(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 not Soak, and by which it could not be Wrought, it nevertheless lost
its Colour. And these Instances (_Pyrophilus_) I am the more carefull to
mention to you, that you may not be much Surpris'd or Discourag'd, if you
should sometimes miss of performing punctually what I affirm my self to
have done in point of changing Colours; since in these Experiments the
over-sight or neglect of such little Circumstances, as in many others would
not be perhaps considerable, may occasion the mis-carrying of a Trial. And
I was willing also to take this occasion of Advertising you in the
repeating of the Experiments mention'd in this Treatise, to make use of the
Juices of Vegetables, and other things prepar'd for your Trials, as soon as
ever they are ready, lest one or other of them grow less fit, if not quite
unfit by delay; and to estimate the Event of the Trials by the Change, that
is produc'd presently upon the due and sufficient Application of Actives to