I
will not undertake that though you'l hardly miss changing the Colour of
your shining Tinglass, yet you will the first or perhaps the second time
hit Right upon the way of making the Glistring Sublimate I have been
mentioning.
_EXPERIMENT IX._
When we Dissolve in _Aqua Fortis_ a mixture of Gold and Silver melted into
one Lump, it usually happens that the Powder of Gold that falls to the
bottom, as not being Dissoluble by that _Menstruum_, will not have its own
Yellow, but appear of a Black Colour, though neither the Gold, nor the
Silver, nor the _Aqua Fortis_ did before manifest any Blackness. And divers
Alchymists, when they make Solutions of Minerals they would Examine, are
very Glad, if they see a Black Powder Praecipitated to the Bottom, taking it
for a Hopefull Sign, that those Particles are of a Golden Nature, which
appear in a Colour so ordinary to Gold parted from other Metalls by _Aqua
Fortis_, that it is a trouble to the Refiner to Reduce the Praecipitated
_Calx_ to its Native Colour. For though, (as we have try'd,) that may be
Quickly enough done by Fire, which will make this Gold look very Gloriously
(as indeed 'tis at least one of the Best wayes that is Practis'd for the
Refining of Gold,) yet it requires both Watchfulness and Skill, to give it
such a Degree of Fire as will serve to Restore it to its Lustre, without
giving it such a One, as may bring it to Fusion, to which the Minuteness of
the _Corpuseles_ it consists of makes the Powder very apt.
Pages:
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161