Recently Thoroddsen and Van Atta (1992, Phys. Fluids A4, 2592) showed
that Kolmogorov's refined similarity hypothesis (1962, J. Fluid Mech.
13, 77; 82) is supported by experimental data from a wind-tunnel study
of a cylinder wake, at Re(lambda) of 550. We show here that the proba
bility density of the Kolmogorov similarity variable approaches a Gaus
sian distribution. The data also suggest that it may obey an even more
demanding conditional similarity, which leads to important conclusion
s regarding the scaling exponents.