requiſite to keep this way from proving fallacious, upon the account of the variations of Colour that may be produc'd by the differing proportions that may be us'd betwixt the Oar and the Glaſs, by the Richneſs or Poorneſs of the Oar it ſelf, by the Degree of Fire, and (eſpecially) by the Length of Time, during which the matter is kept in fuſion; as you will eaſily gather from what you will quickly meet with in the following Annotation upon this preſent 48th Experiment.
Annotation IV.
There is another way and differing enough from thoſe already mention'd, by which Metalls may be brought to exhibit adventitious Colours: For by This, the Metall do's not ſo much impart a Colour to another Body, as receive a Colour from it, or rather both Bodies do by the new Texture reſulting from their miſtion produce a new Colour. I will not inſiſt to this purpoſe upon the Examples afforded us by yellow Orpiment, and common Sea Salt, from which, ſublim'd together, Chymiſts unanimouſly affirm their White or Cryſtalline Arſenick to be made: But 'tis not unworthy our noting, That though Yellow
Orpiment be acknowledg'd to be the Copiouſeſt by far of the two Ingredients of Arſenick, yet this laſt nam'd Body being duely added to the higheſt Colour'd Metall Copper, when 'tis in fuſion, gives it a whiteneſs both within and without. Thus Lapis Calaminaris changes and improves the Colour of Copper by turning it into Braſs. And I have ſometimes by the help of Zinck duely mix'd after a certain manner, given Copper one of the Richeſt Golden Colours that ever I have ſeen the Beſt true Gold Ennobled with. But pray have a care that ſuch Hints fall not into any hands that may mis-imploy them.
Annotation V.
Upon the Knowledge of the differing wayes of making Minerals and Metalls produce their adventitious Colours in Bodies capable of Vitrification, depends the pretty Art of making what Chymiſts by a Barbarous Word are pleas'd to call Amanſes, that is counterfeit, or factitious Gemms, as Emeralds, Rubies, Saphires, Topazes, and the like. For in the making of theſe, though pure Sand or Calcin'd Cryſtal give the Body, yet 'tis for the moſt part ſome Metalline or Mineral Calx, mingled in a
small proportion that gives the Colour. But though I have many years ſince taken delight, to divert my ſelf with this pleaſing Art, and have ſeen very pretty Productions of it, yet beſides that I fear I have now forgot moſt of the little Skill I had in it, this is no place to entertain you with what would rather take up an intire Diſcourſe, than be comprehended in an Annotation; wherefore the few things which I ſhall here take notice of to you, are only what belong to the preſent Argument, Namely,
Firſt, That I have often obſerv'd that Calcin'd Lead Colliquated with fine White Sand or Cryſtal, reduc'd by ignitions and ſubſequent extinctions in Water to a ſubtile Powder, will of it ſelf be brought by a due Decoction to give a cleer Maſs Colour'd like a German Amethyſt. For though this glaſs of Lead, is look'd upon by them that know no better way of making Amanſes, as the grand Work of them all, yet which is an inconvenience that much blemiſhes this way, the Calcin'd Lead it ſelf does not only afford matter to the Amanſes, but has alſo as well as other Metals a Colour of its own, which as I was ſaying, I have often found to be like that of German (as many call them) not Eaſtern Amethyſts.
Secondly, That nevertheleſs this Colour
may be eaſily over-powr'd by thoſe of divers other Mineral Pigments (if I may ſo call them) ſo that with a glaſs of Lead, you may Emulate (for Inſtance) the freſh and lovely Greenneſs of an Emerald, though in divers caſes the Colour which the Lead it ſelf upon Vitrification tends to, may vitiate that of the Pigment, which you would introduce into the Maſs.