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.