H. A. Newton— Biela Meteors of Nov. 27th, 1885. 423 



To the uncertainty of the observation of a path, which with 

 the very best observers amounts to two or three degrees, is to 

 be combined this uncertainty of the amount and direction of its 

 early glancing, which amounts also to several degrees. Besides 

 all this there is the uncertainty due to the fact that any point 

 above the horizon in a meteor path produced backward may 

 have been its radiant. Any radiant that has been determined 

 from a small number of paths must be very unreliable, and if 

 the observations of the paths themselves have not been pub- 

 lished the value of such determination as a contribution to 

 astronomy is still farther diminished. 



Movement of the nodes of the comet's orbit, and corresponding 

 change ofdateofthe shoiver. — The longitudes of the nodes of the 

 orbit of the comet were greatly changed between its discovery 

 in 1772 and its last appearance in 1852. The earth at first 

 passed the node in the second week in December, but a change 

 of ten or twelve days had brought it down to Nov. 27th before 

 1852. 



The following table contains the longitudes of the nodes of 

 the orbit reduced to the equinox of 1885*0, together with the 

 inclination of the orbit to the ecliptic, for the successive appear- 

 ances of the comet. The corresponding quantities for 1859 and 

 1866 are added from the orbits computed by Michez, the com- 

 putation having taken account of the changes of these quanti- 

 ties in the interval from 1852. Since 1866 the perturbations of 

 these quantities have been small, since Jupiter has not been at 

 any time very near to the comet. 



Longitudes of the nodes and inclinations of the orbit of Biela's comet at its successive 



appearances. 



Tear. 



Q 



i 



Tear. 



ft 



i 



Tear. 



& 



i 



1772 

 1806 

 1826 



258°7 

 252-4 

 251-2 



o 

 17-1 

 13-6 

 13-6 



1833 

 1846 

 1852 



249°0 

 246-5 

 246-3 



o 

 13-2 

 12-6 

 12-6 



1859 

 1866 



246°1 

 246-0 



o 

 12-4 

 12-4 



With the progression of the node corresponds a progression 

 of the star-shower, and with the change of inclination corres- 

 ponds a change of radiant to the south. In 1798, on the even- 

 ing of December 6th, Brandes counted for about four hours as 

 many as 400 shooting stars. They diminished rapidly after 10 

 o'clock. In 1838 Mr. Herrick, on the evening of December 

 7th, with an assistant, counted 93 meteors in an hour radiating 

 " from a spot not far from Cassiopeia ; or perhaps, more nearly, 

 from the vicinity of the cluster in the sword of Perseus. The 

 radiant, however, could not well be fixed within three or four 

 degrees." Observations at New Haven and elsewhere show that 

 the maximum was on that evening. In 1817 Professor Heis at 

 Aix la Chapelle observed on the evenings of December 8th 



