air pump

At Wheal Alfred they have a 64-inch cylinder; the air-pump is 20 inches, and the stroke is half that of the engine.

A connecting rod worked a balance-beam, which worked the air-pump, feed-pump, and plug-rod for moving the valves.

The engine was fixed directly over the pump-rods in the shaft, using neither main beam nor air-pump.

Wheal Concord pumping engine, in 1827 had a similar air-pump.

The atmosphere pressing on the piston like steam, the air is drawn from the pipes by a large air-pump and steam-engine.