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

The I. TITLE. Of the dificulty of producing Flame without Air.

EXPERIMENT I.

* 1.1A Piece of red hot Iron, half an Inch in Di∣ameter, and an Inch thick, being con∣vey'd in a glazed melting-Pot into our Recei∣ver, we carefully exhausted the Air, and let∣ting down flowers of Sulphur in a Paper, the Paper was presently consumed, and the Sulphur falling into the Concave Surface of the Iron, only smoaked a little, but did not actually kin∣dle.

EXPERIMENT II.

Another way we made use of to kindle Sul∣phur in Vacuo was, by putting Flowers of Sul∣phur into a Glass-Bubble, and when the Air was exhausted, placing it upon live Coals, the Heat would not kindle the Sulphur, but raise it in the form of a yellow Varnish up to the opposite side of the Glass, and by turning that to the Fire, it would rise again to that side of the Glass which was uppermost.

EXPERIMENT III and IV.

To shew how much interest the Air hath in the production of Flame, when the Sulphur was too cool to burn without Air, we took off the

Receiver, upon which it presently flamed: And another time when the Receiver was thrice successively so far exhausted, that the Sulphur ceased to Flame, each time, that the Air was again let in, we could discern several flashes of fire, which by their blue colour appeared to be Sulphureous flames.

EXPERIMENT V and VI.

* 1.2The Beams of the Sun in the Summer being cast upon Gun-Powder in Vacuo, it first smoak∣ed and then melted, but did not explode whilst I continued the use of the burning Glass. But another time having convey'd the Iron mention∣ed before red hot into our Receiver, as soon as it was exhausted we let down a piece of Pa∣per with Gun-Powder in it, and tho' the Pa∣per was consumed, and the Sulphur melted, yet it did not go off. But the Experiment be∣ing repeated with a grain of very good Sulphur, when it had burnt so long that we no longer expected an Explosion, I let in the Air, and sometime after it went off.

EXPERIMENT VII and VIII.

Several grains of Gun-Powder being convey'd into an exhausted bubble, and that placed up∣on the live Coals, it flamed considerably and afforded sublimate, which by the light of a candle exhibited livid colours of a Rain-Bow. In our Physico-mechanical Experiments, we men∣tioned an Experiment where a Pistol was fired in our Receiver; but the Receiver not being

then sufficienly exhausted we reiterated the Experiment, and found, that when by the help of the Turn-Key, the Trigger of a primed Pistol was pulled by a string purposely fastned to the Trigger and Turn-Key, the Powder in the Pan would not go off, yet when a little Air was let in, the Gun-Powder remaining in the Pan, would flash off when the lock was cocked, and let off as before; yet one thing observa∣ble was, that tho' the Gun-Powder would not explode, when the Receiver was totally exhau∣sted, yet the violent percussion of the flint would cause sparks of fire to fly from it.

EXPERIMENT IX.

Aurum Fulminans was exploded in the ex∣hausted Receiver with a considerable noise, by the Sun-Beams cast upon it with a burning Glass; and a quarter of a grain being let down by the Turn-Key upon a piece of Iron red hot, it exploded with a flash, which was visible; the place where the Experiment was tryed be∣ing purposely dark; and a yellowish powder was scattered about the Cavity of the Receiver.

Notes

• * 1.1

  An endea∣vour to kin∣dle Sulphur in Vacuo Boyliano.
• * 1.2

  Endeavours to explode Gun-Pow∣der in Va∣cuo.