_EXPERIMENT III._
If pieces of White Harts-horn be with a competent degree of Fire distill'd
in a Glass-retort, they will, after the avolation of the Flegm, Spirit,
Volatile Salt, and the looser and lighter parts of the Oleagenous
substance, remain behind of a Cole-black colour. And even Ivory it self
being skilfully Burnt (how I am wont to do it, I have elsewhere set down)
affords Painters one of the best and deepest Blacks they have, and yet in
the Instance of distill'd Harts-horn, the operation being made in
Glass-vessels carefully clos'd, it appears there is no Extraneous Black
substance that Insinuates it self into White Harts-horn, and thereby makes
it turn Black; but that the Whiteness is destroy'd, and the Blackness
generated, only by a Change of Texture, made in the burnt Body, by the
Recess of some parts and the Transposition of others. And though I remember
not that in many Distillations of Harts-horn I ever sound the _Cap. Mort_.
to pass from Black to a true Whiteness, whilst it continu'd in Clos'd
vessels, yet having taken out the Cole-black fragments, and Calcin'd them
in Open vessels, I could in few hours quite destroy that Blackness, &
without sensibly changing their Bulk or Figure, reduce them to great
Whiteness.
Pages:
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154