H. A. Newton— Biela Meteors of Nov. 27th, 1885. 417 



The observed radiant is nearer the zenith than the original 

 direction with which meteors approach the earth. 



An approximate correction for this cause can be easily com- 

 puted. For this we may disregard the height of the air, and 

 assume that the meteors come to the ground. Also, the me- 

 teors may be regarded as coming in a hyperbolic orbit from an 

 infinite distance instead of being only for a finite distance 

 within the dominant influence of the earth's attraction. 



Chart showing the places assigned to the radiant. The cluster is at y Androm- 

 edas. The large star is the place of the radiant corresponding to the Biela 

 orbit of 1852. 









1 



47 



* 



* 



* 



4<? 



* * 



* * * 



*; * 





hl° 



* , 



* * * * * 



* # 







2o° 



25" 



30" " 



Let us consider a single meteor that comes to the earth's sur- 

 face, at the observer's place. The tangent to its path would 

 then be directed to the observed radiant of a group that moved 

 parallel to this single meteor. Let z be the angle which this 

 path makes with the vertical line of the observer and x be the 



