The Bodies, the moſt promiſing for ſuch a purpoſe, might ſeem to be the Metalls, eſpecially Gold, becauſe of the Multitude, and Minuteneſs of its Parts, which might be argu'd from the incomparable Cloſeneſs of its Texture: But though we tried a Solution of Gold made in Aqua Regia firſt, and then in fair Water; yet in regard we were to determine the Pigment we imploy'd, not by Bulk but Weight, and becauſe alſo, that the Yellow Colour of Gold is but a faint one in Compariſon of the deep Colour of Cochineel, we rather choſe this to make our Trials with. But among divers of theſe it will ſuffice to ſet down one, which was carefully made in Veſſels conveniently Shap'd; (and that in the preſence of a Witneſs, and an Aſſiſtant) the Sum whereof I find among my Adverſaria, Regiſtred in the following Words. To which I ſhall only premiſe, (to leſſen the wonder of ſo ſtrange a diffuſion of the Pigment) That Cochineel will be better Diſſolv'd, and have its Colour far more heightn'd by Spirit of Urine, than (I ſay not by common Water, but) by Rectify'd Spirit of Wine it ſelf.
The Note I ſpoke off is this. [One Grain of Cochineel diſſolv'd in a pretty Quantity of Spirit of Urine, and then diſſolv'd
further by degrees in fair Water, imparted a diſcernable, though but a very faint Colour, to about ſix Glaſs-fulls of Water, each of them containing about forty three Ounces and an half, which amounts to above a hundred twenty five thouſand times its own Weight.]
EXPERIMENT XXV.
It may afford a conſiderable Hint (Pyrophilus) to him, that would improve the Art of Dying, to know what change of Colours may be produc'd by the three ſeveral ſorts of Salts already often mention'd, (ſome or other of which may be procur'd in Quantity at reaſonable Rates) in the Juices, Decoctions, Infuſions, and (in a word) the more ſoluble parts of Vegetables. And, though the deſign of this Diſcourſe be the Improvement of Knowledge, not of Trades: yet thus much I ſhall not ſcruple to intimate here, That the Blew Liquors, mention'd in the twentieth and one and twentieth Experiments, are far from being the only Vegetable Subſtances, upon which Acid, Urinous, and Alcalizate Salts have the like Operations to thoſe recited in thoſe two Experiments. For Ripe Privet Berries (for inſtance) being cruſh'd
upon White Paper, though they ſtain it with a Purpliſh Colour, yet if we let fall on ſome part of it two or three drops of Spirit of Salt, and on the other part a little more of the Strong Solution of Pot-aſhes, the former Liquor immediately turn'd that part of the Thick juice or Pulp, on which it fell, into a lovely Red, and the latter turn'd the other part of it into a delightfull Green. Though I will not undertake, that thoſe Colours in that Subſtance ſhall not be much more Orient, than Laſting; and though (Pyrophilus) this Experiment may ſeem to be almoſt the ſame with thoſe already deliver'd concerning Syrrup of Violets, and the Juice of Blew-bottles, yet I think it not amiſs to take this Occaſion to inform you, that this Experiment reaches much farther, than perhaps you yet imagine, and may be of good Uſe to thoſe, whom it concerns to know, how Dying Stuffs may be wrought upon by Saline Liquors. For, I have found this Experiment to ſucceed in ſo many Various Berries, Flowers, Bloſſoms, and other finer Parts of Vegetables, that neither my Memory, nor my Leiſure ſerves me to enumerate them. And it is ſomewhat ſurprizing to ſee, by how Differingly-colour'd Flowers, or Bloſſoms, (for example) the Paper being
ſtain'd, will by an Acid Spirit be immediately turn'd Red, and by any Alcaly or any Urinous Spirit turn'd Green; inſomuch that ev'n the cruſh'd Bloſſoms of Meſerion, (which I gather'd in Winter and froſty Weather) and thoſe of Peaſe, cruſh'd upon White Paper, how remote ſoever their Colours be from Green, would in a moment paſs into a deep Degree of that Colour, upon the Touch of an Alcalizate Liquor. To which let us add, That either of thoſe new Pigments (if I may ſo call them) may by the Affuſion of enough of a contrary Liquor, be preſently chang'd from Red into Green, and from Green into Red, which Obſervation will hold alſo in Syrrup of Violets, Juices of Blew-bottles, &c.
Annotation.
After what I have formerly deliver'd to evince, That there are many Inſtances, wherein new Colours are produc'd or acquir'd by Bodies, which Chymiſts are wont to think deſtitute of Salt, or to whoſe change of Colours no new Acceſſion of Saline Particles does appear to contribute, I think we may ſafely enough acknowledge,