• (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.
Eu`di·om'e·try noun [ Confer French eudiométrie .] (Chemistry) 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. 
the measurement and analysis of gases with the eudiometer.