full of Water, Impregnated by any of them, as it is
directed towards a place more Lightsome or Obscure, being far from
affording a Variety answerable to so promising a Title. And as for what he
tells us, that in the Dark the Infusion of our Wood will resume a
Caeruleous Colour, I wish he had Inform'd us how he Try'd it.

But this brings into my mind, that having sometimes for Curiosity sake,
brought a round Vial with a long Neck fill'd with the Tincture of _Lignum
Nephriticum_ into the Darken'd Room already often mention'd, and holding it
sometimes in, sometimes near the Sun-beams that enter'd at the hole, and
sometimes partly in them, and partly out of them, the Glass being held in
several postures, and look'd upon from several Neighbouring parts of the
Room, disclos'd a much greater Variety of Colours than in ordinary
inlightn'd Rooms it is wont to do; exhibiting, besides the usual Colours, a
Red in some parts, and a Green in others, besides Intermediate Colours
produc'd by the differing Degrees, and odd mixtures of Light and Shade.

By all this You may see, _Pyrophilus_, the reasonableness of what we
elsewhere had occasion to mention, when we have divers times told you, that
it is usefull to have New Experiments try'd over again, though they were,
at first, made by Knowing and Candid Men, such Reiterations of Experiments
commonly exhibiting some New Phaenomena, detecting some Mistake or hinting
some Truth, in reference to them, that was not formerly taken notice of.
And some of our friends have been pleas'd to think, that we have made no
unusefull addition to this Experiment, by shewing a way, how in a moment
our Liquor may be depriv'd of its Blewness, and restor'd to it again by the
affusion of a very few drops of Liquors, which have neither of them any
Colour at all of their own. And that which deserves some particular wonder,
is, that the Caeruleous Tincture of our Wood is subject by the former
Method to be Destroy'd or Restor'd, the Yellowish or Reddish Tincture
continuing what it was. And that you may see, that Salts are of a
considerable use in the striking of Colours, let me add to the many
Experiments which may be afforded us to this purpose by the Dyers Trade,
this Observation; That as far as we have hitherto try'd, those Liquors in
general that are strong of Acid Salts have the Power of Destroying the
Blewness of the Infusion of our Wood, and those Liquors indiscriminatly
that abound with Sulphureous Salts,