Eudiometer :: Eudiometer (n.) An instrument for the volumetric measurement of gases; -- so named because frequently used to determine the purity of the air.
Eudiometrical :: Eudiometrical (a.) Of or pertaining to a eudiometer; as, eudiometrical experiments or results..
Eudiometry :: Eudiometry (n.) The art or process of determining the constituents of a gaseous mixture by means of the eudiometer, or for ascertaining the purity of the air or the amount of oxygen in it..