And I
remember that the other day, I made my self some Sport by an Improvement of
this Observation, for having dissolv'd some Pure Silver in _Aqua Fortis_,
and Evaporated the _Menstruum ad siccitatem_, as they speak, I caus'd a
Quantity of fair Water to be pour'd upon the _Calx_ two or three several
times, and to be at each Evaporated, till the _Calx_ was very Drye, and all
the Greenish Blewness that is wont to appear in Common Crystals of Silver,
was quite carry'd away. Then I made those I meant to Deceive, Moisten some
part of their Skin with their own Spittle, and slightly Rub the moistned
parts with a little of this Prepar'd Silver, Whereupon they Admir'd to see,
that a Snow-white Body laid upon the White Skin should presently produce a
deep Blackness, as if the stains had been made with Ink, especially
considering that this Blackness could not, like that produc'd by ordinary
Ink, be readily Wash'd off, but requir'd many Hours, and part of it some
dayes to its Obliteration. And with the same White _Calx_ and a little Fair
Water we likewise Stain'd the White Hafts of Knives, with a lasting Black
in those parts where the _Calx_ was Plentifully enough laid on, for where
it was laid on but very Thinly, the Stain was not quite of so Deep a
Colour.
Pages:
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163