A device, based on Stokes law, for measuring rate of fluid flow. It is a tapered vertical tube having a circular cross-section in which a float moves in a vertical path to a height dependent upon the rate of fluid flow upward through the tube.
Source:
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2211 (https://doi.org/10.1351/pac199062112167)