AN AURORA OBSERVED IN MISSOURI AND ITS 
CONNECTION WITH SOLAR ACTIVITY. 
By Stuart L. O'Byrne. 
Webster Groves, Mo. 
Brilliant auroral displays are very rarely seen as far south as 
Missouri, but the year 1932 was an exception to this rule, for two 
were seen in the neighborhood of St. Louis in the late spring of 
that year. One, lasting for more than twenty-four hours, was 
widely observed on the nights of May 29th and 30th; the secon 
was seen on June 20th. The following descriptions of these two 
auroras are based on the da tect ys observers in several localities 
near St. Louis, Missouri, and one in Wisconsin. ey are of un- 
usual importance, not only “ate of the rarity of such brilliant 
displays in this latitude, but also because of their probable con- 
nection with activity observed on she ‘vi sun at about the same time. 
Observations at Allenton, Missouri. 
The aurora of May 29th and 30th was observed by the writer on 
the night of May 29th, at Allenton, Missouri (longitude, 90° 40’.2 
W.; latitude, 38° 29’.5 N.). It was watched all night, and the 
following description gives its appearance at various times and 
the sequence of the changes that occurred. 
7:30 P. M. (Central a Time). An arch of light span- 
ning the northern sky w n, its lower boundary very sharply 
defined, and its upper neg fading out a into the sky, which 
was not yet dark. The arc of the horizon embraced by the arch 
of light was found by measurement to Bs 102°, more than a quarter 
of the whole circle of the horizon. (Fig. 1). 
9:18 P. M. The arch began to brighten and within the next few 
minutes, six rays darted downward to the horizon, crossing the 
dark area beneath it. (Fig. 2). Each ray faded out within half 
& minute of its first appearance. Seven or eight others darted down- 
ward as the first ones had done, but from near the ends of the arch. 
9:40 P. M. The arch had widened and brightened further. Sev- 
eral faint rays from 5° to 8° in length darted upward. (Fig. 3). 
10:15 P. M. The dark area below the arch began to glow and 
soon became fully as bright as the arch itself. The color of the 
arch Sangha — pearly-white to a very dilute green. Rays vary- 
ing from 14° to 8° in width appeared in greater numbers, each one 
fading out but Seinen replaced by another. The narrow 
ones were generally the brightest and longest; sometimes they 
oe a length of 15° to 20°. Near the western extremity of the 
ch a bright streamer 15° wide appeared at 10:20 p. m., its west- 
