Experiment XLVII
The Adventitious Colours produc’d upon Metalls, or rather with them, by Saline Liquors, are many of them ſo well known to Chymiſts, that I would not here mention them, but that beſides a not un-needed Teſtimony, I can add ſomething of my own, to what I ſhall repeat about them, and divers Experiments which are familiar to Chymiſts, are as yet unknown to the greateſt part of Ingenious Men.
That Gold diſſolv’d in Aqua Regia ennobles the Menſtruum with its own Colour, is a thing that you cannot (Pyrophilus,) but have often ſeen. The Solutions of Mercury in Aqua-fortis are not generally taken notice of, to give any notable Tincture to the Menſtruum; but ſometimes when the Liquor firſt falls upon the Quick Silver, I have obſerv’d a very remarkable, though not durable, Greenneſs, or Blewneſs to be produc’d, which is a Phænomenon not unfit for you to conſider, though I have not now the leiſure to diſcourſe upon it. Tin Corroded by Aqua-fortis till the Menstruum will work no farther on it, becomes exceeding White, but as we elſewhere note, does very eaſily of it ſelf acquire the conſiſtence, not of a Metalline Calx, but of a Coagulated matter, which we have obſerv’d with pleaſure to look ſo like, either to curdled Milk, or curdled Whites of Eggs, that a perſon unacquainted with ſuch Solutions may eaſily be miſtaken in it. But when I purpoſely prepar’d a Menſtruum that would diſſolve it as Aqua-fortis diſſolves Silver, and not barely Corrode it, and quickly let it fall again, I remember not that I took notice of any particular Colour in the Solution, as if the more Whitiſh Metalls did not much Tinge their Menſtruums, though the conſpicuouſly Colour’d Metalls as Gold, and Copper, do. For Lead diſſolv’d in Spirit of Vinegar or Aqua-fortis gives a Solution cleer enough, and if the Menſtruum be abſtracted appears either Diaphanous or White. Of the Colour of Iron we have elſewhere ſaid ſomething: And ’tis worth noting, that though if that Metall be diſſolv’d in oyl of Vitriol diluted with water, it affords a Salt or Magiſtery ſo like in colour, as well as ſome other Qualities, to other green Vitriol, that Chymiſts do not improperly call it Vitriolum Martis; yet I have purpoſely try’d, that, by changing the Menſtruum, and pouring upon the filings of Steel, inſtead of oyl of Vitriol, Aqua Fortis, (whereof as I remember, I us’d 4 parts to one of the Metall) I obtain’d not a Green, but a Saffron Colour Solution; or rather a thick Liquor of a deep but yellowiſh Red. Common Silver, ſuch as is to be met with in Coines, being diſſolv’d in Aqua fortis, yields a Solution tincted like that of Copper, which is not to be wondred at, becauſe in the coining of Silver, they are wont (as we elſewhere particularly inform you) to give it an Allay of Copper, and that which is ſold in ſhops for refined ſilver, is not (ſo far as we have tryed) ſo perfectly free from that ignobler Metall, but that a Solution of It in Aqua fortis, will give a Venereal Tincture to the Menſtruum. But we could not obſerve upon the ſolution of ſome Silver, which was perfectly refin’d, (ſuch as ſome that we have, from which 8 or 10 times its weight of Lead has been blown off) that the Menſtruum though held againſt the Light in a Cryſtal Vial did manifeſtly diſcloſe any Tincture, only it ſeem’d ſometimes not to be quite deſtitute of a little, but very faint Blewiſhneſs.
But here I muſt take notice, that of all the Metalls, there is not any which doth ſo eaſily and conſtantly diſcloſe its unobvious colour as Copper doth. For not only in acid Menſtruums as Aqua Fortis and Spirit of Vinegar, it gives a Blewiſh green ſolution, but if it be almoſt any way corroded, it appears of one of thoſe two colours, as may be obſerv’d in Verdigreeſe made ſeveral wayes, in that odd preparation of Venus, which we elſewhere teach you to make with Sublimate, and in the common Vitriols of Venus deliver’d by Chymiſts; and ſo conſtant is the diſpoſition of Copper, notwithſtanding the diſguiſe Artiſts put upon it, to diſcloſe the colour we have been mentioning, that we have by forcing it up with Sal Armoniack obtain’d a Sublimate of a Blewiſh Colour. Nay a famous Spagyriſt affirms, that the very Mercury of it is green, but till he teach us an intelligible way of making ſuch a Mercury, we muſt content ourſelves to inform you, that we have had a Cupreous Body, that was Præcipitated out of a diſtill’d Liquor, that ſeem’d to be the the Sulphur of Venus, and ſeem’d even when flaming, of a Greeniſh Colour. And indeed Copper is a Metall ſo eaſily wrought upon by Liquors of ſeveral kinds, that I ſhould tell you, I know not any Mineral, that will concurr to the production of ſuch a variety of Colours as Copper diſſol’d in ſeveral Menſtruums, as Spirit of Vinegar, Aqua fortis, Aqua Regis, Spirit of Nitre, of Urine, of Soot, Oyls of ſeveral kinds, and I know not how many other Liquors, if the variety of ſomewhat differing colours (that Copper will be made to aſſume, as it is wrought upon by ſeveral Liquors) were not comprehended within the Limits of Greeniſh Blew, or Blewiſh Green.
And yet I muſt advertiſe you (Pyrophilus) that being deſirous to try if I could not make with crude Copper a Green Solution without the Blewiſhneſs that is wont to accompany its Vulgar Solutions, I bethought my ſelf of uſing two Menſtruums, which I had not known imploy’d to work on this Metall, and which I had certain Reaſons to make Tryal of, as I ſucceſsfully did. The one of theſe Liquors (if I much miſremember not) was Spirit of Sugar diſtill’d in a Retort, which muſt be warily done, (if you will avoid breaking your glaſſes) and the other, Oyl or Spirit of Turpentine, which affords a fine Green Solution that is uſeful to me on ſeveral occaſions. And yet to ſhew that the adventitious colour may reſult, as well from the true and permanent Copper it ſelf, as the Salts wherewith ’tis corroded, I ſhall add, that if you take a piece of good Dantzick Copperis, or any other Vitriol wherein Venus is prædominant, and having moiſtened it in your Mouth, or with fair water, rubb it upon a whetted knife, or any other bright piece of Steel or Iron, it will (as we have formerly told you) preſent’y ſtain the Steel with a Reddiſh colour, like that of Copper, the reaſon of which, we muſt not now ſtay to inquire.
Annotation I.
I preſume you may have taken notice (Pyrophilus) that I have borrowed ſome of the Inſtances mention’d in this 47th Experiment, from the Laboratories of Chymiſts, and becauſe in ſome (though very few) other paſſages of this Eſſay, I have likewiſe made uſe of Experiments mention’d alſo by ſome Spagyrical Writers, I think it not amiſs to repreſent to you on this Occaſion once for all, ſome things beſides those which I intimated in the præamble of this preſent Experiment; For beſides, that ’tis very allowable for a Writer to repeat an Experiment which he invented not, in caſe he improve it; And beſides that many Experiments familiar to Chymiſts are unknown to the generality of Learned Men, who either never read Chymical proceſſes, or never underſtood their meaning, or never durſt believe them; beſides theſe things, I ſay, I ſhall repreſent, That, as to the few Experiments I have borrowed from the Chymiſts, if they be very Vulgar, ’twould perhaps be difficult to aſcribe each of them its own Author, and ’tis more than the generality of Chymiſts themſelves can do: and if they be not of very known and familiar practiſe among them, unleſs the Authors wherein I found them had given me cauſe to believe, themſelves had try’d them, I know not why I might not ſet them down, as a part of the Phænomena of Colours which I preſent you; Many things unanimouſly enough deliver’d as matters of fact by (I know not how many Chymical Writers) being not to be rely’d on, upon the ſingle Authority of ſuch Authors: For Inſtance, as ſome Spagyriſts deliver (perhaps amongſt ſeveral deceitful proceſſes) that Saccarum Saturni with Spirit of Turpentine will afford a Balſom, ſo Beguinus and many more tell us, that the ſame Concrete (Saccarum Saturni) will yield an incomparably fragrant Spirit, and a pretty Quantity of two ſeveral Oyles, and yet ſince many have complain’d, as well as I have done, that they could find no ſuch odoriferous, but rather an ill-ſented Liquor, and ſcarce any oyl in their Diſtillation of that ſweet Vitriol, a wary perſon would as little build any thing on what they ſay of the former Experiment, as upon what they averr of the later, and therefore I ſcrupled not to mention this Red Balſom of which I have not ſeen any, (but what I made) among my other experiments about redneſs.
Annot. II.
We have ſometimes had the Curioſity to try what Colours Minerals, as Tinglaſs, Antimony, Spelter, &c. would yield in ſeveral Menſtruums, nor have we forborn to try the Colours of ſtones, of which that famous one, (which Helmont calls Paracelſus’s Ludus) though it be digg’d out of the Earth and ſeem a true ſtone, has afforded in Menſtruums capable to diſſolve ſo ſolid a ſtone, ſometimes a Yellowiſh, ſometimes a Red ſolution of both which I can ſhow you. But though I have from Minerals obtain’d with ſeveral Menſtruums very differing Colours, and ſome ſuch as perhaps you would be ſurpriz’d to ſee drawn from ſuch Bodies: yet I muſt now paſs by the particulars, being deſirous to put an End to this Treatiſe, before I put an end to your Patience and my own.
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.