60 



tlEPoaT — 1872, 



on the nights of the 10th and 11th of .ingust, 1871, with the results ohtained 

 from them as computed by Professor Ilerschel, appears in the ' Quarterly 

 Journal of the Meteorological Society ' for November 1871, from which the 

 annexed figure is copied, showing the real heights of first apx^earance and of 



Eeference imnibcrB. 

 3 4 5 6 7 8 9 10 11 12 13 U 15 16 17 13 19 20 



Are- 

 rase. 



120 



100 



80 



60 



a 



W 



40 



20 



120 



100 



a 



60 ^ 



40 



« 



20 



Sea-leTel. 



Eeal Heights of twenty Shooting-stars, doubly observed in England on the nights of ti.e 

 0th to 12th of August, 1871, above the surface of the earth. 



disappearance of twenty shooting-stars of last year's August shower, together 

 witk their average real height. On comparing together the actual hori- 

 zontal distances from the observers at which their apparent points of dis- 

 appearance had been accurately recorded, it appears that a circle 160 miles 

 in diameter represented a field of view within which four fifths of all the 

 terminations of the meteors' visible paths were seen and recorded by the 

 observers, mnppiug their apparent courses at its centre ; and that, on the 

 average, three or four times as many accordances of observations are likely 

 to be obtained by observers at stations separated from each other by distances 

 of between fortj^ and eighty miles, as at places either nearer to or more distant 

 from each other than about these limits. 



The average heights of the meteors thus observed above the earth's surface 

 was 8G miles at first appearance, and 52-5 miles at disappearance ; the average 

 length of path 46 miles, and the average velocity of nine PerseVds contained 

 in the list 51 miles per second. The difficulty of estimatiug exactly the small 

 duration of their rapid flights, and a tendency, by aligning their apparent 



