abounding in Sulphureous parts are to afford a Red Colour, is one,
wherein by the Operation of a Saline Spirit upon a White or Whitish Body,
which according to the _Chymists_ should be altogether Sulphureous, a
Redness may be produc'd, not (as in the former Experiments) slowly, but in
the twinkling of an Eye. We took then of the Essential Oyl of Anniseeds,
which has this Peculiarity, that in Cold weather it loses its Fluidity and
the greatest part of its Transparency, and looks like a White or Whitish
Oyntment, and near at hand seems to consist of a Multitude of little soft
Scales: Of this Coagulated Stuff we spread a little with a Knife upon a
piece of White Paper, and letting fall on it, and mixing with it a drop or
two of Oyl of Vitriol, immediately (as we fore-saw) there emerg'd together
with some Heat and Smoak, a Blood-Red Colour, which therefore was in a
trice produc'd by two Bodies, whereof the one had but a Whitish Colour, and
the other (if carefully rectify'd) had no Colour at all.

_EXPERIMENT XXXVI._

But on this Occasion (_Pyrophilus_) we must add once for all, that in many
of the above-recited Experiments, though the changes of Colour happen'd as
we have mention'd them: yet the emergent or produc'd Colour is oft times
very subject to Degenerate, both quickly and much. Notwithstanding which,
since the Changes, we have set down, do happen presently upon the Operation
of the Bodies upon each other, or at the times by us specify'd; _that_ is
sufficient both to justifie our Veracity, and to shew what we Intend; it
not being Essential to the Genuineness of a Colour to be Durable. For a
fading Leaf, that is ready to Rot, and moulder into Dust, may have as true
a Yellow, as a Wedge of Gold, which so obstinately resists both Time and
Fire. And the reason, why I take occasion from the former Experiment to
subjoyn this general Advertisement, is, that I have several times observ'd,
that the Mixture resulting from the Oyls of Vitriol, and of Anniseeds,
though it acquire a thicker consistence than either of the Ingredients had,
has quickly lost its Colour, turning in a very short time into a dirty
Gray, at least in the Superficial parts, where 'tis expos'd to the Air;
which last Circumstance I therefore mention, because that, though it seem
probable, that this Degeneration of Colours may oft times and in divers
cases proceed from the further Action of the Saline Corpuscles, and the
other Ingredients upon one another, yet