Air-Pump Gauge
a gauge for testing the extent to which the air has been exhausted in the receiver of an air-pump.
It consists of a glass tube bent like a siphon. One leg is closed, as in a barometer, the other open. It is placed under a small bell jar communicating by a stopcock with the receiver, and the more nearly the mercury stands at the same level the more nearly has a vacuum been produced.
AIR-SHIPS. See AERONAUTICS,