28 



REPORT 1871. 



meteors thus identified, together with the particulars of the ohservations 

 from which they are concluded, are entered in the Table opposite. 



The accompanying diagram (drawn on the same scale as that in the last 

 Eeport) readily exhibits to the eye the actual heights at appearance and dis- 

 appearance (or the heights of the centres of the visible paths of the meteors 

 Nos. 1, 4, 9) above the earth's surface. The last vertical line on the right 

 represents (as in the last Report) the average height at first appearance and 

 that at disappearance of all the meteors regarded as identified in the present 

 list, of which the approximate heights of those points have been satisfactorily 

 ascertained. The resulting average heights are : — 



At first appearance. At disappearance. 

 74-1 B. S. miles. 47-6 



Of 16 meteors in the last Heport . . 



Of 10 meteors in the present list . . 71 "7 



Of 20 meteors observed in Aug. 1863 81-6 



54-4 

 57-7 



1 2 



Fig. 1. 



Eeferenee nvimbera. 

 3 4 5 6 7 8 9 10 11 12 13 



120 



100 



I 



•43 





t 



W 



80 



60 



40 



20 



120 



100 



80 



I 



CD 



'u 



m 





60 



40 



20 



Heights at appearance and disappearance of tliirteen shooting-stars simultaneously ob- 

 served at the Royal Observatory, Greenwich, and at other stations in England, August 

 6th-llth, 1870. (Nos. 1, 4, 9 are calculated heights at the centres of the real paths.) 



The present average heights are somewhat less than those observed in the 

 year 1863 ; but they agree more closely with the general average height at 

 first appearance, 70-05 miles, and that at disappearance, 54-22 miles (as given 

 in the Report for 1863, footnote on p. 328), of nearly all the shooting-stars 



1 



