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.