Visualization of the vortex flow pattern in typical jets emitting jet tones was made by means of shadowgraph techniques to show the nature of the ever present process of vortex coalescence in the jet and how this determines the values of the eigenton sound frequencies radiated by the jet. These frequencies are super‐imposed on the noise background radiated by the jet. The dependence of (a) vortex shedding frequency from the orifice, (b) jet‐tone frequencies, and (c) translational velocity of the vortices on Reynolds number (Re) is shown.These studies were carried out with carbon dioxide jets discharging into the atmosphere. The flow channel geometry consisted of an orifice plate containing a sharp‐edged, circular orifice, 0.250 in. in diameter and 0.093 in. thick attached to a large stilling tank partly filled with sound‐absorbing material to eliminate any effects of cavity resonance on the jet. The studies were carried out over the range from Re zero to Re 7000, whereRe = vρt/μandvis mean velocity of discharge of jet; ρ, gas density;t, orifice plate thickness, and μ, gas viscosity.