THE SMITHSONIAN INSTITUTION. 281 



quent discharges of zigzag lightning passing between these horns, 

 projected on a ch^ar sky, as a back-ground. In one instance, two 

 chains of electric fluid were seen to leave the upper one simultaneously 

 3° apart, and unite on reaching the lower cloud. 



3. Curvatcd elecii'ic discharges. 



In the thunder-storm of June 7, 1850, when tlie storm lay to the east- 

 ward, an electric spark passed from the eastern cloud to one in the 

 western ski, apparently in a curvated path. During a thunder-storm 

 occurring on the 30th of June last^ (1856,) I observed an electric spark 

 to describe a semi-circular arc ; the chord or diameter of the arc being 

 45° in extent, parallel with and near to the horizon. 



4. Miscellaneous electric phenomena. 



During the thunder-storm on the prairie west of Freeport, Illinois, 

 on May 30, 1851, a ball of electric fluid apparently emanated from a 

 cloud, and after a few seconds burst, sending brilliant corruscations 

 over the entire vault above. • 



StiU'wafer, Minnesota, Septemher 1, 1851. — In the evening, a small 

 cluster of columnar^shaped clouds rested on the horizon in the south- 

 east, their height being about 15°. Their outlines were distinctly 

 visible in the light of the lunar orb. As I was contemplating these 

 clouds, I observed vivid lightning appear from their upper edge, 

 about midway of the cluster. The lightning appeared like an intensely 

 brilliant disk exactly round, and about 2° in diameter, but of no longer 

 duration than an ordinary electric flash. This was succeeded in a few 

 seconds by another exactly similar flash, which was followed by several 

 others ; the disk of light appearing the same at each succeeding flash, 

 with the exception that it continually decreased in diameter, so that 

 at the end of twenty minutes it presented the apparent size of the sun. 

 Shortly after this, two other similar disks of light would appear 

 simultaneously with the first observed, and about 20° on each side of 

 it. After the last named phenomenon occurred, at about ten succeeding 

 flashes, the central disk sent out at each glow vivid chains of light- 

 ning which were projected far on the sky above. 



Stillwater, Minnesota, June 14 and 15, 1852. — On the evening of 

 the 14th, and morning of the 15th, there was a slight thunder-storm. 

 I noticed that for several succeeding discharges of the electric fluid, 

 there was in every instance a sudden and violent gush of rain 

 immediately jorevious to the flashing of the lightning. I have ob- 

 served a like phenomena on other occasions. 



Stillivater, Minnesota, July 21, 1852. — In the morning, just after 

 daybreak, we had a fine tliunder-storrn. While the storm was yet 

 coming up from the west I observed a vivid discharge of electricity 

 dart from the overhanging cloud to the southeastern horizon, where a 

 very slight spray of rain was falling at the time. There were no 

 clouds visible in that part of the sky beneath the one overhead. No 

 thunder was audible within five or ten minutes of the electric discharge, 

 and the first heard appeared to be located in the opposite direction. 



