Atmosphere : a philosophical work / by George Woodhead.

  • Woodhead, George.
Date:
1852
Catalogue details

Licence: Public Domain Mark

Credit: Atmosphere : a philosophical work / by George Woodhead. Source: Wellcome Collection.

    70/164 page 58
    clear as two and two make four, that the effects of the burning-glass are produced by the joint action of solar light and at- mospheric air; and that the combustion originated by the lens will proceed without the aid of solar light, and by the action of the atmosphere alone. No combustible thing can be ignited in the absence of air. Gunpowder cannot by any means be ex- ploded in vacuo. I have seen the finest gunpowder lie on a red-hot wire, in vacuo, until the wire melted, without either ex- ploding or igniting, or being in any way perceptibly affected. And I have seen the same gunpowder taken out of the receiver and exploded in air, by the remnant of the same wire, ignited by the same galvanic battery; for that was the source whence the fire was derived. If the vacuimi be imperfect, that is, less complete than it might be (for a perfect vacuum is unfea- sible), the gmipowder, after being in con- tact with the connecting wire for a while, begins to smoke and bm'n; effects which are caused partly by the air in the receiver.
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