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 prædominant Colour, and return to the Reddishness of Copper, I was assur'd of the Affirmative; so that among Mineral Bodyes, some of those that are White, may be far more capable, than those I am reasoning with seem to have known, of Eclipsing others, and of making their Colour Prædominant in Mixtures. In further Confirmation of which may be added, that I remember that I also took a lump of Silver and Gold melted together, wherein by the Æstimate of a very Experienced Refiner, there might be about a fourth or third part of Gold, and yet the Yellow Colour of the Gold was so hid by the White of the Silver, that the whole Mass appear'd to be but Silver, and when it was rubb'd upon the Touchstone, an ordinary beholder could scarce have distinguish'd it from the Touch of common Silver; though if I put a little _Aqua Fortis_ upon any part of the White Surface it had given the