ON April 8, a pair of large sunspots, with smaller attendant spots, came into view around the sun's north-east limb. The group crossed the sun's central meridian on April 14·1 U.T. and will reach the western limbon April 20. The latitude of the group is 27° north, and its area on April 8 was 1,500 millionths of the sun's visible hemisphere. Sunspots of this size are found to show, statistically, a marked association with the occurrence of terrestrial magnetic storms, the storm commencing on theaverage about one day after the time of central meridian passage of the associated sunspot.