in many cases much of the Quick
change of Colours seems ascribeable to the Air, as may be made probable by
several reasons: The first whereof may be fetcht from the newly recited
Example of the two Oyls; The next may be, that we have sometimes observ'd
long Window-Curtains of light Colours, to have that part of them, which was
expos'd to the Air, when the Window was open, of one Colour, and the lower
part, that was sheltred from the Air by the Wall, of another Colour: And
the third Argument may be fetch'd from divers Observations, both of others,
and our own; For of that Pigment so well known in Painters Shops, by the
name of _Turnsol_, our Industrious _Parkinson_, in the particular account
he gives of the Plant that bears it, tells us also, That _the Berries when
they are at their full Maturity, have within them between the outer Skin
and the inward Kirnel or Seed, a certain Juice or Moisture, which being
rubb'd upon Paper or Cloath, at the first appears of a fresh and lovely
Green Colour, but presently changeth into a kind of Blewish Purple, upon
the Cloath or Paper, and the same Cloath afterwards wet in Water, and wrung
forth, will Colour the Water into a Claret Wine Colour, and these_
(concludes he) _are those Raggs of Cloath, which are usually call'd_
Turnsol _in the Druggists or Grocers Shops_[21]. And to this Observation of
our _Botanist_ we will add an Experiment of our own, (made before we met
with That) which, though in many Circumstances, very differing, serves to
prove the same thing; for having taken of the deeply Red Juice of
_Buckthorn_ Berries, which I bought of the Man that uses to sell it to the
Apothecaries, to make their Syrrup _de Spina Cervina_, I let some of it
drop upon a piece of White Paper, and having left it there for many hours,
till the Paper was grown dry again, I found what I was inclin'd to suspect,
namely, That this Juice was degenerated from a deep Red to a dirty kind of
Greyish Colour, which, in a great part of the stain'd Paper seem'd not to
have so much as an Eye of Red: Though a little Spirit of Salt or dissolv'd
_Alcaly_ would turn this unpleasant Colour (as formerly I told you it would
change the not yet alter'd Juice) into a Red or Green. And to satisfie my
self, that this Degeneration of Colour did not proceed from the Paper, I
drop'd some of the deep Red or Crimson Juice upon a White glaz'd Tile, and
suffering it to dry on there, I found that ev'n in that Body, on which it
could