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410 II. A. -Newton— Biela Meteors of JS r ov. 27th, 1885. 



At Moncalieri the numbers given by P. Denza are : 



6 h m to 6 h 15 m Rome m. t. 2800 meteors by 2 obs. 

 6 15 < : 6 30 " 3100 " 2 " 



6 30 "6 45 " 3400 " 2j " 



6 45 " 7 " 4500 « 3 " 



7 " 7 15 " 6200 « 4 " 



The count was continued but clouds interfered. By a table 

 quoted below we have for the ratio of the numbers of meteors 

 visible to 2, 3 and 4 observers, 633 : 836 : 1000. P. Denza's 

 observations reduced by these ratios show that the display in- 

 creased in brilliancy until 7 h 15 m when the sky became partly 

 overcast. The maximum indicated by them was then later 

 than 7 h Roman, that is, 6 h 10 m Greenwich time. Prof essor Zona 

 places the maximum earlier. Professor Cacciatori at Palermo 

 gives 7 h 45 m (that is, 6 h 52 m ) as the time of maximum. But 

 clouds are reported during the preceding half hour. Many 

 other observers give times of the maximum display which are 

 more or less indefinite. We shall assume 6 h 15 m Gr. rn. t. as 

 representing very well the mean of all the observations. 



Duration. — From the time of maximum the intensity quite 

 steadily diminished. The numbers counted at Upsala show 

 the course of the shower. The weather was fine and twelve 

 observers under the direction of Messrs. Hildebrand-Hilde- 

 brandson and Charlier, looking toward different quarters of the 

 sky kept count by quarter hours through five hours, with the 

 following result (Greenwich time). 



5 h to 5£ h , 



2545 



6f h 



to 7\ 



3383 



8£ h 



to 



8f h , 



799 



H " H, 



2287 



7 



a hi 



'45 



2497 



8f 



a 



9, 



585 



H " 5f, 



2906 



11 



'¥5 



2072 



9 



(i 



y 4j 



502 



5f " 6, 



3382 



H 



" 7f, 



2295 



n 



ie 



H, 



375 



6 « 6i, 



4213 



71 



" 8, 



1999 



H 



a 



91, 



307 



6i " 6|, 



4422 



8 



" H, 



1336 



9f 



cc 



10, 



268 



6* " 6f, 



3330 



8 4 



" H, 



1341 











The numbers diminished so that at the end of three hours 

 from the time of the maximum there were only one-tenth of 

 the maximum numbers of meteors. The end of the shower 

 was not a definite epoch. Assuming that there was an increase 

 during the sunlight and the twilight corresponding to the later 

 decrease we may say in general terms that the shower lasted as 

 an extraordinary dis}}lay through six hours. Some of the re- 

 ports from observers in Asia give reason to believe that the in- 

 crease was less rapid than the decrease. A few Andromeda 

 meteors were seen in different places on the night of the 26th, 

 28th and 29th, but the number of them on each night was not 

 large. 



