The works of the Honourable Robert Boyle, Esq., epitomiz'd by Richard Boulton ... ; illustrated with copper plates.

CHAP. III. Many Changes of Colour produced by one simple Ingredient.

* 1.1TO make it appear how much the Colours of Bodies depend on the Variation of Texture, and their Modification, I try'd the following Experiments; in which several Phaenomena are exhibited, by the Mixture of a colourless Ingredient, such as Spirit of Salt.

I. If a little Spirit of Salt be mix'd with Sy∣rup of Violets upon a piece of Paper, it is pre∣sently turn'd from a Blew, to a red Colour incli∣ning to a Purple.

II. But if Spirit of Salt be dropp'd in a just Proportion into a Solution of Filings of Copper, made with Spirit of Sal Armoniack, the Blew will be turn'd into a green Colour.

III. Having mixed Syrup of Violets with Spi∣rit of Urine, Harts-horn or Oyl of Tartar per Deliquium, and by that means turn'd it green, I mix'd Spirit of Salt with it, which turn'd it red.

IV. If Spirit of Salt be dropp'd into Wa∣ter, in which Red Rose Leaves well dry'd are put, it will make the Tincture to be of a love∣ly Red.

V. But if Tincture of Brasil be heightned by an addition of Spirit of Hartshorn, or Urine, Spirit of Salt will make it as pale as Sack; so that that which heightened the Red Tincture in the former Experiment, destroys it in this.

VI. Tho an Infusion of Lignum Nephriticum in Water, betwixt it and the Light appears yellow, yet when held so that the Eye may be placed betwixt it and the Window, it appears to be blew, yet upon the dropping of Spirit of Salt into it, it loses that property.

VII. Having dropped Spirit of Salt upon Paper stained with Ink, the black was presently changed into a yellow and blew colour.

VIII. If Filings of Steel be dissolved in Spi∣rit of Salt, the filtrated Liquor will, upon Eva∣poration, shoot into green Cristals; which, if when they are dry they be kept in a Cru∣cible, a moderate Heat will turn them red.

IX. We found that the red Precipitate of Mercury per se would dissolve in Spirit of Salt, tho crude Mercury will not; we likewise found, that the Redness of Minium was wholly de∣stroyed by boyling it in Spirit of Salt, and that the Tincture of Coral extracted with this Menstruum, was wholly void of colour.

X. If Filings of Copper be long digested in a Sand-Furnace, in a good quantity of Spi∣rit of Salt, viz. as much as will cover it the breadth of two Fingers, the Metal being in

part dissolved, will be of a colour not unlike a muddy Red, if held betwixt your Eye and the the light.

XI. But if it stand some hours in a wide-mouthed glass, it will be of a green colour, finer than that which is made by a solution of Mars.

XII. If Spirit of Salt be dropped into a So∣lution of Silver, or Quicksilver in Aqua Fortis, the mixture will be of a milky whiteness, and presently deposite a white Precipitate.

XIII. And the same Phaenomena will like∣wise happen, if Spirit of Salt be dropped up∣on a Tincture of Benjamin, or a Solution of Resinous Jalap.

XIV. Having mixed a sweet Solution of Red Lead in Spirit of Vinegar, with a Tincture of Red Roses, I dropt Spirit of Salt into the mixture, which precipitated the red, and tur∣ned the green mixture into a durable Scarlet, which if disturbed by a mixture of the white precipitate, will be of a Carnation colour.

XV. Spirit of Salt, which was muddy by standing upon Filings of Copper, being boyl'd to a clearness, and set in a wide-mouth'd Cri∣stal Glass, in a small time puts on the colour of a German Amethist; and, in three hours time, a lovely Green.

XVI. Having gathered by filtration the Precipitate of Sublimate dissolved in water, and when it was dry, poured Spirit of Salt upon it, in a glass Vessel, the precipitate at the first will become white, and when the ebul∣lition which succeeds the mixture is ended, it becomes a transparent Liquor.

XVII. Having dropt Spirit of Salt upon a fourth part of Calcined Copper, we found that the mixture produced a Tincture of a muddy Red, and a white Powder, which being acted on by the fire, exhibited several colours.

XVIII. The Solution of Copper, just now mention'd, being put into a Cylindrical Vial, and 2 or 3 Spoonfuls of highly rectify'd Spirit of Wine poured upon it, by shaking the mix∣ture we obtained a Liquor of a green Colour like that of Emeralds.

XIX. A few drops of Spirit of Wine being dropt upon a Taffety Ribband, chang'd its Green into a Blew Colour; and being dropt on a black Ribband, alter'd that, and made it put on that which is call'd a Fading Leaf.

XX. If Spirit of Salt be dropt upon Purple Paper, it presently turns it Red.

XXI. Powder of Antimony being boyl'd to a Dissolution in Spirit of Salt, in a glass Ves∣sel, lost its blackness, and the Solution being dropt into Water, it in a little time subsided in the Form of a white Precipitate.

These Experiments being laid down, it may be necessary for us to observe, how unexpected the Result of most Mixtures are; which may be an Argument against the too frequent use of Compound Prescriptions, since it often not only is uncertain how those Ingredients may destroy the Vertues of each other, but som∣times whether they will duly mix according to Physitians expectation.

Notes

• * 1.1

  Several changes of Colour pro∣duced by one simple In∣gredient.