Experiment XXI
There is a Weed, more known to Plowmen than belov’d by them, whoſe Flowers from their Colour are commonly call’d Blew-bottles, and Corn-weed from their Growing among Corn18. Theſe Flowers ſome Ladies do, upon the account of their Lovely Colour, think worth the being Candied, which when they are, they will long retain ſo fair a Colour, as makes them a very fine Sallad in the Winter. But I have try’d, that when they are freſhly gather’d, they will afford a Juice, which when newly expreſs’d, (for in ſome caſes ’twill ſoon enough degenerate) affords a very deep and pleaſant Blew. Now, (to draw this to our preſent Scope) by dropping on this freſh Juice, a little Spirit of Salt, (that being the Acid Spirit I had then at hand) it immediately turn’d (as I predicted) into a Red. And if inſtead of the Sowr Spirit I mingled with it a little ſtrong Solution of an Alcalizate Salt, it did preſently diſcloſe a lovely Green; the ſame Changes being by thoſe differing ſorts of Saline Liquors, producible in this Natural juice, that we lately mention’d to have happen’d to that factitious Mixture, the Syrrup of Violets. And I remember, that finding this Blew Liquor, when freſhly made, to be capable of ſerving in a Pen for an Ink of that Colour, I attempted by moiſtning one part of a piece of White Paper with the Spirit of Salt I have been mentioning, and another with ſome Alcalizate or Volatile Liquor, to draw a Line on the leiſurely dry’d Paper, that ſhould, e’vn before the Ink was dry, appear partly Blew, partly Red, and partly Green: But though the latter part of the Experiment ſucceeded not well, (whether becauſe Volatile Salts are too Fugitive to be retain’d in the Paper, and Alcalizate ones are too Unctuous, or ſo apt to draw Moiſture from the Air, that they keep the Paper from drying well) yet the former Part ſucceeded well enough; the Blew and Red being Conſpicuous enough to afford a ſurprizing Spectacle to thoſe, I acquaint not with (what I willingly allow you to call) the Trick.
Annotation upon the one and twentieth Experiment.
But leſt you ſhould be tempted to think (Pyrophilus) that Volatile or Alcalizate Salts change Blews into Green, rather upon the ſcore of the eaſie Tranſition of the former Colour into the latter, than upon the account of the Texture, wherein moſt Vegetables, that afford a Blew, ſeem, though otherwiſe differing, to be Allied, I will add, that when I purpoſely diſſolv’d Blew Vitriol in fair Water, and thereby imbu’d ſufficiently that Liquor with that Colour, a Lixiviate Liquor, and a Urinous Salt being Copiouſly pour’d upon diſtinct Parcels of it, did each of them, though perhaps with ſome Difference, turn the Liquor not Green, but of a deep Yellowiſh Colour, almoſt like that of Yellow Oker, which Colour the Precipitated Corpuſcles retain’d, when they had Leiſurely ſubſided to the Bottom. What this Precipitated Subſtance is, it is not needfull now to Enquire in this place, and in another, I have ſhown you, that notwithſtanding its Colour, and its being Obtainable from an Acid Menſtruum by the help of Salt of Tartar, it is yet far enough from being the true Sulphur of Vitriol.