CHICORA METEORITE PRESTON, HENDERSON, RANDOLPH 403 



slowly until it disappeared. Since most of these observers were in 

 the vicinity of Butler, the estimate apphes primarily to the width 

 at that point. 



Observers south of the meteor path, in the northern suburbs of 

 Pittsbm-gh, describe the meteorite as forming a very much larger cloud 

 than was seen at Butler. Williamson's estimates give it a width of 

 about 2,000 feet, wliile Heyl's (36) show it more nearly a mile in 

 greatest width. Both these agi-ee in showing a cloud rather thick in 

 its midheight and tapering off above and below. 



This discrepancy may be understood by reconstructing the probable 

 reactions of the observers, and what thej^ saw and what they missed. 

 Observers at Butler saw the brilliant meteor flash across the sky. 

 Their eyes followed it into the north and then traveled back along 

 the smoke cloud, which was here about 5 miles away and 9 miles up 

 in the air. Their eyes would then linger on the larger cloud and would 

 fail to see the smaller cloud above it, which soon disappeared. And 

 the large upper cloud would be taken for a sim.ple expansion of an 

 extension of the lower cloud. 



Observers to the south, on the other hand, came nearer to seeing 

 the whole thing at once. They could see it all without turning their 

 heads. It was greatly foreshortened to them, so that the bigness of 

 the upper cloud would be more conspicuous. Also the thin-pointed 

 cloud above it would be more noticeable. 



Plate 57 is an attempt to reconstruct the meteor trail as it would 

 be seen from the west by an observer at an infinite distance. Heyl's 

 proportions are used, as these have come in the form of a sketch (fig. 

 19) and hence are possibly more reliable than an estimate of a narrow 

 angle made after the cloud had disappeared. 



The cloud thus has two more or less distinct sections. There is 

 the upf)er section extending from the 12-mile level to the 10-mile, 

 having a length of about 4 miles and an average diameter of 3,500 

 feet. And there is the lower cloud, tapering down from a maximum 

 of about 650 feet. The path makes an angle of 31° with the horizon- 

 tal. The dotted line shows the probable trajectory of the small pieces 

 that fell in the chickenyard at Chicora and suggests that they were 

 detached in this big cloud. As they were not seen coming down, it 

 is probable that by the time they emerged from the cloud their veloc- 

 ity had already fallen to less than a mile a second, which makes this 

 trajectory about right. 



Observers south of Chicora describe the sound made by the meteor- 

 ite as a thunderclap, very prolonged and violent. 



Observers at Chicora compare it to an airplane, or to "the wheels 

 of the thunder wagon." 



Observers north of Chicora call it a hiss. 



