OBSERVATIONS OF LUMINOUS METEORS. 147 



followed by even more violent detonations than accompanied the descent of 

 Ili.it ponderous aerolite It shot from N.N.W. to S.S.E. over that district of 

 Hungary and Galicia, disappearing at a height of 20 miles over a point about 

 30 miles south of Iglo and Eperies. It presented the appearance of a bluish 

 ball of light as large as the moon, followed by a dense train of sparks and 

 ending with a great outburst of such corruscatious as were likened by some 

 to a tree top, and which produced a most intense illumination. Even at 

 Eriinn and in Vienna, where it was seen by Prof. Jelinek, its apparent 

 brilliancy was several times greater than that of Venus, and the duration of 

 its luminous course was variously estimated by different observers at between 

 three and eight seconds. For the position of the radinnt-point, seven re- 

 corded tracks could be compared together, which confirmed the conjecture, 

 already formed by Prof, von Niessl from the observation at Briinn, of its 

 probable situation in Cassiopeia, by indicating 17°, +57° as its true place 

 (within three or four degrees in right ascension and declination), at an alti- 

 tude of 23° above the N.W. by N. horizon, from which the meteor was 

 directed. The earliest point of observation of the meteor along this line was 

 obtained at Lemberg, when the fireball was still 200 miles from its point of 

 disappearance and its height above the earth's surface was 100 miles. Com- 

 paring the lengths of path and durations together which were observed at 

 Lemberg and seven other places, an average velocity of 25 - 5 miles per second 

 is found, by giving equal weights to all the individual results — a velocity 

 which, Prof, von Niessl again notices, considerably exceeds, as before, the 

 theoretical velocity (of 14'5 miles) in a parabolio orbit, and points to 

 hyperbolic elements being probably assignable also to this aerolitic fireball's 

 real orbit. 



With regard to the observed radiant-points of this fireball and of that of 

 April 10, 1874, a rediscussion of the observations of the latter, retaining some 

 previously rejected observations, enables him to present the following im- 

 partial comparison of all the observations available for their eomputatiou in 

 each case : — • 



The almost absolute agreement of these positions can scarcely be altogether 

 accidental ; but it still deserves attention, as Prof. Schiaparelli has pointed 

 out, that unless the velocities agree together, this apparent identity of the 

 radiant-points is not sufficient to establish the identity of the two meteor's 

 orbits, since the cosmical motion is the resultant of two parts, one the motion 

 of the earth itself, and the other the meteor's motion relatively to the earth ; 

 and the latter must be the same in magnitude as well as in direction, in order 

 that two fireballs occurring on the same date of the year may have identi- 

 cally the same motions in space, or about the sun, and that the identity of 

 their orbits round the sun can be inferred. It cannot be said that the ob- 

 served velocities of these two fireballs relatively to the earth were observed 

 to be identical, like their radiant-points ; but if, as seems to accord fairly 

 with the observations, a velocity of between 14 and 25 miles per second is 

 accepted as a common speed, with which both of these fireballs moved rela- 

 tively to the earth, the almost absolute coincidence of their orbits round the 

 sun may then fairly be assumed, and a common origin of this fireball-pair 

 in a system of bodies foreign to the solar system, following each other on 



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