ASTRONOMY. 125 



METEORS AND THE ZODIACAL LIGHT. 



• 



The Biela meteors of Xovohber 27 , 1SS5. — Professor Newton has col- 

 lected all the published data in regard to this great shower, and has 

 submitted it to a thorough discussion in an article of nearly twenty 

 pages of the American Journal of Science for June, 1886. 



We quote merely his summary statement of couclusions : 



"1. The maximum of the shower was near 6^ IS"" Greenwich meantime. 



" 2. Three hours after the maximum the number of meteors had dimin- 

 ished to one- tenth the maximum number, and it is not unreasonable to 

 assume six hours as containing the principal part of the shower. 



" 3. The total hourly number of meteors visible at one place in a very 

 clear sky to some one or other of a very large group of observers may 

 at maximum be regarded as 75,000. 



• " 4. In the densest part of the meteor stream, where and when the 

 earth encountered it, the space that corresponded to each meteoroid 

 was equal to a cube whose edge was about 20 English miles. 



" 5. The dense part of the stream was not over 100,000 miles in thick- 

 ness. 



"6. The zenithal attraction of the Biela meteors was about one-tenth 

 of the observed zenith distance of the radiant. 



" 7. The radiant was an area several degrees across. 



" 8. It is reasonable to suppose that the meteoroids, while in the upper 

 part of the atmosphere, before the paths become luminous, change di- 

 rection by a glancing due to irregularity of form. After the resistance 

 has developed heat enough to melt or burn off projecting angles of the 

 stones, and the tracks become luminous, the forms of the bodies become 

 rounded in front and the paths described are straight lines. 



" 9. The meteoroids encountered by the earth on the 27th of Novem- 

 ber, in 1872 and in 1885, did not leave the immediate neighborhood of 

 the Biela comet earlier than 1811-'45, and may be treated as having at 

 that time orbits osculating that of the comet. The determination of the 

 paths of these meteoroids through their five and seven last revolutions 

 about the sun seems to be a problem capable of complete solution." 



Professor Newton's presidential address at the Buffalo meeting of the 

 American Association, on " Meteorites, meteors, and shooting stars," 

 has been published in Science (8 : 169-76), and in Nature (34 : 532-36). 



M. P. F. Deuza reports that a careful watch maintained on the night 

 of November 27, 1886, at seven observatories on the Italian peninsula, 

 showed no repetition of the great shower of 1885. This would indicate 

 that the stream is of small extent but very dense, and would tend to 

 strengthen the hypothesis that it originated in the recent disintegra- 

 tion of Biela's comet. 



Herr Forster finds for the radiant points of the great meteor showers 

 of 1872 and 18^5 : 



1872 E. A. 230.3 Decl. + 43^.3. 



1885 230.5 + 430.3. 



