formerly mention'd) Observation of the Blind +_Dutch-man_, that Discerns Colours with his Fingers; for he Says, that he +Feels a greater Roughness upon the Surfaces of Black Bodies, than upon +those of Red, or Yellow, or Green. And I remember, that the Diligent +_Bartholinus_ says,[9] that a Blind Earl of _Mansfield_ could Distinguish +White from Black only by the Touch, which would Sufficiently Argue a great +Disparity in the Asperities, or other Superficial Textures of Bodies of +those two Colours, if the Learn'd Relator had Affirm'd the Matter upon his +own Knowledge. + + [9] Hist. Anatom. Cent. 3. Hist. 44. + +II. These, _Pyrophilus_, are the chief things that Occurr to me at present, +about the Nature of Whiteness and Blackness, which it they have Rendred it +so much as Probable, that in _Most_; or at least _Many_ Cases, the Causes +of these Qualities may be such as I have Adventur'd to Deliver, it is as +much as I Pretend to; for till I have Opportunity to Examine the Matter by +some further Tryals, I am not sure, but that in some White and Black +Bodies, there may Concurr to the Colour some peculiar Texture or +Disposition of the Body, whereby the Motion of the Small Corpuscles that +make up the Incident Beams of Light, may be Differingly Modify'd, before +they reach the Eye, especially in this, that White Bodies do not only +Copiously Reflect those Incident Corpuscles Outwards, but Reflect them +Briskly, and do not otherwise Alter them in the manner of their Motion. Nor +shall I now stay to Enquire, whether some of those other ways, (as a +Disposition to Alter the Velocity, the Rotation, or the Order and Manner of +Appulse so the Eye of the Reflected Corpuscles that Compos'd the Incident +Beams of Light) which we mention'd when we consider'd the Production of +Colours in General, may not in some Cases be Applicable to those of White +and Black Bodies: For I am yet so much a _Seeker_ in this Matter, and so +little Wedded to the Opinions I have propos'd, that what I am to add shall +be but the Beginning of a Collection of Experiments and Observation towards +the History of Whiteness and Blackness, without at present interposing my +Explications of them, that so, I may assist your Enquires without much +Fore-stalling or Biassing your Judgment. + + * * * * * + + EXPERIMENT + IN + CONSORT, + Touching + Whiteness & Blackness. + + * * * * * + +EXPERIMENT I. + +Having promis'd in the 114, and 115. Pages of the foregoing Discourse of +Whiteness and Blackness, to shew, that those two Colours may by a change of +Texture in bodies, each of them apart Diaphanous and Colourless, be at +pleasure and in a trice as well Generated as Destroy'd, We shall begin with +Experiments that may acquit us of that promise. + +Take then what Quantity you please of Fair Water, and having Heated it, put +into it as much good Common Sublimate, as it is able to Dissolve, and (to +be sure of having it well glutted:) continue putting in the Sublimate, till +some of it lye Untouch'd in the bottom of the Liquor, Filter this Solution +through Cap-paper, to have it cleer and limpid, and into a spoonfull or two +thereof, (put into a clean glass vessel,) shake about four or five drops +(according as you took more or less of this Solution) of good limpid +Spirits of Urine, and immediately the whole mixture will appear White like +Milk, to which mixture if you presently add a convenient proportion of +Rectifi'd _Aqua Fortis_ (for the number of drops is hard to determine, +because of the Differing Strength of the liquor, but easily found by tryal) +the Whiteness will presently disappear, and the whole mixture become +Transparent, which you may, if you please, again reduce to a good degree of +Whiteness (though inferiour to the first) onely by a more copious affusion +of fresh Spirit of Urine. _N_. First, That it is not so necessary to employ +either _Aqua Fortis_ or Spirit of Urine about this Experiment, but that we +have made it with other liquors instead of these, of which perhaps more +elsewhere. Secondly, That this Experiment, though not made with the same +_Menstruums_, nor producing the same Colour is yet much of Kin to that +other to be mentioned in this Tract among our other Experiments of Colours, +about turning a Solution of Præcipitate into an Orange-colour, and the +Chymical Reason being much alike in both, the annexing it to one of them +may suffice FOR both. + +_EXPERIMENT II._ + +Make a strong Infusion of broken Galls in Fair Water, and having Filtred it +into a clean Vial, add more of the same liquor to it, till you have made it +somewhat Transparent, and sufficiently diluted the Colour, for the credit +of the Experiment, lest otherwise the Darkness of the liquor might make it +be objected, that 'twas already almost Ink; Into this Infusion shake a +convenient quantity of a Cleer, but very strong Solution of Vitriol, and +you shall immediately see the mixture turn Black almost like Ink, and such +a way of producing Blackness is vulgar enough; but if presently after you +doe upon this mixture drop a small quantity of good oyl of Vitriol, and, by +shaking the Vial disperse it nimbly through the two other liquors, you +shall (if you perform your part well, and have employ'd oyl of Vitriol +Cleer and Strong enough) see the Darkness of the liquor presently begin to +be discuss'd, and grow pretty Cleer and Transparent, losing its Inky +Blackness, which you may again restore to it by the affusion of a small +quantity of a very strong Solution of Salt of Tartar. And though neither of +these Atramentous liquors will seem other than very Pale Ink, if you write +with a clean Pen dipt in them, yet that is common to them with some sorts +of Ink that prove very good when Dry, as I have also found, that when I +made these carefully, what I wrote with either of them, especially with the +Former, would when throughly Dry grow Black enough not to appear bad Ink. +This Experiment of taking away and restoring Blackness from and to the +liquors, we have likewise tryed in Common Ink; but there it succeeds not so +well, and but very slowly, by reason that the Gum wont to be employed in +the making it, does by its Tenacity oppose the operations of the above +mention'd Saline liquors. But to consider Gum no more, what some kind of +Præcipitation may have to do in the producing and destroying of Inks +without it, I have elsewhere given you some occasion and assistance to +enquire; But I must not now stay to do so my self, only I shall take notice +to you, that though it be taken for granted that bodies will not be +Præcipitated by Alcalizat Salts, that have not first been dissolved in some +Acid _Menstruums_, yet I have found upon tryals, which my conjectures lead +me to make on purpose, That divers Vegetables _barely infus'd_, or, _but +slightly decocted in common water_, would, upon the affusion of a Strong +and Cleer _Lixivium_ of Potashes, and much more of some other Præcipitating +liquors that I sometimes employ, afford good store of a Crudled matter, +such as I have had in the Præcipitations of Vegetable substances, by the +intervention of Acid things, and that this matter was easily separable from +the rest of the liquor, being left behind by it in the Filtre; and in +making the first Ink mention'd in this Experiment, I found that I could by +Filtration separate pretty store of a very Black pulverable substance, that +remain'd in the Filtre, and when the Ink was made Cleer again by the Oyl of +Vitriol, the affusion of dissolv'd _Sal Tartari_ seem'd but to Præcipitate, +and thereby to Unite and render Conspicuous the particles of the Black +mixture that had before been dispers'd into very Minute and singly +Invisible particles by the Incisive and resolving power of the highly +Corrosive Oyl of Vitriol. + +And to manifest, _Pyrophilus_, that Galls are not so requisite as many +suppose to the making Atramentous Liquors, we have sometimes made the +following Experiment, We took dryed Rose leaves and Decocted them for a +while in Fair Water, into two or three spoonfulls of this Decoction we +shook a few drops of a strong and well filtrated Solution of Vitriol (which +perhaps had it been Green would have done as well) and immediately the +mixture did turn Black, and when into this mixture presently after it was +made, we shook a just Proportion of _Aqua Fortis_, we turn'd it from a +Black Ink to a deep Red one, which by the affusion of a little Spirit of +Urine may be reduc'd immediately to an Opacous and Blackish Colour. And in +regard, _Pyrophilus_, that in the former Experiments, both the Infusion of +Galls, and the Decoction of Roses, and the Solution of Copperis employ'd +about them, are endow'd each of them with its own Colour, there may be a +more noble Experiment of the sudden production of Blackness made by the +way mention'd in the Second Section of the Second Part of our Essays, for +though upon the Confusion of the two Liquors there mention'd, there do +immediately emerge a very Black mixture, yet both the Infusion of +_Orpiment_ and the Solution of _Minium_ were before their being joyn'd +together, Limpid and Colourless. + +_EXPERIMENT III._ + +If pieces of White Harts-horn be with a competent degree of Fire distill'd +in a Glass-retort, they will, after the avolation of the Flegm, Spirit, +Volatile Salt, and the looser and lighter parts of the Oleagenous +substance, remain behind of a Cole-black colour. And even Ivory it self +being skilfully Burnt (how I am wont to do it, I have elsewhere set down) +affords Painters one of the best and deepest Blacks they have, and yet in +the Instance of distill'd Harts-horn, the operation being made in +Glass-vessels carefully clos'd, it appears there is no Extraneous Black +substance that Insinuates it self into White Harts-horn, and thereby makes +it turn Black; but that the Whiteness is destroy'd, and the Blackness +generated, only by a Change of Texture, made in the burnt Body, by the +Recess of some parts and the Transposition of others. And though I remember +not that in many Distillations of Harts-horn I ever sound the _Cap. Mort_. +to pass from Black to a true Whiteness, whilst it continu'd in Clos'd +vessels, yet having taken out the Cole-black fragments, and Calcin'd them +in Open vessels, I could in few hours quite destroy that Blackness, & +without sensibly changing their Bulk or Figure, reduce them to great +Whiteness. So much do these two Colours depend upon the Disposition of the +little parts, that the Bodies wherein they are to be met with do consist +of. And we find, that if Whitewine Tartar, or even the white Crystalls of +such Tartar be burnt without being truly Calcin'd, the _Cap. Mortuum_ (as +the Chymists call the more Fixt part) will be Black. But if you further +continue the Calcination till you have perfectly Incinerated the Tartar, & +kept it long enough in a Strong fire, the remaining _Calx_ will be White. +And so we see that not only other Vegetable substances, but even White +woods, as the Hazel, will yield a Black Charcoal, and afterwards Whitish +ashes; And so Animal substances naturally White, as Bones and Eggshels, +will grow Black upon the being Burnt, and White again when they are +perfectly Calcin'd. + +_EXPERIMENT IV._ + +But yet I much Question whether that Rule delivered by divers, as well +Philosophers as Chymists, _adusta nigra, sed perusta alba_, will hold as +Universally as is presum'd, since I have several Examples to allege against +it: For I have found that by burning Alablaster, so as both to make it +appear to boyl almost like Milk, and to reduce it to a very fine Powder, it +would not at all grow Black, but retain its Pure and Native Whiteness, and +though by keeping it longer than is usual in the fire, I produced but a +faint Yellow, even in that part of the Powder that lay nearest the top of +the Crucible, yet having purposely enquired of an Experienced Stone-cutter, +who is Curious enough in tryng Conclusions in his own Trade, he told me he +had found that if Alabaster or Plaster of Paris be very long kept in a +Strong fire, the whole heap of burnt Powder would exchange its Whiteness +for a much deeper Colour than the Yellow I observ'd. Lead being Calcin'd +with a Strong fire turns (after having purhaps run thorough divers other +Colour) into _Minium_, whose Colour we know is a deep red; and if you urge +this _Minium_, as I have purposely done with a Strong fire, you may much +easier find a Glassie and Brittle Body darker than _Minium_, than any white +_Calx_ or Glass. 'Tis known among Chymists, that the white _Calx_ of +Antimony, by the further and more vehement operation of the fire, may be +melted into Glass, which we have obtain'd of a Red Colour, which is far +deeper than that of the _Calx_ of Burnt Antimony, and though common Glafs +of Antimony being usually Adulterated with _Borax_, have its Colour thereby +diluted, oftentimes to a very pale Yellow; yet not onely ours made more +sincerily, was, as we said, of a Colour less remote from Black, than was +the _Calx_; but we observ'd, that by Melting it once or twice more, and so +exposing it to the further operation of the Fire, we had, as we expected, +the Colour heightned. To which we shall add but this one Instance, (which +is worth the taking notice of in Reference to Colours:) That, if you take +Blew, but Unsophisticated, Vitriol, and burn it very slowly, and with a +Gentle degree of Heat, you may observe, that when it has Burnt but a +Little, and yet so far as that you may rub it to Powder betwixt your +fingers, it will be of a White or Whitish Colour; But if you Prosecute the +Calcination, this Body which by a light Adustion was made White, will pass +through other Colours, as Gray, Yellowish, and Red; and if you further burn +it with a Long and Vehement fire, by that time it comes to be _Perustum_, +it will be of a dark purple, nearer to Black, not only than the first +_Calx_, but than the Vitriol before it at all felt the fire. I might add +that _Crocus_ _Martis_ (_per se_ as they call it) made by the Lasting +violence of the Reverberated flames is not so near a Kin to White, as the +Iron or Steel that afforded it was before its Calcinations; but that I +suppose, these Instances may Suffice to satisfie you, that Minerals are to +be excepted out of the forementioned Rule, which perhaps, though it seldome +fail in substances belonging to the Vegetable or Animal Kingdome, may yet +be Question'd even in some of these, if that be true, which the Judicious +Traveller _Bellonius_ affirms, that Charcoales made out of the Wood of +_Oxycæder_ are White; And I could not find that though in Retorts Hartshorn +and other White Bodies will be Denigrated by Heat, yet Camphire would not +at all lose its Whiteness, though I have purposely kept it in such a heat, +as made it melt and boyl. + +_EXPERIMENT V._ + +And now I speak of Camphire, it puts me in mind of adding this Experiment, +That, though as I said in Clos'd Glasses, I could not Denigrate it by Heat, +but it would Sublime to the sides and top of the Glass, as it was before, +yet not only it will, being set on fire in the Free Air, send forth a +Copious smoak, but having purposely upon some of it that was Flaming, clapt +a Large Glass, almost in the form of a Hive, (but more Slender only) with a +Hole at the top, (which I caus'd to be made to trye Experiments of Fire and +Flame in) it continued so long burning that it Lin'd all the Inside of the +Glass with a Soot as Black as Ink, and so Copious, that the Closeness of +the Vessel consider'd, almost all that part of the White Camphire that did +take Fire, seem'd to have been chang'd into that deep Black Substance. + +_EXPERIMENT VI_ + +And this also brings into my mind another Experiment that I made about the +production of Blackness, whereof, for Reasons too long to be here deduced, +I expected and found a good Success, an it was this: I took Rectifi'd Oyl +of Vitriol (that I might have the Liquor Clean as well as Strong) and by +degrees mixt with it a convenient proportion of the Essential Oyl, as +Chymists call it, of Wormwood, drawn over with store of Water in a Limbec, +and warily Distilling the mixture in a Retort, there remain'd a scarce +credible quantity of dry Matter, Black as a Coal. And because the Oyl of +Wormwood, though a Chymical Oyl drawn by a _Virtuoso_, seem'd to have +somewhat in it of the Colour of the Plant, I Substituted in its Room, the +Pure and Subtile Essential Oyl of Winter-Savory, and mixing little by +little this Liquor, with (if I mis-remember not) an Equal weight of the +formerly mention'd Rectifi'd Oyl of Vitriol, and Distilling them as before +in a Retort, besides what there pass'd over into the Receiver, even these +two clear Liquors left me a Considerable Proportion, (though not so great +as the two former) of a Substance Black as Pitch, which I yet Keep by me +as a Rarity. + +_EXPERIMENT VII._ + +A way of Whiting Wax Cheaply and in Great Quantity may be a thing of good +Oeconomical Use, and we have elsewhere set down the Practice of Trades-men +that Blanch it; But here Treating of Whiteness only in Order to the +Philosophy of Colours, I shall not Examine which of the Slow wayes may be +best Employ'd, to free Wax from the Yellow Melleous parts, but shall rather +set down a Quick way of making it White, though but in very Small +Quantities. Take then a little Yellow Wax, scraped or thinly sliced, and +putting it into a Bolts-head or some other Convenient Glass, pour to it a +pretty deal of Spirit of Wine, and placing the Vessel in Warm Sand, +Encrease the Heat by degrees, till the Spirit of Wine begin to Simper or to +Boyl a little; and continuing that degree of Fire, if you have put Liquor +enough, you will quickly have the Wax dissolv'd, then taking it off the +fire, you may either suffer it to Cool as hastily as with Safety to the +Glass you can, or Pour it whilst 'tis yet Hot into a Filtre of Paper, and +either in the Glass where it Cools, or in the Filtre, you will soon find +the Wax and _Menstruum_ together reduc'd into a White Substance, almost +like Butter, which by letting the Spirit Exhale will shrink into a much +Lesser Bulk, but still retaining its Whiteness. And that which is pretty in +the working of this Magistery of Wax, is, that the Yellowness vanishes, +neither appearing in the Spirit of Wine that passes Limpid through the +Filtre, nor in the Butter of Wax, if I may so call it, that, as I said, is +White. + + +_EXPERIMENT VIII._ + +There is an Experiment, _Pyrophilus_, which though I do not so exactly +remember, and though it be somewhat Nice to make, yet I am willing to +Acquaint You with, because the thing Produc'd, though it be but a +Curiosity, is wont not a little to please the Beholders, and it is a way of +turning by the help of a Dry Substance, an almost Golden-Colour'd Concrete, +into a White one, the Several Tryals are not at present so fresh in my +Memory to enable me to tell you Certainly, whether an Equal onely or a +Double weight of Common Sublimate must be taken in reference to the +Tinglass, but if I mistake not, there was in the Experiment that succeeded +best, Two parts of the Former taken to One of the Latter. These Ingredients +being finely Powdred and Exactly mix'd, we Sublim'd together by degrees of +fire (the due Gradation of which is in this Experiment a thing of main +Importance) there ascended a matter of a very peculiar Texture, for it was +for the most part made up of very Thin, Smooth, Soft and Slippery Plates, +almost like the finest sort of the Scales of Fishes, but of so Lovely a +White Inclining to Pearl-Colour, and of so Curious and Shining a Gloss, +that they appear'd in some respect little Inferiour to Orient Pearls, and +in other Regards, they seem'd to Surpass them, and were Applauded for a +sort of the Prettiest Trifles that we had ever prepar'd to Amuse the Eye. I +will not undertake that though you'l hardly miss changing the Colour of +your shining Tinglass, yet you will the first or perhaps the second time +hit Right upon the way of making the Glistring Sublimate I have been +mentioning. + +_EXPERIMENT IX._ + +When we Dissolve in _Aqua Fortis_ a mixture of Gold and Silver melted into +one Lump, it usually happens that the Powder of Gold that falls to the +bottom, as not being Dissoluble by that _Menstruum_, will not have its own +Yellow, but appear of a Black Colour, though neither the Gold, nor the +Silver, nor the _Aqua Fortis_ did before manifest any Blackness. And divers +Alchymists, when they make Solutions of Minerals they would Examine, are +very Glad, if they see a Black Powder Præcipitated to the Bottom, taking it +for a Hopefull Sign, that those Particles are of a Golden Nature, which +appear in a Colour so ordinary to Gold parted from other Metalls by _Aqua +Fortis_, that it is a trouble to the Refiner to Reduce the Præcipitated +_Calx_ to its Native Colour. For though, (as we have try'd,) that may be +Quickly enough done by Fire, which will make this Gold look very Gloriously +(as indeed 'tis at least one of the Best wayes that is Practis'd for the +Refining of Gold,) yet it requires both Watchfulness and Skill, to give it +such a Degree of Fire as will serve to Restore it to its Lustre, without +giving it such a One, as may bring it to Fusion, to which the Minuteness of +the _Corpuseles_ it consists of makes the Powder very apt. And this brings +into my Mind, that having taken a Flat and Bright piece of Gold, that was +Refin'd by a Curious and Skilfull Person on purpose to Trye to what height +of Purity Gold could be brought by Art, I found that this very piece, as +Glorious as it look'd, being rubb'd a little upon a piece of fine clean +Linnen, did sully it with a kind of Black; and the like I have observ'd in +Refin'd Silver, which I therefore mention, because I formerly suspected +that the Impurity of the Metall might have been the only Cause of what I +have divers times obferv'd in wearing Silver-hilted Swords, Namely, that +where they rubb'd upon my Clothes, if they were of a Light-Colour'd Cloath, +the Affriction would quickly Black them; and Congruously hereunto I have +found Pens Blackt almost all over, when I had a while carri'd them about me +in a Silver Ink-case. To which I shall only add, that whereas in these +several Instances of Denigration, the Metalls are worn off, or otherwise +Reduc'd into very Minute Parts, that Circumstance may prove not Unworthy +your Notice. + +_EXPERIMENT X._ + +That a Solution of Silver does Dye Hair of a Black Colour, is a Known +Experiment, which some persons more Curious than Dextrous, have so +Unluckily made upon themselves as to make their Friends very Merry. And I +remember that the other day, I made my self some Sport by an Improvement of +this Observation, for having dissolv'd some Pure Silver in _Aqua Fortis_, +and Evaporated the _Menstruum ad siccitatem_, as they speak, I caus'd a +Quantity of fair Water to be pour'd upon the _Calx_ two or three several +times, and to be at each Evaporated, till the _Calx_ was very Drye, and all +the Greenish Blewness that is wont to appear in Common Crystals of Silver, +was quite carry'd away. Then I made those I meant to Deceive, Moisten some +part of their Skin with their own Spittle, and slightly Rub the moistned +parts with a little of this Prepar'd Silver, Whereupon they Admir'd to see, +that a Snow-white Body laid upon the White Skin should presently produce a +deep Blackness, as if the stains had been made with Ink, especially +considering that this Blackness could not, like that produc'd by ordinary +Ink, be readily Wash'd off, but requir'd many Hours, and part of it some +dayes to its Obliteration. And with the same White _Calx_ and a little Fair +Water we likewise Stain'd the White Hafts of Knives, with a lasting Black +in those parts where the _Calx_ was Plentifully enough laid on, for where +it was laid on but very Thinly, the Stain was not quite of so Deep a +Colour. + +_EXPERIMENT XI_ + +The Cause of the Blackness of those many Nations, which by one common Name +we are wont to call _Negroes_, has been long since Disputed of by Learned +Men, who possibly had not done amiss, if they had also taken into +Consideration, why some whole races of other Animals besides Men, as Foxes +and Hares, are Distinguish'd by a Blackness not familiar to the Generality +of Animals of the same Species; The General Opinion (to be mention'd a +little lower) has been rejected even by some of the Antient Geographers, +and among our Moderns _Ortelius_ and divers other Learned Men have +Question'd it. But this is no place to mention what thoughts I have had to +and fro about these Matters: Only as I shall freely Acknowledge, that to me +the inquiry seems more Abstruse than it does to many others, and that +because consulting with Authors, and with Books of Voyages, and with +Travellers, to satisfie my self in matters of Fact, I have met with some +things among them, which seem not to agree very well with the Notions of +the most Classick Authors concerning these things; for it being my Present +Work to deliver rather matters Historical than Theorys, I shall Annex Some +few of my Collections, instead of a Solemn Disputation. It is commonly +presum'd that the Heat of the Climate wherein they live, is the reason, why +so many Inhabitants of the Scorching Regions of _Africa_ are Black; and +there is this familiar Observation to Countenance this Conjecture, That we +plainly see that Mowers, Reapers, and other Countrey-people, who spend the +most part of the Hot Summer dayes expos'd to the Sun, have the skin of +their Hands and Faces, which are the parts immediately Expos'd to the Sun +and Air, made of a Darker Colour than before, and consequently tending to +Blackness; And Contrarywise we observe that the _Danes_ and some other +people that Inhabit Cold Climates, and even the _English_ who feel not so +Rigorous a Cold, have usually Whiter faces than the _Spaniards_, +_Portugalls_ and other European Inhabitants of Hotter Climates. But this +Argument I take to be far more Specious than Convincing; for though the +Heat of the Sun may Darken the Colour of the Skin, by that Operation, which +we in _English_ call Sun-burning, yet Experience doth not Evince, that I +remember, That that Heat alone can produce a Discolouring that shall amount +to a true Blackness, like that of _Negroes_, and we shall see by and by +that even the Children of some _Negroes_ not yet 10. dayes Old (perhaps not +so much by three quarters of that time) will notwithstanding their Infancy +be of the same Hue with their Parents. Besides, there is this strong +Argument to be alleg'd against the Vulgar Opinion, that in divers places in +_Asia_ under the same Parallel, or even of the same Degree of Latitude with +the _African_ Regions Inhabited by Blacks, the People are at most but +Tawny;[10] And in _Africa_ it self divers Nations in the Empire of +_Ethiopia_ are not _Negroes_, though Situated in the Torrid Zone, and as +neer the Æquinoctial, as other Nations that are so (as the Black +Inhabitants of _Zeylan_ and _Malabar_ are not in our Globes plac'd so near +the Line as _Amara_ the Famousest place in _Ethiopia_.) Moreover, (that +which is of no small Moment in our present Disquisition) I find not by the +best Navigators and Travellers to the _West-Indies_, whose Books or +themselves I have consulted on this Subject, that excepting perhaps one +place or two of small extent, there are any Blacks Originally Natives of +any part of _America_ (for the Blacks now there have been by the +_Europeans_ long Transplanted thither) though the New World contain in it +so great a Variety of Climates, and particularly reach quite Cross the +Torri'd Zone from one Tropick to another. And enough it be true that the +_Danes_ be a Whiter People than the _Spaniards_, yet that may proceed +rather from other causes (not here to be enquired into) than from the +Coldness of the Climate, since not onely the _Swedes_ and other Inhabitants +of those Cold Countreys, are not usually so White as the _Danes_, nor +Whiter than other Nations in proportion to their Vicinity to the Pole. [And +since the Writing of the former part of this Essay, having an opportunity +on a Solemn occasion to take Notice of the Numerous Train of Some +Extraordinary Embassadours sent from the _Russian_ Emperour to a great +Monarch, observ'd, that (though it were then Winter) the Colour of their +Hair and Skin was far less Whitish than the _Danes_ who Inhabit a milder +Region is wont to be, but rather for the most part of a Darkish Brown; And +the Physician to the Embassadour with whom those _Russes_ came, being ask'd +by me whether in _Muscovy_ it self the Generality of the People were more +inclin'd to have Dark-colour'd Hair than Flaxen, he answer'd Affirmatively; +but seem'd to suspect that the True and Antient _Russians_, a Sept of whom +he told me he had met with in one of the Provinces of that vast Empire, +were rather White like the _Danes_, than any thing near so Brown as the +present _Muscovites_ whom he guesses to be descended of the _Tartars_, and +to have inherited their Colour from them.] But to Prosecute our former +Discourse, I shall add for further Proof of the Conjecture I was +countenancing that good Authors inform us that there are _Negroes_ in +_Africa_ not far from the _Cape of good Hope_, and consequently beyond the +Southern Tropick, and without the Torrid Zone, much about the same Northern +Latitude (or very little more) wherein there are divers _American_ Nations +that are not _Negroes_, and wherein the Inhabitants of _Candia_, some parts +of _Sicily_, and even of _Spain_ are not so much as Tawny-Mores. But (which +is a fresh and strong Argument against the common Opinion,) I find by our +recent Relations of _Greenland_ (our Accounts whereof we owe to the +Curiosity of that Royal _Virtuoso_ the present King of _Denmark_,) that the +Inhabitants are Olive-colour'd, or rather of a Darker Hiew. But if the Case +were the same with Men, and those other kinds of Animals I formerly nam'd, +I should offer something as a considerable proof, That, Cold may do much +towards the making Men White or Black, and however I shall let down the +Observation as I have met with it, as worthy to come into the History of +Whiteness and Blackness, and it is, that in some parts of _Russia_ and of +_Livonia_ it is affirm'd by _Olaus Magnus_ and others, that Hares and Foxes +(some add Partridges) which before were Black, or Red, or Gray, do in the +depth of Winter become White by reason of the great Cold; (for that it +should be, as some conceive, by Looking upon the Snow, seems improbable +upon divers accounts) And I remember that having purposely enquir'd of a +_Virtuoso_ who lately Travell'd through _Livonia_ to _Mosco_ concerning the +Truth of this Tradition, he both told me, he believ'd it, and added, that +he saw divers of those lately nam'd Animals either in _Russia_ or +_Livonia_, (for I do not very well remember whether of the two) which, +though White when he saw them in Winter, they assur'd him had been Black, +or of other Colours before the Winter began, and would be so again when it +was over. But for further satisfaction, I also consulted one that had for +some years been an Eminent Physician in _Russia_, who though he rejected +some other Traditions that are generally enough believ'd concerning that +Countrey, told me nevertheless, that he saw no cause to doubt of this +Tradition of _Olaus Magnus_ as to Foxes and Hares, not onely because 'tis +the common and uncontroul'd Assertion of the Natives, but also because he +himself in the Winter could never that he remember'd see Foxes and Hares of +any other Colour than White; And I my self having seen a small White Fox +brought out of _Russia_ into _England_ towards the latter end of Winter, +foretold those that shew'd him me, that he would change Colour in Summer, +and accordingly coming to look upon him again in _July_, I found that the +Back and Sides, together with the upper part of the Head and Tayl were +already grown of a Dark Colour, the lower part of the Head and Belly +containing as yet a Whiteness. Let me add, that were it not for some +scruple I have, I should think more than what _Olaus_ relates, confirm'd by +the judicious _Olearius_, who was twice employ'd into those parts as a +Publick Minister, who in his Account of _Moscovy_ has this Passage: _The +Hares there are Gray; but in some Provinces they grow white in the Winter_. +And within some few Lines after: _It is not very Difficult to find the +Cause of this Change, which certainly proceeds only from the Outward Cold, +since I know that even in Summer, Hares will change Colour, if they be kept +a competent time in a Cellar_; I say, were it not for Some Scruple, because +I take notice, that in the same Page the Author Affirms, that the like +change of Colour that happens to Hares in some Provinces of _Muscovy_, +happens to them also in _Livonia_, and yet immediately subjoyns, that in +_Curland_ the Hares vary not their Colour in Winter, though these two last +named Countries be contiguous, (that is) sever'd only by the River of +_Dugna_; For it is scarce conceivable how Cold alone should have, in +Countries so near, so strangely differing an operation, though no less +strange a thing is confess'd by many, that ascribe the Complexion of +_Negroes_ to the Heat of the Sun, when they would have the River of +_Cenega_ so to bound the _Moors_, that though on the North-side they are +but Tawny, on the other side they are Black. + + [10] Olearius Voyage de Mosco. et de Perse _liv_. 3. + +There is another Opinion concerning the Complexion of _Negroes_, that is +not only embrac'd by many of the more Vulgar Writers, but likewise by that +ingenious Traveller Mr. _Sandys_, and by a late most learned Critick, +besides other men of Note, and these would have the Blackness of _Negroes_ +an effect of _Noah's_ Curse ratify'd by God's, upon _Cham_; But though I +think that even a Naturalist may without disparagement believe all the +Miracles attested by the Holy Scriptures, yet in this case to flye to a +Supernatural Cause, will, I fear, look like Shifting off the Difficulty, +instead of Resolving it; for we enquire not the First and Universal, but +the Proper, Immediate, and Physical Cause of the Jetty Colour of _Negroes_; +And not only we do not find expressed in the Scripture, that the Curse +meant by _Noah_ to _Cham_, was the Blackness of his Posterity, but we do +find plainly enough there that the Curse was quite another thing, namely +that he should be a Servant of Servants, that is by an Ebraism, a very +Abject Servant to his Brethren, which accordingly did in part come to pass, +when the _Israelites_ of the posterity of _Sem_, subdued the _Canaanites_, +that descended from _Cham_, and kept them in great Subjection. Nor is it +evident that Blackness is a Curse, for Navigators tell us of Black Nations, +who think so much otherwise of their own condition, that they paint the +Devil White. Nor is Blackness inconsistent with Beauty, which even to our +European Eyes consists not so much in Colour, as an Advantageous Stature, a +Comely Symmetry of the parts of the Body, and Good Features in the Face. So +that I see not why Blackness should be thought such a Curse to the +_Negroes_, unless perhaps it be, that being wont to go Naked in those Hot +Climates, the Colour of their Skin does probably, according to the Doctrine +above deliver'd, make the Sun-beams more Scorching to them, than they would +prove to a people of a White Complexion. + +Greater probability there is, That the Principal Cause (for I would not +exclude all concurrent ones) of the Blackness of _Negroes_ is some Peculiar +and Seminal Impression, for not onely we see that _Blackmore_ boyes brought +over into these Colder Climates lose not their Colour; But good Authors +inform us, That the Off-spring of _Negroes_ Transplanted out of _Africa_, +above a hundred years ago, retain still the Complexion of their +Progenitors, though possibly in Tract of time it will decay; As on the +other side, the White people removing into very Hot Climates, have their +Skins by the Heat of the Sun scorch'd into Dark Colours; yet neither they, +nor their Children have been observ'd, even in the Countreys of _Negroes_, +to descend to a Colour amounting to that of the Natives; whereas I remember +I have Read in _Pisos_[11] excellent account of _Brasile_, that betwixt the +_Americans_ and _Negroes_ are generated a distinct sort of Men, which they +call _Cabocles_, and betwixt _Portugalls_ and _Æthiopian_ women, He tells +us, he has sometimes seen Twins, whereof one had a White skin, the other a +Black; not to mention here some other instances, he gives, that the +productions of the mixtures of differing people, that is (indeed,) the +effects of Seminal Impressions which they consequently argue to have been +their Causes; and we shall not much scruple at this, if we consider, that +even Organical parts may receive great Differences from such peculiar +Impressions, upon what account soever they came to be setled in the first +Individual persons, from whom they are Propogated to Posterity, as we see +in the Blobber-Lips and Flat-Noses of most Nations of _Negroes_. And if we +may Credit what Learned men deliver concerning the Little Feet of the +_Chinesses_, the _Macrocephali_ taken notice of by _Hippocrates_, will not +be the only Instance we might apply to our present purpose. And on this +occasion it will not perchance be Impertinent to add something of what I +have observ'd in other Animals, as that there is a sort of Hens that want +Rumps; And that (not to mention that in several places there is a sort of +Crows or Daws that are not Cole-black as ours, but partly of a Whitish +Colour) in spight of _Porphyries_ examples of Inseparable Accidents, I have +seen a perfectly White Raven, as to Bill as well as Feathers, which I +attentively considered, for fear of being impos'd upon. And this recalls +into my Memory, what a very Ingenious Physician has divers times related to +me of a young Lady, to whom being call'd, he found that though she much +complain'd of want of Health, yet there appear'd so little cause either in +her Body, or her Condition to Guess that She did any more than fancy her +self Sick, that scrupling to give her Physick, he perswaded her Friends +rather to divert her Mind by little Journeys of Pleasure, in one of which +going to Visit St. _Winifrids_ Well, this Lady, who was a _Catholick_, and +devout in her Religion, and a pretty while in the Water to perform some +Devotions, and had occasion to fix her Eyes very attentively upon the Red +pipple-stones, which in a scatter'd order made up a good part of those that +appear'd through the water, and a while after growing Bigg, she was +deliver'd of a Child, whose White Skin was Copiously speckl'd with spots of +the Colour and Bignesss of those Stones, and though now this Child have +already liv'd several years, yet she still retains them. I have but two +things to add concerning the Blackness of _Negroes_, the one is, that the +Seat of that Colour seems to be but the thin _Epidermes_, or outward Skin, +for I knew a young _Negroe_, who having been lightly Sick of the Small Pox +or Measles, (for it was doubted which of the two was his Disease) I found +by enquiry of a person that was concern'd for him, that in those places +where the little Tumors had broke their passage through the Skin, when they +were gone, they left Within specks behind them; And the lately commended +_Piso_ assures us, that having the opportunity in _Brasil_ to Dissect many +_Negroes_, he cleerly found that their Blackness went no deeper than the +very outward Skin, which _Cuticula_ or _Epidermis_ being remov'd, the +undermost Skin or _Cutis_ appear'd just as White as that of _Europæan_ +Bodyes. And the like has been affirmed to me by a Physician of our own, +whom, hearing he had Dissectcd a _Negroe_ here in _England_, I consulted +about this particular. The other thing to be here taken notice of +concerning _Negroes_ is, That having enquir'd of an Intelligent +acquaintance of mine (who keeps in the _Indies_ about 300. of them as well +Women as Men to work in his Plantations,) whether their Children come Black +into the world; he answer'd, That they did not, but were brought forth of +almost the like Reddish Colour with our _European_ Children; and having +further enquir'd, how long it was before these Infants appear'd Black, be +reply'd, that 'twas not wont to be many daies. And agreeable to this +account I find that, given us in a freshly publish'd French Book written by +a _Jesuit_, that had good opportunity of Knowing the Truth of what he +Delivers, for being one of the Missionaries of his Order into the Southern +_America_ upon the Laudable Design of Converting Infidels to Christianity, +he Baptiz'd several Infants, which when newly Born, were much of the same +Colour with _European_ Babes, but within about a Week began to appear of +the Hue of their Parents. But more Pregnant is the Testimony of our +Countrey-man _Andrew Battel_, who being sent Prisoner by the _Portugalls_ +to _Angola_, liv'd there, and in the adjoyning Regions, partly as a +Prisoner, partly as a Pilot, and partly as a Souldier, near 18. years, and +he mentioning the _African_ Kingdom of _Longo_, peopl'd with Blacks, has +this passage:[12] _The Children in this Countrey are Born White, and change +their Colour in two dayes to a Perfect Black_. As for Example, _The_ +Portugalls _which dwell in the Kingdome of_ Longo _have sometimes Children +by the_ Negroe_-women, and many times the Fathers are deceived, thinking, +when the Child is Born, that it is theirs, and within two dayes it proves +the Son or Daughter of a_ Negroe,_ which the_ Portugalls _greatly grieve +at_; And the same person has elsewhere a Relation, which, if he have made +no use at all of the liberty of a Traveller, is very well worth our Notice, +since this, together with that we have formerly mention'd of Seminal +Impressions, shews a possibility, that a Race of _Negroes_ might be begun, +though none of the Sons of _Adam_, for many Precedent Generations were of +that Complexion. For I see not why it should not be at least as possible, +that White Parents may sometimes have Black Children, as that _African +Negroes_ should sometimes have lastingly White ones, especially since +concurrent causes may easily more befriend the Productions of the Former +kind, than under the scorching Heat of _Africa_ those of the Latter. And I +remember on the occasion of what he delivers, that of the White Raven +formerly mention'd, the Possessor affirm'd to me, that in the Nest out of +which he was taken White, they found with him but one other Young one, and +that he was of as Jetty a Black as any common Raven. But let us hear our +Author himself[13]; _Here are_ (sayes he, speaking of the formerly +mention'd Regions) _Born in this Countrey White Children, which is very +rare among them, for their Parents are_ Negroes; _And when any of them are +Born, they are presented to the King, and are call'd_ Dondos; _these are as +White as any White Men. These are the Kings Witches, and are brought up in +Witchcraft, and alwayes wait on the King: There is no man that dare meddle +with these_ Dondos, _if they go to the Market they may take what they lift, +for all Men stand in awe of them. The King of_ Longo _hath four of them_. +And yet this Countrey in our Globes is plac'd almost in the midst of the +Torrid Zone (four or five Degrees Southward of the Line.) And our Author +elsewhere tells us of the Inhabitants, that they are so fond of their +Blackness, that they will not suffer any that is not of that Colour (as the +_Portugalls_ that come to Trade thither) to be so much as Buri'd in their +Land, of which he annexes a particular example,[14] that may be seen in his +Voyage preserv'd by our Industrious Countreyman Mr. _Purchas_. But it is +high time for me to dismiss Observations, and go on with Experiments. + + [11] _Piso_ Nat. & Med. Hist. _Brasil. lib_ 1. in fine. + + [12] _Purchas_ Pilgrim. Second part, Seventh Book 3. Chap. Sect 5. + + [13] _Purchas_. Ibid. + + [14] _Purchas_ Ibid. in fin + +_EXPERIMENT XII._ + +The way, _Pyrophilus,_ of producing Whiteness by Chymical Præcipitations is +very well worth our observing, for thereby Bodyes of very Differing Colours +as well as Natures, though dissolv'd in Several Liquors, are all brought +into _Calces_ or Powders that are White. Thus we find that not only +Crabs-eyes, that are of themselves White, and Pearls that are almost so, +but _Coral_ and _Minium_ that are Red, being dissolv'd in Spirit of +Vinegar, may be uniformly Præcipitated by Oyl of _Tartar_ into White +Powders. Thus Silver and Tin separately dissolv'd in _Aqua Fortis_, will +the one Præcipitate it self, and the other be Præcipitated by common +Salt-water into a White _Calx_, and so will Crude Lead and Quicksilver +first dissolv'd likewise in _Aqua Fortis_. The like _Calx_ will be afforded +as I have try'd by a Solution of that shining Mineral Tinglass dissolv'd in +_Aqua Fortis_, and Præcipitated out of it; and divers of these _Calces_ may +be made at least as Fair and White, if not better Colour'd, if instead of +Oyl of _Tartar_ they were Præcipitated with Oyl of _Vitriol_, or with +another Liquor I could Name. Nay, that Black Mineral _Antimony_ it self, +being reduc'd by and with the Salts that concurr to the Composition of +common Sublimate, into that Cleer though Unctuous Liquor that Chymists +commonly call Rectifi'd Butter of _Antimony_, will by the bare affusion of +store of Fair Water be struck down into that Snow-white Powder, which when +the adhering Saltness is well wash'd off, Chymists are pleas'd to call +_Mercurius Vitæ_, though the like Powder may be made of _Antimony_, without +the addition of any _Mercury_ at all. And this Lactescence if I may so call +it, does also commonly ensue when Spirit of Wine, being Impregnated with +those parts of Gums or other Vegetable Concretions, that are suppos'd to +abound with Sulphureous Corpuscles, fair Water is suddenly pour'd upon the +Tincture or Solution. And I remember that very lately I did, for Tryal +sake, on a Tincture of _Benjamin_ drawn with Spirit of Wine, and brought to +be as Red as Blood, pour some fair Water, which presently mingling with the +Liquor, immediately turn'd the whole Mixture White. But if such Seeming +Milks be suffer'd to stand unstirr'd for a convenient while, they are wont +to let fall to the bottome a Resinous Substance, which the Spirit of Wine +Diluted and Weakned by the Water pour'd into it was unable to support any +longer. And something of Kin to this change of Colour in Vegetables is +that, which Chymists are wont to observe upon the pouring of Acid Spirits +upon the Red Solution of _Sulphur_, dissolv'd in an Infusion of Pot-ashes, +or in some other sharp _Lixivium_, the Præcipitated _Sulphur_ before it +subsides, immediately turning the Red Liquor into a White one. And other +Examples might be added of this way of producing Whiteness in Bodyes by +Præcipitating them out of the Liquors wherein they have been Dissolv'd; but +I think it may be more usefull to admonish you, _Pyrophilus_, that this +observation admits of Restrictions, and is not so Universal, as by this +time perhaps you have begun to think it; For though most Præcipitated +Bodyes are White, yet I know some that are not; For Gold Dissolv'd in _Aqua +Regis_, whether you Præcipitate it with Oyl of _Tartar_, or with Spirit of +_Sal Armoniack_, will not afford a White but a Yellow _Calx_. _Mercury_ +also though reduc'd into Sublimate, and Præcipitated with Liquors abounding +with Volatile Salts, as the Spirits drawn from Urine, Harts-horn, and other +Animal substances, yet will afford, as we Noted in our first Experiment +about Whiteness and Blackness, a White Præcipitate, yet with some Solutions +hereafter to be mentioned, it will let fall an Orange-Tawny Powder. And so +will Crude _Antimony_, if, being dissolv'd in a strong Lye, you pour (as +farr as I remember) any Acid Liquor upon the Solution newly Filtrated, +whilst it is yet Warm. And if upon the Filtrated Solution of _Vitriol_, you +pour a Solution of one of these fix'd Salts, there will subside a Copious +substance, very farr from having any Whiteness, which the Chymists are +pleas'd to call, how properly I have elsewhere examin'd, the _Sulphur of +Vitriol_. So that most part of Dissolv'd Bodyes being by Præcipitation +brought to White Powders, and yet some affording Præcipitates of other +Colours, the reason of both the Phænomena may deserve to be enquir'd into. + + +_EXPERIMENT XIII._ + +Some Learned Modern Writers[15] are of Opinion, that the Account upon which +Whiteness and Blackness ought to be call'd, as they commonly are, the two +Extreme Colours, is, That Blackness (by which I presume is meant the Bodyes +endow'd with it) receives no other Colours; but Whiteness very easily +receives them all; whence some of them compare Whiteness to the +_Aristotelian Materia prima_, that being capable of any sort of Forms, as +they suppose White Bodyes to be of every kind of Colour. But not to Dispute +about Names or Expressions, the thing it self that is affirm'd as Matter of +Fact, seems to be True enough in most Cases, not in all, or so, as to hold +Universally. For though it be a common observation among Dyers, That +Clothes, which have once been throughly imbu'd with Black, cannot so well +afterwards be Dy'd into Lighter Colours, the præexistent Dark Colour +infecting the Ingredients, that carry the Lighter Colour to be introduc'd, +and making it degenerate into Some more Sad one; Yet the Experiments lately +mention'd may shew us, that where the change of Colour in Black Bodies is +attempted, not by mingling Bodyes of Lighter Colours with them, but by +Addition of such things as are proper to alter the Texture of those +Corpuscles that contain the Black Colour, 'tis no such difficult matter, as +the lately mention'd Learned Men imagine, to alter the Colour of Black +Bodyes. For we saw that Inks of several Kinds might in a trice be depriv'd +of all their Blackness; and those made with Logwood and Red-Roses might +also be chang'd, the one into a Red, the other into a Reddish Liquor; and +with Oyl of _Vitriol_ I have sometimes turn'd Black pieces of Silk into a +kind of Yellow, and though the Taffaty were thereby made Rotten, yet the +spoyling of that does no way prejudice the Experiment, the change of Black +Silk into Yellow, being never the less True, because the Yellow Silk is the +less good. And as for Whiteness, I think the general affirmation of its +being so easily Destroy'd or Transmuted by any other Colour, ought not to +be receiv'd without some Cautions and Restrictions. For whereas, according +to what I formerly Noted, Lead is by Calcination turned into that Red +Powder we call _Minium_; And Tin by Calcination reduc'd to a White _Calx_, +the common Putty that is sold and us'd so much in Shops, instead of being, +as it is pretended and ought to be, only the _Calx_ of Tin, is, by the +Artificers that make it, to save the charge of Tin, made, (as some, of +themselves have confess'd, and as I long suspected by the Cheap rate it may +be bought for) but of half Tin and half Lead, if not far more Lead than +Tin, and yet the Putty in spight of so much Lead is a very White Powder, +without disclosing any mixture of _Minium_. And so if you take two parts of +Copper, which is a High-colour'd Metall, to but one of Tin, you may by +Fusion bring them into one Mass, wherein the Whiteness of the Tin is much +more Conspicuous and Predominant than the Reddishness of the Copper. And on +this occasion it may not be Impertinent to mention an Experiment, which I +relate upon the Credit of a very Honest man, whom I purposely enquir'd of +about it, being my self not very fond of making Tryals with _Arsenick_, the +Experiment is this, That if you Colliquate _Arsenick_ and Copper in a due +proportion, the _Arsenick_ will Blanch the Copper both within and without, +which is an Experiment well enough Known; but when I enquir'd, whether or +no this White mixture being skilfully kept a while upon the Cupel would not +let go its _Arsenick_, which made Whiteness its prædominant Colour, and +return to the Reddishness of Copper, I was assur'd of the Affirmative; so +that among Mineral Bodyes, some of those that are White, may be far more +capable, than those I am reasoning with seem to have known, of Eclipsing +others, and of making their Colour Prædominant in Mixtures. In further +Confirmation of which may be added, that I remember that I also took a lump +of Silver and Gold melted together, wherein by the Æstimate of a very +Experienced Refiner, there might be about a fourth or third part of Gold, +and yet the Yellow Colour of the Gold was so hid by the White of the +Silver, that the whole Mass appear'd to be but Silver, and when it was +rubb'd upon the Touchstone, an ordinary beholder could scarce have +distinguish'd it from the Touch of common Silver; though if I put a little +_Aqua Fortis_ upon any part of the White Surface it had given the +Touchstone, the Silver in the moistned part being immediately taken up and +conceal'd by the Liquor, the Golden Particles would presently disclose that +native Yellow, and look rather as if Gold, than if the above mention'd +mixture, had been rubb'd upon the Stone. + + [15] See _Scaliger_ Exercit. 325. Sect. 9. + +_EXPERIMENT XIV._ + +I took a piece of Black-horn, (polish'd as being part of a Comb) this with +a piece of broken glass I scrap'd into many thin and curdled flakes, some +shorter and some longer, and having laid a pretty Quantity of these +scrapings together, I found, as I look'd for, that the heap they compos'd +was White, and though, if I laid it upon a clean piece of White Paper, its +Colour seem'd somewhat Eclips'd by the greater Whiteness of the Body it was +compar'd with, looking somewhat like Linnen that had been sulli'd by a +little wearing, yet if I laid it upon a very Black Body, as upon a Beaver +Hatt, it then appear'd to be of a good White, which Experiment, that you +may in a trice make when you please, seems very much to Disfavour both +their Doctrine that would have Colours to flow from the Substantial Forms +of Bodyes, and that of the Chymists also, who ascribe them to one or other +of their three Hypostatical Principles; for though in our Case there was so +great a Change made, that the same Body without being substantially either +Increas'd or Lessened, passes immediately from one extreme Colour to +another (and that too from Black to White) yet this so great and sudden +change is effected by a slight Mechanical Transposition of parts, there +being no Salt or _Sulphur_ or _Mercury_ that can be pretended to be Added +or Taken away, nor yet any substantial Form that can reasonably be suppos'd +to be Generated and Destroy'd, the Effect proceeding only from a Local +Motion of the parts which so vary'd their Position as to multiply their +distinct Surfaces, and to Qualifie them to Reflect far more Light to the +Eye, than they could before they were scrap'd off from the entire piece of +Black horn. + +_EXPERIMENT XV._ + +And now, _Pyrophilus_, it will not be improper for us to take some notice +of an Opinion touching the cause of Blackness, which I judged it not so +seasonable to Question, till I I had set down some of the Experiments, that +might justifie my dissent from it. You know that of late divers Learned +Men, having adopted the three Hypostatical Principles, besides other +Notions of the Chymists, are very inclinable to reduce all Qualities of +Bodies to one or other of those three Principles, and Particularly assign +for the cause of Blackness the Sootie steam of _adust_ or _torrifi'd +Sulphur_. But I hope that what we have deliver'd above to countenance the +Opinion we have propos'd about the Cause of Blackness, will so easily +supply you with several Particulars that may be made use of against this +Opinion, that I shall now represent to You but two things concerning it. + + +And First it seems that the favourers of the Chymicall Theories might have +pitcht upon some more proper term, to express the Efficient of Blackness +than _Sulphur adust_; for we know that _common Sulphur_, not only when +Melted, but even when Sublim'd, does not grow Black by suffering the Action +of the fire, but continues and ascends Yellow, and rather more than less +White, than it was before its being expos'd to the fire. And if it be set +on fire, as when we make that acid Liquor, that Chymists call _Oleum +Sulphuris per campanam_, it affords very little Soot, and indeed the flame +yeelds so little, that it will scarce in any degree Black a sheet of White +Paper, held a pretty while over the flame and smoak of it, which is +observed rather to Whiten than Infect linnen, and which does plainly make +Red Roses grow very Pale, but not at all Black, as far as the Smoak is +permitted to reach the leaves. And I can shew you of a sort of fixt Sulphur +made by an Industrious Laborant of your acquaintance, who assur'd me that +he was wont to keep it for divers weeks together night and day in a naked +and Violent fire, almost like that of the Glass-house, and when, to +satisfie my Curiosity, I made him take out a lump of it, though it were +glowing hot (and yet not melted,) it did not, when I had suffered it to +cool, appear Black, the true Colour of it being a true Red. I know it may +be said, that _Chymists_ in the Opinion above recited mean the _Principle +of Sulphur_, and not _common Sulphur_ which receives its name, not from its +being _all_ perfectly of a Sulphureous Nature, but for that _plenty_ and +_Predominancy_ of the Sulphureous Principle in it. But allowing this, 'tis +easie to reply, that still according to this very Reason, torrifi'd Sulphur +should afford more Blackness, than most other concretes, wherein that +Principle is confess'd to be far less copious. Also when I have expos'd +Camphire to the fire in Close Vessels, as Inflamable, and consequenly +(according to the Chymists) as Sulphureous a Body as it is, I could not by +such a degree of Heat, as brought it to Fusion, and made it Boyl in the +glass, impress any thing of Blackness, or of any other Colour, than its own +pure White, upon this Vegetable concrete. But what shall we say to Spirit +of Wine, which being made by a Chymical Analysis of the Liquor that affords +it, and being totally Inflamable, seems to have a full right to the title +they give it of _Sulphur Vegetabile_, & yet this fluid Sulphur not only +contracts not any degree of Blackness by being often so heated, as to be +made to Boyl, but when it burns away with an Actual flame, I have not found +that it would discolour a piece of White Paper held over it, with any +discernable soot. Tin also, that wants not, according to the Chymists, a +_Sulphur Joviale_, when throughly burned by the fire into a _Calx_, is not +Black, but eminently White. And I lately noted to you out of _Bellonius_, +that the Charcoals of Oxy-cedar are not of the former of these two Colours, +but of the latter. And the Smoak of our Tinby coals here in _England_, has +been usually observ'd, rather to Blanch linnen then to Black it. To all +which, other Particulars of the like nature might be added, but I rather +choose to put you in mind of the third Experiment, about making Black +Liquors, or Inks, of Bodies that were non of them Black before. For how can +it be said, that when those Liquors are put together actually Cold, and +continue so after their mixture, there intervenes any new _Adustion of +Sulphur_ to produce the emergent Blackness? (and the same question will be +appliable to the Blackness produc'd upon the blade of a Knife, that has cut +Lemmons and some kind of Sowr apples, if the juyce (though both Actually +and Potentially Cold) be not quickly wip'd of) And when by the instilling +either of a few drops of Oyl of Vitriol as in the second Experiment, or of +a little of the Liquor mention'd in the Passage pointed at in the fourth +Experiment, (where I teach at once to Destroy one black Ink, and make +another) the Blackness produc'd by those Experiments is presently +destroy'd; if the Colour proceeded only from the Plenty of Sulphurous +parts, torrify'd in the Black Bodies, I demand, what becomes of them, when +the Colour so suddenly dissappears? For it cannot Reasonably be said, that +all those that suffic'd to make so great a quantity of Black Matter, should +resort to so very small a proportion of the Clarifying Liquor, (if I may so +call it) as to be deluted by it, with out at all Denigrating it. And if it +be said that the Instill'd Liquor dispers'd those Black Corpuscles, I +demand, how that Dispersion comes to destroy their Blackness, but by making +such a Local Motion of their parts, as destroys their former Texture? which +may be a Matter of such moment in cases like ours, that I remember that I +have in few houres, without addition, from Soot it self, attain'd pretty +store of Crystalline Salt, and good store of Transparent Liquor, and (which +I have on another occasion noted as remarkable) this so Black Substance had +its Colour so alter'd, by the change of Texture it receiv'd from the fire, +wherewith it was distill'd, that it did for a great while afford such +plenty of very white Exhalations, that the Receiver, though large, seem'd +to be almost fill'd with Milk. + +Secondly, But were it granted, as it is in some cases not Improbable, that +divers Bodies may receive a Blackness from a Sootie Exhalation, occasion'd +by the Adustion of their Sulphur, which (for the Reasons lately mention'd I +should rather call their Oyly parts;) yet still this account is applicable +but to some Particular Bodies, and will afford us no General Theory of +Blackness. For if, for example, White Harts-horn, being, in Vessels well +luted to each other, expos'd to the fire, be said to turn Black by the +Infection of its own Smoak, I think I may justly demand, what it is that +makes the Smoak or Soot it self Black, since no Such Colour, but its +contrary, appear'd before in the Harts-horn? And with the same Reason, when +we are told, that torrify'd Sulphur makes bodies Black, I desire to be told +also, why Torrefaction makes Sulphur it self Black? nor will there be any +Satisfactory Reason assign'd of these Quæries, without taking in those +Fertile as well as intelligible Mechanical Principles of the Position and +Texture of the Minute parts of the body in reference to the Light and the +Eye; and these applicable Principles may Serve the turn in many cases, +where the Adustion of Sulphur cannot be pretended; as in the appearing +Blackness of an Open window, lookt upon at a somewhat remote distance from +the house, as also in the Blackness Men think they see in the Holes that +happen to be in White linnen, or Paper of the like Colour; and in the +Increasing Blackness immediatly Produc'd barely by so rubbing Velvet, whose +Piles were Inclin'd before, as to reduce them to a more Erected posture, in +which and in many other cases formerly alleg'd, there appears nothing +requisite to the Production of _the_ Blackness, but the hindering of the +incident Beams of Light from rebounding plentifully enough to the Eye. To +be short, those I reason with, do concerning Blackness, what the Chymists +are wont also to do concerning other Qualities, namely to content +themselves to tell us, in what Ingredient of a Mixt Body, the Quality +enquir'd after, does reside, instead of explicating the Nature of it, which +(to borrow a comparison from their own Laboratories) is much as if in an +enquiry after the cause of Salivation, they should think it enough to tell +us, that the several Kinds of Præcipitates of Gold and _Mercury_) as +likewise of Quick-silver and Silver (for I know that make and use of such +Precipitates also) do Salivate upon the account of the _Mercury_, which +though Disguis'd abounds in them, whereas the Difficulty is as much to know +upon what account _Mercury_ it self, rather than other Bodies, has that +power of working by Salivation. Which I say not, as though it were not +_something_ (and too often the most we can arrive at) to discover in which +of the Ingredients of a Compounded Body, the Quality, whose Nature is +sought, resides, but because, though this Discovery it self may pass for +_something_, and is oftentimes more than what is taught us about the same +subjects in the Schools, yet we ought not to think it _enough_, when more +Clear and Particular accounts are to be had. + + * * * * * + + THE + Experimental History + OF + COLOURS + Begun. + + * * * * * + + The Third PART. + + * * * * * + + Containing + Promiscuous Experiments + About + COLOURS. + + * * * * * + +EXPERIMENT I. + +Because that, according to the Conjectures I have above propos'd, one of +the most General Causes of the Diversity of Colours in Opacous Bodyes, is, +that some reflect the Light mingl'd with more, others with less of Shade +(either 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._ + +But on this Occasion (_Pyrophilus_) we must add once for all, that in many +of the above-recited Experiments, though the changes of Colour happen'd as +we have mention'd them: yet the emergent or produc'd Colour is oft times +very subject to Degenerate, both quickly and much. Notwithstanding which, +since the Changes, we have set down, do happen presently upon the Operation +of the Bodies upon each other, or at the times by us specify'd; _that_ is +sufficient both to justifie our Veracity, and to shew what we Intend; it +not being Essential to the Genuineness of a Colour to be Durable. For a +fading Leaf, that is ready to Rot, and moulder into Dust, may have as true +a Yellow, as a Wedge of Gold, which so obstinately resists both Time and +Fire. And the reason, why I take occasion from the former Experiment to +subjoyn this general Advertisement, is, that I have several times observ'd, +that the Mixture resulting from the Oyls of Vitriol, and of Anniseeds, +though it acquire a thicker consistence than either of the Ingredients had, +has quickly lost its Colour, turning in a very short time into a dirty +Gray, at least in the Superficial parts, where 'tis expos'd to the Air; +which last Circumstance I therefore mention, because that, though it seem +probable, that this Degeneration of Colours may oft times and in divers +cases proceed from the further Action of the Saline Corpuscles, and the +other Ingredients upon one another, yet in many cases much of the Quick +change of Colours seems ascribeable to the Air, as may be made probable by +several reasons: The first whereof may be fetcht from the newly recited +Example of the two Oyls; The next may be, that we have sometimes observ'd +long Window-Curtains of light Colours, to have that part of them, which was +expos'd to the Air, when the Window was open, of one Colour, and the lower +part, that was sheltred from the Air by the Wall, of another Colour: And +the third Argument may be fetch'd from divers Observations, both of others, +and our own; For of that Pigment so well known in Painters Shops, by the +name of _Turnsol_, our Industrious _Parkinson_, in the particular account +he gives of the Plant that bears it, tells us also, That _the Berries when +they are at their full Maturity, have within them between the outer Skin +and the inward Kirnel or Seed, a certain Juice or Moisture, which being +rubb'd upon Paper or Cloath, at the first appears of a fresh and lovely +Green Colour, but presently changeth into a kind of Blewish Purple, upon +the Cloath or Paper, and the same Cloath afterwards wet in Water, and wrung +forth, will Colour the Water into a Claret Wine Colour, and these_ +(concludes he) _are those Raggs of Cloath, which are usually call'd_ +Turnsol _in the Druggists or Grocers Shops_[21]. And to this Observation of +our _Botanist_ we will add an Experiment of our own, (made before we met +with That) which, though in many Circumstances, very differing, serves to +prove the same thing; for having taken of the deeply Red Juice of +_Buckthorn_ Berries, which I bought of the Man that uses to sell it to the +Apothecaries, to make their Syrrup _de Spina Cervina_, I let some of it +drop upon a piece of White Paper, and having left it there for many hours, +till the Paper was grown dry again, I found what I was inclin'd to suspect, +namely, That this Juice was degenerated from a deep Red to a dirty kind of +Greyish Colour, which, in a great part of the stain'd Paper seem'd not to +have so much as an Eye of Red: Though a little Spirit of Salt or dissolv'd +_Alcaly_ would turn this unpleasant Colour (as formerly I told you it would +change the not yet alter'd Juice) into a Red or Green. And to satisfie my +self, that this Degeneration of Colour did not proceed from the Paper, I +drop'd some of the deep Red or Crimson Juice upon a White glaz'd Tile, and +suffering it to dry on there, I found that ev'n in that Body, on which it +could not Soak, and by which it could not be Wrought, it nevertheless lost +its Colour. And these Instances (_Pyrophilus_) I am the more carefull to +mention to you, that you may not be much Surpris'd or Discourag'd, if you +should sometimes miss of performing punctually what I affirm my self to +have done in point of changing Colours; since in these Experiments the +over-sight or neglect of such little Circumstances, as in many others would +not be perhaps considerable, may occasion the mis-carrying of a Trial. And +I was willing also to take this occasion of Advertising you in the +repeating of the Experiments mention'd in this Treatise, to make use of the +Juices of Vegetables, and other things prepar'd for your Trials, as soon as +ever they are ready, lest one or other of them grow less fit, if not quite +unfit by delay; and to estimate the Event of the Trials by the Change, that +is produc'd presently upon the due and sufficient Application of Actives to +Passives, (as they speak) because in many cases the effects of such +Mixtures may not be lasting, and the newly produc'd Colour may in a little +time degenerate. But, (_Pyrophilus_) I forgot to add to the two former +Observations lately made about Vegetables, a third of the same Import, made +in Mineral substances, by telling you, That the better to satisfie a Friend +or two in this particular, I sometimes made, according to some Conjectures +of mine, this Experiment; That having dissolv'd good Silver in +_Aqua-fortis_, and Precipitated it with Spirit of Salt, upon the first +Decanting of the Liquor, the remaining Matter would be purely White; but +after it had lain a while uncover'd, that part of it, that was Contiguous +to the Air, would not only lose its Whiteness, but appear of a very Dark +and almost Blackish Colour, I say that part that was Contiguous to the Air, +because if that were gently taken off, the Subjacent part of the same Mass +would appear very White, till that also, having continu'd a while expos'd +to the Air, would likewise Degenerate. Now whether the Air perform these +things by the means of a Subtile Salt, which we elsewhere show it not to be +destitute of, or by a peircing Moisture, that is apt easily to insinuate it +self into the Pores of some Bodies, and thereby change their Texture, and +so their Colour; Or by solliciting the Avolation of certain parts of the +Bodies, to which 'tis Contiguous; or by some other way, (which possibly I +may elsewhere propose and consider) I have not now the leisure to +discourse. And for the same reason, though I could add many other +Instances, of what I formerly noted touching the emergency of Redness upon +the Digestion of many Bodies, insomuch that I have often seen upon the +Borders of _France_ (and probably we may have the like in _England_) a sort +of Pears, which digested for some time with a little Wine, in a Vessel +exactly clos'd, will in not many hours appear throughout of a deep Red +Colour, (as also that of the Juice, wherein they are Stew'd, becomes) but +ev'n on pure and white Salt of Tartar, pure Spirit of Wine, as clear as +Rock-water, will (as we elsewhere declare) by long Digestion acquire a +Redness; Though I say such Instances might be Multiply'd, and though there +be some other Obvious changes of Colours, which happen so frequently, that +they cannot but be as well Considerable as Notorious; such as is the +Blackness of almost all Bodies burn'd in the open Air: yet our haste +invites us to resign you the Exercise of enquiring into the Causes of these +Changes. And certainly, the reason both _why_ the Soots of such differing +Bodies are almost all of them all Black, _why_ so much the greater part of +Vegetables should be rather Green than of any other Colour, and +particularly (which more directly concerns this place) _why_ gentle Heats +do so frequently in Chymical Operations produce rather a Redness than +another Colour in digested _Menstruums_, not only Sulphureous, as Spirit of +Wine, but Saline, as Spirit of Vinegar, may be very well worth a serious +Inquiry; which I shall therefore recommend to _Pyrophilus_ and his +Ingenious Friends. + + [21] _Parkinson_, Thea. Bot. Trib. 4 cap. 12. + +_EXPERIMENT XXXVII._ + +It may seem somewhat strange, that if you take the Crimson Solution of +_Cochineel_, or the Juice of Black Cherries, and of some other Vegetables +that afford the like Colour, (which because many take but for a deep Red, +we do with them sometimes call it so) and let some of it fall upon a piece +of Paper, a drop or two of an Acid Spirit, such as Spirit of Salt, or +_Aqua-fortis_, will immediately turn it into a fair Red. Whereas if you +make an Infusion of Brazil in fair Water, and drop a little Spirit of Salt +or _Aqua-fortis_ into it, that will destroy its Redness, and leave the +Liquor of a Yellow, (sometimes Pale) I might perhaps plausibly enough say +on this occasion, that if we consider the case a little more attentively, +we may take notice, that the action of the Acid Spirit seems in both cases, +but to weaken the Colour of the Liquor on which it falls. And so though it +destroy Redness in the Tincture of Brazil, as well as produce Red in the +Tincture of _Chochineel_, its Operations may be Uniform enough, since as +Crimson seems to be little else than a very deep Red, with (perhaps) an Eye +of Blew, so some kinds of Red seem (as I have lately noted) to be little +else than heightned Yellow. And consequently in such Bodies, the Yellow +seems to be but a diluted Red. And accordingly Alcalizate Solutions and +Urinous Spirits, which seem dispos'd to Deepen the Colours of the Juices +and Liquors of most Vegetables, will not only restore the Solution of +_Cochineel_ and the Infusion of Brazil to the Crimson, whence the Spirit of +Salt had chang'd them into a truer Red; but will also (as I lately told +you) not only heighthen the Yellow Juice of Madder into Red, but advance +the Red Infusion of Brazil to a Crimson. But I know not whether it will not +be much safer to derive these Changes from vary'd Textures, than certain +kinds of Bodies; and you will perhaps think it worth while, that I should +add on this occasion, That it may deserve some Speculation, why, +notwithstanding what we have been observing, though Blew and Purple seem to +be deeper Colours than Red, and therefore the Juices of Plants of either of +the two former Colours may (congruously enough to what has been just now +noted) be turn'd Red by Spirit of Salt or _Aqua-fortis_, yet Blew Syrrup of +Violets and some Purples should both by Oyl of Tartar and Spirit of Urine +be chang'd into Green, which seems to be not a deeper but a more diluted +Colour than Blew, if not also than Purple. + +_EXPERIMENT XXXVIII._ + +It would much contribute to the History of Colours, if _Chymists_ would in +their Laboratories take a heedfull notice, and give us a faithfull account +of the Colours observ'd in the Steams of Bodies either Sublim'd or +Distill'd, and of the Colours of those Productions of the Fire, that are +made up by the Coalition of those Steams. As (for Instance) we observe in +the Distilling of pure Salt peter, that at a certain season of the +Operation, the Body, though it seem either Crystalline, or White, affords +very Red Fumes: whereas though Vitriol be Green or Blew, the Spirit of it +is observ'd to come over in Whitish Fumes. The like Colour I have taken +notice of in the Fumes of several other Concretes of differing Colours, and +Natures, especially when Distill'd with strong Fires. And we elsewhere +note, that ev'n Soot, as Black as it is, has fill'd our Receivers with such +copious White Fumes, that they seem'd to have had their In-sides wash'd +with Milk. And no less observable may be, the Distill'd Liqours, into which +such Fumes convene, (for though we will not deny, that by skill and care a +Reddish Liqour may be obtain'd from Nitre) yet the common Spirit of it, in +the making ev'n of which store of these Red Fumes are wont to pass over +into the Receiver, appears not to be at all Red. And besides, that neither +the Spirit of Vitriol, nor that of Soot is any thing White; And, besides +also, that as far as I have observ'd, most (for I say not all) of the +Empyreumatical Oyls of Woods, and other Concretes, are either of a deep +Red, or of a Colour between Red and Black; besides this, I say, 'tis very +remarkable that notwithstanding that great Variety of Colours to be met +with in the Herbs, Flowers, and other Bodies wont to be Distill'd in +_Balneo_: yet (as far at least as our common Distillers Experience +reacheth) all the Waters and Spirits that first come over by that way of +Distillation, leave the Colours of their Concretes behind them, though +indeed there be one or two Vegetables not commonly taken notice of, whose +Distill'd Liqours I elsewhere observe to carry over the Tincture of the +Concrete with them. And as in Distillations, so in Sublimations, it were +worth while to take notice of what comes up, in reference to our present +scope, by purposely performing them (as I have in some cafes done) in +conveniently shap'd Glasses, that the Colour of the ascending Fumes may be +discern'd; For it may afford a Naturalist good Information to observe the +Congruities or the Differences betwixt the Colours of the ascending Fumes, +and those of the _Flowers_, they compose by their Convention. For it is +evident, that these _Flowers_, do many of them in point of Colour, much +differ, not only from one another, but oft times from the Concretes that +afforded them. Thus, (not here to repeat what I formerly noted of the Black +Soots of very differingly Colour'd Bodies) though Camphire and Brimstone +afford _Flowers_ much of their own Colour, save that those of Brimstone are +wont to be a little Paler, than the Lumps that yielded them; yet ev'n of +Red _Benzoin_, that sublim'd Substance, which _Chymists_ call its +_Flowers_, is wont to be White or Whitish. And to omit other Instances, +ev'n one and the same Black Mineral, Antimony, may be made to afford +_Flowers_, some of them Red, and some Grey, and, which is more strange, +some of them purely White. And 'tis the Prescription of some Glass-men by +exquisitely mingling a convenient proportion of Brimstone, Sal-Armoniack, +and Quicksilver, and Subliming them, together, to make a Sublimate of an +excellent Blew; and though having caus'd the Experiment to be made, we +found the produc'd Sublimate to be far from being of a lovely Colour, (as +was promis'd) that there and there, it seem'd Blewish, and at least was of +a Colour differing enough from either of the Ingredients, which is +sufficient for our present purpose. But a much finer Colour is promis'd by +some of the Empiricks, that pretend to Secrets, who tell us, that Orpiment, +being Sublim'd, will afford among the Parts of it that fly Upward, some +little Masses, which, though the Mineral it self be of a good Yellow, will +be Red enough to emulate Rubies, both in Colour and Translucency. And this +Experiment may, for ought I know, sometimes succeed; for I remember, that +having in a small Bolt-head purposely sublim'd some powder'd Orpiment, we +could in the Lower part of the Sublimate discern here and there some +Reddish Lines, though much of the Upper part of the Sublimate consisted of +a matter, which was not alone purely Yellow, but transparent almost like a +Powder. And we have also this way obtain'd a Sublimate, the Lower part +whereof though it consisted not of Rubies, yet the small pieces of it, +which were Numerous enough, were of a pleasant Reddish Colour, and +Glitter'd very prettily. But to insist on such kind of Trials and +Observations (where the ascending Fumes of Bodies differ in Colour from the +Bodies themselves) though it might indeed Inrich the History of Colours, +would Robb me of too much of the little time I have to dispatch what I have +further to tell you concerning them. + +_EXPERIMENT XXXIX_ + +Take the dry'd Buds (or Blossoms) of the Pomegranate Tree, (which are +commonly call'd in the Shops _Balaustiums_) pull off the Reddish Leaves, +and by a gentle Ebullition of them in fair Water, or by a competent +Infusion of them in like Water well heated, extract a faint Reddish +Tincture, which if the Liquor be turbid, you may Clarifie it by Filtrating +it Into this, if you pour a little good Spirit of Urine, or some other +Spirit abounding in the like sort of Volatile Salts, the Mixture will +presently turn of a dark Greenish Colour, but if instead of the +fore-mention'd Liquor, you drop into the simple Infusion a little rectify'd +Spirit of Sea-Salt, the Pale and almost Colourless Liquor will immediately +not only grow more Transparent, but acquire a high Redness, like that of +Rich Claret Wine, which so suddenly acquir'd Colour, may as quickly be +Destroy'd and turn'd into a dirty Blewish Green, by the affusion of a +competent quantity of the above-mention'd Spirit of Urine. + +_Annotation._ + +This Experiment may bring some Light to, and receive some from a couple of +other Experiments, that I remember I have met with in the ingenious +_Gassendus_'s Animadversions upon _Epicurus_'s Philosophy, whilst I was +turning over the Leaves of those Learned Commentaries; (my Eyes being too +weak to let me read such Voluminous Books quite thorough) And I the less +scruple (notwithstanding my contrary Custom in this Treatise) to set down +these Experiments of another, because I shall a little improve the latter +of them, and because by comparing there with that which I have last +recited, we may be assisted to Conjecture upon what account it is, that Oyl +of Vitriol heightens the Tincture of Red-rose Leaves, since Spirit of Salt, +which is a highly Acid _Menstruum_, but otherwise differing enough from Oyl +of Vitriol, does the same thing. Our Authors Experiments then, as we made +them, are these; We took about a Glass-full of luke-warm Water, and in it +immerg'd a quantity of the Leaves of _Senna_, and presently upon the +Immersion there did not appear any Redness in the Water, but dropping into +it a little Oyl of Tartar, the Liquor soon discover'd a Redness to the +watchfull Eye, whereas by a little of that Acid Liquor of Vitriol, which is +like the former, undeservedly called Oyl, such a Colour would not be +extracted from the infused _Senna_. On the other side we took some Red-rose +Leaves dry'd, and having shaken them into a Glass of fair Water, they +imparted to it no Redness, but upon the affusion of a little Oyl of Vitriol +the Water was immediately turn'd Red, which it would not have been, if +instead of Oyl of Vitriol, we had imployed Oyl of Tartar to produce that +Colour: That these were _Gassendus_ his Experiments, I partly remember, and +was assur'd by a Friend, who lately Transcribed them out of _Gassendus_ his +Book, which I therefore add, because I have not now that Book at hand. And +the design of _Gassendus_ in these Experiments our Friend affirms to be, to +prove, that of things not Red a Redness may be made only by Mixture, and +the Varied position of parts, wherein the Doctrine of that Subtil +Philosopher doth not a little Authorize, what we have formerly delivered +concerning the Emergency and Change of Colours. But the instances, that we +have out of him set down, seem not to be the most Eminent, that may be +produced of this truth: For our next Experiment will shew the production of +several Colours out of Liquors, which have not any of them any such Colour, +nor indeed any discernable one at all; and whereas though our Author tells +us, that there was no Redness either in the Water, or the Leaves of +_Senna_, or the Oyl of Tartar; And though it be true, that the Predominant +Colour of the Leaves of _Senna_ be another than Red, yet we have try'd, +that by steeping that Plant a Night even in Cold water, it would afford a +very deep Yellow or Reddish Tincture without the help of the Oyl of Tartar, +which seems to do little more than assist the Water to extract more nimbly +a plenty of that Red Tincture, wherewith the Leaves of _Senna_ do of +themselves abound, and having taken off the Tincture of _Senna_, made only +with fair Water, before it grew to be Reddish, and Decanted it from the +Leaves, we could not perceive, that by dropping some Oyl of Tartar into it, +that Colour was considerable, though it were a little heightned into a +Redness; which might have been expected, if the particles of the Oyl did +eminently Co-operate, otherwise than we have expressed, to the production +of this Redness. + +And as for the Experiment with Red-rose Leaves, the same thing may be +alleged, for we found that such Leaves by bare Infusion for a Night and Day +in fair Water, did afford us a Tincture bordering at least upon Redness, +and that Colour being conspicuous in the Leaves themselves, would not by +some seem so much to be produc'd as to be extracted by the affusion of Oyl +of Vitriol. And the Experiment try'd with the dry'd Leaves of Damask-roses +succeeded but imperfectly, but that is indeed observable to our Authors +purpose, that Oyl of Tartar will not perform in this Experiment what Oyl of +Vitriol doth; but because this last named Liquor is not so easily to be +had, give me leave to Advertise you, that the Experiment will succeed, if +instead of it you imploy _Aqua-fortis_. And though some Trials of our own +formerly made, and others easily deducible from what we have already +deliver'd, about the different Families and Operations of Salt, might +enable us to present you an Experiment upon Red-rose Leaves, more +accommodated to our Authors purpose, than that which he hath given us; yet +our Reverence to so Candid a Philosopher, invites us rather to improve his +Experiment, than substitute another in its place. Take therefore of the +Tincture of Red-rose Leaves, (for with Damask-rose Leaves the Experiment +succeedeth not well) made as before hath been taught with a little Oyl of +Vitriol, and a good quantity of fair Water, pour off this Liquor into a +clear Vial, half fill'd with Limpid water; till the Water held against the +Light have acquir'd a competent Redness, without losing its Transparency, +into this Tincture drop leisurely a little good Spirit of Urine, and +shaking the Vial, which you must still hold against the Light, you shall +see the Red Liquor immediately turn'd into a fine Greenish Blew, which +Colour was not to be found in any of the Bodies, upon whose Mixture it +emerg'd, and this Change is the more observable, because in many Bodies the +Degenerating of Blew into Red is usual enough, but the turning of Red into +Blew is very unfrequent. If at every drop of Spirit of Urine you shake the +Vial containing the Red Tincture, you may delightfully observe a pretty +variety of Colours in the passage of that Tincture from a Red to a Blew, +and sometimes we have this way hit upon such a Liquor, as being look't upon +against and from the Light, did seem faintly to emulate the above-mention'd +Tincture of _Lignum Nephriticum_. And if you make the Tincture of Red-roses +very high, and without Diluting it with fair Water, pour on the Spirit of +Urine, you may have a Blew so deep, as to make the Liquor Opacous, but +being dropt upon White Paper the Colour will soon disclose it self. Also +having made the Red, and consequently the Blew Tincture very Transparent, +and suffer'd it to rest in a small open Vial for a Day or two, we found +according to our Conjecture, that not only the Blew but the Red Colour also +was Vanish'd; the clear Liquor being of a bright Amber Colour, at the +bottom of which subsided a Light, but Copious feculency of almost the same +Colour, which seems to be nothing but the Tincted parts of the Rose Leaves +drawn out by the Acid Spirits of the Oyl of Vitriol, and Precipitated by +the Volatile Salt of the Spirit of Urine, which makes it the more probable, +that the Redness drawn by the Oyl of Vitriol, was at least as well an +extraction of the Tinging parts of the Roses, as a production of Redness; +and lastly, if you be destitute of Spirit of Urine, you may change the +Colour of the Tincture of Roses with many other Sulphureous Salts, as a +strong Solution of Pot-ashes, Oyl of Tartar, &c. which yet are seldome so +free from Feculency, as the Spirituous parts of Urine becomes by repeated +Distillation. + +_Annotation_. + +On this, occasion, I call to mind, that I found, a way of producing, though +not the same kind of Blew, as I have been mentioning, yet a Colour near of +Kin to it, namely, a fair Purple, by imploying a Liquor not made Red by +Art, instead of the Tincture of Red-roses, made with an Acid Spirit; And my +way was only to take Log-wood, (a Wood very well known to Dyers) having by +Infusion the Powder of it a while in fair Water made that Liquor Red, I +dropt into it a _Tantillum_ of an Urinous Spirit, as that of Sal-Armoniack, +(and I have done the same thing with an _Alcali_) by which the Colour was +in a moment turn'd into a Rich, and lovely Purple. But care must be had, +that you let not fall into a Spoonfull above two or three Drops, lest the +Colour become so deep, as to make the Liquor too Opacous. And (to answer +the other part of _Gassendus_ his Experiment) if instead of fair Water, I +infus'd the Log-wood in Water made somewhat sowr by the Acid Spirit of +Salt, I should obtain neither a Purple Liquor, nor a Red, but only a Yellow +one. + +_EXPERIMENT XL._ + +The Experiment I am now to mention to you, _Pyrophilus_, is that which both +you, and all the other _Virtuosi_ that have seen it, have been pleas'd to +think very strange; and indeed of all the Experiments of Colours, I have +yet met with, it seems to be the fittest to recommend the Doctrine propos'd +in this Treatise, and to shew that we need not suppose, that all Colours +must necessarily be Inherent Qualities, flowing from the Substantial Forms +of the Bodies they are said to belong to, since by a bare Mechanical change +of Texture in the Minute parts of Bodies; two Colours may in a moment be +Generated quite _De novo,_ and utterly Destroy'd. For there is this +difference betwixt the following Experiment, and most of the others +deliver'd in these Papers, that in this, the Colour that a Body already +had, is not chang'd into another, but betwixt two Bodies, each of them +apart devoid of Colour, there is in a moment generated a very deep Colour, +and which if it were let alone, would be permanent; and yet by a very small +Parcel of a third Body, that has no Colour of its own, (lest some may +pretend I know not what Antipathy betwixt Colours) this otherwise permanent +Colour will be in another trice so quite Destroy'd, that there will remain +no foot-stepts either of it or of any other Colour in the whole Mixture. + +The Experiment is very easie, and it is thus perform'd: Take good common +Sublimate, and fully satiate with it what quantity of Water you please, +Filtre the Solution carefully through clean and close Paper, that it may +drop down as Clear and Colourless as Fountain water. Then when you'l shew +the Experiment, put of it about a Spoonfull into a small Wine-glass, or any +other convenient Vessel made of clear Glass, and droping in three or four +drops of good Oyl of Tartar, _per Deliquium_; well Filtred that it may +likewise be without Colour, these two Limpid Liquors will in the twinkling +of an Eye turn into an Opacous mixture of a deep Orange Colour, which by +keeping the Glass continually shaking in your hand, you must preserve from +setling too soon to the Bottom; And when the Spectators have a little +beheld this first Change, then you must presently drop in about four or +five drops of Oyl of Vitriol, and continuing to shake the Glass pretty +strongly, that it may the Nimbler diffuse it self, the whole Colour, if you +have gone Skilfully to work, will immediately disappear, and all the Liquor +in the Glass will be Clear and Colourless as before, without so much as a +Sediment at the Bottom. But for the more gracefull Trial of this +Experiment, 'twill not be amiss to observe, First, That there should not be +taken too much of the Solution of Sublimate, nor too much of the Oyl of +Tartar drop'd in, to avoid the necessity of putting in so much Oyl of +Vitriol as may make an Ebullition, and perhaps run over the Glass. +Secondly, That 'tis convenient to keep the Glass always a little shaking, +both for the better mixing of the Liquors, and to keep the Yellow Substance +from Subsiding, which else it would in a short time do, though when 'tis +subsided it will retain its Colour, and also be capable of being depriv'd +of it by the Oyl newly mention'd. Thirdly, That if any Yellow matter stick +at the sides of the Glass, 'tis but inclining the Glass, till the clarify'd +Liquor can wash alongst it, and the Liquor will presently imbibe it, and +deprive it of its Colour. + +Many have somewhat wondred, how I came to light upon this Experiment, but +the Notions or Conjectures I have about the differing Natures of the +Several Tribes of Salts, having led me to devise the Experiment, it will +not be difficult for me to give you the Chymical Reason, if I may so speak, +of the _Phænomenon_. Having then observ'd, that _Mercury_ being dissolv'd +in Some _Menstruums_, would yield a dark Yellow Precipitate, and supposing +that, as to this, common Water, and the Salts that stick to the _Mercury_ +would be equivalent to those Acid _Menstruums_, which work upon the +_Quick-silver_, upon the account of their Saline particles, I substituted a +Solution of Sublimate in fair Water, instead of a Solution of _Mercury_ in +_Aqua-fortis_, or Spirit of _Nitre_, that simple Solution being both +clearer and free from that very offensive Smell, which accompanies the +Solutions of _Mercury_ made with those other corrosive Liquors; then I +consider'd, that That, which makes the Yellow Colour, is indeed but a +Precipitate made by the means of the Oyl of Tartar, which we drop in, and +which, as _Chymists_ know, does generally precipitate Metalline Bodies +corroded by Acid Salts; so that the Colour in our case results from the +Coalition of the Mercurial particles with the Saline ones, wherewith they +were formerly associated, and with the Alcalizate particles of the Salt of +Tartar that swim up and down in the Oyl. Wherefore considering also, that +very many of the effects of Lixiviate Liquors, upon the Solutions of other +Bodies, may be destroy'd by Acid _Menstruums_, as I elsewhere more +particularly declare, I concluded, that if I chose a very potently Acid +Liquor, which by its Incisive power might undo the work of the Oyl of +Tartar, and disperse again those Particles, which the other had by +Precipitation associated, into such minute Corpuscles as were before singly +Inconspicuous, they would become Inconspicuous again, and consequently +leave the Liquor as Colourless as before the Precipitation was made. + +This, as I said, _Pyrophilus_, seems to be the Chymical reason of this +Experiment, that is such a reason, as, supposing the truth of those +Chymical Notions I have elsewhere I hope evinc'd, may give such an account +of the _Phænomena_ as Chymical Notions can supply us with; but I both here +and elsewhere make use of this way of speaking, to intimate that I am +sufficiently aware of the difference betwixt a Chymical Explication of a +_Phænomenon_, and one that is truly Philosophical or Mechanical; as in our +present case, I tell you something, when I tell you that the Yellowness of +the Mercurial Solution and the Oyl of Tartar is produc'd by the +Precipitation occasion'd by the affusion of the latter of those Liquors, +and that the destruction of the Colour proceeds from the Dissipation of +that Curdl'd matter, whose Texture is destroy'd, and which is dissolv'd +into Minute and Invisible particles by the potently Acid _Menstruum_, which +is the reason, why there remains no Sediment in the Bottom, because the +infused Oyl takes it up, and resolves it into hidden or invisible Parts, as +Water does Salt or Sugar. But when I have told you all this, I am far from +thinking I have told all that such an Inquisitive Person as your self would +know, for I presume you would desire as well as I to learn (at least) why +the Particles of the _Mercury_, of the Tartar, and of the Acid Salts +convening together, should make rather an Orange Colour than a Red, or a +Blew, or a Green, for 'tis not enough to say what I related a little +before, that divers Mercurial Solutions, though otherwise made, would yield +a Yellow precipitate, because the Question will recurr concerning them; and +to give it a satisfactory answer, is, I freely acknowledge, more than I +dare as yet pretend to. + +But to confirm my conjecture about the Chymical reason of our Experiment, I +may add, that as I have (_viz._ pag. 34th. of this Treatise) elsewhere (on +another occasion) told you, with Saline Liquors of another kind and nature +than Salt of Tartar, (namely, with Spirit of Urine, and Liquors of kin to +that) I can make the _Mercury_ precipitate out of the first simple Solution +quite of another Colour than that hitherto mention'd; Nay, if instead of +altering the Precipitating liquor, I alter'd the Texture of the Sublimate +in such a way as my Notions about Salt requir'd, I could produce the same +_Phænomenon_. For having purposely Sublim'd together Equal parts (or +thereabout) of Sal-Armoniack and Sublimate, first diligently Mix'd, the +ascending Flowers being diffolv'd in fair Water, and Filtred, gave a +Solution Limpid and Colourless, like that of the other Sublimates, and yet +an _Akaly_ drop'd into this Liquor did not turn it Yellow but White. And +upon the same Grounds we may with _Quick-silver_, without the help of +common Sublimate, prepare another sort of Flowers dissoluble in Water +without Discolouring it, with which I could likewise do what I newly +mention'd; to which I shall add, (what possibly you'l somewhat wonder at) +That so much does the Colour depend upon the Texture resulting from the +Convention of the several sorts of Corpuscles, that though in out +Experiment, Oyl of Vitriol destroys the Yellow Colour, yet with +_Quick-silver_ and fair Water, by the help of Oyl of Vitriol alone, we may +easily make a kind of Precipitate of a fair and permanent Yellow, as you +will e're long (in the forty second Expement of this third Part) be taught. +And I may further add, that I chose Oyl of Vitriol, not so much for any +other or peculiar Quality, as for its being, when 'tis well rectify'd, +(which 'tis somewhat hazardous to bring it to be) not only devoid of Colour +and in Smells, but extremely Strong and Incisive; For though common and +undephlegmated _Aqua-fortis_ will not perform the same thing well, yet that +which is made exceeding Strong by being carefully Dephlegm'd, will do it +pretty well, though not so well as Oyl of Vitriol which is so Strong, that +even without Rectification it may for a need be made use of. I will not +here tell you what I have try'd, that I may be able to deprive at pleasure +the Precipitate that one of the Sulphureous Liquors had made, by the +copious Affusion of the other: Because I found, though this Experiment is +too ticklish to let me give a full account of it in few words, I shall +therefore tell you, that it is not only for once, that the other +above-mention'd Experiment may be made, the same Numerical parcels of +Liquor being still imploy'd in it; for after I have Clarify'd the Orange +Colour'd Liquor, by the addition of as little of the Oyl of Viriol as will +suffice to perform the effect, I can again at pleasure re-produce the +Opacous Colour, by the dropping in of fresh Oyl of Tartar, and destroy it +again by the Re-affusion of more of the Acid _Menstruum_; and yet oftner if +I please, can I with these two contrariant Liquors recall and disperse the +Colour, though by reason of the addition of so much new Liquor, in +reference to the Mercurial particles, the Colour will at length appear more +dilute and faint. + +_An improvement of the fortieth Experiment_. + +And, _Pyrophilus_, to confirm yet further the Notions that led me to think +on the propos'd Experiment, I shall acquaint you with another, which when I +had conveniency I have sometimes added to it, and which has to the +Spectators appear'd little less Odd than the first; And though because the +Liquor, requisite to make the Trial succeed well, must be on purpose +prepar'd anew a while before, because it will not long retain its fitness +for this work, I do but seldome annex this Experiment to the other, yet I +shall tell you how I devis'd it, and how I make it. If you boyl Crude +Antimony in a strong and clear _Lixivium_, you shall separate a Substance +from it, which some Modern _Chymists_ are pleas'd to call its Sulphur, but +how deservedly I shall not here examine, having elsewhere done it in an +Opportune place; wherefore I shall now but need to take notice, that when +this suppos'd Sulphur (not now to call it rather a kind of _Crocus_) is let +fall by the Liquor upon its Refrigeration, it often settles in Flakes, or +such like parcels of a Yellow Substance, (which being by the precedent +dissolution reduc'd into Minute parts, may peradventure be made to take +Fire much more easily than the Grosser Powder of unprepar'd Antimony would +have done.) Considering therefore, that common Sulphur boyl'd in a +_Lixivium_ may be Precipitated out of it by Rhenish-wine or White-wine, +which are Sowrish Liquors, and have in them, as I elsewhere shew, an Acid +Salt; and having found also by Trial, that with other Acid Liquors I could +Precipitate out of Lixiviate Solvents some other Mineral concretions +abounding with Sulphureous parts, of which sort is crude Antimony, I +concluded it to be easie to Precipitate the Antimony dissolv'd, as was +lately mention'd, with the Acid Oyl of Vitriol; and though common Sulphur +yields a White Precipitate, which the _Chymists_ call _Lac Sulphuris_, yet +I suppos'd the Precipitated Antimony would be of a deep Yellow Colour, as +well, if made with Oyl of Vitriol, as if made only by Refrigeration and +length of Time. From this 'twas easie to deduce this Experiment, that if +you put into one Glass some of the freshly Impregnated and Filtrated +Solution of Antimony, and into another some of the Orange-Colour'd Mixture, +(which I formerly shew'd you how to make with a Mercurial Solution and Oyl +of Tartar) a few drops of Oyl of Vitriol dropp'd into the last mention'd +Glass, would, as I told you before, turn the Deep Yellow mixture into a +Cleer Liquor; whereas a little of the same Oyl dropp'd out of the same Viol +into the other Glass would presently (but not without some ill sent) turn +the moderately cleer Solution into a Deep Yellow Substance, But this, as I +Said, succeeds not well, unless you employ a _Lixivium_ that has but newly +dissolv'd Antimony, and has not yet let it fall. But yet in Summer time, if +your _Lixivium_ have been duly Impregnated and well Filtred after it is +quite cold, it will for some dayes (perhaps much longer than I had occasion +to try) retain Antimony enough to exhibit, upon the Affusion of the +Corrosive Oyl, as much of a good Yellow Substance as is necessary to +satisfie the Beholders of the Possibility of the Experiment. + +_Reflections upon the XL. Experiment Compared with the X. and XX._ + +The Knowledge of the Distinction of Salts which we have propos'd, whereby +they are discriminated into _Acid, Volatile,_ or _Salfuginous_ (if I may +for Distinction sake so call the Fugitive Salts of Animal Substances) and +_fix'd_ or _Alcalizate_, may possibly (by that little part which we have +already deliver'd, of what we could say of its Applicableness) appear of so +much Use in Natural Philosophy (especially in the Practick part of it) that +I doubt not but it will be no Unwelcome Corollary of the Preceding +Experiment, if by the help of it I teach you to distinguish, which of those +Salts is Predominant in Chymical Liquors, as well as whether any of them be +so or not. For though in our Notes upon the X. and XX. Experiments I have +shown you a way by means of the Tincture of _Lignum Nephriticum_, or of +Syrrup of Violets, to discover whether a propounded Salt be Acid or not, +yet you can thereby only find in general that such and such Salts belong +not to the Tribe of Acids, but cannot determine whether they belong to the +Tribe of Urinous Salts (under which for distinction sake I comprehend all +those Volatile Salts of Animal or other Substances that are contrary to +Acids) or to that of Alcalies. For as well the one as the other of these +Salino-Sulphurous Salts will restore the Cæruleous Colour to the Tincture +of _Lignum Nephriticum_, and turn that of Syrrup of Violets into Green. +Wherefore this XL. Experiment does opportunely supply the deficiency of +those. For being sollicitous to find out some ready wayes of discriminating +the Tribes of Chymical Salts, I found that all those I thought fit to make +Tryal of, would, if they were of a Lixiviate Nature, make with Sublimate +dissolv'd in Fair Water an _Orange Tawny_ Precipitate; whereas if they were +of an Urinous Nature the Precipitate would be _White_ and Milky. So that +having alwayes by me some Syrrup of Violets and some Solution of Sublimate, +I can by the help of the first of those Liquors discover in a trice, +whether the propounded Salt or Saline Body be of an Acid Nature or no, if +it be I need (you know) inquire no further; but if it be not, I can very +easily, and as readily distinguish between the other two kinds of Salts, by +the White or Orange-Colour that is immediately produc'd, by letting fall a +few Drops or Grains of the Salt to be examin'd, into a spoonfull of the +cleer Solution of Sublimate. For Example, it has been suppos'd by some +eminently Learned, That when Sal Armoniack being mingled with an Alcaly is +forc'd from it by the Fire in close Vessels, the Volatile Salt that will +thereby be obtain'd (if the Operation be skilfully perform'd,) is but a +more fine and subtile sort of Sal Armoniack, which, 'tis presum'd, this +Operation do's but more exquisitely purifie, than common Solutions, +Filtrations, and Coagulations. But this Opinion may be easily shown to be +Erroneous, as by other Arguments, so particularly by the lately deliver'd +Method of distinguishing the Tribes of Salts. For the Saline Spirit of Sal +Armoniack, as it is in many other manifest Qualities very like the Spirit +of Urine, so like, that it will in a trice make Syrrup of Violets of a +Lovely Green, turn a Solution of good Verdigrease into an Excellent Azure, +and make the Solution of a Sublimate yield a White Precipitate, insomuch +that in most (for I say not all of the Experiments) where I Aim onely at +producing a sudden change of Colour, I scruple not to use Spirit of Sal +Armoniack when it is at hand, instead of Spirit of Urine, as indeed it +seems chiefly to consist (besides the flegm that helps to make it fluid) of +the Volatile Urinous Salt (yet not excluding that of Soot) that abounds in +the Sal Armoniack and is set at liberty from the Sea Salt wherewith it was +formerly associated, and clogg'd, by the Operation of the Alcaly, that +divides the Ingredients of Sal Armoniack, and retains that Sea Salt with it +self. What use may be made of the like way of exploration in that inquiry +which puzzles so many Modern Naturalists, whether the Rich Pigment (which +we have often had occasion to mention) belongs to the Vegetable or Animal +Kingdome, you may find in another place where I give you some account of +what I try'd about Cocheneel. But I think it needless to exemplifie here +our Method by any other Instances, many such being to be met with in divers +parts of this Treatise; but I will rather advertise you, that, by this way +of examining Chymical Liquors, you may not onely in most Cases conclude +_Affirmatively_, but in some Cases _Negatively_. As since Spirit of Wine, +and as far as I have try'd, those Chymical Oyles which Artists call +Essential, did not (when I us'd them as I had us'd the several Families of +Salts upon that Syrrup) turn Syrrup of Violets Red or Green, nor the +Solution of Sublimate White or Yellow, I inferr'd it may thence be probably +argued, that either they are destitute of Salt, or have such as belongs not +to either of the three Grand families already often mention'd. When I went +to examine the Spirit of Oak or of such like Concretes forced over through +a Retort, I found by this means amongst others, that (as I elsewhere show) +these Chymists are much mistaken in it, that account it a simple Liquor, +and one of their Hypostatical Principles: for not to mention what flegm it +may have, I found that with a few drops of one of this sort of Spirits +mix'd with a good proportion of Syrrup of Violets, I could change the +Colour and make it Purplish, by the affinity of which Colour to Redness, I +conjectur'd that this Spirit had some Acid Corpuscles in it, and +accordingly I found that as it would destroy the Blewness of a Tincture of +_Lignum Nephriticum_, so being put upon Corals it would Corrode them, as +common Spirit of Vinegar, and other Acid Liquors are wont to do. And +farther to examine whether there were not a great part of the Liquor that +was not of an Acid nature, having separated the Sour or Vinegar-like part +from the rest, which (if I mistake not) is far the more Copious, we +concluded as we had conjectured, the other or remaining part, though it had +a strong taste as well as smell, to be of a nature differing from that of +either of the three sorts of Salts above mention'd, since it did as little +as Spirit of Wine, and Chymical Oyls, alter the Colour either of Syrrup of +Violets or Solution of Sublimate, whence we also inferr'd that the change +that had been made of that Syrrup into a Purple Colour, was effected by the +Vinegar, that was one of the two Ingredients of the Liquor, which was wont +to pass for a Simple or Uncompounded Spirit. And, upon this account, 'twas +of the Spirit of Oak (and the like Concretes) freed from it's Vinegar that +I elsewhere told you, that I had not then observ'd it, (and I have repeated +the Tryal but very lately) to destroy the Cæruleous Tincture of _Lignum +Nephriticum_. But this onely, _en passant_; for the Chief thing I had to +add was this, That by the same way may be examin'd and discover'd, divers +changes that are produc'd in Bodies either by Nature only, or by Art; +either of them being able by changing the Texture of some Concretes I could +name, to qualifie them to Operate after a New manner upon the above +mention'd Syrrup, or Solution, or both. And by this means, to tell you that +upon the by, I have been able to discover, that there may be made Bodies, +which though they run _per Deliquium_, as readily as Salt of Tartar, belong +in other respects, not to the family of Alcaliz, much less to that of +Salfuginous, or that of Acid Salts. Perhaps too, I may know a way of making +a highly operative Saline Body that shall neither change the Colour of +Syrrup of Violets, nor Precipitate the Solution of Sublimate; And, I can +likewise if I please conceal by what Liquors I perform such changes of +Colour, as I have been mentioning to you, by quite altering the Texture of +some ordinary Chymical productions, the Exploration of which is the main +use of the fortieth Experiment, which I think teaches not a little, if it +teach us to discover the nature of those things (in reference to Salt) that +are obtain'd by the ordinary Chymical Analysis of mix'd Bodyes, though +perhaps there may be other Bodyes prepar'd by Chymistry which may have the +same Effects in the change of Colours; and yet be produc'd not from what +Chymists call the Resolution of Bodies, but from their Composition. But the +discoursing of things of this nature is more proper for another place. I +shall now onely add, what might perhaps have been more seasonably told you +before; That the Reason why the way of Exploration of Salts hitherto +deliver'd, succeeds in the Solution of Sublimate, depends upon the +particular Texture of that Solution, as well as upon the differing Natures +of the Saline Liquors imploy'd to Precipitate it. For Gold dissolv'd in +_Aqua Regia_, whether you Precipitate it with Oyl of Tartar which is an +Alcaly, or with Spirit of Urine, or Sal Armoniack which belongs to the +family of Volatile Salts, will either way afford a Yellow substance: though +with such an Acid Liquor, as, I say not Spirit of Salt, the Body that +yields it, being upon the matter an Ingredient of _Aqua Regis_, but Oyl of +Vitriol it self, I did not find that I could Precipitate the Metall out of +the Solution, or destroy the Colour of it, though the same Oyl of Vitriol +would readily Precipitate Silver dissolv'd in _Aqua-fortis_. And if you +dissolve pure Silver in _Aqua-fortis_, and suffer it to shoot into +Crystals, the cleer Solution of these made in fair Water, will afford a +very White Precipitate, whether it be made with an Alcaly, or an Acid +Spirit, as that of Salt, whereas, which may seem somewhat strange, with +Spirit of Sal Armoniack (that I us'd was made of Quicklime) I could obtain +no such White Precipitate; that Volatile Spirit, nor (as I remember) that +of Urine, scarce doing any more than striking down a very small quantity of +Matter, which was neither White nor Whitish, so that the remaining Liquor +being suffer'd to evaporate till the superfluous Moisture was gone, the +greatest part of the Metalline Corpuscles with the Saline ones that had +imbib'd them, concoagulated into Salt, as is usual in such Solutions, +wherein the Metall has not been Precipitated. + +_EXPERIMENT XLI._ + +Of Kin to the last or fortieth Experiment is another which I remember I +have sometimes shewn to _Virtuosi_ that were pleas'd not to dislike it. I +took Spirit of Urine made by Fermentation, and with a due proportion of +Copper brought into small parts, I obtain'd a very lovely Azure Solution, +and when I saw the Colour was such as was requisite, pouring into a clean +Glass, about a spoonfull of this tincted Liquor, (of which I us'd to keep a +Quantity by me,) I could by shaking into it some drops of Strong Oyl of +Vitriol, deprive it in a trice of its Deep Colour, and make it look like +Common-water. + +_Annotation_. + +This Experiment brings into my mind this other, which oftentimes succceds +well enough, though not quite so well as the former; Namely, that if into +about a small spoonfull of a Solution of good French Verdigrease made in +fair Water, I drop't and shak'd some strong Spirit of Salt, or rather +deflegm'd _Aqua Fortis_, the Greenness of the Solution would be made in a +trice almost totally to disappear, & the Liquor held against the Light +would scarce seeme other than Cleer or Limpid, to any but an Attentive Eye, +which is therefore remarkable; because we know that _Aqua-fortis_ corroding +Copper, which is it that gives the Colour to Verdigrease, is wont to reduce +it to a Green Blew Solution. But if into the other altogether or almost +Colourless Liquor I was speaking of, you drop a just quantity either of Oyl +of Tartar or Spirit of Urine, you shall find that after the Ebullition is +ceas'd, the mixture will disclose a lively Colour, though somewhat +differing from that which the Solution of Verdigrease had at first. + +_EXPERIMENT XLII._ + +That the Colour (_Pyrophilus_) of a Body may be chang'd by a Liquor which +of it self is of no Colour, provided it be Saline, we have already +manifested by a multitude of instances. Nor doth it seem so strange, +because Saline Particles swimming up and down in Liquors, have been by many +observ'd to be very operative in the Production and change of Colours. But +divers of our Friends that are not acquainted with Chymical Operations have +thought it very strange that a White Body, and a Dry one too, should +immediately acquire a rich new Colour upon the bare affusion of +Spring-Water destitute as well of adventitious Salt as of Tincture. And yet +(_Pyrophilus_) the way of producing such a change of Colours may be easily +enough lighted on by those that are conversant in the Solutions of Mercury. +For we have try'd, that though by Evaporating a Solution of Quick-Silver in +_Aqua-fortis_, and abstracting the Liquor till the remaining matter began +to be well, but not too strongly dryed, fair Water pour'd on the remaining +_Calx_ made it but somewhat Yellowish; yet when we took good Quick-Silver, +and three or four times its weight of Oyl of Vitriol, in case we in a Glass +Retort plac'd in Sand drew off the Saline _Menstruum_ from the Metalline +Liquor, till there remain'd a dry _Calx_ at the bottome, though this +Precipitate were a Snow White Body, yet upon pouring on it a large quantity +of fair Water, we did almost in a moment perceive it to pass from a Milky +Colour to one of the loveliest Light Yellows that ever we had beheld. Nor +is the Turbith Mineral, that Chymists extol for its power to Salivate, and +for other vertues, of a Colour much inferiour to this, though it be often +made with a differing proportion of the Ingredients, a more troublesome +way. For _Beguinus_,[22] who calls it _Mercurius præcipitatus optimus_, +takes to one part of Quick-Silver, but two of Liquor, and that is Rectifi'd +Oyl of Sulphur, which is (in _England_ at least) far more scarce and dear +than Oyl of Vitriol; he also requires a previous Digestion, two or three +Cohobations, and frequent Ablutions with hot Distill'd Water, with other +prescriptions, which though they may conduce to the Goodness of the +Medicine, which is that he aims at, are troublesome, and, our Tryals have +inform'd you unneccessary to the _obtaining the Lemmon Colour_ which he +regards not. But though we have very rarely seen either in Painters Shops, +or elsewhere a finer Yellow than that which we have divers times this way +produc'd (which is the more considerable, because durable and pleasant +Yellows are very hard to be met with, as may appear by the great use which +Painters are for its Colours sake fain to make of that pernicious and heavy +Mineral, Orpiment) yet I fear our Yellow is too costly, to be like to be +imploy'd by Painters, unless about Choice pieces of Work, nor do I know how +well it will agree with every Pigment, especially, wich Oyl'd Colours. And +whether this Experiment, though it have seem'd somewhat strange to most we +have shown it to, be really of another Nature than those wherein Saline +Liquors are imploy'd, may, as we formerly also hinted, be so plausibly +doubted, that whether the Water pour'd on the _Calx_, do barely by imbibing +some of its Saline parts alter its Colour by altering its Texture, or +whether by dissolving the Concoagulated Salts, it does become a Saline +_Menstruum_, and, as such, work upon the Mercury, I freely leave to you +(_Pyrophilus_) to consider. And that I may give you some Assistance in your +Enquiry, I will not only tell you, that I have several times with fair +Water wash'd from this _Calx_, good store of strongly tasted Corpuscles, +which by the abstraction of the _Menstruum_, I could reduce into Salt; but +I will also subjoyn an Experiment, which I devis'd, to shew among other +things, how much a real and permanent Colour may be as it were drawn forth +by a Liquor that has neither Colour, nor so much as Saline or other Active +parts, provided it can but bring the parts of the Body it imbibes to +convene into clusters dispos'd after the manner requisite to the exhibiting +of the emergent Colour. The Experiment was this. + + [22] _Beguinus_, Tyr. Chy. Lib. 2º. Cap. 13º. + +_EXPERIMENT XLIII._ + +We took good common Vitriol, and having beaten it to Powder, and put it +into a Crucible, we kept it melted in a gentle heat, till by the +Evaporation of some parts, and the shuffling of the rest, it had quite lost +its former Colour, what remain'd we took out, and found it to be a friable +_Calx_, of a dirty Gray. On this we pour'd fair Water, which it did not +Colour Green or Blew, but only seem'd to make a muddy mixture with it, then +stopping the Vial wherein the Ingredients were put, we let it stand in a +quiet place for some dayes, and after many hours the water having dissolv'd +a good part of the imperfectly calcin'd Body, the Vitriolate Corpuscles +swiming to and fro in the Liquor, had time by their opportune Occursions to +constitute many little Masses of Vitriol, which gave the water they +impregnated a fair Vitriolate Colour; and this Liquor being pour'd off, the +remaining dirty Powder did in process of time communicate the like Colour, +but not so deep, to a second parcel of cleer Water that we pour'd on it. +But this Experiment _Pyrophilus_ is, (to give you that hint by the way) of +too Luciferous a Nature to be fit to be fully prosecuted, now that I am in +haste, and willing to dispatch what remains. And we have already said of +it, as much as is requisite to our present purpose. + +_EXPERIMENT XLIV._ + +It may (_Pyrophilus_) somewhat contribute towards the shewing how much some +Colours depend upon the less or greater mixture, and (as it were,) +Contemperation of the Light with shades, to observe, how that sometimes the +number of Particles, of the same Colour, receiv'd into the Pores of a +Liquor, or swiming up and down in it, do seem much to vary the Colour of +it. I could here present you with particular instances to show, how in many +(if not most) consistent Bodyes, if the Colour be not a Light one, as +White, Yellow, or the like, the closeness of parts in the Pigments makes it +look Blackish, though when it is display'd and laid on thinly, it will +perhaps appear to be either Blew, or Green, or Red. But the Colours of +consistent Pigments, not being those which the Preamble of this Experiment +has lead you to expect Examples in, I shall take the instances I am now to +give you, rather from Liquors than Dry Bodyes. If then you put a little +fair Water into a cleer and slender Vial, (or rather into one of those +pipes of Glass, which we shall by and by mention;) and let fall into it a +few drops of a strong Decoction or Infusion of _Cochineel_, or (for want of +that) of _Brazil_; you may see the tincted drops descend like little Clouds +into the Liquor; through which, if, by shaking the Vial, you diffuse them, +they will turn the water either of a Pinck Colour, or like that which is +wont to be made by the washing of raw flesh in fair Water; by dropping a +little more of the Decoction, you may heighten the Colour into a fine Red, +almost like that which ennobles Rubies; by continuing the affusion, you may +bring the Liquor to a kind of a Crimson, and afterwards to a Dark and +Opacous Redness, somewhat like that of Clotted Blood. And in the passage of +the Liquor from one of these Colours to the other, you may observe, if you +consider it attentively, divers other less noted Colours belonging to Red, +to which it is not easie to give Names; especially considering how much the +proportion of the Decoction to the fair Water, and the strength of that +Decoction, together with that of the trajected Light and other +Circumstances, may vary the Phænomena of this Experiment. For the +convenienter making whereof, we use instead of a Vial, any slender Pipe of +Glass of about a foot or more in length, and about the thickness of a mans +little finger; For, if leaving one end of this Pipe open, you Seal up the +other Hermetically, (or at least stop it exquisitely with a Cork well +fitted to it, and over-laid with hard Sealing Wax melted, and rubb'd upon +it;) you shall have a Glass, wherein may be observ'd the Variations of the +Colours of Liquors much better than in large Vials, and wherein Experiments +of this Nature may be well made with very small quantities of Liquor. And +if you please, you may in this Pipe produce variety of Colours in the +various parts of the Liquor, and keep them swimming upon one another +unmix'd for a good while. And some have marveil'd to see, what variety of +Colours we have sometimes (but I confess rather by chance than skill) +produc'd in those Glasses, by the bare infusion of Brazil, variously +diluted with fair Water, and alter'd by the Infusion of several Chymical +Spirits and other Saline Liquors devoid themselves of Colour, and when the +whole Liquor is reduc'd to an Uniform degree of Colour, I have taken +pleasure to make that very Liquor seem to be of Colours gradually +differing, by filling with it Glasses of a Conical figure, (whether the +Glass have its basis in the ordinary position, or turn'd upwards.) And yet +you need not Glasses of an extraordinary shape to see an instance of what +the vari'd mixture of Light and Shadow can do in the diversifying of the +Colour. For if you take but a large round Vial, with a somewhat long and +slender Neck, and filling it with our Red Infusion of Brazil, hold it +against the Light, you will discern a notable Disparity betwixt the Colour +of that part of the Liquor which is in the Body of the Vial, and that which +is more pervious to the Light in the Neck. Nay, I remember, that I once had +a Glass and a Blew Liquor (consisting chiefly (or only, if my memory +deceive me not,) of a certain Solution of Verdigrease) so fitted for my +purpose, that though in other Glasses the Experiment would not succeed, yet +when that particular Glass was fill'd with that Solution, in the Body of +the Vial it appear'd of a Lovely Blew, and in the neck, (where the Light +did more dilute the Colour,) of a manifest Green; and though I suspected +there might be some latent Yellowness in the substance of the neck of the +Glass, which might with the Blew compose that Green, yet was I not +satisfi'd my self with my Conjecture, but the thing seem'd odd to me, as +well as to divers curious persons to whom it was shown. And I lately had a +Broad piece of Glass, which being look'd on against the Light seem'd clear +enough, and held from the Light appear'd very lightly discolour'd, and yet +it was a piece knock'd off from a great lump of Glass, to which if we +rejoyn'd it, where it had been broken off, the whole Mass was as green as +Grass. And I have several times us'd Bottles and stopples that were both +made (as those, I had them from assur'd me) of the very same Metall, and +yet whilst the bottle appear'd but inclining towards a Green, the Stopple +(by reason of its great thickness) was of so deep a Colour that you would +hardly believe they could possibly be made of the same materials. But to +satisfie some Ingenious Men, on another occasion, I provided my self of a +flat Glass (which I yet have by me,) with which if I look against the Light +with the Broad side obverted to the Eye, it appeares like a good ordinary +window Glass; but if I turn the Edge of it to my Eye, and place my Eye in a +convenient posture in reference to the Light, it may contend for deepness +of Colour with an Emerald. And this Greeness puts me in mind of a certain +thickish, but not consistent Pigment I have sometimes made, and can show +you when you please, which being dropp'd on a piece of White Paper appears, +where any quantity of it is fallen, of a somewhat Crimson Colour, but being +with ones finger spread thinly on the Paper does presently exhibit a fair +Green, which seems to proceed only from its disclosing its Colour upon the +Extenuation of its Depth into Superficies, if the change be not somewhat +help'd by the Colours degenerating upon one or other of the Accounts +formerly mention'd. Let me add, that having made divers Tryals with that +Blew substance, which in Painters shops is call'd _Litmase_, we have +sometimes taken Pleasure to observe, that being dissolv'd in a due +proportion of fair Water, the Solution either oppos'd to the Light, or +dropp'd upon White paper, did appear of a deep Colour betwixt Crimson and +Purple; and yet that being spread very thin on the Paper and suffer'd to +dry on there, the Paper was wont to appear Stain'd of a Fine Blew. And to +satisfie my selfe, that the diversity came not from the Paper, which one +might suspect capable of inbibing the Liquor, and altering the Colour, I +made the Tryal upon a flat piece of purely White Glass'd Earth, (which I +sometimes make use of about Experiments of Colours) with an Event not +unlike the former. + +And now I speak of _Litmass_, I will add, that having this very day taken a +piece of it, that I had kept by me these several years, to make Tryals +about Colours, and having let fall a few drops of the strong Infusion of it +in fair water, into a fine Crystal Glass, shap'd like an inverted Cone, and +almost full of fair Water, I had now (as formerly) the pleasure to see, and +to show others, how these few tincted drops variously dispersing themselves +through the Limpid Water, exhibited divers Colours, or varieties of Purple +and Crimson. And when the Corpuscles of the Pigment seem'd to have equally +diffus'd themselves through the whole Liquor, I then by putting two or +three drops of Spirit of Salt, first made an odd change in the Colour of +the Liquor, as well as a visible commotion among its small parts, and in a +short time chang'd it wholly into a very Glorious Yellow, like that of a +Topaz. After which if I let fall a few drops of the strong and heavy +Solution of Pot-ashes, whose weight would quickly carry it to the sharp +bottome of the Glass, there would soon appear four very pleasant and +distinct Colours; Namely, a Bright, but Dilute Colour at the picked bottome +of the Glass; a Purple, a little higher; a deep and glorious Crimson, +(which Crimson seem'd to terminate the operation of the Salt upward) in the +confines betwixt the Purple and the Yellow; and an Excellent Yellow, the +same that before enobled the whole Liquor, reaching from thence to the top +of the Glass. And if I pleas'd to pour very gently a little Spirit of Sal +Armoniack, upon the upper part of this Yellow, there would also be a Purple +or a Crimson, or both, generated there, so that the unalter'd part of the +Yellow Liquor appear'd intercepted betwixt the two Neighbouring Colours. + +My scope in this 3d. Experiment (_Pyrophilus_) is manifold, as first to +invite you to be wary in judging of the Colour of Liquors in such Glasses +as are therein recommended to you, and consequently as much, if not more, +when you imploy other Glasses. Secondly, That you may not think it strange, +that I often content my self to rub upon a piece of White paper, the Juice +of Bodies I would examine, since not onely I could not easily procure a +sufficient Quantity of the juices of divers of them; but in several Cases +the Tryals of the quantities of such Juices in Glasses would make us more +lyable to mistakes, than the way that in those cases I have made use of. +Thirdly, I hope you will by these and divers other particulars deliver'd in +this Treatise, be easily induc'd to think that I may have set down many +Phænomena very faithfully, and just as they appear'd to me, and yet by +reason of some unheeded circumstance in the conditions of the matter, and +in the degree of Light, or the manner of trying the Experiment, you may +find some things to vary from the Relations I make of them. Lastly, I +design'd to give you an opportunity to free your self from the amazement +which possesses most Men, at the Tricks of those Mountebancks that are +commonly call'd Water-drinkers. For though not only the vulgar, but ev'n +many persons that are far above that Rank, have so much admir'd to see, a +man after having drunk a great deal of fair water, to spurt it out again in +the form of Claret Wine, Sack, and Milk, that they have suspected the +intervening of Magick, or some forbidden means to effect what they +conceived above the power of Art; yet having once by chance had occasion to +oblige a Wanderer that made profession of that and other Jugling Tricks, I +was easily confirm'd by his Ingenious confession to me, That this so much +Admir'd Art, indeed consisted rather in a few Tricks, than in any great +Skill, in altering the Nature and Colours of things. And I am easy to be +perswaded; that there may be a great deal of Truth in a little Pamphlet +Printed divers years ago in English, wherein the Author undertakes to +discover, and that (if I mistake not) by the confession of some of the +Complices themselves, That a famous Water-drinker then much Admir'd in +_England_, perform'd his pretended Transmutations of Liquors by the help of +two or three inconsiderable preparations and mixtures of not unobvious +Liquors, and chiefly of an Infusion of Brazil variously diluted and made +Pale or Yellowish, (and otherwise alter'd) with Vinegar, the rest of their +work being perform'd by the shape of the Glasses, by Craft and Legerdemane. +And for my part, that which I marvel at in this business, is, the Drinkers +being able to take down so much Water, and spout it out with that violence; +though Custome and a Vomit seasonably taken before hand, may in some of +them much facilitate the work. But as for the changes made in the Liquors, +they were but few and slight in comparison of those, that the being +conversant in Chymical Experiments, and dextrous in applying them to the +Transmuting of Colours, may easily enough enable a man to make, as ev'n +what has been newly deliver'd in this, and the foregoing Experiment; +especially if we add to it the things contained in the XX, the XXXIX and +the XL. Experiments, may perhaps have already perswaded You. + +_EXPERIMENT XLV._ + +You may I presume (_Pyrophilus_) have taken notice, that in this whole +Treatise, I purposely decline (as far as I well can) the mentioning of +Elaborate Chymical Experiments, for fear of frighting you by their +tediousness and difficulty; but yet in confirmation of what I have been +newly telling you about the possibility of Varying the Colours of Liquors, +better than the Water-drinkers are wont to do, I shall add, that _Helmont_ +used to make a preparation of Steel, which a very Ingenious Chymist, his +Sons Friend, whom you know, sometimes employes for a succedaneum to the +Spaw-waters, by Diluting this _Essentia Martis Liquida_ (as he calls it) +with a due proportion of Water. Now that for which I mention to you this +preparation, (which as he communicated to me, I know he will not refuse to +_Pyrophilus_) is this, that though the Liquor (as I can shew you when you +please) be almost of the Colour of a German (not an Oriental) Amethyst, and +consequently remote enough from Green, yet a very few drops being let fall +into a Large proportion of good Rhenish, or (in want of that) White Wine +(which yet do's not quite so well) immediately turn'd the Liquor into a +lovely Green, as I have not without delight shown several curious Persons. +By which _Phænomenon_ you may learn, among other things, how requisite it +is in Experiments about the changes of Colours heedfully to mind the +Circumstances of them; for Water will not, as I have purposely try'd, +concurr to the production of any such Green, nor did it give that Colour to +moderate Spirit of Wine, wherein I purposely dissolv'd it, and Wine it self +is a Liquor that few would suspect of being able to work suddenly any such +change in a Metalline preparation of this Nature; and to satisfie my self +that this new Colour proceeds rather from the peculiar Texture of the Wine, +than from any greater Acidity, that Rhenish or White-wine (for that may not +absurdly be suspected) has in comparison of Water; I purposely sharpen'd +the Solution of this Essence in fair Water, with a good quantity of Spirit +of Salt, notwithstanding which, the mixture acquir'd no Greenness. And to +vary the Experiment a little, I try'd, that if into a Glass of Rhenish Wine +made Green by this Essence, I dropp'd an Alcalizate Solution, or Urinous +Spirit, the Wine would presently grow Turbid, and of an odd Dirty Colour; +But if instead of dissolving the Essence in Wine, I dissolv'd it in fair +Water sharpen'd perhaps with a little Spirit of Salt, then either the +Urinous Spirit of Sal Armoniack, or the solution of the fix'd Salt of +Pot-ashes would immediately turn it of a Yellowish Colour, the fix'd or +Urinous Salt Precipitating the Vitriolate substance contain'd in the +Essence. But here I must not forget to take notice of a circumstance that +deserves to be compar'd with some part of the foregoing Experiment, for +whereas our Essence imparts a Greenness to Wine, but not to Water, the +Industrious _Olaus Wormius_[23] in his late _Musæum_ tells us of a rare +kind of Turn-Sole which he calls _Bezetta Rubra_ given him by an Apothecary +that knew not how it was made, whose lovely Redness would be easily +communicated to Water, if it were immers'd in it; but scarce to Wine, and +not at all to Spirit of Wine, in which last circumstance it agrees with +what I lately told you of our Essence, notwithstanding their disagreement +in other particulars. + + [23] Libr. 2do Cap. 34. + +_EXPERIMENT XLVI._ + +We have often taken notice, as of a remarkable thing, that Metalls as they +appear to the Eye, before they come to be farther alter'd by other Bodyes, +do exhibit Colours very different from those which the Fire and the +_Menstruum_, either apart, or both together, do produce in them; especially +considering that these Metalline Bodyes are after all these disguises +reducible not only to their former Metalline Consistence and other more +radical properties, but to their Colour too, as if Nature had given divers +Metalls to each of them a double Colour, an _External_, and an _Internal_; +But though upon a more attentive Consideration of this difference of +Colours, it seem'd probable to me, that divers (for I say not all) of those +Colours which we have just now call'd _Internal_, are rather produc'd by +the Coalition of Metalline Particles with those of the Salts, or other +Bodyes employ'd to work on them, than by the bare alteration of the parts +of the Metalls themselves: and though therefore we may call the obvious +Colours, Natural or Common, & the others Adventitious, yet because such +changes of Colours, from whatsoever cause they be resolv'd to proceed may +be properly enough taken in to illustrate our present Subject, we shall not +scruple to take notice of some of them, especially because there are among +them such as are produc'd without the intervention of Saline _Menstruums_. +Of the Adventitious Colours of Metalline Bodies the Chief sorts seem to be +these three. The first, such Colours as are produc'd without other +Additaments by the Action of the fire upon Metalls. The next such as emerge +from the Coalition of Metalline Particles with those of some _Menstruum_ +imploy'd to Corrode a Metall or Precipitate it; And the last, The Colours +afforded by Metalline Bodyes either Colliquated with, or otherwise +Penetrating into, other Bodies, especially fusible ones. But these +(_Pyrophilus,_) are only as I told you, the _Chief_ sorts of the +adventitious Colours of Metalls, for there may others belong to them, of +which I shall hereafter have occasion to take notice of some, and of which +also there possibly may be others that I never took notice of. + +And to begin with the first sort of Colours, 'tis well enough known to +Chymists, that Tin being Calcin'd by fire alone is wont to afford a White +_Calx_, and Lead Calcin'd by fire alone affords that most Common Red-Powder +we call _Minium:_ Copper also Calcin'd _per se_, by a long or violent fire, +is wont to yield (as far as I have had occasion to take notice of it) a +very Dark or Blackish Powder; That Iron likewise may by the Action of +Reverberated flames be turn'd into a Colour almost like that of Saffron, +may be easily deduc'd from the Preparation of that Powder, which by reason +of its Colour and of the Metall 'tis made of is by Chymists call'd, _Crocus +Martis per se_. And that _Mercury_ made by the stress of Fire, may be +turn'd into a Red Powder, which Chymists call Precipitate _per se_, I +elsewhere more particularly declare. + +_Annotation I._ + +It is not unworthy the Admonishing you, (_Pyrophilus_,) and it agrees very +well with our Conjectures about the dependence of the change of a Body's +Colour upon that of its Texture, that the same Metall may by the successive +operation of the fire receive divers Adventitious Colours, as is evident in +Lead, which before it come to so deep a Colour as that of _Minium_, may +pass through divers others. + +_Annotation II_. + +Not only the _Calces_, but the Glasses of Metalls, Vitrify'd _per se_, may +be of Colours differing from the Natural or Obvious Colour of the Metall; +as I have observ'd in the Glass of Lead, made by long exposing Crude Lead +to a violent fire, and what I have observ'd about the Glass or Slagg of +Copper, (of which I can show you some of an odd kind of Texture,) may be +elsewhere more conveniently related. I have likewise seen a piece of very +Dark Glass, which an Ingenious Artificer that show'd it me profess'd +himself to have made of Silver alone by an extreme _Violence_ (which seems +to be no more than is needfull) of the fire. + +_Annotation III_. + +Minerals also by the Action of the Fire may be brought to afford Colours +very differing from their own, as I not long since noted to you about the +variously Colour'd Flowers of Antimony, to which we may add the Whitish +Grey-Colour of its _Calx_, and the Yellow or Reddish Colour of the Glass, +where into that _Calx_ may be flux'd. + +And I remember, that I elsewhere told you, that Vitriol Calcin'd with a +very gentle heat, and afterwards with higher and higher degrees of it, may +be made to pass through several Colours before it descends to a Dark +Purplish Colour, whereto a strong fire is wont at length to reduce it. But +to insist on the Colours produc'd by the Operation of fire upon several +Minerals would take up farr more time than I have now to spare. + +_EXPERIMENT XLVII._ + +The Adventitious Colours produc'd upon Metalls, or rather with them, by +Saline Liquors, are many of them so well known to Chymists, that I would +not here mention them, but that besides a not un-needed Testimony, I can +add something of my own, to what I shall repeat about them, and divers +Experiments which are familiar to Chymists, are as yet unknown to the +greatest part of Ingenious Men. + +That Gold dissolv'd in _Aqua Regia_ ennobles the _Menstruum_ with its own +Colour, is a thing that you cannot (_Pyrophilus_,) but have often seen. The +Solutions of Mercury in _Aqua-fortis_ are not generally taken notice of, to +give any notable Tincture to the _Menstruum_; but sometimes when the Liquor +first falls upon the Quick Silver, I have observ'd a very remarkable, +though not durable, Greenness, or Blewness to be produc'd, which is a +_Phænomenon_ not unfit for you to consider, though I have not now the +leisure to discourse upon it. Tin Corroded by _Aqua-fortis_ till the +_Menstruum_ will work no farther on it, becomes exceeding White, but as we +elsewhere note, does very easily of it self acquire the consistence, not of +a Metalline _Calx_, but of a Coagulated matter, which we have observ'd with +pleasure to look so like, either to curdled Milk, or curdled Whites of +Eggs, that a person unacquainted with such Solutions may easily be mistaken +in it. But when I purposely prepar'd a _Menstruum_ that would dissolve it +as _Aqua-fortis_ dissolves Silver, and not barely Corrode it, and quickly +let it fall again, I remember not that I took notice of any particular +Colour in the Solution, as if the more Whitish Metalls did not much Tinge +their _Menstruums_, though the conspicuously Colour'd Metalls as Gold, and +Copper, do. For Lead dissolv'd in Spirit of Vinegar or _Aqua-fortis_ gives +a Solution cleer enough, and if the _Menstruum_ be abstracted appears +either Diaphanous or White. Of the Colour of Iron we have elsewhere said +something: And 'tis worth noting, that though if that Metall be dissolv'd +in oyl of Vitriol diluted with water, it affords a Salt or Magistery so +like in colour, as well as some other Qualities, to other green Vitriol, +that Chymists do not improperly call it _Vitriolum Martis_; yet I have +purposely try'd, that, by changing the _Menstruum_, and pouring upon the +filings of Steel, instead of oyl of Vitriol, _Aqua Fortis_, (whereof as I +remember, I us'd 4 parts to one of the Metall) I obtain'd not a Green, but +a Saffron Colour Solution; or rather a thick Liquor of a deep but yellowish +Red. Common Silver, such as is to be met with in Coines, being dissolv'd in +_Aqua fortis_, yields a Solution tincted like that of Copper, which is not +to be wondred at, because in the coining of Silver, they are wont (as we +elsewhere particularly inform you) to give it an Allay of Copper, and that +which is sold in shops for refined silver, is not (so far as we have tryed) +so perfectly free from that ignobler Metall, but that a Solution of It in +_Aqua fortis_, will give a Venereal Tincture to the _Menstruum_. But we +could not observe upon the solution of some Silver, which was perfectly +refin'd, (such as some that we have, from which 8 or 10 times its weight of +Lead has been blown off) that the _Menstruum_ though held against the Light +in a Crystal Vial did manifestly disclose any Tincture, only it seem'd +sometimes not to be quite destitute of a little, but very faint +Blewishness. + +But here I must take notice, that of all the Metalls, there is not any +which doth so easily and constantly disclose its unobvious colour as Copper +doth. For not only in acid _Menstruums_ as _Aqua Fortis_ and Spirit of +Vinegar, it gives a Blewish green solution, but if it be almost any way +corroded, it _appears of one of those_ two colours, as may be observ'd in +Verdigreese made several wayes, in that odd preparation of _Venus_, which +we elsewhere teach you to make with Sublimate, and in the common Vitriols +of _Venus_ deliver'd by Chymists; and so constant is the disposition of +Copper, notwithstanding the disguise Artists put upon it, to disclose the +colour we have been mentioning, that we have by forcing it up with _Sal +Armoniack_ obtain'd a Sublimate of a Blewish Colour. Nay a famous Spagyrist +affirms, that the very Mercury of it is green, but till he teach us an +intelligible way of making such a Mercury, we must content ourselves to +inform you, that we have had a Cupreous Body, that was Præcipitated out of +a distill'd Liquor, that seem'd to be the the Sulphur of _Venus_, and +seem'd even when flaming, of a Greenish Colour. And indeed Copper is a +Metall so easily wrought upon by Liquors of several kinds, that I should +tell you, I know not any Mineral, that will concurr to the production of +such a variety of Colours as Copper dissol'd in several _Menstruums_, as +Spirit of Vinegar, _Aqua fortis_, _Aqua Regis_, Spirit of Nitre, of Urine, +of Soot, Oyls of several kinds, and I know not how many other Liquors, if +the variety of somewhat differing colours (that Copper will be made to +assume, as it is wrought upon by several Liquors) were not comprehended +within the Limits of Greenish Blew, or Blewish Green. + +And yet I must advertise you (_Pyrophilus_) that being desirous to try if I +could not make with crude Copper a Green Solution without the Blewishness +that is wont to accompany its Vulgar Solutions, I bethought my self of +using two _Menstruums_, which I had not known imploy'd to work on this +Metall, and which I had certain Reasons to make Tryal of, as I successfully +did. The one of these Liquors (if I much misremember not) was Spirit of +Sugar distill'd in a Retort, which must be warily done, (if you will avoid +breaking your glasses) and the other, Oyl or Spirit of Turpentine, which +affords a fine Green Solution that is useful to me on several occasions. +And yet to shew that the adventitious colour may result, as well from the +true and permanent Copper it self, as the Salts wherewith 'tis corroded, I +shall add, that if you take a piece of good _Dantzick_ Copperis, or any +other Vitriol wherein _Venus_ is prædominant, and having moistened it in +your Mouth, or with fair water, rubb it upon a whetted knife, or any other +bright piece of Steel or Iron, it will (as we have formerly told you) +present'y stain the Steel with a Reddish colour, like that of Copper, the +reason of which, we must not now stay to inquire. + +_Annotation I._ + +I presume you may have taken notice (_Pyrophilus_) that I have borrowed +some of the Instances mention'd in this 47th Experiment, from the +Laboratories of Chymists, and because in some (though very few) other +passages of this Essay, I have likewise made use of Experiments mention'd +also by some Spagyrical Writers, I think it not amiss to represent to you +on this Occasion once for all, some things besides those which I intimated +in the præamble of this present Experiment; For besides, that 'tis very +allowable for a Writer to repeat an Experiment which he invented not, in +case he improve it; And besides that many Experiments familiar to Chymists +are unknown to the generality of Learned Men, who either never read +Chymical processes, or never understood their meaning, or never durst +believe them; besides these things, I say, I shall represent, That, as to +the few Experiments I have borrowed from the Chymists, if they be very +Vulgar, 'twould perhaps be difficult to ascribe each of them its own +Author, and 'tis more than the generality of Chymists themselves can do: +and if they be not of very known and familiar practise among them, unless +the Authors wherein I found them had given me cause to believe, themselves +had try'd them, I know not why I might not set them down, as a part of the +_Phænomena_ of Colours which I present you; Many things unanimously enough +deliver'd as matters of fact by (I know not how many Chymical Writers) +being not to be rely'd on, upon the single Authority of such Authors: For +Instance, as some Spagyrists deliver (perhaps amongst several deceitful +processes) that _Saccarum Saturni_ with Spirit of Turpentine will afford a +Balsom, so _Beguinus_ and many more tell us, that the same Concrete +(_Saccarum Saturni_) will yield an incomparably fragrant Spirit, and a +pretty Quantity of two several Oyles, and yet since many have complain'd, +as well as I have done, that they could find no such odoriferous, but +rather an ill-sented Liquor, and scarce any oyl in their Distillation of +that sweet Vitriol, a wary person would as little build any thing on what +they say of the former Experiment, as upon what they averr of the later, +and therefore I scrupled not to mention this Red Balsom of which I have not +seen any, (but what I made) among my other experiments about redness. + +_Annot. II._ + +We have sometimes had the Curiosity to try what Colours Minerals, as +Tinglass, Antimony, Spelter, &c. would yield in several _Menstruums_, nor +have we forborn to try the Colours of stones, of which that famous one, +(which _Helmont_ calls _Paracelsus's Ludus_) though it be digg'd out of the +Earth and seem a true stone, has afforded in _Menstruums_ capable to +dissolve so solid a stone, sometimes a Yellowish, sometimes a Red solution +of both which I can show you. But though I have from Minerals obtain'd with +several _Menstruums_ very differing Colours, and some such as perhaps you +would be surpriz'd to see drawn from such Bodies: yet I must now pass by +the particulars, being desirous to put an End to this Treatise, before I +put an end to your Patience and my own. + +_Annotation III._ + +And yet before I pass to the next Experiment, I must put you in mind, that +the Colours of Metals may in many cases be further alter'd by imploying, +either præcipitating Salts, or other convenient Substances to act upon +their Solutions. Of this you may remember, that I have given you several +Instances already, to which may be added such as these, That if Quicksilver +be dissolv'd in _Aqua fortis_, and Præcipitated out of the Solution, either +with water impregnated with Sea salt, or with the spirit of that Concrete, +it falls to the Bottom in the form of a white powder, whereas if it be +Præcipitated with an Alcaly, it will afford a Yellowish or tawny powder, +and if there be no Præcipitation made, and the _Menstruum_ be drawn off +with a convenient fire, the corroded Mercury will remain in the bottom, in +the form of a substance that may be made to appear of differing Colours by +differing degrees of Heat; As I remember that lately having purposely +abstracted _Aqua fortis_ from some Quicksilver that we had dissolv'd in it, +so that there remain'd a white _Calx_, exposing that to several degrees of +Fire, and afterwards to a naked one, we obtain'd some new Colours, and at +length the greatest part of the _Calx_ lying at the Bottome of the Vial, +and being brought partly to a Deep Yellow, and partly to a Red Colour, the +rest appear'd elevated to the upper part and neck of the Vial, some in the +form of a Reddish, and some of an Ash-Colour Sublimate. But of the +differing Colours which by differing wayes and working of Quick Silver with +Fire, and Saline Bodies, may be produc'd in Precipitates, I may elsewhere +have occasion to take further notice. I also told you not long since, that +if you corrode Quick-silver with Oyl of Vitriol instead of _Aqua-fortis_, +and abstract the _Menstruum_, there will remain a White _Calx_ which by the +Affusion of Fair Water presently turns into a Lemmon Colour. And ev'n the +_Succedaneum_ to a _Menstruum_ may sometimes serve the turn to change the +Colours of a Metal. The lovely Red which Painters call Vermillion, is made +of Mercury, which is of the Colour of Silver, and of Brimstone which is of +Kin to that of Gold, Sublim'd up together in a certain proportion, as is +vulgarly known to Spagyrists. + +_EXPERIMENT XLVIII._ + +The third chief sort of the Adventitious Colours of Metals, is, that which +is produc'd by associating them (especially when Calcin'd) with other +fusible Bodies, and Principally Venice, and other fine Glass devoid of +Colour. + +I have formerly given you an Example, whereby it may appear, that a Metal +may impart to Glass a Colour much differing from its own, when I told you, +how with Silver, I had given Glass a lovely Golden Colour. And I shall now +add, that I have Learn'd from one of the Chief Artificers that sells +Painted Glass, that those of his Trade Colour it Yellow with a preparation +of the _Calx_ of Silver. Though having lately had occasion among other +Tryals to mingle a few grains of Shell-silver (such as is imploy'd with the +Pensil and Pen) with a convenient proportion of powder'd Crystal Glass, +having kept them two or three hours in fusion, I was surpriz'd to find the +Colliquated Mass to appear upon breaking the Crucible of a lovely Saphirine +Blew, which made me suspect my Servant might have brought me a wrong +Crucible, but he constantly affirm'd it to be the same wherein the Silver +was put, and considerable Circumstances countenanc'd his Assertion, so that +till I have opportunity to make farther Tryal, I cannot but suspect, either +that Silver which is not (which is not very probable) brought to a perfect +Fusion and Colliquation with Glass, may impart to it other Colours than +when Neal'd upon it, or else (which is less unlikely) that though Silver +Beaters usually chuse the finest Coyn they can get, as that which is most +extensive under the Hammer, yet the Silver-leaves of which this Shel-silver +was made, might retain so much Copper as to enable it to give the +predominant tincture to the Glass. + +For, I must proceed to tell you (_Pyrophilus_) as another instance of the +Adventitious Colours of Metals, that which is something strange, Namely, +That though Copper Calcin'd _per se_ affords but a Dark and basely Colour'd +_Calx_, yet the Glassmen do with it, as themselves inform me, Tinge their +Glass green. And I remember, that when once we took some crude Copper, and +by frequent Ignition quenching it in Water had reduc'd it to a Dark and +Ill-colour'd Powder, and afterward kept it in Fusion in about a 100. times +its weight of fine Glass, we had, though not a Green, yet a Blew colour'd +Mass, which would perhaps have been Green, if we had hit right upon the +Proportion of the Materials, and the Degree of Fire, and the Time wherein +it ought to be kept in Fusion, so plentifully does that Metal abound in a +Venerial Tincture, as Artists call it, and in so many wayes does it +disclose that Richness. But though Copper do as we have said give somewhat +near the like Colour to Glass, which it does to _Aqua-fortis_, yet it seems +worth inquiry, whether those new Colours which Mineral Bodies disclose in +melted Glass, proceed from the Coalition of the Corpuscles of the Mineral +with the Particles of the Glass as such, or from the Action (excited or +actuated by fire) of the Alcalizate Salt (which is a main Ingredient of +Glass,) upon the Mineral Body, or from the concurrence of both these +Causes, or else from any other. But to return to that which we were saying, +we may observe that _Putty_ made by calcining together a proportion of Tin +and Lead, as it is it self a White _Calx_, so does it turn the _Pitta di +Crystallo_ (as the Glassmen call the matter of the Purer sort of Glass, +wherewith it is Colliquated into a White Mass, which if it be opacous +enough is employ'd, as we elsewhere declare, for White Amel. But of the +Colours which the other Metals may be made to produce in Colourless Glass, +and other Vitrifiable Bodies, that have native Colours of their own, I must +leave you to inform your self upon Tryal, or at least must forbear to do it +till another time, considering how many Annotations are to follow, upon +what has in this and the two former Experiments been said already. + +_Annotation I._ + +When the Materials of Glass being melted with Calcin'd Tin, have compos'd a +Mass Undiaphanous and White, this White Amel is as it were the Basis of all +those fine Concretes that Goldsmiths and several Artificers imploy in the +curious Art of Enamelling. For this White and Fusible substance will +receive into it self, without spoyling them, the Colours of divers other +Mineral substances, which like it will indure the fire. + +_Annotation II._ + +So that as by the present (XLVIII.) Experiment it appears, that divers +Minerals will impart to fusible Masses, Colours differing from their own; +so by the making and compounding of Amels, it may appear, that divers +Bodies will both retain their Colour in the fire, and impart the _same_ to +some others wherewith they were vitrifi'd, and in such Tryals as that +mention'd in the 17. Experiment, where I told you, that ev'n in Amels a +Blew and Yellow will compound a Green. 'Tis pretty to behold, not only that +some Colours are of so fix'd a Nature, as to be capable of mixture without +receiving any detriment by the fire, that do's so easily destroy or spoyl +those of other Bodies; but Mineral Pigments may be mingled by fire little +less regularly and successfully, than in ordinary Dyeing Fatts, the vulgar +Colours are wont to be mingled by the help of Water. + +_Annotation III._ + +'Tis not only Metalline, but other Mineral Bodies, that may be imploy'd, to +give Tinctures unto Glass (and 'tis worth noting how small a quantity of +some Mineral substances, will Tinge a Comparatively vast proportion of +Glass, and we have sometimes attempted to Colour Glass, ev'n with Pretious +Stones, and had cause to think the Experiment not cast away. And 'tis known +by them that have look'd into the Art of Glass, that the Artificers use to +tinge their Glass Blew, with that Dark Mineral _Zaffora_, (some of my +Tryals on which I elsewhere acquaint you) which some would have to be a +Mineral Earth, others a Stone, and others neither the one, nor the other, +but which is confessedly of a Dark, but not a Blew Colour, though it be not +agreed of what particular Colour it is. 'Tis likewise though a familiar yet +a remarkable practise among those that Deal in the making of Glass, to +imploy (as some of themselves have inform'd me) what they call Manganess, +and some Authors call _Magnesia_ (of which I make particular mention in +another Treatise) to exhibit in Glass not only other Colours than its own, +(which is so like in Darkness or blackishness to the Load stone, that 'tis +given by Mineralists, for one of the Reasons of its Latine Name) but +Colours differing from one another. For though they use it, (which is +somewhat strange) to Clarifye their Glass, and free it from that Blewish +Greenish Colour, which else it would too often be subject to, yet they also +imploy it in certain proportions, to tinge their Glass both with a Red +colour, and with a Purplish or Murry, and putting in a greater Quantity, +they also make with it that deep obscure Glass which is wont to pass for +Black, which agrees very well with, and may serve to confirm what we noted +near the beginning of the 44th Experiment, of the seeming Blackness of +those Bodies that are overcharg'd with the Corpuscles of such Colours, as +Red, or Blew, or Green, &c. And as by several Metals and other Minerals we +can give various Colours to Glass, so on the other side, by the differing +Colours that Mineral Oars, or other Mineral Powders being melted with Glass +disclose in it, a good Conjecture may be oftentimes made of the Metall or +known Mineral, that the Oar propos'd, either holds, or is most of kin to. +And this easie way of examining Oars, may be in some cases of good use, and +is not ill deliver'd by _Glauber_, to whom I shall at present refer you, +for a more particular account of it: unless your Curiosity command also +what I have observ'd about these matters; only I must here advertise you, +that great circumspection is requisite to keep this way from proving +fallacious, upon the account of the variations of Colour that may be +produc'd by the differing proportions that may be us'd betwixt the Oar and +the Glass, by the Richness or Poorness of the Oar it self, by the Degree of +Fire, and (especially) by the Length of Time, during which the matter is +kept in fusion; as you will easily gather from what you will quickly meet +with in the following Annotation upon this present 48th Experiment. + +_Annotation IV._ + +There is another way and differing enough from those already mention'd, by +which Metalls may be brought to exhibit adventitious Colours: For by This, +the Metall do's not so much impart a Colour to another Body, as receive a +Colour from it, or rather both Bodies do by the new Texture resulting from +their mistion produce a new Colour. I will not insist to this purpose upon +the Examples afforded us by yellow Orpiment, and common Sea Salt, from +which, sublim'd together, Chymists unanimously affirm their White or +Crystalline Arsenick to be made: But 'tis not unworthy our noting, That +though Yellow Orpiment be acknowledg'd to be the Copiousest by far of the +two Ingredients of Arsenick, yet this last nam'd Body being duely added to +the highest Colour'd Metall Copper, when 'tis in fusion, gives it a +whiteness both within and without. Thus _Lapis Calaminaris_ changes and +improves the Colour of Copper by turning it into Brass. And I have +sometimes by the help of Zinck duely mix'd after a certain manner, given +Copper one of the Richest Golden Colours that ever I have seen the Best +true Gold Ennobled with. But pray have a care that such Hints fall not into +any hands that may mis-imploy them. + +_Annotation V._ + +Upon the Knowledge of the differing wayes of making Minerals and Metalls +produce their adventitious Colours in Bodies capable of Vitrification, +depends the pretty Art of making what Chymists by a Barbarous Word are +pleas'd to call _Amanses_, that is counterfeit, or factitious Gemms, as +Emeralds, Rubies, Saphires, Topazes, and the like. For in the making of +these, though pure Sand or Calcin'd Crystal give the Body, yet 'tis for the +most part some Metalline or Mineral _Calx_, mingled in a small proportion +that gives the Colour. But though I have many years since taken delight, to +divert my self with this pleasing Art, and have seen very pretty +Productions of it, yet besides that I fear I have now forgot most of the +little Skill I had in it, this is no place to entertain you with what would +rather take up an intire Discourse, than be comprehended in an Annotation; +wherefore the few things which I shall here take notice of to you, are only +what belong to the present Argument, Namely, + +First, That I have often observ'd that Calcin'd Lead Colliquated with fine +White Sand or Crystal, reduc'd by ignitions and subsequent extinctions in +Water to a subtile Powder, will of it self be brought by a due Decoction to +give a cleer Mass Colour'd like a _German_ Amethyst. For though this glass +of Lead, is look'd upon by them that know no better way of making +_Amanses_, as the grand Work of them all, yet which is an inconvenience +that much blemishes this way, the Calcin'd Lead it self does not only +afford matter to the _Amanses_, but has also as well as other Metals a +Colour of its own, which as I was saying, I have often found to be like +that of _German_ (as many call them) not Eastern Amethysts. + +Secondly, That nevertheless this Colour may be easily over-powr'd by those +of divers other Mineral Pigments (if I may so call them) so that with a +glass of Lead, you may Emulate (for Instance) the fresh and lovely +Greenness of an Emerald, though in divers cases the Colour which the Lead +it self upon Vitrification tends to, may vitiate that of the Pigment, which +you would introduce into the Mass. + +Thirdly, That so much ev'n these Colours depend upon Texture, that in the +Glass of Lead it self made of about three parts of _Lytharge_ or _Minium_ +Colliquated with one of very finely Powder'd Crystal or Sand, we have taken +pleasure to make the mixture pass through differing Colours, as we kept it +more or less in the Fusion. For it was not usually till after a pretty long +Decoction that the Mass attain'd to the Amethystin Colour. + +Fourthly and lastly, That the degrees of Coction and other Circumstances +may so vary the Colour produc'd in the same mass, that in a Crucible that +was not great I have had fragments of the same Mass, in some of which +perhaps not so big as a Hazel-Nut, you may discern four distinct Colours. + +_Annotation VI._ + +You may remember (_Pyrophilus_) that when I mention'd the three sorts of +adventitious Colours of Metals, I mention'd them but as the chief, not the +only. For there may be other wayes, which though they do not in so strict a +sense belong to the adventitious Colours of Metals, may not inconveniently +be reduc'd to them. And of these I shall name now a couple, without denying +that there may be more. + +The first may be drawn from the practise of those that Dye Scarlet. For the +famousest Master in that Art, either in _England_ or _Holland_, has +confess'd to me, that neither others, nor he can strike that lovely Colour +which is now wont to be call'd the _Bow-Dye_, without their Materials be +Boyl'd in Vessels, either made of, or lin'd with a particular Metall. But +of what I have known attempted in this kind, I must not as yet for fear of +prejudicing or displeasing others give you any particular Account.[24] + +The other way (_Pyrophilus_) of making Metals afford unobvious Colours, is +by imbuing divers Bodies with Solutions of them made in their proper +_Menstruum's_, As (for Instance) though Copper plentifully dissolv'd in +_Aqua fortis_, will imbue several Bodies with the Colour of the Solution; +Yet Some other Metalls will not (as I elsewhere tell you) and have often +try'd. Gold dissolv'd in _Aqua Regia_, will, (which is not commonly known) +Dye the Nails and Skin, and Hafts of Knives, and other things made of +Ivory, not with a Golden, but a Purple Colour, which though it manifest it +self but slowly, is very durable, and scarce ever to be wash'd out. And if +I misremember not, I have already told you in this Treatise, that the purer +Crystals of fine Silver made with _Aqua fortis_, though they appear White, +will presently Dye the Skin and Nails, with a Black, or at least a very +Dark Colour, which Water will not wash off, as it will ordinary Ink from +the same parts. And divers other Bodies may the Same way be Dy'd, some of a +Black, and others of a Blackish Colour. + + [24] See the latter end of the fiftieth Experiment. + +And as Metalline, so likewise Mineral Solutions may produce Colours +differing enough from those of the Liquors themselves. I shall not fetch an +Example of this, from what we daily see happen in the powdring of Beef, +which by the Brine imploy'd about it (especially if the flesh be over +salted) do's oftentimes appear at our Tables of a Green, and sometimes of a +Reddish Colour, (deep enough) nor shall I insist on the practise of some +that deal in Salt Petre, who, (as I suspected, and as themselves +acknowledg'd to me) do, with the mixture of a certain proportion of that; +and common Salt, give a fine Redness, not only to Neats Tongues, but which +is more pretty as well as difficult, to such flesh, as would otherwise be +purely White; These Examples, I say, I shall decline insisting on, as +chusing rather to tell you, that I have several times try'd, that a +Solution of the Sulphur of Vitriol, or ev'n of common Sulphur, though the +Liquor appear'd clear enough, would immediately tinge a piece of new Coin, +or other clean Silver, sometimes with a Golden, sometimes with a deeper, +and more Reddish colour, according to the strength of the Solution, and the +quantity of it, that chanc'd to adhere to the Metall; which may take off +your wonder that the water of the hot Spring at _Bath_, abounding with +dissolv'd Substances of a very Sulphureous Nature, should for a while, as +it were gild, the new or clean pieces of Silver coyn, that are for a due +time immers'd in it. And to these may be added those formerly mention'd +Examples of the adventitious Colours of Mineral Bodies; which brings into +my mind, that, ev'n Vegetable Liquors, whether by degeneration, or by +altering the Texture of the Body that imbibes them, may stain other Bodies +with Colours differing enough, from their own, of which very good +Herbarists have afforded us a notable Example, by affirming that the Juice +of _Alcanna_ being green (in which state I could never here procure it) +do's yet Dye the Skin and Nails of a Lasting Red. But I see this Treatise +is like to prove too bulky without the addition of further Instances of +this Nature. + +_EXPERIMENT XLIX._ + +Meeting the other day, _Pyrophilus_, in an _Italian_ book, that treats of +other matters, with a way of preparing what the Author calls a _Lacca_ of +Vegetables, by which the _Italians_ mean a kind of Extract fit for +Painting, like that rich _Lacca_ in English commonly call'd _Lake_, which +is imploy'd by Painters as a glorious Red. And finding the Experiment not +to be inconsiderable, and very defectively set down, it will not be amiss +to acquaint you with what some Tryals have inform'd us, in reference to +this Experiment, which both by our Italian Author, and by divers of his +Countrymen, is look'd upon as no trifling Secret. + +Take then the root call'd in Latin _Curcuma_, and in English Turmerick, +(which I made use of, because it was then at hand, and is among Vegetables +fit for that purpose one of the most easiest to be had) and when it is +beaten, put what Quantity of it you please into fair Water, adding to every +pound of Water about a spoonfull or better of as strong a _Lixivium_ or +Solution of Potashes as you can well make, clarifying it by Filtration +before you put it to the Decocting water. Let these things boyl, or rather +simper over a soft Fire in a clean glaz'd Earthen Vessel, till you find by +the Immersion of a sheet of White Paper (or by some other way of Tryal) +that the Liquor is sufficiently impregnated with the Golden Tincture of the +Turmerick, then take the Decoction off the Fire, and Filter or Strain it +that it may be clean, and leisurely dropping into it a strong Solution of +Roch Allum, you shall find the Decoction as it were curdl'd, and the +tincted part of it either to emerge, to subside, or to swim up and down, +like little Yellow flakes; and if you pour this mixture into a Tunnel lin'd +with Cap Paper, the Liquor that Filtred formerly so Yellow, will now pass +clean thorow the Filtre, leaving its tincted, and as it were curdled parts +in the Filtre, upon which fair Water must be so often pour'd, till you have +Dulcifi'd the matter therein contain'd, the sign of which Dulcification is +(you know) when the Water that has pass'd through it, comes from it as +tasteless as it was pour'd on it. And if without Filtration you would +gather together the flakes of this Vegetable Lake, you must pour a great +Quantity of fair Water upon the Decoction after the affusion of the +Alluminous Solution, and you shall find the Liquor to grow clearer, and the +Lake to settle together at the bottom, or emerge to the top of the Water, +though sometimes having not pour'd out a sufficient Quantity of fair Water, +we have observ'd the Lake partly to subside, and partly to emerge, leaving +all the middle of the Liquor clear. But to make this Lake fit for use, it +must by repeated affusions of fresh Water, be Dulcifi'd from the adhering +Salts, as well as that separated by Filtration, and be spread and suffer'd +to dry leisurely upon pieces of Cloth, with Brown Paper, or Chalk, or +Bricks under them to imbibe the Moisture[25]. + + [Page 372] +_Annotation I._ + +Whereas it is presum'd that the Magistery of Vegetables obtain'd this way +consists but of the more Soluble and Coloured parts of the Plants that +afford it, I must take the liberty to Question the supposition. And for my +so doing, I shall give you this account. + +According to the Notions (such as they were) that I had concerning Salts; +Allom, though to sense a Homogeneous Body, ought not to be reckon'd among +true Salts, but to be it self look'd upon as a kind of Magistery, in regard +that as Native Vitriol (for such I have had) contains both a Saline +substance and a Metall, whether Copper, or Iron, corroded by it, and +associated with it; so Allom which may be of so near a kin to Vitriol, that +in some places of _England_ (as we are assur'd by good Authority the same +stone will sometimes afford both) seems manifestly to contain a peculiar +kind of Acid Spirit, generated in the Bowels of the Earth, and some kind of +stony matter dissolv'd by it. And though in making our ordinary Allom, the +Workmen use the Ashes of a Sea Weed (vulgarly call'd Kelp) and Urine: yet +those that should know, inform us, that, here in _England_, there is +besides the factitious Allom, Allom made by Nature Without the help of +those Additaments. Now (_Pyrophilus_) when I consider'd this composition of +Allom, and that Alcalizate Salts are wont to Præcipitate what acid Salts +have dissolv'd, I could not but be prone to suspect that the Curdled +Matter, which is call'd the Magistery of Vegetables, may have in it no +inconsiderable proportion of a stony substance Præcipitated out of the +Allom by the _Lixivium_, wherein the Vegetable had been decocted, and to +shew you, that there is no necessity, that all the curdl'd substance must +belong to the Vegetable, I shall add, that I took a strong Solution of +Allom, and having Filtred it, by pouring in a convenient Quantity of a +strong Solution of Potashes, I presently, as I expected, turn'd the mixture +into a kind of white Curds, which being put to Filtre, the Paper retain'd a +stony _Calx_, copious enough, very White, and which seem'd to be of a +Mineral Nature, both by some other signes, and this, that little Bits of it +being put upon a live Coal, which was Gently Blown whilst they were on it, +they did neither melt nor fly away, and you may keep a Quantity of this +White substance for a good while, (nay for ought I can guess for a very +long one) in a red hot Crucible without losing or spoiling it; nor did hot +Water wherein I purposely kept another parcel of such _Calx_, seem to do +any more than wash away the looser adhering Salts from the stony substance, +which therefore seem'd unlikely to be separable by ablutions (though +reiterated) from the Præcipitated parts of the Vegetable, whose Lake is +intended. And to shew you, that there is likewise in Allom a Body, with +which the fix'd Salt of the Alcalizate Solution will concoagulate into a +Saline Substance differing from either of them, I shall add, that I have +taken pleasure to recover out of the slowly exhal'd Liquor, that pass'd +through the filtre, and left the foremention'd _Calx_ behind, a Body that +at least seem'd a Salt very pretty to look on, as being very White, and +consisting of an innumerable company of exceeding slender, and shining +Particles, which would in part easily melt at the flame of a Candle, and in +part flye away with some little noise. But of this substance, and its odd +Qualities more perhaps elsewhere; for now I shall only take notice to you, +that I have likewise with Urinous Salts, such as the Spirit of Sal +Armoniack, as well as with the Spirit of Urine it self, Nay, (if I much +mistake not) ev'n with Stale Urine undistil'd, easily Precipitated such a +White _Calx_ as I was formerly speaking of, out of a Limpid Solution of +Allom, so that there is need of Circumspection in judging of the Natures of +Liquors by Precipitations wherein Allom intervenes, else we may sometimes +mistakingly imagine that to be Precipitated out of a Liquor by Allom, which +is rather Precipitated out of Allom by the Liquor: And this puts me in mind +to tell you, that 'tis not unpleasant to behold how quickly the Solution of +Allom (or injected lumps of Allom) do's occasion the severing of the +colour'd parts of the Decoction from the Liquor that seem'd to have so +perfectly imbib'd them. + + [25] _The Curious Reader that desires further Information concerning + Lakes, may Resort to the 7th Book of_ Neri's _Art of Glass, Englished (6 + or 7 years since the Writing of this 49th Experiment) and Illustrated + with Learned Observations, by the Inquisitive and experienc'd Dr._ + Charles Merret. + +_Annot. II._ + +The above mention'd way of making Lakes we have tryed not only with +Turmerick, but also with Madder, which yielded us a Red Lake; and with Rue, +which afforded us an extract, of (almost if not altogether) the same Colour +with that of the leaves. + +But in regard that 'tis Principally the Alcalizate Salt of the Pot-ashes, +which enables the water to Extract so powerfully the Tincture of the +Decocted Vegetables, I fear that our Author may be mistaken by supposing +that the Decoction will alwayes be of the very same Colour with the +Vegetable it is made off. For Lixiviate Salts, to which Pot-ashes eminently +belong, though by peircing and opening the Bodies of Vegetables, they +prepare and dispose them to part readily with their Tincture, yet some +Tinctures they do not only draw out, but likewise alter them, as may be +easily made appear by many of the Experiments already set down in this +Treatise, and though Allom being of an Acid Nature, its Solutions may in +some Cases destroy the Adventitious Colours produc'd by the Alcaly, and +restore the former: yet besides that Allom is not, as I have lately shown, +a meer Acid Salt, but a mixt Body, and besides, that its operations are +languid in comparison of the activity of Salts freed by Distillation, or by +Incineration and Dissolution, from the most of their Earthy parts, we have +seen already Examples, that in divers Cases an Acid Salt will not restore a +Vegetable substance to the Colour of which an Alcalizate one had depriv'd +it, but makes it assume a third very differing from both, as we formerly +told you, that if Syrrup of Violets were by an Alcaly turn'd Green, (which +Colour, as I have try'd, may be the same way produc'd in the Violet-leaves +themselves without any Relation to a Syrrup) an Acid Salt would not make it +Blew again, but Red. And though I have by this way of making Lakes, made +Magisteries (for such they seem to be) of Brazil, and as I remember of +Cochinele it self, and of other things, Red, Yellow or Green which Lakes +were enobled with a Rich Colour, and others had no bad one; yet in some the +colour of the Lake seem'd rather inferiour than otherwise to that of the +Plant, and in others it seem'd both very differing, and much worse; but +Writing this in a time and place where I cannot provide my self of Flowres +and other Vegetables to prosecute such Tryals in a competent variety of +Subjects, I am content not to be positive in delivering a judgment of this +way of Lakes, till Experience, or You, _Pyrophilus_, shall have afforded me +a fuller and more particular Information. + +_Annotation III._ + +And on this occasion (_Pyrophilus_) I must here (having forgot to do it +sooner) advertise you once for all, that having written several of the +foregoing Experiments, not only in haste but at seasons of the year, and in +places wherein I could not furnish my self with such Instruments, and such +a variety of Materials, as the design of giving you an Introduction into +the History of Colours requir'd, it can scarce be otherwise but that divers +of the Experiments, that I have set down, may afford you some matter of new +Tryals, if you think fit to supply the deficiencies of some of them +(especially the freshly mention'd about Lakes, and those that concern +Emphatical Colours) which deficiencies for want of being befriended with +accommodations I could better discern than avoid. + +_Annotation IV._ + +The use of Allom is very great as well as familiar in the Dyers Trade, and +I have not been ill pleas'd with the use I have been able to make of it in +preparing other pigments than those they imploy with Vegetable Juices. But +the Lucriferous practises of Dyers and other Tradesmen, I do, for Reasons +that you may know when you please, purposely forbear in this Essay, though +not strictly from pointing at, yet from making it a part of my present work +explicitly and circumstantially to deliver, especially since I now find +(though late and not without some Blushes at my prolixity) that what I +intended but for a short Essay, is already swell'd into almost a Volume. + +_EXPERIMENT L._ + +Yet here, _Pyrophilus_, I must take leave to insert an Experiment, though +perhaps you'l think its coming in here an Intrusion, For I confess its more +proper place would have been among those Experiments, that were brought as +proofs and applications of our Notions concerning the differences of Salts; +but not having remembred to insert it in its fittest place, I had rather +take notice of it in this, than leave it quite unmention'd: partly because +it doth somewhat differ from the rest of our Experiments about Colours, in +the way whereby 'tis made; and partly because the grounds upon which I +devis'd it, may hint to you somewhat of the Method I use in Designing and +Varying Experiments about Colours, and upon this account I shall inform +you, not only What I did, but Why I did it. + +I consider'd then that the work of the former Experiments was either to +change the Colour of a Body into another, or quite to destroy it, without +giving it a successor, but I had a mind to give you also a way, whereby to +turn a Body endued with one Colour into two Bodies, of Colours, as well as +consistencies, very distinct from each other, and that by the help of a +Body that had it self no Colour at all. In order to this, I remembred, that +finding the Acidity of Spirit of Vinegar to be wholly destroy'd by its +working upon _Minium_ (or calcin'd Lead) whereby the Saline particles of +the _Menstruum_ have their Taste and Nature quite alter'd, I had, among +other Conjectures I had built upon that change, rightly concluded, that the +Solution of Lead in Spirit of Vinegar would alter the Colour of the Juices +and Infusions of Several Plants, much after the like manner that I had +found Oyl of Tartar to do; and accordingly I was quickly satisfied upon +Tryal, that the Infusion of Rose-leaves would by a small quantity of this +Solution well mingl'd with it, be immediately turn'd into a somewhat sad +Green. + +And further, I had often found, that Oyl of Vitriol, though a potently Acid +_Menstruum_, will yet Præcipitate many Bodies, both Mineral and others, +dissolv'd not onely in _Aqua fortis_ (as some Chymists have observ'd) but +particularly in Spirit of Vinegar, and I have further found, that the +_Calces_ or Powders Præcipitated by this Liquor were usually fair and +White. + +Laying these things together, 'twas not difficult to conclude, that if upon +a good Tincture of Red Rose-leaves made with fair Water, I dropp'd a pretty +quantity of a strong and sweet Solution of _Minium_, the Liquor would be +turn'd into the like muddy Green Substance, as I have formerly intimated to +You, that Oyl of Tartar would reduce it to, and that if then I added a +convenient quantity of good Oyl of Vitriol, this last nam'd Liquor would +have two distinct operations upon the Mixture, the one, that it would +Præcipitate that resolv'd Lead in the form of a White Powder; the other, +that it would Clarifie the muddy Mixture, and both restore, and exceedingly +heighten the Redness of the Infusion of Roses, which was the most copious +Ingredient of the Green composition, and accordingly trying the Experiment +in a Wine glass sharp at the bottom (like an inverted Cone) that the +subsiding Powder might seem to take up the more room, and be the more +conspicuous, I found that when I had shaken the Green Mixture, that the +colour'd Liquor might be the more equally dispersed, a few drops of the +rectifi'd Oyl of Vitriol did presently turn the opacous Liquor into one +that was cleer and Red, almost like a Rubie, and threw down good store of a +Powder, which when 'twas settl'd, would have appear'd very White, if some +interspers'd Particles of the red Liquor had not a little Allay'd the +Purity, though not blemish'd the Beauty of the Colour. And to shew you, +_Pyrophilus_, that these Effects do not flow from the Oyl of Vitriol, as it +is such, but as it is a strongly Acid _Menstruum_, that has the property +both to Præcipitate Lead, as well as some other Concretes out of Spirit of +Vinegar, and to heighten the Colour of Red Rose-leaves, I add, that I have +done the same thing, though perhaps not quite so well with Spirit of Salt, +and that I could not do it with _Aqua-fortis_, because though that potent +_Menstruum_ does as well as the others heighthen the Redness of Roses, yet +it would not like them Precipitate Lead out of Spirit of Vinegar, but would +rather have dissolv'd it, if it had not found it dissolv'd already. + +And as by this way we have produc'd a Red Liquor, and a White Precipitate +out of a Dirty Green magistery of Rose-leaves, so by the same Method, you +may produce a fair Yellow, and sometimes a Red Liquor, and the like +Precipitate, out of an Infusion of a curious Purple Colour. For you may +call to mind, that in the Annotation upon the 39th. Experiment I intimated +to you, that I had with a few drops of an Alcaly turn'd the Infusion of +Logg-wood into a lovely Purple. Now if instead of this Alcaly I substituted +a very Strong and well Filtrated Solution of _Minium_, made with Spirit of +Vinegar, and put about half as much of this Liquor as there was of the +Infusion of Logg-wood, (that the mixture might afford a pretty deal of +Precipitate,) the affusion of a convenient proportion of Spirit of Salt, +would (if the Liquors were well and nimbly stirr'd together) presently +strike down a Precipitate like that formerly mention'd, and turn the Liquor +that swam above it, for the most part into a lovely Yellow. + +But for the advancing of this Experiment a little further, I consider'd, +that in case I first turn'd a spoonfull of the infusion of Logg-wood +Purple, by a convenient proportion of the Solution of _Minium_, the +Affusion of Spirit of Sal Armnoniack, would Precipitate the Corpuscles of +Lead conceal'd in the Solution of _Minium_, and yet not destroy the Purple +colour of the Liquor; whereupon I thus proceeded; I took about a spoonfull +of the _fresh_ Tincture of Logg-wood, (for I found that if it were _stale_ +the Experiment would not alwayes succeed,) and having put to it a +convenient proportion of the Solution of _Minium_ to turn it into a deep +and almost opacous Purple, I then drop'd in as much Spirit of Sal +Armoniack, as I guess'd would Precipitate about half or more (but not all) +of the Lead, and immediately stirring the mixture well together, I mingled +the Precipitated parts with the others, so that they fell to the bottom, +partly in the form of a Powder, and partly in the form of a Curdled +Substance, that (by reason of the Predominancy of the Ting'd Corpuscles +over the White) retain'd as well as the Supernatant Liquor; a Blewish +Purple colour sufficiently Deep, and then instantly (but yet Warily,) +pouring on a pretty Quantity of Spirit of Salt, the matter first +Precipitated, was, by the above specified figure of the bottome of the +Glass preserv'd from being reach'd by the Spirituous Salt; which hastily +Precipitated upon it a new Bed (if I may so call it) of White Powder, being +the remaining Corpuscles of the Lead, that the Urinous Spirit had not +struck down: So that there appear'd in the Glass three distinct and very +differingly colour'd Substances; a Purple or Violet-colour'd Precipitate at +the bottom, a White and Carnation (sometimes a Variously colour'd) +Precipitate over That, and at the Top of all a Transparent Liquor of a +lovely Yellow, or Red. + +Thus you see, _Pyrophilus_, that though to some I may have seem'd to have +lighted on this (50th.) Experiment by chance, and though others may +imagine, that to have excogitated it, must have proceeded from some +extraordinary insight into the nature of Colours, yet indeed, the devising +of it need not be look'd upon as any great matter, especially to one that +is a little vers'd in the notions, I have in these, and other Papers hinted +concerning the differences of Salts. And perhaps I might add upon more than +conjecture, that these very notions and some particulars scatteringly +deliver'd in this Treatise, being skilfully put together, may suggest +divers matters (at least,) about Colours, that will not be altogether +Despicable. But those hinted, _Pyrophilus_, I must now leave such as You to +prosecute, having already spent farr more time than I intended to allow my +self in acquainting You with particular Experiments and Observations +concerning the changes of Colour, to which I might have added many more, +but that I hope I may have presented You with a competent number to make +out in some measure what I have at the beginning of this Essay either +propos'd as my Design in this Tract, or deliver'd as my Conjectures +concerning these matters. And it not being my present Designe, as I have +more than once Declar'd, to deliver any Positive Hypothesis or solemn +Theory of Colours, but only to furnish You with some Experiments towards +the framing of such a Theory; I shall add nothing to what I have said +already, but a request that you would not be forward to think I have been +mistaken in any thing I have deliver'd as matter of Fact concerning the +changes of Colours, in case you should not every time you trye it, find it +exactly to succeed. For besides the Contingencies to which we have +elsewhere shewn some other Experiments to be obnoxious, the omission or +variation of a seemingly unconsiderable circumstance, may hinder the +success of an Experiment, wherein no other fault has been committed. Of +which truth I shall only give you that single and almost obvious, but yet +illustrious instance of the Art of Dying Scarlets, for though you should +see every Ingredient that is us'd about it, though I should particularly +inform You of the weight of each, and though you should be present at the +kindling of the fire, and at the increasing and remitting of it, when ever +the degree of Heat is to be alter'd, and though (in a word) you should see +every thing done so particularly that you would scarce harbour the least +doubt of your comprehending the whole Art: Yet if I should not disclose to +You, that the Vessels, that immediately contain the Tinging Ingredients, +are to be made of or to be lin'd with Tin, You would never be able by all +that I could tell you else (at-least, if the Famousest and Candidest +Artificers do not strangely delude themselves) to bring your Tincture of +Chochinele to Dye a perfect Scarlet. So much depends upon the very Vessel, +wherein the Tinging matters are boyl'd, and so great an Influence may an +unheeded Circumstance have on the Success of Experiments concerning +Colours. + + * * * * * + + _FINIS._ + + * * * * * + + A SHORT + ACCOUNT + OF SOME + OBSERVATIONS + Made by Mr. _BOYLE_ + + About a _Diamond_ that _Shines_ in the Dark. + + First enclosed in a Letter written to + a Friend, + +And now together with it annexed to the Foregoing + Treatise, upon the score of the + Affinity Betwixt + _Light_ and _Colours_. + + * * * * * + + _LONDON,_ + + Printed for _Henry Herringman_. 1664 + + * * * * * + + A COPY + OF THE + LETTER + + That Mr. _Boyle_ wrote to Sir _Robert Morray_, + to accompany the _Observations_ touching + the _Shining Diamond_. + +_SIR,_ + +Though Sir _Robert Morray_ and Monsieur _Zulichem_ be Persons that have +deserv'd so well of the Commonwealth of Learning, that I should think my +self unworthy to be look'd upon as a Member of it, if I declin'd to Obey +them, or to Serve them; yet I should not without Reluctancy send you the +Notes, you desire for him, if I did not hope that you will transmit +together with them, some Account why they are not less unworthy of his +perusal; which, that you may do; I must inform you, how the writing of them +was Occasion'd, which in short was thus. As I was just going out of Town, +hearing that an Ingenious Gentleman of my Acquaintance, lately return'd +from _Italy_, had a Diamond, that being rubb'd, would shine in the Dark, +and that he was not far off, I snatch'd time from my Occasions to make him +a Visit, but finding him ready to go abroad, and having in vain try'd to +make the Stone yield any Light in the Day time, I borrow'd it of him for +that Night, upon condition to restore it him within a Day or two at +furthest, at _Gresham_ College, where we appointed to attend the meeting of +the Society, that was then to be at that place. And hereupon I hasted that +Evening out of Town, and finding after Supper that the Stone which in the +Day time would afford no discernable Light, was really Conspicuous in the +Dark, I was so taken with the Novelty, and so desirous to make some use of +an opportunity that was like to last so little a while, that though at that +time I had no body to assist me but a Foot-Boy, yet sitting up late, I made +a shift that Night to try a pretty number of such of the things that then +came into my thoughts, as were not in that place and time unpracticable. +And the next Day being otherwise imploy'd, I was fain to make use of a +drowsie part of the Night to set down hastily in Writing what I had +observ'd, and without having the time in the Morning, to stay the +transcribing of it, I order'd the Observations to be brought after me to +_Gresham_ College, where you may remember, that they were together with the +Stone it self shown to the Royal Society, by which they had the good +Fortune not to be dislik'd, though several things were through hast +omitted, some of which you will find in the Margin of the inclosed Paper. +The substance of this short Narrative I hope you will let Monsieur +_Zulichem_ know, that he may be kept from expecting any thing of finish'd +in the Observations, and be dispos'd to excuse the want of it. But such as +they are, I hope they will prove (without a Clinch) Luciferous Experiments, +by setting the Speculations of the Curious on work, in a diligent Inquiry +after the Nature of Light, towards the discovery of which, perhaps they +have not yet met with so considerable an Experiment, since here we see +Light produc'd in a dead and opacous Body, and that not as in rotten Wood, +or in Fishes, or as in the _Bolonian_ Stone, by a Natural Corruption, or by +a Violent Destruction of the Texture of the Body, but by so slight a +Mechanical operation upon its Texture, as we seem to know what it is, and +as is immediately perform'd, and that several wayes without at all +prejudicing the Body, or making any sensible alterations in its Manifest +Qualities. And I am the more willing to expose my hasty Tryals to Monsieur +_Zulichem_, and to You, because, he being upon the Consideration of +Dioptricks, so odd a _Phænomenon_ relateing to the Subject, as probably he +treats of, Light will, I hope, excite a person to consider it, that is wont +to consider things he treats of very well. And for you Sir, I hope you will +both recrute and perfect the Observations you receive, For you know that I +cannot add to them, having a good while since restor'd to Mr. _Clayton_ the +Stone, which though it be now in the hands of a Prince that so highly +deserves, by understanding them, the greatest Curiosities; yet he +vouchsafes you that access to him as keeps me from doubting, you may easily +obtain leave to make further Tryals with it, of such a Monarch as ours, +that is not more inquisitive himself, than a favourer of them that are so. +I doubt not but these Notes will put you in mind of the Motion you made to +the Society, to impose upon me the Task of bringing in, what I had on other +occasions observ'd concerning shining Bodies. But though I deny not, that I +sometimes made observations about the _Bolonian_ Stone, and try'd some +Experiments about some other shining Bodies; Yet the same Reasons that +reduc'd me then to be unwilling to receive ev'n their commands, must now be +my Apology for not answering your Expectations, Namely the abstruse nature +of Light, and my being already over-burden'd, and but too much kept +imploy'd by the Urgency of the Press, as well as by more concerning and +distracting Occasions. But yet I will tell you some part of what I have met +with in reference to the Stone, of which I send you an account. Because I +find on the one side, that a great many think it no Rarity upon a mistaken +perswasion, that not only there are store of Carbuncles, of which this is +one; but that all Diamonds and other Glistering Jewels shine in the Dark. +Whereas on the other side there are very Learn'd Men, who (plausibly +enough) deny that there are any Carbuncles or shining Stones at all. + +And certainly, those Judicious men have much more to say for themselves, +than the others commonly Plead, and therefore did deservedly look upon Mr. +_Clayton_'s Diamond as a great Rarity. For not only _Boetius de Boot_, who +is judg'd the best Author on this Subject, ascribes no such Virtue to +Diamonds, but begins what he delivers of Carbuncles, with this passage.[26] +_Magna fama est Carbunculi. Is vulgo putatur in tenebris Carbonis instar +lucere; fortassis quia Pyropus seu Anthrax appellatus a veteribus fuit. +Verum hactenus nemo nunquam verè asserere ausus fuit, se gemmam noctu +lucentem vidisse. Garcias ab Horto proregis Indiæ Medicus, refert se +allocutum fuisse, qui se vidisse affirmarent. Sed iis fidem non habuit._ +And a later Author, the Diligent and Judicious _Johannes de Laet_ in his +Chapter of Carbuncles and of Rubies, has this passage. _Quia autem +Carbunculi, Pyropi & Anthraces a veteribus nominantur, vulgo creditum fuit, +Carbonis instar in tenebris lucere, quod tamen nullâ gemmâ hastenus +deprehensum, licet à quibusdam temerè jactetur._ And the recentest Writer I +have met with on this Subject, _Olaus Wormius_, in his Account of his well +furnish'd _Musæum_, do's, where he treats of Rubies, concurr with the +former Writers by these Words.[27] _Sunt qui Rubinum veterum Carbunculum +esse existimant, sed deest una illa nota, quod in tenebris instar Anthracis +non luceat: Ast talem Carbunculum in rerum naturâ non inveniri major pars +Authoram existimant. Licet unum aut alterum in India apud Magnates quosdam +reperiri scribant, cum tamen ex aliorum relatione id habeant saltem, sed +ipsi non viderint._ In confirmation of which I shall only add, that hearing +of a Rubie, so very Vivid, that the Jewellers themselves have several times +begg'd leave of the fair Lady to whom it belong'd, that they might try +their choicest Rubies by comparing them with That, I had the Opportunity by +the Favour of this Lady and her Husband, (both which I have the Honour to +be acquainted with) to make a Trial of this famous Rubie in the Night, and +in a Room well Darkn'd, but not only could not discern any thing of Light, +by looking on the Stone before any thing had been done to it, but could not +by all my Rubbing bring it to afford the least Glimmering of Light. + + [26] Boetius de Boot. Gem. & Lapid. Histor. Lib. 3. Cap. 8. + + [27] Musæi Wormiani. Cap. 17. + +But, Sir, though I be very backward to admit strange things for truths, yet +I am not very forward to reject them as impossibilities, and therefore I +would not discourage any from making further Inquiry, whether or no there +be Really in _Rerum natura_, any such thing as a true Carbuncle or Stone +that without Rubbing will shine in the Dark. For if such a thing can be +found, it may afford no small Assistance to the Curious in the +Investigation of Light, besides the Nobleness and Rarity of the thing it +selfe. And though _Vartomannus_ was not an Eye witness of what he relates, +that the King of _Pegu_, one of the Chief Kings of the _East-Indies_, had a +true Carbuncle of that Bigness and Splendour, that it shin'd very +Gloriously in the Dark, and though _Garcias ab Horto_, the _Indian_ +Vice-Roys Physician, speaks of another Carbuncle, only upon the Report of +one, that he Discours'd with, who affirmed himself to have seen it; yet as +we are not sure that these Men that gave themselves out to be Eye-witnesses +speak true, yet they may have done so for ought we know to the contrary. +And I could present you with a much considerabler Testimony to the same +purpose, if I had the permission of a Person concern'd, without whose leave +I must not do it. I might tell you that _Marcus Paulus Venetus_[28] (whose +suppos'd Fables, divers of our later Travellours and Navigatours have since +found to be truths) speaking of the King of _Zeilan_ that then was, tells +us, that he was said to have the best Rubie in the World, a Palm long and +as big as a mans Arm, without spot, shining like a Fire, and he subjoyns, +that the Great _Cham_, under whom _Paulus_ was a considerable Officer, sent +and offer'd the value of a City for it; But the King answer'd, he would not +give it for the treasure of the World, nor part with it, having been his +Ancestours. And I could add, that in the Relation made by two _Russian_ +Cossacks of their Journey into _Catay_[29], written to their Emperour, they +mention'd their having been told by the people of those parts, that their +King had a Stone, which Lights as the Sun both Day and Night, call'd in +their Language _Sarra_, which those Cossacks interpret a Ruby. But these +Relations are too uncertain for me to build any thing upon, and therefore I +shall proceed to tell you, that there came hither about two years since out +of _America_, the Governour of one of the Principal Colonies there, an +Ancient _Virtuoso_, and one that has the Honour to be a member of the Royal +Society; this Gentleman finding some of the chief Affairs of his Country +committed to another and me, made me divers Visits, and in one of them when +I enquir'd what Rare Stones they had in those parts of the _Indies_ he +belong'd to, he told me, that the _Indians_ had a Tradition that in a +certain hardly accessible Hill, a pretty way up in the Country, there was a +Stone which in the Night time shin'd very vividly, and to a great distance, +and he assur'd me, that though he thought it not fit to venture himself so +far among those Savages, yet he purposely sent thither a bold _Englishman_, +with some Natives to be his guides, and that this Messenger brought him +back word, that at a distance from the Hillock he had plainly perceiv'd +such a shining Substance as the _Indians_ Tradition mention'd, and being +stimulated by Curiosity, had slighted those Superstitious Fears of the +Inhabitants, and with much ado by reason of the Difficulty of the way, had +made a shift to clamber up to that part of the Hill, where, by a very +heedful Observation, he suppos'd himself to have seen the Light: but +whether 'twere that he had mistaken the place, or for some other Reason, he +could not find it there, though when he was return'd to his former Station, +he did agen see the Light shining in the same place where it shone before. +A further Account of this Light I expect from the Gentleman that gave me +this, who lately sent me the news of his being landed in that Country. And +though I reserve to my self a full Liberty of Believing no more than I see +cause; yet I do the less scruple to relate this, because a good part of it +agrees well enough with another Story that I shall in the next place have +occasion to subjoyn, in order whereunto I shall tell you, that though the +Learned Authors I formerly mention'd, tell us, that no Writer has affirm'd +his having himself seen a real Carbuncle, yet, considering the Light of Mr. +_Claytons_ Diamond, it recall'd into my mind, that some years before, when +I was Inquisitive about Stones, I had met with an old _Italian_ Book highly +extoll'd to me by very competent Judges, and that though the Book were very +scarce, I had purchas'd it at a dear Rate, for the sake of a few +considerable passages I met with in it, and particularly one, which being +very remarkable in it self, and pertinent to our present Argument, I shall +put it for you, though not word for word, which I fear I have forgot to do, +yet as to the Sense, into _English_. + + [28] _Purchas_'s Pilgrim. lib. 1. cap. 4. pag. 104. + + [29] In the year 1619. + +_Having promis'd_ (Says our Author)[30] _to say something of that most +precious sort of Jewels,_ Carbuncles, _because they are very rarely to be +met with, we shall briefly deliver what we know of them. In_ Clement _the +seventh's time, I happen'd to see one of_ _them at a certain_ Ragusian +_Merchants, nam'd_ Beigoio di Bona, _This was a Carbuncle white, of that +kind of whiteness which we said was to be found in those Rubies of which we +made mention a little above,_ (where he had said that those Rubies had a +kind of Livid Whiteness or Paleness like that of a Calcidonian) _but it had +in it a Lustre so pleasing and so marveilous, that it shin'd in the Dark, +but not as much as colour'd Carbuncles, though it be true, that in an +exceeding Dark place I saw it shine in the manner of fire almost gone out. +But as for colour'd Carbuncles, it has not been my Fortune to have seen +any, wherefore I will onely set down what I Learn'd about them Discoursing +in my Youth with a_ Roman _Gentleman of antient Experience in matters of +Jewels, who told me, That one_ Jacopo Cola _being by Night in a Vineyard of +his, and espying something in the midst of it, that shin'd like a little_ +glowing Coal, at the foot of a Vine, went near towards the place where he +thought himself to have seen that fire, but not finding it, he said, that +being return'd to the same place, whence he had first descry'd it, and +perceiving there the same splendor as before, he mark'd it so heedfully, +that he came at length to it, where he took up a very little Stone, which +he carry'd away with Transports and Joy. And the next day carrying it about +to show it divers of his Friends, whilst he was relating after what manner +he found it, there casually interven'd a _Venetian_ Embassadour, +exceedingly expert in Jewels, who presently knowing it to be a Carbuncle, +did craftily before he and the said _Jacopo_ parted (so that there was no +Body present that understood the Worth of so Precious a Gemm) purchase it +for the Value of 10. Crowns, and the next day left _Rome_ to shun the being +necessitated to restore it, and (as he affirm'd) it was known within some +while after that the said _Venetian_ Gentleman did in _Constantinople_ sell +that Carbuncle to the then Grand Seignior, newly come to the Empire, for a +hundred thousand Crowns. _And this is what I can say_ concerning +_Carbuncles_, and this is not a little at least as to the first part of +this account, where our _Cellini_ affirms himself to have seen a Real +Carbuncle with his own Eyes, especially since this Author appears wary in +what he delivers, and is inclin'd rather to lessen, than increase the +wonder of it. And his Testimony is the more considerable, because though he +were born a Subject neither to the Pope nor the then King of _France_ (that +Royal _Virtuoso_ _Francis_ the first) yet both the one and the other of +those Princes imploy'd him much about making of their Noblest Jewels. What +is now reported concerning a Shining Substance to be seen in one of the +Islands about _Scotland_, were very improper for me to mention to Sr. +_Robert Morray_, to whom the first Information was Originally brought, and +from whom I expect a farther (for I scarce dare expect a convincing) +account of it. But I must not omit that some _Virtuoso_ questioning me the +other day at _White-Hall_ about Mr. _Claytons_ Diamond, and meeting amongst +them an Ingenious _Dutch_ Gentleman, whose Father was long Embassador for +the Netherlands in _England_, I Learn'd of him, that, he is acquainted with +a person, whose Name he told (but I do not well remember it) who was +Admiral of the _Dutch_ in the _East-Indies_, and who assur'd this Gentleman +_Monsieur Boreel_, that at his return from thence he brought back with him +into _Holland_ a Stone, which though it look'd but like a Pale Dull +Diamond, such as he saw Mr. _Claytons_ to be, yet was it a Real Carbuncle, +and did without rubbing shine so much, that when the Admiral had occasion +to open a Chest which he kept under Deck in a Dark place, where 'twas +forbidden to bring Candles for fear of Mischances, as soon as he open'd the +Trunck, the Stone would by its Native Light, shine so as to Illustrate a +great part of it, and this Gentleman having very civilly and readily +granted me the request I made him, to Write to the Admiral, who is yet +alive in _Holland_, (and probably may still have the Jewel by him,) for a +particular account of this Stone, I hope ere long to receive it, which will +be the more welcome to me, not onely because so unlikely a thing needs a +cleer evidence, but because I have had some suspition of that (supposing +the truth of the thing) what may be a shining Stone in a very hot Countrey +as the _East-Indies_, may perhaps cease to be so (at least in certain +seasons,) in one as cold as _Holland_. For I observ'd in the Diamond I send +you an account of, that not onely rubbing but a very moderate degree of +warmth, though excited by other wayes, would make it shine a little. And +'tis not impossible that there may be Stones as much more susceptible than +that, of the Alterations requisite to make a Diamond shine, as that +appeares to be more susceptible of them, than ordinary Diamonds. And I +confess to you, that this is not the only odd suspition (for they are not +so much as conjectures) that what I try'd upon this Diamond suggested to +me. For not here to entertain you with the changes I think may be effected +ev'n in harder sorts of Stones, by wayes not vulgar, nor very promising, +because I may elsewhere have occasion to speak of them, and this Letter is +but too Prolix already, that which I shall now acknowledge to you is, That +I began to doubt whether there may not in some Cases be some Truth in what +is said of the right Turquois, that it often changes Colour as the wearer +is Sick or Well, and manifestly loses its splendor at his Death. For when I +found that ev'n the warmth of an Affriction that lasted not above a quarter +of a minute, Nay, that of my Body, (whose Constitution you know is none of +the hottest) would make a manifest change in the solidest of Stones a +Diamond, it seem'd not impossible, that certain warm and Saline steams +issuing from the Body of a living man, may by their plenty or paucity, or +by their peculiar Nature, or by the total absence of them, diversifie the +Colour, and the splendor of so soft a Stone as the Turquois. And though I +admir'd to see, that I know not how many Men otherwise Learn'd, should +confidently ascribe to Jewels such Virtues as seem no way competible to +Inanimate Agents, if to any Corporeal ones at all, yet as to what is +affirm'd concerning the Turquois's changing Colour, I know not well how to +reject the Affirmation of so Learned (and which in this case is much more +considerable) so Judicious a Lapidary as _Boetius de Boot_[31], who upon +his own particular and repeated Experience delivers so memorable a +Narrative of the Turquois's changing Colour, that I cannot but think it +worth your Perusal, especially since a much later and very Experienc'd +Author, _Olaus Wormius_,[32] where he treats of that Stone, Confirms it +with this Testimony. _Imprimis memorandum exemplum quod Anshelmus Boetius +de seipso refert, tam mutati Coloris, quam à casu preservationis. Cui & +ipse haud dissimile adferre possum, nisi ex Anshelmo petitum quis putaret._ +I remember that I saw two or three years since a _Turcois_ (worn in a Ring) +wherein there were some small spots, which the _Virtuoso_ whose it was +asur'd me he had observ'd to grow sometimes greater sometimes less, and to +be sometimes in one part of the Stone, sometimes in another. And I having +encourag'd to make Pictures from time to time of the Stone, and of the +Situation of the cloudy parts, thatso their Motion may be more +indisputable, and better observ'd, he came to me about the midle of this +very week, and assur'd me that he had, as I wish'd, made from time to time +Schemes or Pictures of the differing parts of the Stone, whereby the +several Removes and motions of the above mentioned Clouds are very +manifest, though the cause seem'd to him very occult: these Pictures he has +promis'd to show me, and is very ready to put the Stone it self into my +hands. But the ring having been the other day casually broken upon his +finger, unless it can be taken out, and set again without any considerable +heat, he is loath to have it medled with, for fear its peculiarity should +be thereby destroy'd. And possibly his apprehension would have been +strengthen'd, if I had had opportunity to tell him what is related by the +Learned _Wormius_[33] of an acquaintance of his, that had a _Nephritick_ +stone, of whose eminent Virtues he had often Experience ev'n in himself, +and for that cause wore it still about his Wrist; and yet going upon a time +into a Bath of fair Water only, wherein certain Herbs had been boyl'd, the +Stone by being wetted with this decoction, was depriv'd of all his Virtue, +whence _Wormius_ takes Occasion to advertise the sick, to lay by such +stones whensoever they make use of a Bath. And we might expect to find +_Turcos_ likewise, easily to be wrought upon in point of Colour, if that +were true, which the curious _Antonio Neri_, in his ingenious _Arte +Vetraria_[34] teaches of it, namely, That _Turcois's discolour'd_ and grown +white, will regain and acquire an excellent Colour, if you but keep them +two or three days at most cover'd with Oyl of sweet Almonds kept in a +temperate heat by warm ashes, I say if it were true, because I doubt +whether it be so, and have not as yet had opportunity to satisfie my self +by Tryals, because I find by the confession of the most Skilfull Persons +among whom I have laid out for _Turcoises_, that the true ones are great +rarities, though others be not at all so. And therefore I shall now only +mind you of one thing that you know as well as I, namely, that the rare +Stone which is called _Oculus Mundi_, if it be good in its Kind, will have +so great a change made in its Texture by being barely left a while in the +Languidest of Liquors, common Waters, that from Opacous it will become +Transparent, and acquire a Lustre of which it will again be depriv'd, +without using any other Art or Violence, by leaving it a while in the Air. +And before experience had satisfy'd us of the truth of this, it seem'd as +unlikely that common Water or Air, should work such great changes in that +Gemm, as it now seems that the Effluviums of a human Body should effect +lesser changes in a _Turcois_, especially if more susceptible of them, than +other Stones of the same kind. But both my Watch and my Eyes tell me that +'tis now high time to think of going to sleep, matters of this Nature, will +be better, as well as more easily, clear'd by Conference, than Writing. And +therefore since I think you know me too well to make it needfull for me to +disclame Credulity, notwithstanding my having entertain'd you with all +these Extravagancies; for you know well, how wide a difference I am wont to +put betwixt things that barely _may be_, and things that _are_, and between +those Relations that are but not unworthy to be inquir'd into, and those +that are not worthy to be actually believ'd; without making Apologies for +my Ravings, I shall readily comply with the drowsiness that calls upon me +to release You, and the rather, because Monsieur _Zulichem_ being concern'd +in your desire to know the few things I have observed about the shining +Stone. To entertain those with Suspicions that are accustomed not to +acquiesce but in Demonstrations, were a thing that cannot be look'd upon as +other than very improper by, + +SIR, + +_Your most Affectionate_ + +and + +_most Faithfull Servant,_ + +RO. BOYLE. + + [30] Benvonuto Cellini _nell Arte del_ Gioiellare, _Lib._ 1. _pag._ 10. + + [31] The Narrative in the Authors own words, is this. _Ego_ (sayes he) + _sanctè affirmare possum me unam aureo Annulo inclusam perpetuo gestare, + cujus facultatem (si gemmæ est) nunquam satis admirari potui. Gestaverat + enim ante Triginta annos Hispanus quidam non procula puternis ædibus + habitans. Is cum vitâ functus esset, & ipsius suspellex (ut moris apud + nos est) venum exposita esset, inter cætera etiam Turcois exponebatur. + Verum nemo (licet complures eo concurrissent, ut eam propter Coloris + Elegantiam, quam vivo Domino habuerat emerent) sibi emptam voluit, + pristinum enim nitorem & Colorem prorsus amiserat, ut potius Malachites, + quam Turcois videretur. Aderat tum temporis gemmæ habendæ desiderio etiam + parens & frater meus, qui antea sæpius gratiam & elegantiam ipsius + viderant, mirabundi eam nunc tam esse deformem, Emit eam nihilominus + pater, satisque vili pretio, qua omnibus contemptui erat, ac presentes + non eam esse quam Hispanus gestarat, arbitrarentur. Domum reversus Pater, + qui tam turpem Gemmam gestare sibi indecorum putabat, eam mihi dono dat, + inquiens; Quandoquidem, fili mi, vulgi fama est, Turcoidem, ut facultates + suas exercere possit, dono dari debere tibi eam devoveo, ego acceptam + Gemmam sculptori trado, at gentilitia mea insignia illi, quamadmodum + fieri solet, in Jaspide Chalcedono, aliisque Ignobilioribus Gemmis, + insculperat. Turpe enim existimabam, hujusmodi Gemmâ ornatus gratia, dum + gratiam nullam haberet, uti. Paret Sculptor redditque Gemmam, quam gesto + pro annulo Signatorio. Vix per mensem gestaram, redit illi pristinus + color, sed non ita nitens propter Sculpturam, ac inæqualem superficiem. + Miramur omnes gemmam, atque id præcipuè quod color indies pulchrior + fieret. Id quià observabam, nunquam fere eam à manu deposui, ita ut nunc + adhuc candem gestem._ + + [32] _Olaus Wormius, in Musæ. 18º pag. 186._ + + [33] _Musæ. Worm._ pag. 99. + + [34] Arte Vetraria, lib. 7 cap. 102. + + * * * * * + + OBSERVATIONS + + Made this 27th.[35] + of _October_ 1663. about + Mr. _Clayton's_ + Diamond.[36] + +Being look'd on in the Day time, though in a Bed, whose Curtains were +carefully drawn, I could not discern it to Shine at all, though well +Rubb'd, but about a little after Sun-set, whilst the Twilight yet lasted, +Nay, this Morning[37] a pretty while after Sun-rising, (but before I had +been abroad in the more freely inlightned Air of the Chamber) I could upon +a light Affriction easily perceive the Stone to Shine. + + [35] These were brought in and Read before the Royal Society, (the Day + following) _Oct._ 28. 1663. + + [36] _The Stone it self being to be shown to the Royal Society, when the + Observations were deliver'd, I was willing (being in haste) to omit the + Description of it, which is in short, That it was a Flat or Table + Diamond, of about a third part of an Inch in length, and somewhat less in + breadth, that it was a Dull Stone, and of a very bad Water, having in the + Day time very little of the Vividness of ev'n ordinary Diamonds, and + being Blemished with a whitish Cloud about the middle of it, which + covered near a third part of the Stone._ + + [37] _Hast made me forget to take notice that I went abroad the same + Morning, the Sun shining forth clear enough, to look upon the Diamond + though a_ Microscope, _that I might try whether by that Magnifying Glass + any thing of peculiar could be discern'd in the Texture of the Stone, and + especially of the whitish Cloud that possest a good part of it. But for + all my attention I could not discover any peculiarity worth mentioning._ + +Secondly, The Candles being removed, I could not in a Dark place discern +the Stone to have any Light, when I looked on it, without having Rubb'd or +otherwise prepar'd it. + +Thirdly, By two white Pibbles though hard Rubb'd one against another, nor +by the long and vehement Affriction of Rock Crystal against a piece of Red +cloath, nor yet by Rubbing two Diamonds set in Ring, as I had Rubb'd this +Stone, I could produce any sensible degree of Light. + +Fourthly, I found this Diamond hard enough, not only to enable me to write +readily with it upon Glass, but to Grave on Rock Crystal it self. + +Fifthly, I found this to have like other Diamonds, an Electrical +faculty.[38] + + [38] V. _For it drew light Bodies like Amber, Jet, and other Concretes + that are noted to do so; But its attractive power seem'd inferiour to + theirs._ + +Sixthly, Being rubb'd upon my Cloaths, as is usual for the exciting of +Amber, Wax, and other Electrical Bodies, it did in the Dark manifestly +shine like Rotten Wood, or the Scales of Whitings, or other putrified Fish. + +Seventhly, But this Conspicuousness was Fainter than that of the Scales, +and Slabber (if I may so call it) of Whitings, and much Fainter than the +Light of a Glow-worm, by which I have been sometimes able to Read a short +Word, whereas after an ordinary Affriction of this Diamond I was not able +to discern distinctly by the Light of it any of the nearest Bodies: And +this Glimmering also did very manifestly and considerably Decay presently +upon the ceasing of the Affriction, though the Stone continued Visible some +while after. + +Eighthly, But if it were Rubb'd upon a convenient Body for a pretty while, +and Briskly enough, I found the Light would be for some moments much more +considerable, almost like the Light of a Glow-worm, insomuch after I ceased +Rubbing, I could with the Chaf'd stone exhibit a little Luminous Circle, +like that, but not so bright as that which Children make by moving a stick +Fir'd at the end, and in this case it would continue Visible about seven or +eight times as long as I had been in Rubbing it. + +Ninthly, I found that holding it a while near[39] the Flame of a Candle, +(from which yet I was carefull to avert my Eyes) and being immediately +remov'd into the Dark, it disclosed some faint Glimmering, but inferiour to +that, it was wont to acquire by Rubbing. And afterward holding it near a +Fire that had but little Flame, I found the Stone to be rather less than +more excited, than it had been by the Candle. + + [39] IX. _We durst not hold it in the Flame of a Candle, no more than put + it into a naked Fire; For fear too Violent a Heat (which has been + observ'd to spoil many other precious Stones) should vitiate and impair a + Jewel, that was but borrow'd, and was suppos'd to be the only one of its + Kind._ + +Tenthly, I likewise indeavour'd to make it Shine, by holding it a pretty +while in a very Dark place, over a thick piece of Iron, that was well +Heated, but not to that Degree as to be Visibly so. And though at length I +found, that by this way also, the Stone acquired some Glimmering, yet it +was less than by either of the other ways above mention'd. + +Eleventhly, I also brought it to some kind of Glimmering Light, by taking +it into Bed with me, and holding it a good while upon a warm part of my +Naked Body. + +Twelfthly, To satisfie my self, whether the Motion introduc'd into the +Stone did generate the Light upon the account of its producing Heat there, +I held it near the Flame of a Candle, till it was qualify'd to shine pretty +well in the Dark, and then immediately I apply'd a slender Hair to try +whether it would attract it, but found not that it did so; though if it +were made to shine by Rubbing, it was as I formerly noted Electrical. And +for further Confirmation, though I once purposedly kept it so near the hot +Iron I just now mention'd, as to make it sensibly Warm, yet it shin'd more +Dimly than it had done by Affriction or the Flame of a Candle, though by +both those ways it had not acquir'd any warmth that was sensible. + +Thirteenthly, Having purposely rubb'd it upon several Bodies differing as +to Colour, and as to Texture, there seem'd to be some little Disparity in +the excitation (if I may so call it) of Light. Upon White and Red Cloths it +seem'd to succeed best, especially in comparison of Black ones. + +Fourteenthly, But to try what it would do rubb'd upon Bodies more hard, and +less apt to yield Heat upon a light Affriction, than Cloath, I first rubb'd +it upon a white wooden Box, by which it was excited, and afterwards upon a +piece of purely Glazed Earth, which seem'd during the Attrition to make it +Shine better than any of the other Bodies had done, without excepting the +White ones, which I add, lest the Effect should be wholly ascrib'd to the +disposition White Bodies are wont to have to Reflect much Light. + +Fifteenthly, Having well excited the Stone, I nimbly plung'd it under +Water[40], that I had provided for that purpose, and perceiv'd it to Shine +whilst it was beneath the Surface of that Liquor, and this I did divers +times. But when I indeavour'd to produce a Light by rubbing it upon the +lately mentioned Cover of the Box, the Stone and it being both held beneath +the Surface of the Water, I did not well satisfie my self in the Event of +the Trial; But this I found, if I took the Stone out, and Rubb'd it upon a +piece of Cloath, it would not as else it was wont to do, presently acquire +a Luminousness, but needed to be rubb'd manifestly much longer before the +desired Effect was found. + + [40] XV. _We likewise Plung'd it as soon as we had excited it, under + Liquors of several sorts, as Spirit of Wine, Oyl both Chymical and + express'd, an Acid Spirit, and as I remember an Alcalizate Solution, and + found not any of those various Liquors to destroy its Shining property._ + +Sixteenthly, I also try'd several times, that by covering it with my warm +Spittle (having no warm Water at hand) it did not lose his Light.[41] + + [41] XVI. _Having found by this Observation, that a warm Liquor would not + extinguish Light in the Diamond, I thought fit to try, whether by reason + of its warmth it would not excite it, and divers times I found, that if + it were kept therein, till the Water had leisure to communicate some of + its Heat to it, it would often shine as soon as it was taken out, and + probably we should have seen it Shine more, whilst it was in the Water, + if some degree of Opacity which heated Water is wont to acquire, upon the + score of the Numerous little Bubbles generated in it, had not kept us + from discerning the Lustre of the Stone._ + +Seventeenthly, Finding that by Rubbing the Stone with the Flat side +downwards, I did by reason of the Opacity of the Ring; and the sudden Decay +of Light upon the ceasing of the Attrition, probably lose the sight of the +Stones greatest Vividness; and supposing that the Commotion made in one +part of the stone will be easily propagated all over, I sometimes held the +piece of Cloath upon which I rubb'd it, so, that one side of the Stone was +exposed to my Eye, whilst I was rubbing the other, whereby it appear'd more +Vivid than formerly, and to make Luminous Tracts by its Motions too and +fro. And sometimes holding the Stone upwards, I rubb'd its Broad side with +a fine smooth piece of Transparent Horn, by which means the Light through +that Diaphanous Substance, did whilst I was actually rubbing the Stone, +appear so Brisk that sometimes and in some places it seem'd to have little +Sparks of fire. + +Eighteenthly, I took also a piece of flat Blew Glass, and having rubb'd the +Diamond well upon a Cloath, and nimbly clapt the Glass upon it, to try +whether in case the Light could peirce it, it would by appearing Green, or +of some other Colour than Blew, assist me to guess whether it self were +sincere or no. But finding the Glass impervious to so faint a Light, I then +thought it fit to try whether that hard Bodies would not by Attrition +increase the Diamonds Light so as to become penetrable thereby, and +accordingly when I rubb'd the Glass briskly upon the Stone, I found the +Light to be Conspicuous enough, and somewhat Dy'd in its passage, but found +it not easie to give a Name to the Colour it exhibited. + +Lastly, To comply with the Suspition I had upon the whole Matter, that the +chief manifest Change wrought in the Stone, was by Compression of its +parts, rather than Incalescence, I took a piece of white Tile well Glaz'd, +and if I press'd the Stone hard against it, it seem'd though I did not rub +it to and fro, to shine at the Sides: And however it did both very +manifestly and vigorously Shine, if whilst I so press'd it, I mov'd it any +way upon the Surface of the Tile, though I did not make it draw a Line of +above a quarter of an Inch long, or thereabouts. And though I made it not +move to and fro, but only from one end of the short Line to the other, +without any return or Lateral motion. Nay, after it had been often rubb'd, +and suffer'd to lose its Light again, not only it seem'd more easie to be +excited than at the beginning of the Night; but if I did press hard upon it +with my Finger, at the very instant that I drew it briskly off, it would +disclose a very Vivid but exceeding short Liv'd Splendour, not to call it a +little Coruscation.[42] So that a _Cartesian_ would scarce scruple to think +he had found in this Stone no slight Confirmation of his Ingenious Masters +_Hypothesis_, touching the Generation of Light in Sublunary Bodies, not +sensibly Hot. + + [42] _I after bethought my self of imploying a way, which produc'd the + desir'd Effect both sooner and better. For holding betwixt my Fingers a + Steel Bodkin, near the Lower part of it, I press'd the point hard against + the Surface of the Diamond, and much more if I struck the point against + it, the Coruscation would be extremely suddain, and very Vivid, though + very Vanishing too, and this way which commonly much surpris'd and + pleas'd the Spectators, seem'd far more proper than the other, to show + that pressure alone, if forcible enough, though it were so suddain, and + short, that it could not well be suppos'd to give the Stone any thing + near a sensible degree of Warmth, as may be suspected of Rubbing, yet + 'tis sufficient to generate a very Vivid Light._ + + * * * * * + +A Postscript. + +Annexed some Hours after the Observations were Written. + +_So many particulars taken notice of in one Night, may make this Stone +appear a kind of Prodigie, and the rather, because having try'd as I +formerly noted, not only a fine Artificial Crystal, and some also that is +Natural, but a Ruby and two Diamonds, I did not find that any of these +disclos'd the like Glimmering of Light;[43] yet after all, perceiving by +the Hardness, and the Testimony of a Skilfull Goldsmith, that this was +rather a Natural than Artificial Stone; for fear lest there might be some +difference in the way of Setting, or in the shape of the Diamonds I made +use of, neither of which was like this, a flat Table-stone, I thought fit +to make a farther Trial of my own Diamonds, by such a brisk and assiduous +Affriction as might make amends for the Disadvantages above-mention'd, in +case they were the cause of the unsuccessfulness of the former Attempts: +And accordingly I found, that by this way I could easily bring a Diamond I +wore on my Finger to disclose a Light, that was sensible enough, and +continued so though I cover'd it with Spittle, and us'd some other trials +about it. And this will much lessen the wonder of all the formerly +mention'd Observations, by shewing that the properties that are so strange +are not peculiar to one Diamond, but may be found in others also, and +perhaps in divers other hard and_ Diaphanous _Stones. Yet I hope that what +this Discovery takes away from the Wonder of these Observations, it will +add to the Instructiveness of them, by affording pregnants Hints, towards +the Investigation of the Nature of Light._ + + [43] We afterwards, try'd precious Stones, as Diamonds, Rubies, Saphires, + and Emeralls, &c. but found not any of them to Shine except some + Diamonds, and of these we were not upon so little practice, able to + fore-tell before hand, which would be brought to Shine, and which would + not; For several very good Diamonds, either would not Shine at all, or + much less than others that were farr inferiour to them. And yet those + Ingenious Men are mistaken, that think a Diamond must be foul and cloudy, + as Mr. _Claytons_ was, to be fit for Shining; for as we could bring some + such to afford a Glimmering Light, so with some clear and excellent + Diamonds, we could do the like. But none of those many that we try'd of + all Kinds, were equal to the Diamond on which the Observations were made, + not only considering the degree of Light it afforded, but the easiness + wherewith it was excited, and the Comparatively great duration of its + Shining. + +FINIS. + + * * * * * + +Transcriber's notes. + +The Errata of the printed book have all been corrected. +They were as follows: + +Pag. 142. l. 20. These words, And to manifest, with the rest of what is by +a mistake further printed in this fourth Experiment, belongeth, and is to +be referred to the end of the second Eperiment, p.137. pag. 145. l. 1. leg. +matter. 146. l. 4. leg. Bolts-head. pag 161. in the marginal note l. 2. +dele de ib. l. 3. lege lib 1. p 163. l. ult. insert where between the words +places and the. p. 164 l. 1. dele that. ibid, l. 8. leg Epidermis. ibid. l. +19 leg. 300. for 200. p. 169. l. 22. leg. into it. p. 170. l. 23. & 24. +leg. Some Solutions hereafter to be mentioned, for the Solutions of +Potashes, and other Lixiviate Salts. p. 171. l. 6. insert part of between +the words most and dissolved p. 176. l. ult. insert the participle it +between the words Judged and not p. 234. l. 4. leg. Woud-wax or Wood-wax. +p. 320 l. 29. leg. urine for urne. + +In addition I have corrected the following original typos: + +The preface: I devis'd tbem -> I devis'd them +The preface: make Expements -> make Experiments +The Publisher to the reader: made of Eperiments -> made of Experiments +I. Ch. III.6 divers Expements -> divers Experiments +I. Ch. III.13 epecially with some sorts -> especially with some sorts +II. Ch. II.8 Slightet Texture -> Slightest Texture +II. Exp. I two Colonrs -> two Colours +II. Exp. XIII were the change of Colour -> where the change +III. Exp. XII avoiding of Ambignity -> avoiding of Ambiguity +III. Exp. XXIX Juice of this Sipce -> Juice of this Spice +III. Exp. XL forty second Expement -> forty second Experiment +III. Exp. XLIV keep them swimning -> keep them swimming +III. Exp. XLVI it seem'd propable to me -> it seem'd probable to me +III. Exp. XLVII where not comprehended -> were not comprehended +III. Exp. XLVIII frequent Igintion -> frequent Ignition +III. Exp. L I could tell yon -> I could tell you +A Copy of the Letter: nemo unqnam vere -> nemo nunquam vere +(ib.): what is reladed -> what is related +Observations: carefulsy drawn -> carefully drawn + +- and emended +Phoenomenon/a to Phaenomenon/a 10 times and +Coeruleous etc. -> Caeruleous 20 times + +*** END OF THE PROJECT GUTENBERG EBOOK 14504 *** |