AIR AS MOTIVE POWER.
Air has of course not been overlooked, and it has the advantage of possessing the quality of perfect and inexhaustible elasticity according to pressure; its greatest disadvantage is that it must be “stored” and runs down steadily by use like a compressed metallic spring, hence requiring compressing stations. At intervals in this century, plans and drawings for vehicles to be run by air have been presented by successive inventors, and a system of tram-car service thus propelled has been tried experimentally in France. An air-driven tricycle has also been built in Chicago. What will be made out of this particular motor we must wait to see.