OBSERVATIONS OF LUMINOUS METEORS, 



85 



the August meteors in the present year was rendered ahnost momentary, 

 apparently by the great brightness of the moonlight ; whUc the absence of 



Fig. 5. 



Reference Numbers. 

 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Ifi. 



Heights at first appearance and disappearance of sixteen shooting-stars observed in 

 England, August 5th-lltb, 1870. (Nos. 6 and 14 are heights at centres of the real paths.) 



smaU stars of reference near the meteor's course, necessitating distant align- 

 ments of the apparent paths with the larger stars, prevented the average 

 length of path of the observed meteor-tracks from being at the same time 

 much diminished. Both the length of path and the velocity * are on this 

 account rather larger than those of twenty shooting-stars which were 

 similarly observed in August 1863 (forty-seven miles, and thirty-four mUes 

 per second. See Report for 1863, pp. 327-330). Among the meteors in- 

 cluded in the Hst, Nos. 3 and 13 belong to different meteoric showers (N,^, ^^, 

 and Tj) from that of the regular Perseids ; and the latter meteor presents a 

 velocity considerably below the average of all the remaining velocities of the 

 list. Although the disturbing influence of the moon's hght appears to have 

 exaggerated and to have rendered somewhat uncertain the velocities obtained 

 on this occasion, the velocities of these two meteors are omitted from the 

 average velocity of the Perseids or meteors of the August shower, of which 



* Forty-eight miles, and forty-six miles per second (average of the Perseids). Velo- 

 oities of the meteors Nos. 3 13, thirty -nine, and seventeen miles per second. 



