CHAP. I. (continued 2)

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 Scaliger⁵, Latet natura hæc, (ſays he, Speaking of that of Colour) & ſicut aliarum rerum ſpecies in profundiſſima caligine inſcitiæ humanæ.