Signedunsigned
FunctionEarly eudiometers measured only the approximate volume of gases. This more sophisticated apparatus, invented by Volta, was more accurate. Both the tube and the cylinder were filled with a liquid, usually mercury or water, and inverted in a pneumatic through like any other eudiometer. But in this instrument specific quantities of different gases were introduced directly into the cylinder from the small measuring device. The reaction, touched off by an electric spark, occurred in the heavy glass cylinder. When the stopcock was opened, the residue rose into the upper tube whose small diameter and accurate calibration enabled the experimenter to make very precise measurements.
Published ReferencesDavid P. Wheatland, The Apparatus of Science at Harvard, 1765-1800 (Cambridge: Harvard University Press, 1968), 168.