Annotation I.

It is not unworthy the Admonishing you, (Pyrophilus,) and it agrees very well with our Conjectures about the dependence of the change of a Body’s Colour upon that of its Texture, that the same Metall may by the successive operation of the fire receive divers Adventitious Colours, as is evident in Lead, which before it come to so deep a Colour as that of Minium, may pass through divers others.

Annotation II.

Not only the Calces, but the Glasses of Metalls, Vitrify’d per se, may be of Colours differing from the Natural or Obvious Colour of the Metall; as I have observ’d in the Glass of Lead, made by long exposing Crude Lead to a violent fire, and what I have observ’d about the Glass or Slagg of Copper, (of which I can show you some of an odd kind of Texture,) may be elsewhere more conveniently related.  I have likewise seen a piece of very Dark Glass, which an Ingenious Artificer that show’d it me profess’d himself to have made of Silver alone by an extreme Violence (which seems to be no more than is needfull) of the fire.

Annotation III.

Minerals also by the Action of the Fire may be brought to afford Colours very differing from their own, as I not long since noted to you about the variously Colour’d Flowers of Antimony, to which we may add the Whitish Grey-Colour of its Calx, and the Yellow or Reddish Colour of the Glass, where into that Calx may be flux’d.

And I remember, that I elsewhere told you, that Vitriol Calcin’d with a very gentle heat, and afterwards with higher and higher degrees of it, may be made to pass through several Colours before it descends to a Dark Purplish Colour, whereto a strong fire is wont at length to reduce it.  But to insist on the Colours produc’d by the Operation of fire upon several Minerals would take up farr more time than I have now to spare.

EXPERIMENT XLVII.

The Adventitious Colours produc’d upon Metalls, or rather with them, by Saline Liquors, are many of them so well known to Chymists, that I would not here mention them, but that besides a not un-needed Testimony, I can add something of my own, to what I shall repeat about them, and divers Experiments which are familiar to Chymists, are as yet unknown to the greatest part of Ingenious Men.

That Gold dissolv’d in Aqua Regia ennobles the Menstruum with its own Colour, is a thing that you cannot (Pyrophilus,) but have often seen.  The Solutions of Mercury in Aqua-fortis are not generally taken notice of, to give any notable Tincture to the Menstruum; but sometimes when the Liquor first falls upon the Quick Silver, I have observ’d a very remarkable, though not durable, Greenness, or Blewness to be produc’d, which is a Phaenomenon not unfit for you to consider, though I have not now the leisure to discourse upon it.  Tin Corroded by Aqua-fortis till the