Royal Astronomical Society. 549 



the Annuaire de Bruxelles for 1837. M. Quetelet was chiefly solici- 

 tous to determine the velocity of the meteors. He obtained six cor- 

 responding observations from which this element could be deduced, 

 and the results varied from 10 to 25 English miles in a second. The 

 mean of the six results gave a velocity of nearly 1 7 miles per second, 

 a little less than that of the earth in its orbit. ' 



The last set of corresponding observations referred to in the paper 

 was made in Switzerland on the 10th of August, 1838; a circum- 

 stantial account of which is given by M. Wartmann in Quetelet's 

 Correspondance Mathematique, for July 1839. M. Wartmann and 

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

 selves at the Observatory of Geneva ; and the corresponding obser- 

 vations were made by M. Reynier and an assistant at Planchettes, a 

 village about 60 miles to the north-east 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. The trajectories were then pro- 

 jected on a large planisphere. The extent of the trajectories de- 

 scribed by the meteors was very different, varying from 8° to 70° of 

 angular space, and the velocities appeared also to differ considerably; 

 but the average velocity concluded by M. Wartmann was 25° per 

 second. It was found, from the comparison of the simultaneous ob- 

 servations, 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 moved in a direction 

 opposite to that of the earth in its orbit, the relative velocity must 

 be diminished by the earth's velocity (about 19 miles in a second). 

 This still leaves upwards of 220 mijes per second for the absolute 

 velocity of the meteor, which is more than eleven times the orbital 

 velocity of the earth, seven and a half times that of the planet 

 Mercury, and probably greater than that of the comets at their peri- 

 helia. 



From the above results, it is obvious that the heights and velo- 

 cities of the shooting- stars are exceedingly various and uncertain ; 

 but if the observations are in any respect worthy of confidence, they 

 prove that many of these meteors (according to Wartmann's observa- 

 tions, by far the greater number) are, during the time of their visi- 

 bility, far beyond the limits to which atmosphere is supposed to ex- 

 tend, and that their velocities greatly exceed that which is due to 

 bodies moving at the same distance from the sun under the influence 

 of solar gravitation. 



It is perhaps impossible to form any correct estimate of the abso- 

 lute magnitudes of the meteors. Their apparent magnitudes differ 

 greatly ; the greater number resembling stars of the third or fourth 

 magnitude, while many are equal to stars of the first, and some even 

 surpass Jupiter and Venus in brilliancy. It is remarkable that the 



