Relations expressing the acoustic inertance and resistance of short open tubes in terms ofkvaare reviewed. The tube radius isa;kvis the complex wave number for viscosity waves. Analogous relations giving the acoustical impedance of a cylindrical cavity in terms ofkTa, wherekTis the thermal wave number, are considered. Viscous and thermal losses have sometimes been incorrectly separated in the literature. Past measurements, showing disagreement between theory and experiment for smallkva, are cited. New measurements of inertance and associated resistance, in the range of|kva|from 1 to 77, are reported. The method of standing wave analysis used. In some instances the inertance tube is incorporated in an adjustable‐cavity resonator. Inertance values after end corrections agree with theory within 2.5 percent. Corrected resistance values generally agree with theory within 3 percent for|kva|<10.Greater discrepancies for larger values ofkvaare attributed to excessive losses in very short cavities. Consideration of present results together with published data for larger values ofkvaindicates close agreement of theory and experiment for a range ofkvaextending at least from unity to several hundred.