Turbulence intensity, scale, and spectrum measurements were made on model jets of 1 in. and 2-in. diam at various mean velocities. The indications are that only in the fully developed flow is turbulence intensity invariant with mean velocity; intensity in the core, in the turbulent annulus, and in the transition region decreases in varying degrees with mean velocity increase. Longitudinal and radial scales of turbulence were found to increase in the annulus in proportion to about the square root of axial distance, and longitudinal scale is about 65 per cent greater than radial scale. Both radial and longitudinal scales seem to be essentially constant with mean velocity. Turbulence spectra were found to consist of a sharply peaked band of frequencies in the core, degenerating to a slightly peaked broad band at points in the mixing regions.