Further note on the effect on cosmic‐ray intensity of the magnetic storm of March 1, 1942

In a previous note [Terr. Mag., 47, 185–186 (1942)], the authors called attention to the considerable decrease in cosmic‐ray intensity at Cheltenham (Maryland) and Huancayo (Peru) observed during the magnetic storm of March 1, 1942. In Figure 1 of that note two bihourly mean values, one on February 28 and the other on March 7, for Cheltenham, were nearly seven per cent above the pre‐storm average. Such an apparent sudden large increase in intensity had not been observed before and the values were therefore questioned. The first of these values was corroborated, however, by independent observations at Norfolk (Virginia) [E. B. Berry and V. F. Hess, Terr. Mag., 47, 251‐256 (1942)].