AEROLITES. 133 



hours, were supposed by Chiadni and Schnurrer to be occa 

 sioned by the passage of meteoric masses before the sun's disk. 

 Since the period that streams of meteoric shootmg stars were 

 first considered with reference to the direction of their orbit 

 as a closed ring, the epochs of these mysterious celestial phe- 

 nomena have been observed to present a remarkable connec 

 tion with the regular recurrence of swarms of shooting stars 

 Adolph Erman has evinced great acuteness of mind in his ac- 

 curate investiofation of the facts hitherto observed on this sub- 

 ject, and his researches have enabled him to discover the con- 

 nection of the sun's conjunction with the August asteroids on 

 the 7th of February, and with the November asteroids on the 

 12th of May, the latter period corresponding with the days 

 of St. Mamert (May 11th), St. Pancras (May 12th), and St. 

 Servatius (May 13th), which, according to popular belief, 

 were accounted " cold days."^ 



The Greek natural philosophers, who were but little dis 

 posed to pursue observations, but evinced inexhaustible fer 

 tility of imagination in giving the most various interpretation 

 of half-perceived facts, have, however, left some hypotheses 

 reofardinor shooting stars and meteoric stones which strikingly 

 accord with the views now almost universally admitted of 

 the cosmical process of these phenomena. " Falling stars," 

 says Plutarch, in his life of Lysander,t " are, according to 



* Adolph Erman, in Poggend., Annalen, 1839, bd. xlviii., s. 582- 

 601. Biot had preNaously thrown doubt regarding the probability of 

 the November stream reappearing in the beginning of May (Comptes 

 Rendns, 1836, t. ii., p. 670). Madler has examined the mean depres- 

 sion of temperature on the three ill-named days of May by Berlin ob- 

 servations for eighty-six years ( Verhandl. des Vereins zur Befurd. des 

 Gartenbaues, 183"4, s. 377), and found a retrogression of temperature 

 amounting to 20-2 Fahr. from the 11th to the 13th of May, a period at 

 wliich nearly the most rapid advance of heat takes place. It is much 

 to be desired that this phenomenon of depressed temperature, which 

 some have felt inclined to attribute to the melting of the ice in the 

 northeast of Europe, should be also investigated in very remote spots, 

 as in America, or i*i the southern hemisphere. (Comp. Bull, de VAcad. 

 Imp. de Si. Petershourg, 1843, t. i.. No. 4.) 



t Plut., Vitce par. in Lysandro, cap. 22. The statement of Dama- 

 cho9 (Daimachos), that for seventy days continuously there was a fiery 

 cloud seen in the sky, emitting sparks like falling stars, and which then, 

 sinkii^g nearer to the earth, let fall the stone of iEgos Potamos, " which, 

 however, was only a small pai't of it," is extremely improbable, since 

 the direction and velocity of the fire-cloud would in that case of neces- 

 sity have to remain for so many days the same as those of the earth ; 

 and this, in the fire-ball of the 19th of July, 1686, described by Halley 

 ( Trans., vol. xxix., p. 163), lasted only a few minutes. It is not alto- 

 gether certain whether Daimachos, the writer, -Kepi evaef'ELag, was the 



