elſe it would in a ſhort time do, though when 'tis ſubſided it will retain its Colour, and alſo be capable of being depriv'd of it by the Oyl newly mention'd. Thirdly, That if any Yellow matter ſtick at the ſides of the Glaſs, 'tis but inclining the Glaſs, till the clarify'd Liquor can waſh alongſt it, and the Liquor will preſently imbibe it, and deprive it of its Colour.
Many have ſomewhat wondred, how I came to light upon this Experiment, but the Notions or Conjectures I have about the differing Natures of the Several Tribes of Salts, having led me to deviſe the Experiment, it will not be difficult for me to give you the Chymical Reaſon, if I may ſo ſpeak, of the Phænomenon. Having then obſerv'd, that Mercury being diſſolv'd in Some Menſtruums, would yield a dark Yellow Precipitate, and ſuppoſing that, as to this, common Water, and the Salts that ſtick to the Mercury would be equivalent to thoſe Acid Menſtruums, which work upon the Quick-ſilver, upon the account of their Saline particles, I ſubſtituted a Solution of Sublimate in fair Water, inſtead of a Solution of Mercury in Aqua-fortis, or Spirit of Nitre, that ſimple Solution being both clearer and free from that very offenſive Smell, which accompanies the Solutions
of Mercury made with thoſe other corroſive Liquors; then I conſider'd, that That, which makes the Yellow Colour, is indeed but a Precipitate made by the means of the Oyl of Tartar, which we drop in, and which, as Chymiſts know, does generally precipitate Metalline Bodies corroded by Acid Salts; ſo that the Colour in our caſe reſults from the Coalition of the Mercurial particles with the Saline ones, wherewith they were formerly aſſociated, and with the Alcalizate particles of the Salt of Tartar that ſwim up and down in the Oyl. Wherefore conſidering alſo, that very many of the effects of Lixiviate Liquors, upon the Solutions of other Bodies, may be deſtroy'd by Acid Menstruums, as I elſewhere more particularly declare, I concluded, that if I choſe a very potently Acid Liquor, which by its Inciſive power might undo the work of the Oyl of Tartar, and diſperſe again thoſe Particles, which the other had by Precipitation aſſociated, into ſuch minute Corpuſcles as were before ſingly Inconſpicuous, they would become Inconſpicuous again, and conſequently leave the Liquor as Colourleſs as before the Precipitation was made.
This, as I ſaid, Pyrophilus, ſeems to be the Chymical reaſon of this Experiment, that
is ſuch a reaſon, as, ſuppoſing the truth of thoſe Chymical Notions I have elſewhere I hope evinc'd, may give ſuch an account of the Phænomena as Chymical Notions can ſupply us with; but I both here and elſewhere make uſe of this way of ſpeaking, to intimate that I am ſufficiently aware of the difference betwixt a Chymical Explication of a Phænomenon, and one that is truly Philoſophical or Mechanical; as in our preſent caſe, I tell you ſomething, when I tell you that the Yellowneſs of the Mercurial Solution and the Oyl of Tartar is produc'd by the Precipitation occaſion'd by the affuſion of the latter of thoſe Liquors, and that the deſtruction of the Colour proceeds from the Diſſipation of that Curdl'd matter, whoſe Texture is deſtroy'd, and which is diſſolv'd into Minute and Inviſible particles by the potently Acid Menſtruum, which is the reaſon, why there remains no Sediment in the Bottom, becauſe the infuſed Oyl takes it up, and reſolves it into hidden or inviſible Parts, as Water does Salt or Sugar. But when I have told you all this, I am far from thinking I have told all that ſuch an Inquiſitive Perſon as your ſelf would know, for I preſume you would deſire as well as I to learn (at leaſt) why the Particles of the
Mercury, of the Tartar, and of the Acid Salts convening together, ſhould make rather an Orange Colour than a Red, or a Blew, or a Green, for 'tis not enough to ſay what I related a little before, that divers Mercurial Solutions, though otherwiſe made, would yield a Yellow precipitate, becauſe the Queſtion will recurr concerning them; and to give it a ſatisfactory anſwer, is, I freely acknowledge, more than I dare as yet pretend to.
But to confirm my conjecture about the Chymical reaſon of our Experiment, I may add, that as I have (viz. pag. 34th. of this Treatiſe) elſewhere (on another occaſion) told you, with Saline Liquors of another kind and nature than Salt of Tartar, (namely, with Spirit of Urine, and Liquors of kin to that) I can make the Mercury precipitate out of the firſt ſimple Solution quite of another Colour than that hitherto mention'd; Nay, if inſtead of altering the Precipitating liquor, I alter'd the Texture of the Sublimate in ſuch a way as my Notions about Salt requir'd, I could produce the ſame Phænomenon. For having purpoſely Sublim'd together Equal parts (or thereabout) of Sal-Armoniack and Sublimate, firſt diligently Mix'd, the aſcending Flowers being diffolv'd in fair Water,
and Filtred, gave a Solution Limpid and Colourleſs, like that of the other Sublimates, and yet an Akaly drop'd into this Liquor did not turn it Yellow but White. And upon the ſame Grounds we may with Quick-ſilver, without the help of common Sublimate, prepare another ſort of Flowers diſſoluble in Water without Diſcolouring it, with which I could likewiſe do what I newly mention'd; to which I ſhall add, (what poſſibly you'l ſomewhat wonder at) That ſo much does the Colour depend upon the Texture reſulting from the Convention of the ſeveral ſorts of Corpuſcles, that though in out Experiment, Oyl of Vitriol deſtroys the Yellow Colour, yet with Quick-ſilver and fair Water, by the help of Oyl of Vitriol alone, we may eaſily make a kind of Precipitate of a fair and permanent Yellow, as you will e're long (in the forty ſecond Expement of this third Part) be taught. And I may further add, that I choſe Oyl of Vitriol, not ſo much for any other or peculiar Quality, as for its being, when 'tis well rectify'd, (which 'tis ſomewhat hazardous to bring it to be) not only devoid of Colour and in Smells, but extremely Strong and Inciſive; For though common and undephlegmated Aqua-fortis will not perform
the ſame thing well, yet that which is made exceeding Strong by being carefully Dephlegm'd, will do it pretty well, though not ſo well as Oyl of Vitriol which is ſo Strong, that even without Rectification it may for a need be made uſe of. I will not here tell you what I have try'd, that I may be able to deprive at pleaſure the Precipitate that one of the Sulphureous Liquors had made, by the copious Affuſion of the other: Becauſe I found, though this Experiment is too tickliſh to let me give a full account of it in few words, I ſhall therefore tell you, that it is not only for once, that the other above-mention'd Experiment may be made, the ſame Numerical parcels of Liquor being ſtill imploy'd in it; for after I have Clarify'd the Orange Colour'd Liquor, by the addition of as little of the Oyl of Viriol as will ſuffice to perform the effect, I can again at pleaſure re-produce the Opacous Colour, by the dropping in of freſh Oyl of Tartar, and deſtroy it again by the Re-affuſion of more of the Acid Menſtruum; and yet oftner if I pleaſe, can I with theſe two contrariant Liquors recall and diſperſe the Colour, though by reaſon of the addition of ſo much new Liquor, in reference to the Mercurial particles, the Colour will at length appear more dilute and faint.