Precipitate were a Snow White Body, yet upon pouring on it a large quantity
of fair Water, we did almost in a moment perceive it to pass from a Milky
Colour to one of the loveliest Light Yellows that ever we had beheld. Nor
is the Turbith Mineral, that Chymists extol for its power to Salivate, and
for other vertues, of a Colour much inferiour to this, though it be often
made with a differing proportion of the Ingredients, a more troublesome
way. For _Beguinus_,[22] who calls it _Mercurius præcipitatus optimus_,
takes to one part of Quick-Silver, but two of Liquor, and that is Rectifi'd
Oyl of Sulphur, which is (in _England_ at least) far more scarce and dear
than Oyl of Vitriol; he also requires a previous Digestion, two or three
Cohobations, and frequent Ablutions with hot Distill'd Water, with other
prescriptions, which though they may conduce to the Goodness of the
Medicine, which is that he aims at, are troublesome, and, our Tryals have
inform'd you unneccessary to the _obtaining the Lemmon Colour_ which he
regards not. But though we have very rarely seen either in Painters Shops,
or elsewhere a finer Yellow than that which we have divers times this way
produc'd (which is the more considerable, because durable and pleasant
Yellows are very hard to be met with, as may appear by the great use which
Painters are for its Colours sake fain to make of that pernicious and heavy
Mineral, Orpiment) yet I fear our Yellow is too costly, to be like to be
imploy'd by Painters, unless about Choice pieces of Work, nor do I know how
well it will agree with every Pigment, especially, wich Oyl'd Colours. And
whether this Experiment, though it have seem'd somewhat strange to most we
have shown it to, be really of another Nature than those wherein Saline
Liquors are imploy'd, may, as we formerly also hinted, be so plausibly
doubted, that whether the Water pour'd on the _Calx_, do barely by imbibing
some of its Saline parts alter its Colour by altering its Texture, or
whether by dissolving the Concoagulated Salts, it does become a Saline
_Menstruum_, and, as such, work upon the Mercury, I freely leave to you
(_Pyrophilus_) to consider. And that I may give you some Assistance in your