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

CHAP. XII. New Experiments about the weakned Spring, and unheeded Effects of the Air, com∣municated in the Philos. Transact. of Decemb. 75.

TO try whether, as some Corrosions of Bodies in close Vessels increase the Spring of the Air, so others may not weaken it; and likewise to discover whether some Ef∣fects of the Air may not depend on some un∣heeded Qualities, I made the following Expe∣riments, which I shall lay down when I shall have made some Tryals. the Changes of Co∣lour in Solutions of Copper, by the Influ∣ence of the Air.

EXPERIMENT I.

* 1.1FILINGS of crude Copper being put in∣to a Crystal Glass of a Conical Figure, with as much Spirit of Salt, as stood a Fingers breadth above the Filings; we cover'd the Ves∣sel with a Stopple exactly adapted to it; upon a Solution of the Copper, the Colour of the Liquor was a dark Brown; but it soon lost that Colour, and was clear again like common Wa∣ter; but when, by taking out the Stopple, the Liquor was again expos'd to the Air, it first acquir'd a brown Colour upon the Top, and that penetrating deeper into the Liquor by de∣grees;

it, in a quarter of an hour, was wholly tinged with a brown Colour again; and so it successive∣ly laid down, and re-acquir'd that Colour, as it was stopp'd up, or expos'd to the Air, till at the last, being kept up a Month, it kept the brown Colour it had acquir'd in the Air unalter'd.

EXPERIMENT II.

A Bottle of the same Liquor with the for∣mer, and which was much clearer, being expos'd to the open Air, in half an hours time was not in the least alter'd; but the Vessel be∣ing again clos'd up for two or three hours, it acquir'd a faint Green; and the Glass being again unstopp'd 24 hours, the Green was deep enough, but not very transparent.

EXPERIMENT III.

ABout 3 Spoonful of the brown Tincture of Copper, was shut up in a Receiver, ca∣pable of holding ten times as much; It retain'd it's Colour half a Year in Vacuo, and then being expos'd to the Air, it acquir'd a Green in about an hour, without the Precipitation of any mud∣dy Sediment.

EXPERIMENT IV.

SOme of the aforemention'd Tincture being left a considerable time in a Window, lost it's Colour, and appear'd like common Water; but towards the latter end of December, being expos'd to the Air, it acquir'd a faint and mode∣rately transparent Green.

EXPERIMENT V.

* 1.2FILINGS of Copper, and as much recti∣fied Spirit of fermented Urine, as rose an Inch above them; being shut up in a Conical Glass with a mercurial Gage, in some hours the Mercury in the seal'd Leg was depress'd.

EXPERIMENT VI.

A Gage being shut up in a Receiver, with the same Ingredients as in the former Ex∣periment; In some time the Spirit acquir'd a very pleasant blew Colour, and two or three Days after, that Colour began to grow fainter and fainter; so that at the end of the fourth Day, it had wholly lost it's Colour: But being expos'd to the Air, in four or five Minutes the Top of the Liquor began to turn Blew, and at the end of ten Minutes, it diffus'd it self through∣out the Whole, and five Minutes after, grew so strong, as almost to be Opacous. The Liquor shut up again, in two or three days time grew clear. And this Experiment being try'd seve∣ral times, had the like Success. In trying these Experiments, I forbore to shake the Glass, lest the Alterations should be suppos'd to a∣rise from any Sediment rais'd and mix'd with the Liquor, tho' for the most part, none was to be perceiv'd.

EXPERIMENT VII.

* 1.3HAving enclos'd Filings of Copper with Spirit of Sal Armoniack, enough to cover them an Inch, we shut up, with them, a Gage; In some time, the Spirit had got a blew Colour, and in the mean time, for two or three Days the Mercury in the seal'd Leg descended near 1/•• of an Inch. The like Success we had, when the Experiment was try'd several times after.

EXPERIMENT VIII.

* 1.4A Mercurial Gage with Coral and Spirit of Vinegar, being enclos'd in a Conical Glass, whilst the Menstruum work'd on the Coral, se∣veral Bubbles were produc'd, which breaking in the Cavity of the Vessel, compress'd the Air into ⅔ parts of the Space it possess'd before; but after the Operation of the Menstruum was ended, the Compression declin'd, till the com∣press'd Air regain'd it's Extent within a third of what it was dispossess'd of by the Com∣pression.

* 1.5Spirit of Vinegar and Minium, being after the like manner enclos'd with a Gage in a Co∣nical Glass, tho' the Minium was in a great measure dissolv'd, yet the Gage, discover'd no Alteration in the Air.

EXPERIMENT IX.

* 1.6ABOUT the 20th of August we put Fi∣lings of Copper into a Viol, with as much Spirit of Sal Armon. as cover'd them an Inch; In three Days it had acquir'd a deep blew Colour, and almost lost it again: The Viol being open'd, in five Minutes it was of a deep Blew; but being shut up again nine Days, it lost it's Colour.

EXPERIMENT X.

THE same Ingredients being shut up in a Viol hermetically seal'd, presently ac∣quir'd a deep Blew, and in twelve Days after lost it again; during which time, the Mercury in the open Leg was impell'd up; but, when in the Night the Seal was broken open, there succeeded a Noise, and the Mercury in the short∣er Leg was rais'd briskly near 3/•• of an Inch; and tho' the Air had access to the Liquor, at an Orifice no larger than a Pea; yet, in a Minute and a half, the Surface of the Liquor had acquir'd a lovely fair Colour a quarter of an Inch deep; and in five Minutes, the whole was Blew.

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Notes

• * 1.1

  Change of Colour in a Solution of Copper.
• * 1.2

  Filings of Copper and Spirit of Wine.
• * 1.3

  Filings of Copper with Spirit of Sal Armon.
• * 1.4

  Coral and Spirit of Vinegar.
• * 1.5

  Spirit of Vinegar and Mini∣um.
• * 1.6

  Filing of Copper with Sp. of Sal Armon.