Watheroo Magnetic Observatory, October to December, 1944

(Latitude 30° 19′.1 S., longitude 115° 52′.6 or 7h 43m.5 E. of Gr.)December 15–18—A disturbance of moderately severe intensity began with a “sudden commencement” in all three elements at 18h 52m GMT, December 15. Small rapid fluctuations began at 23h 35m on the same day and continued intermittently until 10h 20m December 16, these fluctuations being particularly active between 06h 50m and 08h 00m, December 16. At 13h 30m, December 16, large sweeping movements began in all three elements, H decreasing to a minimum value at 15h 57m and the Z‐trace going beyond the limits of registration between 13h 52m and 15h 38m. After 20h 30m, December 16, the traces steadied somewhat although still slightly disturbed, with H still considerably below its normal value. At 08h 54m, December 17, the traces again became more disturbed with fairly large sweeping movements taking place in all three elements, and with H increasing in mean value. At 23h 00m, December 17, these leisurely movements gave place to small fluctuations which persisted until 08h 30m, December 18, after which the traces resumed their normal character. A faint aurora was observed between 15h and 18h, December 16. Ranges: D, 32′.2; H, 263 gammas; Z, greater than 197 gammas.