METEORIC STONES AND SHOOTING STARS. 439 



the whole, there were 7 under 45 miles ; 9 between 45 and 90 ; 6 above 90 ; 

 and the highest was above 140 miles. There were only two observed so com- 

 pletely as to afford data for determining the velocity. The first gave 25 miles, 

 and the second from 17 to 21 miles, in a second. The most remarkable result 

 was, that one of them, certainly, was observed not to fall, but to move in a 

 direction away from the earth. 



By these observations a precise idea was first obtained of the altitudes, dis- 

 tances, and velocities, of these singular meteors. A similar but more extended 

 plan of observation was organized by Brandes, in 1823, and carried into effect 

 at Breslau and the neighboring towns, by a considerable number of persons, 

 observing at the same time on concerted nights. Between April and October 

 about 1800 shooting stars were noted at the different places out of which 

 number 62 were found which had been observed simultaneously at more than 

 one station, in such a manner that their respective altitudes could be deter- 

 mined, and 36 others of which the observations furnished data for estimating 

 the entire orbits. Of these 98, the heights (at the time of extinction) of 4 were 

 computed to be under 15 English miles ; of 13, between 15 and 30 miles ; of 

 22, between 30 and 45 ; of 33, between 45 and 70 ; of 13, between 70 and 90 ; 

 and of 11, above 90 miles. Of these last, two had an altitude of about 140 

 miles, one of 220 miles, one of 280, and there was one of which the height 

 was estimated to exceed 460 miles. 



On the 36 computed orbits, in 26 instances the motion was downward, in 

 one case horizontal, and in the remaining nine more or less upward. The 

 velocities were between 18 and 36 miles in a second. The trajectories were 

 frequently not straight lines, but incurvated, sometimes in the horizontal and 

 sometimes in the vertical direction, and sometimes they were of a serpentine 

 form. The predominating direction of the motion of the meteors from north- 

 east to southwest, contrary to that of the earth in its orbit, was very remarka- 

 ble, and is important in reference to their physical theory. 



A similar set of observations was made in Belgium, in 1824, under the di- 

 rection of M. Quetelet, the results of which are published in the Annnaire de 

 Bruxdles for 1837. M. Quetelet was chiefly solicitous to determine the velocity 

 of the meteors. He obtained six corresponding observations, from which this 

 element could be deduced, and the result varied from 10 to 25 English miles 

 in a second. The mean of the six results gave a velocity of nearly 17 miles 

 per second, a little less than that of the earth in its orbit. 



Another set of corresponding observations was made in Switzerland, on the 

 10th of August, 1838, a circumstantial account of which is given by M. Wart- 

 manri in QueleleCs Correspondence Mathematique for July, 1839. M. Wart- 

 mann and five other observers, provided with celestial charts, stationed them- 

 selves at the observatory of Geneva, and the corresponding observations were 

 made at Planchettes, a village about sixty miles to the northeast of that city. 



In the space of seven and a half hours the number of meteors observed by the 

 six observers at Geneva was 381, and during five and a half hours the number 

 observed at Planchettes by two observers, was 104. All the circumstances of 

 the phenomena the place of the apparition and disappearance of each meteor, 

 the time it continued visible, its brightness relatively to the fixed stars, whether 

 accompanied with a train, &c. were carefully noted, and the trajectories de- 

 scribed by the meteors, were very different, varying from 8 to 70 of angular 

 space. The velocities appeared also to differ considerably ; but the average 

 velocity was supposed by M. Wartmann to be 25 per second. It was found, 

 from the comparison of the simultaneous observations, that the average height 

 above the ground was about 550 miles ; and hence the relative velocity was 

 computed to be about 240 miles in a second. But as the greater number 



