of the Mechanical use of Colours among Painters and Dyers, doth depend upon
the Knowledge of what Colours may be produc'd by the Mixtures of Pigments
so and so Colour'd. And (as we lately intimated) 'tis of advantage to the
contemplative Naturalist, to know how many and which Colours are Primitive
(if I may so call them) and Simple, because it both eases his Labour by
confining his most sollicitous Enquiry to a small Number of Colours upon
which the rest depend, and assists him to judge of the nature of particular
compounded Colours, by shewing him from the Mixture of what more Simple
ones, and of what Proportions of them to one another, the particular Colour
to be consider'd does result. But because to insist on the Proportions, the
Manner and the Effects of such Mixtures would oblige me to consider a
greater part of the Painters Art and Dyers Trade, than I am well acquainted
with, I confin'd my self to make Trial of _several ways to produce Green_,
by the composition of Blew and Yellow. And shall in this place both
Recapitulate most of the things I have Dispersedly deliver'd already
concerning that Subject, and Recruit them.

And first, whereas Painters (as I noted above) are wont to make Green by
tempering Blew and Yellow, both of them made into a soft Consistence, with
either Water or Oyl, or some Liquor of Kin to one of those two, according
as the Picture is to be Drawn with those they call _water Colours_, or
those they term _Oyl Colours_, I found that by choosing fit Ingredients,
and mixing them in the form of Dry Powders, I could do, what I could not if
the Ingredients were temper'd up with a Liquor; But the Blew and Yellow
Powders must not only be finely Ground, but such as that the Corpuscles of
the one may not be too unequal to those of the other, lest by their
Disproportionate Minuteness the Smaller cover and hide the Greater. We us'd
with good success a slight Mixture of the fine Powder of Bise, with that of
Orpiment, or that of good Yellow Oker, I say a _slight_ Mixture, because we
found that an _exquisite_ Mixture did not do so well, but by lightly