Kolmogorov's second hypothesis has been examined for the case of turbulence generated behind a very large grid. The turbulent Reynolds number RΛ = 280 was sufficient to obtain a short inertial subrange. The one-dimensional subrange constant a1 = 0·48 ± 0·06 is in agreement with recent determinations made in geophysical flows. Isotropy was tested by comparing the transverse velocity spectrum with the transverse spectrum predicted from the longitudinal spectrum using the isotropic relations. The comparison showed the flow to be isotropic everywhere except at the largest scales.

It was observed that at high wavenumbers the spectra were attenuated by effects of finite wire length. The wire-length corrections suggested by Wyngaard (1968) were found to be inadequate. New corrections based on experimentally determined universal spectra are proposed.