273 HEPOiiT— 186y. . 



APPENDIX. 



I. Meteoes Doubly Observed. 



Seveeal of the large meteors described in the foregoing catalogue having, 

 from their extraordinary brightness, attracted the attention of observers at 

 many places in England, as well as in neighbouring places on the Continent, 

 to ■which the course of their aerial flight was more immediately directed, the 

 comparison of the accounts affords, in some instances, approximate estimates 

 of the real heights and distances of their luminouB paths. 



The course of the large meteor seen in central Erance on the evening of 

 the 5th of September, 1868, although imperfectly determined by the English 

 observations in Auvergnc and at Geneva, must yet have been little less than 

 100 miles in length over the valleys of the Seine, the Yonue, and the Loire, 

 north and west of the mountains of Cote d'Or and Auvergue, directed, ap- 

 parently at no great inclination to the horizon, from north-east to south- 

 west, at a height of u])wards of fifty miles above the earth. In the absence 

 of more complete descriptions of its apparent course, only the general direc- 

 tion of its real path and the nearest departments of Erance (Yonne and 

 Cher) over which tbc meteor must have been conspicuous can be pointed 

 out. The very distant observations of the same meteor at Aosta and Elorence, 

 however, indicate for the earlier portion of this meteor's flight a far more 

 extraordinary length of course than is common among large fireballs. The 

 following notice of a careful stirdy of its real jiath and altitude will accord- 

 ingly be read with more than ordinarj' interest. (See Comptes Eendus for 

 August 2, 186'J, vol. Ixix. p. 326.) 



" Meteors. — In a jiapcr addressed last week to the Ereuch Academy of 

 Sciences, M. A. Tissot examines the circumstances accompanying the passage 

 of the remarkable bolis of the 5th of September, 1868. It was seen to pass 

 over Belgrade, Laybach, Bergamo, Saulieu, Civray-sur-Cher, and Mettra}' *. 

 At Bergamo, M. Zezioli found that in 17 seconds it described an arc, the 

 extremities of which were respectively, in right ascension 17°, N. dcclin. 

 3° ; E.A. 202°, N. decl. 27°. At Tremont, M. Magnin, while observing 

 Jupiter, had at one moment both the planet and the fireball in the field of his 

 telescope. M. Mugnier at Saulieu and M. BadiUer at Civray-sur-Chcr both 

 saw it in the zenith. Letting alone the two latter data, which are somewhat 

 uncertain, tliere is just enough left to enable us to determine the position of 

 one point of the meteor's path, and those of two right lines between which 

 it moved during a known space of time. Erom this may be obtained the 

 minima of velocity with respect to the earth and the sun, and which are re- 

 spectively SO and 71 kilometres per second. Now were the orbit described 

 elliptical, or even parabolic, the velocity could not exceed 42 kilometres ; 

 there can therefore be no doubt that the trajectory was an hyperbola. This 

 is, we believe, the first time that the path of a fireball his been ascertained 

 from reliable mathematical data. Erom this starting-point M. Tissot pro- 

 ceeds to correct the doubtful observation of Civray, and finds that the meteor 

 passed over that place at a distance of 3° 12" from the zenith. The lowest 

 altitude of the bolis was 111 kilometres; the eccentricity of the geocentric 

 hyperbola was 124, and its two asymptotes formed an angle of one degree 



* M. Tissot states tliat tho path of the meteor was vertically over these places ; its 

 altitudp nf rfs disappearance over Meltray, in Indve ct Loire, 798 kilometres (496 miles) 

 IVom Uergauio, being ;i07 kilometres (191 miles), and the lowest altitude of ils course 

 was 111 kilometres (69 miles). The meteor therefore shot upwards (!); and the whole 

 length of its course from Belgrade, in Servia, to Mettray was nearly 1000 miles ! 



