EXPERIMENT XXII.
Our next Experiment (Pyrophilus) will perhaps ſeem to be of a contrary Nature
to the two former, made upon Syrrup of Violets, and Juice of Blew-bottles. For as in them by the Affuſion of Oyl of Tartar, a Blewiſh Liquor is made Green, ſo in this, by the ſole Mixture of the ſame Oyl, a Greeniſh Liquor becomes Blew. The hint of this Experiment was given us by the practice of ſome Italian Painters, who being wont to Counterfeit Ultra-marine Azure (as they call it) by Grinding Verdigreaſe with Sal-Armoniack, and ſome other Saline Ingredients, and letting them Rot (as they imagine) for a good while together in a Dunghill, we ſuppos'd, that the change of Colour wrought in the Verdigreaſe by this way of Preparation, muſt proceed from the Action of certain Volatile and Alcalizate Salts, abounding in ſome of the mingled Concretes, and brought to make a further Diſſolution of the Copper abounding in the Verdigreaſe, and therefore we Conjectur'd, that if both the Verdigreaſe, and ſuch Salts were diſſolv'd in fair Water, the ſmall Parts of both being therein more ſubdivided, and ſet at liberty, would have better acceſs to each other, and thereby Incorporate much the more ſuddenly; And accordingly we found, that if upon a ſtrong Solution of good French Verdigreaſe (for 'tis that we
are wont to imploy, as the beſt) you pour a juſt quantity of Oyl of Tartar, and ſhake them well together, you ſhall immediately ſee a notable Change of Colour, and the Mixture will grow thick, and not tranſparent, but if you ſtay a while, till the Groſſer part be Precipitated to, and ſetled in the Bottom, you may obtain a clear Liquor of a very lovely Colour, and exceeding delightfull to the Eye. But, you muſt have a care to drop in a competent Quantity of Oyl of Tartar, for elſe the Colour will not be ſo Deep, and Rich; and if inſtead of this Oyl you imploy a clear Lixivium of Pot-aſhes, you may have an Azure ſomewhat Lighter or Paler than, and therefore differing from, the former. And if inſtead of either of theſe Liquors, you make uſe of Spirit of Urine, or of Harts-horn, you may according to the Quantity and Quality of the Spirit you pour in, obtain ſome further Variety (though ſcarce conſiderable) of Cæruleous Liquors. And yet lately by the help of this Urinous Spirit we made a Blew Liquor, which not a few Ingenious Perſons, and among them, ſome, whoſe Profeſſion makes them very Converſant with Colours, have looked upon with ſome wonder. But theſe Azure Colour'd Liquors
ſhould be freed from the Subſiding matter, which the Salts of Tartar or Urine precipitate out of them, rather by being Decanted, than by Filtration. For by the latter of theſe ways we have ſometimes found, the Colour of them very much Impair'd, and little Superiour to that of the groſſer Subſtance, that it left in the Filtre.
EXPERIMENT XXIII.
That Roſes held over the Fume of Sulphur, may quickly by it be depriv'd of their Colour, and have as much of their Leaves, as the Fume works upon, burn'd pale, is an Experiment, that divers others have tried, as well as I. But (Pyrophilus) it may ſeem ſomewhat ſtrange to one that has never conſider'd the Compounded nature of Brimſtone, That, whereas the Fume of Sulphur will, as we have ſaid, Whiten the Leaves of Roſes; That Liquor, which is commonly call'd Oyl of Sulphur per Campanam, becauſe it is ſuppos'd to be made by the Condenſation of theſe Fumes in Glaſſes ſhap't like Bells, into a Liquor, does powerfully heighten the Tincture of Red Roſes, and make it more Red and Vivid, as we have eaſily tried by putting ſome Red-Roſe Leaves,
that had been long dried, (and ſo had loſt much of their Colour) into a Vial of fair Water. For a while after the Affuſion of a convenient Quantity of the Liquor we are ſpeaking of, both the Leaves themſelves, and the Water they were Steep'd in, diſcover'd a very freſh and lovely Colour.
EXPERIMENT XXIV.
It may (Pyrophilus) ſomewhat ſerve to Illuſtrate, not only the Doctrine of Pigments, and of Colours, but divers other Parts of the Corpuſcular Philoſophy; as that explicates Odours, and many other things, not as the Schools by Aery Qualities, but by Real, though extremely Minute Bodies; to examine, how much of a Colourleſs Liquor, a very ſmall Parcel of a Pigment may Imbue with a diſcernable Colour. And though there be ſcarce any thing of Preciſeneſs to be expected from ſuch Trials, yet I preſum'd, that (at leaſt) I ſhould be able to ſhow a much further Subdiviſion of the Parts of Matter into Viſible Particles, than I have hitherto found taken notice of, and than moſt men would imagine; no Body, that I know of, having yet attempted to reduce this Matter to any Meaſure.