ALL the data on atmospheric perturbations related to geomagnetic disturbances1–7 have so far been derived from the drag analysis of artificial satellites with perigees located in low or moderate latitudes. The amplitudes of these perturbations can be accounted for4 by assuming that the heating of the atmosphere above the height of 350 km is proportional to the 3-hourly geomagnetic index ap. A study of 46 atmospheric drag perturbations of Explorer IX (Satellite 1961 δ1, inclination 38.8°) during a 283-day interval in the year 1961 has yielded7 for the atmospheric heating the relation c= ΔT/Δap= 1.0° (temperature T in °K). A plot of the observed data is given in Fig. 1. If allowance is made for the limited resolution of the drag determinations, the value of the coefficient c must be increased to 1.2°.