H. A. Newton— Biela Meteors of Nov. 27th, J 885. 411 



Hourly number of meteors at the time of maximum^ — As has 

 been noticed in other showers the meteors were not evenly dis- 

 tributed in time but came somewhat fitfully. There is more- 

 over great discrepancy in the numbers counted by different 

 observers. The numbers of persons counting, the precautions 

 to prevent duplication, the relative directions in which they 

 looked, and the state of the sky are in many cases not given, 

 and this renders the comparison of numbers reported from dif- 

 ferent places difficult. 



An experiment made in 1865 by the writer gave the follow- 

 ing ratios (y) for the numbers of shooting stars seen by from 

 one to twelve observers (x). The group of observers is pre- 

 sumed in each case to have the points toward which they are 

 looking symmetrically distributed over the heavens.* 



X 



y 



X 



y 



X 



y 



1 



325 



5 



1106 



9 



1399 



2 



633 



6 



1200 



10 



1451 



3 



836 



7 



1282 



11 



1509 



4 



1000 



8 



1348 



12 



1560 



These values of y should increase toward a limit when x 

 increases indefinitely. The limit is evidently more than 2000, 

 and as the differences near the end of the table decrease very 

 slowly, I do not regard 2400 an extravagant estimate. I shall 

 therefore use that factor in some subsequent computations. 



Of the shower of Nov. 27th no published set of observations 

 show more completely the course and intensity of the shower 

 than those above cited made at Upsala. They imply at the 

 maximum an hourly number of 4x4422 X2400-H 1560 (that is 

 about 27000) for the total number visible at Upsala. They also 

 give for the quarter-hour number for one observer at their 

 maximum 4422 X 325 -f- 1560 (that is, about 60 per minute.) 



At Marseilles three observers (Stephan, Borrelly and Coggia) 

 in several trials counted over 600 per minute, which represents 

 233 per minute, for one observer and a total hourly number of 

 over 100,000. At moonrise (10£ h ) there were 50 to 60 a minute 

 counted. 



At Palermo the maximum number per minute reported was 

 214 for two observers from 7* 43 m to 7 h 48 m . 



At Geneva 55 to 60 a minute were reported. The sky was 

 partly clouded. 



* Dr. Kleiber {Astr. Nachr., No. 2621) has given a similar table from some ob- 

 servations made by him in 1884 at St. Petersburg. As he has in his discus- 

 sion, however, taken every possible combination of his eight observers instead 

 of considering such combinations as contain observers looking to different parts 

 of the heavens, Dr. Kleiber's numbers and mine represent different quantities, 

 and are not properly comparable. His method of reduction seems to me faulty, 

 and to have vitiated his results for practical use. 



