Note:  Do not rely on this information. It is very old.

Compressed Air Engine

Compressed Air Engine. A type of motor much used for certain special kinds of work, in which the motive power is supplied by high-pressure air. The engine is pretty much the same in principle as the steam-engine, compressed air supplying the place of high-pressure steam. This air is compressed by suitable pumping machinery, which may be at some distance from the air-engine. Such an arrangement is convenient in boring, tunnelling, or similar work, where it is difficult to introduce steam or other motors, and where the pressure energy required may readily be conducted to the scene of operations by air-pipes from the distant pumps.