I think it may be more usefull to admonish you, _Pyrophilus_, that this observation admits of Restrictions, and is not so Universal, as by this time perhaps you have begun to think it; For though most Præcipitated Bodyes are White, yet I know some that are not; For Gold Dissolv'd in _Aqua Regis_, whether you Præcipitate it with Oyl of _Tartar_, or with Spirit of _Sal Armoniack_, will not afford a White but a Yellow _Calx_. _Mercury_ also though reduc'd into Sublimate, and Præcipitated with Liquors abounding with Volatile Salts, as the Spirits drawn from Urine, Harts-horn, and other Animal substances, yet will afford, as we Noted in our first Experiment about Whiteness and Blackness, a White Præcipitate, yet with some Solutions hereafter to be mentioned, it will let fall an Orange-Tawny Powder. And so will Crude _Antimony_, if, being dissolv'd in a strong Lye, you pour (as farr as I remember) any Acid Liquor upon the Solution newly Filtrated, whilst it is yet Warm. And if upon the Filtrated Solution of _Vitriol_, you pour a Solution of one of these fix'd Salts, there will subside a Copious substance, very farr from having any Whiteness, which the Chymists are pleas'd to call, how properly I have elsewhere examin'd, the _Sulphur of Vitriol_. So that most part of Dissolv'd Bodyes being by Præcipitation brought to White Powders, and yet some affording Præcipitates of other Colours, the reason of both the Phænomena may deserve to be enquir'd into. _EXPERIMENT XIII._ Some Learned Modern Writers[15] are of Opinion, that the Account upon which Whiteness and Blackness ought to be call'd, as they commonly are, the two Extreme Colours, is, That Blackness (by which I presume is meant the Bodyes endow'd with it) receives no other Colours; but Whiteness very easily receives them all; whence some of them compare Whiteness to the _Aristotelian Materia prima_, that being capable of any sort of Forms, as they suppose White Bodyes to be of every kind of Colour. But not to Dispute about Names or Expressions, the thing it self that is affirm'd as Matter of Fact, seems to be True enough in most Cases, not in all, or so, as to hold Universally. For though it be a common 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 præexistent 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