Green, which seems to proceed only from its disclosing its Colour upon the
Extenuation of its Depth into Superficies, if the change be not somewhat
help'd by the Colours degenerating upon one or other of the Accounts
formerly mention'd. Let me add, that having made divers Tryals with that
Blew substance, which in Painters shops is call'd _Litmase_, we have
sometimes taken Pleasure to observe, that being dissolv'd in a due
proportion of fair Water, the Solution either oppos'd to the Light, or
dropp'd upon White paper, did appear of a deep Colour betwixt Crimson and
Purple; and yet that being spread very thin on the Paper and suffer'd to
dry on there, the Paper was wont to appear Stain'd of a Fine Blew. And to
satisfie my selfe, that the diversity came not from the Paper, which one
might suspect capable of inbibing the Liquor, and altering the Colour, I
made the Tryal upon a flat piece of purely White Glass'd Earth, (which I
sometimes make use of about Experiments of Colours) with an Event not
unlike the former.

And now I speak of _Litmass_, I will add, that having this very day taken a
piece of it, that I had kept by me these several years, to make Tryals
about Colours, and having let fall a few drops of the strong Infusion of it
in fair water, into a fine Crystal Glass, shap'd like an inverted Cone, and
almost full of fair Water, I had now (as formerly) the pleasure to see, and
to show others, how these few tincted drops variously dispersing themselves
through the Limpid Water, exhibited divers Colours, or varieties of Purple
and Crimson. And when the Corpuscles of the Pigment seem'd to have equally
diffus'd themselves through the whole Liquor, I then by putting two or
three drops of Spirit of Salt, first made an odd change in the Colour of
the Liquor, as well as a visible commotion among its small parts, and in a
short time chang'd it wholly into a very Glorious Yellow, like that of a
Topaz. After which if I let fall a few drops of the strong and heavy
Solution of Pot-ashes, whose weight would quickly carry it to the sharp