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

CHAP. XXI. Some Additional Experiments relating to Suspicions about the Hidden Qualities of the Air.

EXPERIMENT I.

* 1.1HAving pour'd Water upon the Calx of Dant∣zick Vitriol, part of it, soon after it was sufficiently impregnated, with the Vitriol re∣maining in the Calx, was filtred and gently ab∣stracted, and yeilded several Grains of a Salt of Vitriol, not much different from that which had been calcined. Another Portion of Water was left in the Air six Weeks, upon the calcined Vitriol in a wide mouth'd Glass, and then being abstracted as the former, it yeilded a Salt much like Salt-Petre, and different from the former. And Colcothar which had lain several Months in the Air free from Rain, being turn'd into a Lixivium, yeilded a Salt much whiter than Vitriol, and of a different Figure. From whence it appears, that the Air hath considerable Force in varying Salts obtainable from calcin'd Vitriol.

EXPERIMENT II.

DUlcifi'd Colcothar of Venereal Vitriol being expos'd to the Air in January and Februa∣ry, increas'd in Weight 4 ¼ Grains.

EXPERIMENT III.

THE 12th of March, Eight Ounces of Out∣landish Vitriol calcin'd to a Redness, be∣ing put into a broad and flat Metalline Vessel; and into another Vessel smaller than the other, we put 2 Ounces of Colcothar, so that the Su∣perficies of the latter, was larger, in respect of it's Quantity than the Superficies of the other. June 25. We weigh'd these Powders, and found that the 8 Ounces had gain'd a Drachm and 16 Grains, and the 2 Ounces had gain'd as much within a Grain. Then the Powders being put into the same Vessels, August the 4th, the smal∣ler Quantity weigh'd 26 Grains more than it did in June. Whence it appears, that different Cir∣cumstances cause notable Disparities in the In∣crease of Weight.

EXPERIMENT IV.

TWO Ounces of small Lumps of Marcha∣sites, which were partly shining, and part∣ly darkish, and seem'd well dispos'd to yeild Vitriol, were kept in a pure Air, and gain'd 12 Grains in Weight in seven Weeks.

EXPERIMENT V.

SPIRIT of Salt being put upon Filings of Copper, and kept in a moderate Heat, when it had acquir'd a thick and muddy Colour, we decanted it into a clean Glass, with a wide Mouth, and left it a competent time expos'd to the Air,

till it had acquir'd a fair Green; yet nothing was precipitated to the Bottom to make it clear.

EXPERIMENT VI.

I Once Observ'd, that the Fumes of a sharp Liquor acted more powerfully on a certain Metal, held in the Air, than the Menstruum, from whence those Fumes rose, would do it self. And it is observ'd in some Mines in Hungary, that the Fumes render those Ladders soonest unserviceable, which were nearest the Top of the Grove, where there is a more free access of Air.

EXPERIMENT VII.

A Soft Chymical Substance, which would smoak in the open Air, being conveigh'd into our Pneumatick Engin in a Viol, when the Air was exhausted, ceased to smoak; and by continuing there some time, would not smoak again, when it was re-expos'd to the Air, till the fresh Air had blown upon it some time. This Preparation, being kept in the Vessel it was prepar'd in six Weeks, would cease to smoak, when the Vessel was but cover'd with a piece of Paper; and another remarkable thing was, that when it was contain'd some time in a Receiver, close Luted, it would soon so glut the Air with it's Steams, as not to be able to smoak longer.

Notes

• * 1.1

  Experi∣ments rela∣ting to oc∣cult Quali∣ties of the Air.