es should be very warily made, may appear
among other things, by the Instance I have chosen to give in Roses. For
though, (as I formerly told you) the Dry'd Leaves, both of the Damask, and
of Red ones, give a Red Tincture to Water sharpen'd with Acid Salts, yet
the one sort of Leaves is known to have a Purgative faculty,[20] and the
other are often, and divers ways, imploy'd for Binding.

[20] See _Parkinson_ Th. Boran. Trib. 9. cap. 26.

And I also choose (_Pyrophilus_) to subjoyn this twenty ninth Experiment to
those that precede it, about the change of the Colours of Vegetables by
Salts, for these two reasons: The first, that you may not easily entertain
Suspitions, if in the Trials of an Experiment of some of the Kinds formerly
mention'd, you should meet with an Event somewhat differing from what my
Relations may have made you expect. And the second, That you may hereby be
invited to discern, that it may not be amiss to take notice of the
particular Seasons wherein you gather the Vegetables which in Nicer
Experiments you make use of. For, it I were not hindred both by haste and
some justifiable Considerations, I could perhaps add considerable
Instances, to those lately deliver'd, for the making out of this
Observation; but for certain reasons I shall at present substitute a
remarkable passage to be met with in that Laborious Herbarist Mr.
_Parkinson_, where treating of the Virtues of the (already divers times
mention'd) Buckthorn Berries, he subjoyns the following account of several
Pigments that are made of them, not only according to the several ways of
Handling them, but according to the differing Seasons of Maturity, at which
they are Gather'd; _Of these Berries_, (says he) _are made three several
sorts of Colours as they shall be gather'd, that is, being gather'd while
they are Green, and kept Dry, are call'd Sapberries, which being steep'd
into some Allom-water, or fresh bruis'd into Allom-water, they give a
reasonable fair Yellow Colour which Painters use for their Work, and
Book-binders to Colour the edges of Books, and Leather-dressers to Colour
Leather, as they use also to make a Green Colour, call'd Sap-green, taken
from the Berries when they are Black, being bruis'd and put into a Brass or
Copper Kettle or Pan, and there suffer'd to abide three or four_ _Days, or
a little heated upon the Fire, and some beaten Allom put unto them, and
afterwards press'd forth, the Juice or Liquor is usually put in great