observation among Dyers, That Clothes, which have once been throughly imbu’d with Black, cannot so well afterwards be Dy’d into Lighter Colours, the praeexistent Dark Colour infecting the Ingredients, that carry the Lighter Colour to be introduc’d, and making it degenerate into Some more Sad one; Yet the Experiments lately mention’d may shew us, that where the change of Colour in Black Bodies is attempted, not by mingling Bodyes of Lighter Colours with them, but by Addition of such things as are proper to alter the Texture of those Corpuscles that contain the Black Colour, ’tis no such difficult matter, as the lately mention’d Learned Men imagine, to alter the Colour of Black Bodyes.  For we saw that Inks of several Kinds might in a trice be depriv’d of all their Blackness; and those made with Logwood and Red-Roses might also be chang’d, the one into a Red, the other into a Reddish Liquor; and with Oyl of Vitriol I have sometimes turn’d Black pieces of Silk into a kind of Yellow, and though the Taffaty were thereby made Rotten, yet the spoyling of that does no way prejudice the Experiment, the change of Black Silk into Yellow, being never the less True, because the Yellow Silk is the less good.  And as for Whiteness, I think the general affirmation of its being so easily Destroy’d or Transmuted by any other Colour, ought not to be receiv’d without some Cautions and Restrictions.  For whereas, according to what I formerly Noted, Lead is by Calcination turned into that Red Powder we call Minium; And Tin by Calcination reduc’d to a White Calx, the common Putty that is sold and us’d so much in Shops, instead of being, as it is pretended and ought to be, only the Calx of Tin, is, by the Artificers that make it, to save the charge of Tin, made, (as some, of themselves have confess’d, and as I long suspected by the Cheap rate it may be bought for) but of half Tin and half Lead, if not far more Lead than Tin, and yet the Putty in spight of so much Lead is a very White Powder, without disclosing any mixture of Minium.  And so if you take two parts of Copper, which is a High-colour’d Metall, to but one of Tin, you may by Fusion bring them into one Mass, wherein the Whiteness of the Tin is much more Conspicuous and Predominant than the Reddishness of the Copper.  And on this occasion it may not be Impertinent to mention an Experiment, which I relate upon the Credit of a very Honest man, whom I purposely enquir’d of about it, being my self not very fond of making Tryals with Arsenick, the Experiment is this, That if you Colliquate Arsenick and Copper in a due proportion, the Arsenick will Blanch the Copper both within and without, which is an Experiment well enough Known; but when I enquir’d, whether or no this White mixture being skilfully kept a while upon the Cupel would not let go its Arsenick, which made Whiteness its praedominant Colour, and return to the Reddishness of Copper, I was assur’d