Airometer

The air passes through large iron pipes, from the engine-house to an airometer, which stands at the centre of the works.

Source: wiktionary

I claim the combination and arrangement of a vaporizer, an air-forcing apparatus, and an airometer, the whole being constructed to operate together, substantially as described..

Source: wiktionary

In a gas-engine, the combination, with the carburetor and the lamps arranged below the same, of the airometer connected to said carburetor , and the pump-piston cylinder connected by valved pipes with said airometer and carburetor, substantially as shown and described .

Source: wiktionary

The airometer is built upon the principle that in the cylinder consumption of compressed air, the speed of the air passage is dependent upon the pressure, and that the number of cubic feet of free air used is in direct proportion to the speed the air body assumes when filling the cylinder..

Source: wiktionary