clean thorow the Filtre, leaving its tincted, and as it were curdled parts
in the Filtre, upon which fair Water must be so often pour'd, till you have
Dulcifi'd the matter therein contain'd, the sign of which Dulcification is
(you know) when the Water that has pass'd through it, comes from it as
tasteless as it was pour'd on it. And if without Filtration you would
gather together the flakes of this Vegetable Lake, you must pour a great
Quantity of fair Water upon the Decoction after the affusion of the
Alluminous Solution, and you shall find the Liquor to grow clearer, and the
Lake to settle together at the bottom, or emerge to the top of the Water,
though sometimes having not pour'd out a sufficient Quantity of fair Water,
we have observ'd the Lake partly to subside, and partly to emerge, leaving
all the middle of the Liquor clear. But to make this Lake fit for use, it
must by repeated affusions of fresh Water, be Dulcifi'd from the adhering
Salts, as well as that separated by Filtration, and be spread and suffer'd
to dry leisurely upon pieces of Cloth, with Brown Paper, or Chalk, or
Bricks under them to imbibe the Moisture[25].

[Page 372]
_Annotation I._

Whereas it is presum'd that the Magistery of Vegetables obtain'd this way
consists but of the more Soluble and Coloured parts of the Plants that
afford it, I must take the liberty to Question the supposition. And for my
so doing, I shall give you this account.

According to the Notions (such as they were) that I had concerning Salts;
Allom, though to sense a Homogeneous Body, ought not to be reckon'd among
true Salts, but to be it self look'd upon as a kind of Magistery, in regard
that as Native Vitriol (for such I have had) contains both a Saline
substance and a Metall, whether Copper, or Iron, corroded by it, and