Hydrostatics and pneumatics / [Dionysius Lardner].

  • Dionysius Lardner
Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: Hydrostatics and pneumatics / [Dionysius Lardner]. Source: Wellcome Collection.

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    CHAP. VII. THE AIR GUN, AIR BALLOON, AND DIVING BELL. THE AIR GUN. FIRST ATTEMPTS AT BALLOONS. LANA’s BAL- LOON OF RAREFIED AIR. FIRE BALLOONS. MONTGOLFIER’S Balloon — first ascent. — balloons inflated with hy- drogen. — parachute. — blanchard’s experiment. — CAUSES OF THE EFFICACY OF THE PARACHUTE. — ASCENT OF GAY LUSSAC AND BIOT. APPEARANCES IN THE HIGHER RE- GIONS OF THE ATMOSPHERE. THE DIVING BELL. The Air Gun. (171.) The air gun is an instrument for projecting balls or other missiles by the elastic force of condensed air. A strong metal ball is constructed, furnished with a small hole, and a valve opening inwards: in this ball air may be condensed to any degree which its strength is capable of bearing, by means of a condensing syringe screwed into the hole. When this condensation has been accomplished, the ball is detached from the syringe and screwed at the breech of a gun, constructed so that a trigger is capable of opening the valve. The hall being placed in the barrel near the breech, and fitting the barrel so as to be air-tight, is exposed to the pressure of the condensed air the moment the valve is opened: this pressure propels it along the barrel, and continues to act upon it so long as the valve is opened. It is thus projected from the gun in the same manner as that in which a ball is urged by the expansive force of exploded gunpowder. The force of projection obviously depends on the degree of condensation which is given to the air in the ball. The stock of the gun may contain a magazine of balls, and be furnished with a simple mechanism by which these balls may be transferred in succession into the barrel, so that the gun is easily and quickly loaded after each discharge.