Noise temperatures at 3000 Mc were compared with the corresponding electron temperatures for the positive columns of some cold cathode discharges in argon. The noise temperatures were measured using a superheterodyne receiver of low noise figure, by comparing the noise outputs of the various tubes with that from a commercial fluorescent lamp of measured noise output, a rapid comparison between known and unknown noise powers being effected by means of a hand‐operated wave‐guide switch. The noise temperature of the fluorescent lamp in its mounting was measured by comparison with an absolute standard consisting of an incandescent tungsten filament lamp fitted in a suitable wave‐guide holder. Electron temperatures were measured by the Langmuir single‐probe method. It is concluded that for most of the tubes measured, noise temperature, and electron temperature are in close agreement as required by the theories.