AEROLITES. 107 



shooting stars, than in those of sporadic occurrence ; and it 

 has further been remarked, that in the periodically-recurring 

 falls in the month of August, as, for instance, in the year 1839, 

 the meteors came principally from one point between Perseus 

 and Taurus, towards the latter of which constellations the 

 Earth was then moving. This peculiarity of the phenomenon, 

 manifested in the retrograde direction of the orbits in No- 

 vember and August, should be thoroughly investigated by 

 accurate observations, in order that it may either be fully 

 confirmed or refuted. 



The heights of shooting stars, that is to say, the heights 

 of the points at which they begin and cease to be visible, 

 vary exceedingly, fluctuating between 16 and 140 miles. 

 This important result, and the enormous velocity of these 

 problematical asteroids, were first ascertained by Benzenberg 

 and Brandes, by simultaneous observations and determina- 

 tions of parallax at the extremities of a base line of 49,020 

 feet in length.* The relative velocity of motion is from 18 

 to 36 miles in a second, and consequently equal to planetary 



Between the 12th and 13th of November, 1822, shooting stars, inter- 

 mingled with fire balls, were seen in large numbers by Kloden, at 

 Potsdam. (Gilbert's Ann., bd. Ixxii. s. 291.) 



On the 13th of November, 1831, at 4 o'clock in the morning, a great 

 shower of falling stars was seen by Captain Berard, on the Spanish 

 coast, near Carthagena del Levante. (Annuaire, 1836, p. 297.) 



In the night between the 12th and 13th of November, 1833, occurred 

 the phenomenon so admirably described by Professor Olmsted, in 

 North America. 



In the night of the 13-1 4th of November, 1834, a similar fall of 

 shooting stars was seen in North America, although the numbers were 

 not quite so considerable. (Poggend. Annalen, bd. xxxiv. s. 129.) 



On the 13th of November, 1835, a barn was set on fire by the fall of 

 a sporadic fire ball, at Belley, in the Department de TAin. (An- 

 nuaire, 1836, p. 296.) 



In the year 1838, the stream showed itself most decidedly on the 

 night of the 13-1 4th of November. (Astron. Nadir., 1838, No. 372.) 



* I am well aware that, amongst the 62 shooting stars simultane- 

 ously observed in Silesia, in 1823, at the suggestion of Professor 

 Brandes, some appeared to have an elevation of 183 to 240, or even 

 400 miles. (Brandes, Unterhaltungen fur Freunde der Astronomic und 

 Physik, heft i. s. 48. Instructive Narratives for the Lovers of 

 Astronomy and Physics.) But Olbers considered that all determina- 

 tions for elevations beyond 120 miles must be doubtful, owing to the 

 nallness of the parallax. 



