An improvement of the fortieth Experiment.
And, Pyrophilus, to confirm yet further the Notions that led me to think on the propos'd Experiment, I ſhall acquaint you with another, which when I had conveniency I have ſometimes added to it, and which has to the Spectators appear'd little leſs Odd than the firſt; And though becauſe the Liquor, requiſite to make the Trial ſucceed well, muſt be on purpoſe prepar'd anew a while before, becauſe it will not long retain its fitneſs for this work, I do but ſeldome annex this Experiment to the other, yet I ſhall tell you how I devis'd it, and how I make it. If you boyl Crude Antimony in a ſtrong and clear Lixivium, you ſhall ſeparate a Subſtance from it, which ſome Modern Chymiſts are pleas'd to call its Sulphur, but how deſervedly I ſhall not here examine, having elſewhere done it in an Opportune place; wherefore I ſhall now but need to take notice, that when this ſuppos'd Sulphur (not now to call it rather a kind of Crocus) is let fall by the Liquor upon its Refrigeration, it often ſettles in Flakes, or ſuch like parcels of a Yellow Subſtance, (which being by the precedent
diſſolution reduc'd into Minute parts, may peradventure be made to take Fire much more eaſily than the Groſſer Powder of unprepar'd Antimony would have done.) Conſidering therefore, that common Sulphur boyl'd in a Lixivium may be Precipitated out of it by Rheniſh-wine or White-wine, which are Sowriſh Liquors, and have in them, as I elſewhere ſhew, an Acid Salt; and having found alſo by Trial, that with other Acid Liquors I could Precipitate out of Lixiviate Solvents ſome other Mineral concretions abounding with Sulphureous parts, of which ſort is crude Antimony, I concluded it to be eaſie to Precipitate the Antimony diſſolv'd, as was lately mention'd, with the Acid Oyl of Vitriol; and though common Sulphur yields a White Precipitate, which the Chymiſts call Lac Sulphuris, yet I ſuppos'd the Precipitated Antimony would be of a deep Yellow Colour, as well, if made with Oyl of Vitriol, as if made only by Refrigeration and length of Time. From this 'twas eaſie to deduce this Experiment, that if you put into one Glaſs ſome of the freſhly Impregnated and Filtrated Solution of Antimony, and into another ſome of the Orange-Colour'd Mixture, (which I formerly ſhew'd you how to make with a
Mercurial Solution and Oyl of Tartar) a few drops of Oyl of Vitriol dropp'd into the laſt mention'd Glaſs, would, as I told you before, turn the Deep Yellow mixture into a Cleer Liquor; whereas a little of the ſame Oyl dropp'd out of the ſame Viol into the other Glaſs would preſently (but not without ſome ill ſent) turn the moderately cleer Solution into a Deep Yellow Subſtance, But this, as I Said, ſucceeds not well, unleſs you employ a Lixivium that has but newly diſſolv'd Antimony, and has not yet let it fall. But yet in Summer time, if your Lixivium have been duly Impregnated and well Filtred after it is quite cold, it will for ſome dayes (perhaps much longer than I had occaſion to try) retain Antimony enough to exhibit, upon the Affuſion of the Corroſive Oyl, as much of a good Yellow Subſtance as is neceſſary to ſatisfie the Beholders of the Poſſibility of the Experiment.
Reflections upon the XL. Experiment Compared with the X. and XX.
The Knowledge of the Diſtinction of Salts which we have propos'd, whereby they are diſcriminated into Acid, Volatile,
or Salfuginous (if I may for Diſtinction ſake ſo call the Fugitive Salts of Animal Subſtances) and fix'd or Alcalizate, may poſſibly (by that little part which we have already deliver'd, of what we could ſay of its Applicableneſs) appear of ſo much Uſe in Natural Philoſophy (eſpecially in the Practick part of it) that I doubt not but it will be no Unwelcome Corollary of the Preceding Experiment, if by the help of it I teach you to diſtinguiſh, which of thoſe Salts is Predominant in Chymical Liquors, as well as whether any of them be ſo or not. For though in our Notes upon the X. and XX. Experiments I have ſhown you a way by means of the Tincture of Lignum Nephriticum, or of Syrrup of Violets, to diſcover whether a propounded Salt be Acid or not, yet you can thereby only find in general that ſuch and ſuch Salts belong not to the Tribe of Acids, but cannot determine whether they belong to the Tribe of Urinous Salts (under which for diſtinction ſake I comprehend all thoſe Volatile Salts of Animal or other Subſtances that are contrary to Acids) or to that of Alcalies. For as well the one as the other of theſe Salino-Sulphurous Salts will reſtore the Cæruleous Colour to the Tincture of Lignum Nephriticum, and turn that of Syrrup of Violets
into Green. Wherefore this XL. Experiment does opportunely ſupply the deficiency of thoſe. For being ſollicitous to find out ſome ready wayes of diſcriminating the Tribes of Chymical Salts, I found that all thoſe I thought fit to make Tryal of, would, if they were of a Lixiviate Nature, make with Sublimate diſſolv'd in Fair Water an Orange Tawny Precipitate; whereas if they were of an Urinous Nature the Precipitate would be White and Milky. So that having alwayes by me ſome Syrrup of Violets and ſome Solution of Sublimate, I can by the help of the firſt of thoſe Liquors diſcover in a trice, whether the propounded Salt or Saline Body be of an Acid Nature or no, if it be I need (you know) inquire no further; but if it be not, I can very eaſily, and as readily diſtinguiſh between the other two kinds of Salts, by the White or Orange-Colour that is immediately produc'd, by letting fall a few Drops or Grains of the Salt to be examin'd, into a ſpoonfull of the cleer Solution of Sublimate. For Example, it has been ſuppos'd by ſome eminently Learned, That when Sal Armoniack being mingled with an Alcaly is forc'd from it by the Fire in cloſe Veſſels, the Volatile Salt that will thereby be obtain'd (if the Operation be skilfully perform'd,)
is but a more fine and ſubtile ſort of Sal Armoniack, which, 'tis preſum'd, this Operation do's but more exquiſitely purifie, than common Solutions, Filtrations, and Coagulations. But this Opinion may be eaſily ſhown to be Erroneous, as by other Arguments, ſo particularly by the lately deliver'd Method of diſtinguiſhing the Tribes of Salts. For the Saline Spirit of Sal Armoniack, as it is in many other manifeſt Qualities very like the Spirit of Urine, ſo like, that it will in a trice make Syrrup of Violets of a Lovely Green, turn a Solution of good Verdigreaſe into an Excellent Azure, and make the Solution of a Sublimate yield a White Precipitate, inſomuch that in moſt (for I ſay not all of the Experiments) where I Aim onely at producing a ſudden change of Colour, I ſcruple not to uſe Spirit of Sal Armoniack when it is at hand, inſtead of Spirit of Urine, as indeed it ſeems chiefly to conſiſt (beſides the flegm that helps to make it fluid) of the Volatile Urinous Salt (yet not excluding that of Soot) that abounds in the Sal Armoniack and is ſet at liberty from the Sea Salt wherewith it was formerly aſſociated, and clogg'd, by the Operation of the Alcaly, that divides the Ingredients of Sal Armoniack, and retains that Sea Salt with it ſelf. What uſe may be
made of the like way of exploration in that inquiry which puzzles ſo many Modern Naturaliſts, whether the Rich Pigment (which we have often had occaſion to mention) belongs to the Vegetable or Animal Kingdome, you may find in another place where I give you ſome account of what I try'd about Cocheneel. But I think it needleſs to exemplifie here our Method by any other Inſtances, many ſuch being to be met with in divers parts of this Treatiſe; but I will rather advertiſe you, that, by this way of examining Chymical Liquors, you may not onely in moſt Caſes conclude Affirmatively, but in ſome Caſes Negatively. As ſince Spirit of Wine, and as far as I have try'd, thoſe Chymical Oyles which Artiſts call Eſſential, did not (when I us'd them as I had us'd the ſeveral Families of Salts upon that Syrrup) turn Syrrup of Violets Red or Green, nor the Solution of Sublimate White or Yellow, I inferr'd it may thence be probably argued, that either they are deſtitute of Salt, or have ſuch as belongs not to either of the three Grand families already often mention'd. When I went to examine the Spirit of Oak or of ſuch like Concretes forced over through a Retort, I found by this means amongſt others, that (as I elſewhere ſhow) theſe Chymiſts are