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We have measured the cooling power at Norway Station (70°.5 S, 2°.5 W)with kata-thermometers for air-temperature (Ta) between + 1 and --41° C, and for wind speeds (v) at 10 m leve! up to 27 m sec-1• The linear proportionality of the cooling power (H) to (36.5-Ta), for a constant wind speed, is shown to hold in this temperature-interval for a wind speed less than about 12 m sec-1• We used four kata-thermometers, and it turned out that they gave systematic different values of the cooling power for equal meteorological conditions. Comparing the individual values with their mean we find a maximum deviation of about ± 20 % . W e have supposed that this is due to errors in the calibration, subjective errors plus dissimilarities in the shape of the bulbs. The latter will cause differences in the turbulence around the bulbs, and consequently in the effective cooling of the wind. The possible difference in the cooling power of the air due to differences in the shape will probably not emerge during calibrations in a still air chamber. In spite of the dissimilar climatic conditions in Antarctica and Europe we found that a formula based upon two of our Katas, with which we have taken by far the most measurements, corresponds fairly well to the mean of the Kata-formulae found in Europe. The maximum deviation of the values given by European formulae from those derived by the Norway Station formula is about ± 20 %. We have here omitted the formula of HILL (1919), as it reveals a fairly large deviation from the other formulae.