of both which I can show you. But though I have from Minerals obtain'd with
several _Menstruums_ very differing Colours, and some such as perhaps you
would be surpriz'd to see drawn from such Bodies: yet I must now pass by
the particulars, being desirous to put an End to this Treatise, before I
put an end to your Patience and my own.

_Annotation III._

And yet before I pass to the next Experiment, I must put you in mind, that
the Colours of Metals may in many cases be further alter'd by imploying,
either præcipitating Salts, or other convenient Substances to act upon
their Solutions. Of this you may remember, that I have given you several
Instances already, to which may be added such as these, That if Quicksilver
be dissolv'd in _Aqua fortis_, and Præcipitated out of the Solution, either
with water impregnated with Sea salt, or with the spirit of that Concrete,
it falls to the Bottom in the form of a white powder, whereas if it be
Præcipitated with an Alcaly, it will afford a Yellowish or tawny powder,
and if there be no Præcipitation made, and the _Menstruum_ be drawn off
with a convenient fire, the corroded Mercury will remain in the bottom, in
the form of a substance that may be made to appear of differing Colours by
differing degrees of Heat; As I remember that lately having purposely
abstracted _Aqua fortis_ from some Quicksilver that we had dissolv'd in it,
so that there remain'd a white _Calx_, exposing that to several degrees of
Fire, and afterwards to a naked one, we obtain'd some new Colours, and at
length the greatest part of the _Calx_ lying at the Bottome of the Vial,
and being brought partly to a Deep Yellow, and partly to a Red Colour, the
rest appear'd elevated to the upper part and neck of the Vial, some in the
form of a Reddish, and some of an Ash-Colour Sublimate. But of the
differing Colours which by differing wayes and working of Quick Silver with
Fire, and Saline Bodies, may be produc'd in Precipitates, I may elsewhere