hence, that the Heat agitating and shuffling the Corpuscles of the Body
expos'd to it, does in process of time so change its Texture, as that the
Transposed parts do Modifie the incident Light otherwise, than they did
when the Matter appear'd of another Colour.

_EXPERIMENT XXXI._

Among the several changes of Colour, which Bodies acquire or disclose by
Digestion, it it very remarkable, that _Chymists_ find a Redness rather
than any other Colour in most of the Tinctures they Draw, and ev'n in the
more Gross Solutions they make of almost all Concretes, that abound either
with Mineral or Vegetable Sulphur, though the _Menstruum_ imploy'd about
these Solutions or Tinctures be never so Limpid or Colourless.

This we have observ'd in I know not how many Tinctures drawn with Spirit of
Wine from _Jalap_, _Guaicum_, and several other Vegetables; and not only in
the Solutions of _Amber_, _Benzoin_, and divers other Concretes made with
the same _Menstruum_, but also in divers Mineral Tinctures. And, not to
urge that familiar Instance of the Ruby of Sulphur, as _Chymists_ upon the
score of its Colour, call the Solution of Flowers of Brimstone, made with
the Spirit of Turpentine, nor to take notice of other more known Examples
of the aptness of Chymical Oyls, to produce a Red Colour with the Sulphur
they extract, or dissolve; not to insist (I say) upon Instances of this
nature, I shall further represent to you, as a thing remarkable, that, both
Acid and Alcalizate Salts, though in most other cases of such contrary
Operations, in reference to Colours, will with many Bodies that abound with
Sulphureous, or with Oyly parts, produce a Red; as is manifest partly in
the more Vulgar Instances of the Tinctures, or Solutions of Sulphur made
with _Lixiviums_, either of Calcin'd Tartar or Pot-ashes, and other Obvious
examples, partly by this, that the true Glass of Antimony extracted with