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.