In further illustration of the merits of the association coefficient for extensive search and survey purposes, a broad study is made of the time and (for summer only) space association s between anomalies in monthly rainfall on the Australian mainland. There appears a marked persistence down the East Coast in spring and early summer, but little at other times and places and none in January to March: thus late summer rainfall is a random product of its individual months. For summer monthly rainfalls the strongest regional bond is found in the North-Central and North-Eastern districts, and these rainfalls show slight but significant association with prior (October and November) Darwin pressure. Coastal districts on a spacing of about 1,000 miles exhibit little mutual association in the main summer months.
C. H. B. Priestley (Sat,) studied this question.