elsewhere note, does very easily of it self acquire the consistence, not of
a Metalline _Calx_, but of a Coagulated matter, which we have observ'd with
pleasure to look so like, either to curdled Milk, or curdled Whites of
Eggs, that a person unacquainted with such Solutions may easily be mistaken
in it. But when I purposely prepar'd a _Menstruum_ that would dissolve it
as _Aqua-fortis_ dissolves Silver, and not barely Corrode it, and quickly
let it fall again, I remember not that I took notice of any particular
Colour in the Solution, as if the more Whitish Metalls did not much Tinge
their _Menstruums_, though the conspicuously Colour'd Metalls as Gold, and
Copper, do. For Lead dissolv'd in Spirit of Vinegar or _Aqua-fortis_ gives
a Solution cleer enough, and if the _Menstruum_ be abstracted appears
either Diaphanous or White. Of the Colour of Iron we have elsewhere said
something: And 'tis worth noting, that though if that Metall be dissolv'd
in oyl of Vitriol diluted with water, it affords a Salt or Magistery so
like in colour, as well as some other Qualities, to other green Vitriol,
that Chymists do not improperly call it _Vitriolum Martis_; yet I have
purposely try'd, that, by changing the _Menstruum_, and pouring upon the
filings of Steel, instead of oyl of Vitriol, _Aqua Fortis_, (whereof as I
remember, I us'd 4 parts to one of the Metall) I obtain'd not a Green, but
a Saffron Colour Solution; or rather a thick Liquor of a deep but yellowish
Red. Common Silver, such as is to be met with in Coines, being dissolv'd in
_Aqua fortis_, yields a Solution tincted like that of Copper, which is not
to be wondred at, because in the coining of Silver, they are wont (as we
elsewhere particularly inform you) to give it an Allay of Copper, and that
which is sold in shops for refined silver, is not (so far as we have tryed)
so perfectly free from that ignobler Metall, but that a Solution of It in
_Aqua fortis_, will give a Venereal Tincture to the _Menstruum_. But we
could not observe upon the solution of some Silver, which was perfectly
refin'd, (such as some that we have, from which 8 or 10 times its weight of
Lead has been blown off) that the _Menstruum_ though held against the Light