Annotation III.
And yet before I paſs to the next Experiment, I muſt put you in mind, that the Colours of Metals may in many caſes be further alter'd by imploying, either præcipitating Salts, or other convenient Subſtances to act upon their Solutions. Of this you may remember, that I have given you ſeveral Inſtances already, to which may be added ſuch as theſe, That if Quickſilver be diſſolv'd in Aqua fortis, and Præcipitated out of the Solution, either with water impregnated with Sea ſalt, or with the ſpirit of that Concrete, it falls to the Bottom in the form of a white powder, whereas if it be Præcipitated with an Alcaly, it will afford a Yellowiſh or tawny powder, and if there be no Præcipitation made, and the Menſtruum be drawn off with a convenient
fire, the corroded Mercury will remain in the bottom, in the form of a ſubſtance that may be made to appear of differing Colours by differing degrees of Heat; As I remember that lately having purpoſely abſtracted Aqua fortis from ſome Quickſilver that we had diſſolv'd in it, ſo that there remain'd a white Calx, expoſing that to ſeveral degrees of Fire, and afterwards to a naked one, we obtain'd ſome new Colours, and at length the greateſt part of the Calx lying at the Bottome of the Vial, and being brought partly to a Deep Yellow, and partly to a Red Colour, the reſt appear'd elevated to the upper part and neck of the Vial, ſome in the form of a Reddiſh, and ſome of an Aſh-Colour Sublimate. But of the differing Colours which by differing wayes and working of Quick Silver with Fire, and Saline Bodies, may be produc'd in Precipitates, I may elſewhere have occaſion to take further notice. I alſo told you not long ſince, that if you corrode Quick-ſilver with Oyl of Vitriol inſtead of Aqua-fortis, and abſtract the Menſtruum, there will remain a White Calx which by the Affuſion of Fair Water preſently turns into a Lemmon Colour. And ev'n the Succedaneum to a Menſtruum may ſometimes ſerve the turn to change the Colours of a Metal. The lovely
Red which Painters call Vermillion, is made of Mercury, which is of the Colour of Silver, and of Brimſtone which is of Kin to that of Gold, Sublim'd up together in a certain proportion, as is vulgarly known to Spagyriſts.
EXPERIMENT XLVIII.
The third chief ſort of the Adventitious Colours of Metals, is, that which is produc'd by aſſociating them (eſpecially when Calcin'd) with other fuſible Bodies, and Principally Venice, and other fine Glaſs devoid of Colour.
I have formerly given you an Example, whereby it may appear, that a Metal may impart to Glaſs a Colour much differing from its own, when I told you, how with Silver, I had given Glaſs a lovely Golden Colour. And I ſhall now add, that I have Learn'd from one of the Chief Artificers that ſells Painted Glaſs, that thoſe of his Trade Colour it Yellow with a preparation of the Calx of Silver. Though having lately had occaſion among other Tryals to mingle a few grains of Shell-ſilver (ſuch as is imploy'd with the Penſil and Pen) with a convenient proportion of powder'd Cryſtal Glaſs, having kept them two or three
hours in fuſion, I was ſurpriz'd to find the Colliquated Maſs to appear upon breaking the Crucible of a lovely Saphirine Blew, which made me ſuſpect my Servant might have brought me a wrong Crucible, but he conſtantly affirm'd it to be the ſame wherein the Silver was put, and conſiderable Circumſtances countenanc'd his Aſſertion, ſo that till I have opportunity to make farther Tryal, I cannot but ſuſpect, either that Silver which is not (which is not very probable) brought to a perfect Fuſion and Colliquation with Glaſs, may impart to it other Colours than when Neal'd upon it, or elſe (which is leſs unlikely) that though Silver Beaters uſually chuſe the fineſt Coyn they can get, as that which is moſt extenſive under the Hammer, yet the Silver-leaves of which this Shel-ſilver was made, might retain ſo much Copper as to enable it to give the predominant tincture to the Glaſs.
For, I muſt proceed to tell you (Pyrophilus) as another inſtance of the Adventitious Colours of Metals, that which is ſomething ſtrange, Namely, That though Copper Calcin'd per ſe affords but a Dark and baſely Colour'd Calx, yet the Glaſsmen do with it, as themſelves inform me, Tinge their Glaſs green. And I remember, that when once we took ſome crude Copper,
and by frequent Ignition quenching it in Water had reduc'd it to a Dark and Ill-colour'd Powder, and afterward kept it in Fuſion in about a 100. times its weight of fine Glaſs, we had, though not a Green, yet a Blew colour'd Maſs, which would perhaps have been Green, if we had hit right upon the Proportion of the Materials, and the Degree of Fire, and the Time wherein it ought to be kept in Fuſion, ſo plentifully does that Metal abound in a Venerial Tincture, as Artiſts call it, and in ſo many wayes does it diſcloſe that Richneſs. But though Copper do as we have ſaid give ſomewhat near the like Colour to Glaſs, which it does to Aqua-fortis, yet it ſeems worth inquiry, whether thoſe new Colours which Mineral Bodies diſcloſe in melted Glaſs, proceed from the Coalition of the Corpuſcles of the Mineral with the Particles of the Glaſs as ſuch, or from the Action (excited or actuated by fire) of the Alcalizate Salt (which is a main Ingredient of Glaſs,) upon the Mineral Body, or from the concurrence of both theſe Cauſes, or elſe from any other. But to return to that which we were ſaying, we may obſerve that Putty made by calcining together a proportion of Tin and Lead, as it is it ſelf a White Calx, ſo does it turn the Pitta di Cryſtallo (as the