this Nature.

_EXPERIMENT XLIX._

Meeting the other day, _Pyrophilus_, in an _Italian_ book, that treats of
other matters, with a way of preparing what the Author calls a _Lacca_ of
Vegetables, by which the _Italians_ mean a kind of Extract fit for
Painting, like that rich _Lacca_ in English commonly call'd _Lake_, which
is imploy'd by Painters as a glorious Red. And finding the Experiment not
to be inconsiderable, and very defectively set down, it will not be amiss
to acquaint you with what some Tryals have inform'd us, in reference to
this Experiment, which both by our Italian Author, and by divers of his
Countrymen, is look'd upon as no trifling Secret.

Take then the root call'd in Latin _Curcuma_, and in English Turmerick,
(which I made use of, because it was then at hand, and is among Vegetables
fit for that purpose one of the most easiest to be had) and when it is
beaten, put what Quantity of it you please into fair Water, adding to every
pound of Water about a spoonfull or better of as strong a _Lixivium_ or
Solution of Potashes as you can well make, clarifying it by Filtration
before you put it to the Decocting water. Let these things boyl, or rather
simper over a soft Fire in a clean glaz'd Earthen Vessel, till you find by
the Immersion of a sheet of White Paper (or by some other way of Tryal)
that the Liquor is sufficiently impregnated with the Golden Tincture of the
Turmerick, then take the Decoction off the Fire, and Filter or Strain it
that it may be clean, and leisurely dropping into it a strong Solution of
Roch Allum, you shall find the Decoction as it were curdl'd, and the
tincted part of it either to emerge, to subside, or to swim up and down,
like little Yellow flakes; and if you pour this mixture into a Tunnel lin'd
with Cap Paper, the Liquor that Filtred formerly so Yellow, will now pass