Air-Gun
an instrument designed to propel balls by the elastic force of condensed aid. A strong metal globe is formed, furnished with a small hole and a valve opening inward. Into this hole a condensing syringe is screwed. When, en by means of this apparatus, the condensation has been brought to the requisite point of intensity, the globe is detached from the syringe and screwed at the breech of a gun, so constructed that the valve may be opened by means of a trigger. A ball is then inserted in the barrel near the breech, so fitting it as to render it air-tight, and, the trigger being pulled, the elasticity of the condensed air impels it with considerable force.