fortis_, and suffer it to shoot into
Crystals, the cleer Solution of these made in fair Water, will afford a
very White Precipitate, whether it be made with an Alcaly, or an Acid
Spirit, as that of Salt, whereas, which may seem somewhat strange, with
Spirit of Sal Armoniack (that I us'd was made of Quicklime) I could obtain
no such White Precipitate; that Volatile Spirit, nor (as I remember) that
of Urine, scarce doing any more than striking down a very small quantity of
Matter, which was neither White nor Whitish, so that the remaining Liquor
being suffer'd to evaporate till the superfluous Moisture was gone, the
greatest part of the Metalline Corpuscles with the Saline ones that had
imbib'd them, concoagulated into Salt, as is usual in such Solutions,
wherein the Metall has not been Precipitated.

_EXPERIMENT XLI._

Of Kin to the last or fortieth Experiment is another which I remember I
have sometimes shewn to _Virtuosi_ that were pleas'd not to dislike it. I
took Spirit of Urine made by Fermentation, and with a due proportion of
Copper brought into small parts, I obtain'd a very lovely Azure Solution,
and when I saw the Colour was such as was requisite, pouring into a clean
Glass, about a spoonfull of this tincted Liquor, (of which I us'd to keep a
Quantity by me,) I could by shaking into it some drops of Strong Oyl of
Vitriol, deprive it in a trice of its Deep Colour, and make it look like
Common-water.

_Annotation_.

This Experiment brings into my mind this other, which oftentimes succceds
well enough, though not quite so well as the former; Namely, that if into
about a small spoonfull of a Solution of good French Verdigrease made in
fair Water, I drop't and shak'd some strong Spirit of Salt, or rather
deflegm'd _Aqua Fortis_, the Greenness of the Solution would be made in a
trice almost totally to disappear, & the Liquor held against the Light
would scarce seeme other than Cleer or Limpid, to any but an Attentive Eye,
which is therefore remarkable; because we know that _Aqua-fortis_ corroding
Copper, which is it that gives the Colour to Verdigrease, is wont to reduce
it to a Green Blew Solution. But if into the other altogether or almost
Colourless Liquor I was speaking of, you drop a just quantity either of Oyl
of Tartar or Spirit of Urine, you shall find that after the Ebullition is
ceas'd, the mixture will disclose a lively Colour, though somewhat
differing from that which the Solution of Verdigrease had at