Frequency of 12,330 measured heights of aurora from southern Norway in the years 1911-1944

(1) Since 1911, I have had at my disposition a network of auroral stations in southern Norway and about 32,000 usable auroral photographs have been taken. Among these are several thousand taken simultaneously from two or more stations to determine the height and situation of the aurora. The results obtained during 1911-22 are described in Geofysiske Publikasjoner [see 1 of “References” at end of paper]. Since 1922 only selected auroras have been measured.