Kirkwood.] - ^4:Z [Se-pt. 2, 



Biela's Comet and the Large Meteors of November 27-30. By Professor 

 Daniel Kirkwood. 



{Bead before the American Philosophical Society, September 2, 1881.') 



The well-known catalogue of Greg, published in the Report of the 

 British Association for 1860, p. 115 et seg., designates the last days of 

 November as one of the dates at which an unusual number of fire-balls 

 and meteoric stones had fallen since the commencement of the nineteenth 

 century. In the Danville Quarterly Review for December, 1861, the 

 gradual dissolution of Biela's comet was suggested as the source of those 

 periodic displays,* and the same theory was again advanced in the 

 author's "Meteoric Astronomy" (1867), pp. 54, 121, and 126-129. The 

 suggestion has also been made independently by others. 



We give below the most distinguished star showers derived from the 

 scattered portions of Biela's comet : — 



1798. 7 December ; recognized as Andromedes by Newton. 



1830. 7 December ; Quetelet's catalogue. 



1838. 5 to 7 December ; recognized by Newton. 



1850. 29 November ; Quetelet. 



1872. 27 November. 



1885. 27 November. 



From 1798 to 1885, we have eighty-seven years = 6.692 x 13 ; and the 

 series is harmonized in the following scheme : — 



1798 to 1838 = 40 years = 6 x 6.66 + 



1830 to 1850 = 20 " = 3 X 6.66 + 



1838 to 1872 = 34 " = 5 X 6.80. 



1872 to 1885 = 13 " = 2 X 6.50. 



The dates, it will be observed, indicate considerable extension of the 

 cluster, or rather, perhaps, the existence of several groups. 



The remarkable fall of meteoric iron during the shower of Bielids on 

 the 27th of November, 1885,f at once suggests the inquiry whether traces 

 of the same period can be found in the recurrence of fire-balls and aerolites 

 at the identical epoch. The following dates, except the last, are all 

 derived from the catalogue of Mr. R. P. Greg : — 



1809. 29 November ; a fireball at Munich. 



1810, 28 November, 9.30 p. m. ; an aerolitic meteor at Cape Matapan. 



*" The division of Biela's comet into two distinct parts suggests several interesting 

 questions in cometary physics. * * * May not the force, whatever it is, that has pro- 

 duced o>ie separation, again divide the parts ? and may not this action continue until the 

 fragments become invisible? According to the theory now generally received, the ijeri- 

 odic phenomena of shooting stars are produced by the intersections of the orbits of such 

 nebulous bodies with the earth's annual path. * * * May not our periodic meteors 

 be the debris of ancient but now disintegrated comets whose matter has become distrib- 

 uted around tlieir orbits?" — Danville Quarterly Review, Dec, 1.S61, p. 637. 



t Amer. Journ. of Sci., March, 1887. 



