Colour, so I have found, that not only the Volatile Salts of all Animal Substances I have us’d, as Spirit of Harts-horn, of Urine, of Sal-Armoniack, of Blood, &c. but also all the Alcalizate Salts I have imploy’d, as the Solution of Salt of Tartar, of Pot-ashes, of common Wood-ashes, Lime-water, &c. will immediately change the Blew Syrrup, into a perfect Green.  And by the same way (to hint that upon the by) I elsewhere show you, both the changes that Nature and Time produce, in the more Saline parts of some Bodies, may be discover’d, and also how ev’n such Chymically prepar’d Bodies, as belong not either to the Animal Kingdome, or to the Tribe of Alcali’s, may have their new and superinduc’d Nature successfully Examin’d.  In this place I shall only add, that not alone the Changing the Colour of the Syrrup, requires, that the Changing Body be more strong, of the Acid, or other sort of Salt that is Predominant in it, than is requisite for the working upon the Tincture of Lignum Nephriticum; but that in this is also, the Operation of the formerly mention’d Salts upon our Syrrup, differs from their Operation upon our Tinctures, that in this Liquor, if the Caeruleous Colour be Destroy’d by an Acid Salt, it may be Restor’d by one that is either Volatile, or Lixiviate; whereas in Syrrup of Violets, though one of these contrary Salts will destroy the Action of the other, yet neither of them will restore the Syrrup to its native Blew; but each of them will Change it into the Colour which it self doth (if I may so speak) affect, as we shall have Occasion to show in the Notes on the twenty fifth Experiment.

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 Corn[18].  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