The New Student's Reference Work/Air Gun

Air Gun, a weapon for shooting bullets or other projectiles by means of condensed air. The air is forced into a vessel, usually in the stock, by means of a condensing syringe. When the finger touches the trigger, the air reaches into the space behind the bullet and drives it out of the barrel, and when the finger is taken away the vessel is again closed. Thus several shots may be fired, but with less force each time. At its greatest, the force is not equal to an ordinary charge of gunpowder.