90 RESEARCHES CONCERNING THE PERIODICAL 



observed." Also, Quetelet^'^ remarks that Mr. Boguslawski obtained "results 

 analoo-ous" to those of his table for the relative velocities of the meteors of 

 August 9th, 1837. On the 29th of August, 1838, the younger Littrow^' ob- 

 tained corresponding observations of several meteors in Vienna and its vicinity. 

 An effort by Mr. E. C. Herrick and others, in April, 1839, in New Haven, 

 Middlebury, Williamstown, Cambridge, and other places, was unsuccessful for 

 Avant of coincidences, like a similar attempt of Brandes and others in 1817. The 

 method adopted in all instances is to prove the id entity ^^ of the meteors seen 

 at two different places. Then the space traversed, and the duration give the 

 relative velocity. The Vienna observations of 1838, for relative velocities, 

 have not been fully reduced, the memorandums for duration not being 

 complete. Such results, as far as obtained, are given in Table I., chiefly 

 from Quetelet's Memoir on Shooting Stars. The results obtained by Twi- 

 ning, and the remarks quoted from Olbers and Quetelet are important in the 

 present inquiry, as they show that the mean relative velocity, 18.3 geogra- 

 phical miles per second from all the results yet obtained, may be taken for a 

 first approximation in estimating the elements of the elliptic orbits of those 

 meteors or asteroids whose relative direction is known. It is much to be 

 desired that Table I. should be farther extended, and, as an encouragement to 

 enterprise in this department of meteorology, we have the high authority of 

 Bessel," who " doubts not that every desirable degree of perfection is attainable 

 by observation, in so far as regards our knowledge of the geometrical relations 

 of shooting stars." 



On examining Table I. it will appear that the single results arrange them- 

 selves on both sides of the mean result 18.3 miles per second, with an average 

 discrepancy of about 5.2 miles per second. As far as we can judge from so 

 small a number of results, necessarily somewhat imperfect, it would seem that 

 the mean relative velocity of shooting stars tends towards that of the earth in its 

 orbit, namely, 16.4589 geographical miles (of 60 to a degree) per second, with 



" Catalogue, &;c., p. 6. Note. 



^7 Annalen der K. K. Sternwarte in Wien, 1838. p. xviii. 



^* See Loomis' Notice of Brandes' Memoir, above quoted, p. 98. 



^9 Uber Sternschnuppen Astr. Nachr. 381, p. 50. " Ich zweifle nicht, dass die Kentniss der 

 Sternschnuppen, in so fern von den geometrischen Verhiiltnissen, die man daran wahrnehraen 

 kann, die Rede ist, so vollstandig gemacht werden kann, als man zu wUnschen berechtigt ist." 



