Some aspects of the periodic flow of an incompressible fluid through a circular tube of large length to diameter ratio have been studied. Expressions for the analogous acoustic resistance and inductance of the tube are presented. An experimental investigation of the resistance and inductance is described in which the tube dimensions, the viscosity of the fluid, and the frequency of the periodic motion are varied over a wide range. The experimental results are found to be in good agreement with the predictions of the hydro‐dynamical theory.