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.
