_ THURSDAY, DECEMBER 5, 1872 
THE COMETARY STAR-SHOWER 
© OME months have now elapsed since an announce- 
ment by Mr. Hind informed astronomers that a 
_ well-known telescopic comet, first seen in the years 1772 
and 1805, and rediscovered in 1826 by the astronomer 
Biela, of Josephstadt, in Bohemia, when it was first recog- 
nised as periodic, would make its nearest approach to the 
earth towards the close of this year ; and its apparent 
__ place on successive nights was duly foretold, to assist them 
_ in their search for its existence. On the last two occa- 
_ sions of its expected returns, in 1859 and 1866, no signs 
_ of the missing comet were detected. The favourable 
circumstances under which it was expected to be ob- 
served, during its last approach to the earth in 1869, and 
the absence of any notice of its having been seen during 
the last two months of its anticipated reappearance in the 
present year, makes it hardly doubtful that, as an interest- 
ing study and examination with the most powerful modern 
telescopes, it has at length ceased to be any longer 
visible. When at its greatest brightness in the year 
_ 1805, it was seen by Olbers, with the naked eye, and 
in its subsequent returns, it was frequently attentively 
observed with the most powerful means and by the most 
expert astronomers. During its appearance in 1846 it 
_ was first distinctly perceived to separate into two portions, 
_ gradually receding from each other until they gained a 
greatest distance, which was estimated on that occasion at 
_ 157,000 miles, The two portions remained visible as two 
distinct comets at their next return in 1852, with a widened 
- interval between them, which had increased to 1,250,000 
miles, With nearly equal brightness, and with perfect 
cometary appearance, these two bodies travelled side by 
side, and journeyed together, doubtless, to separate still 
_ further from each other in their further circulations round 
_ thesun. Such is the telescopic history of Biela’s comet. 
In the year 1818 a telescopic comet was discovered by 
Pons, the astronomer, at Marseilles, whose date of 
appearance, at least a year before the time of a 
_ punctual return, cannot have been a reappearance of 
Biela’s comet, but the position of its orbit, as far 
as it could be calculated from the imperfect data 
that were obtained, are so similar to that of Biela’s 
_ that its relation to that comet appears not improbably to 
‘be of the same kind as that which formerly connected 
_ together the two portions of the recently divided cometary 
pair, and the orbit and periodic time of this third comet 
_ probably differ but little from those of the principal comet 
from which it may fairly be presumed to have been 
derived. Such groupings of comets on nearly parallel 
_ courses appear to be distinguishable in the more remark- 
_able cases, recently pointed out by Hoek, of some comets 
with hyperbolic orbits ; and the revolution of more than 
_ one telescopic comet is thought to have been discovered in 
_ the same orbit with the periodically-returning cometof 1866, 
with which the meteor-current of the great November star- 
shower, at its recent return, was shown by Schiaparelli, 
Adams, and Oppolzer, to be in remarkable agreement. 
“In a later letter to the Zvmes, in August last, Mr. 
‘Hind pointed out the satisfactory coincidence of 
No. 162--voL, vit. 
NATURE 
77 
which Prof. Schiaparelli, the former coadjutor of 
Secchi, and now the able director of the Observatory 
at Milan, was the first discoverer, between the orbit of 
another comet of considerable brightness seen in 1862, 
and the course of the meteors of the well-known August 
star-shower, an unusually bright display of which was re- 
corded shortly after the appearance of that comet in the 
following year. Another example of distinct resemblance 
between the orbit of a meteor current and that of a perio- 
dic comet was early discovered by the German astrono- 
mers Drs, Weiss and Galle in the case of the meteor shower 
of April 19-20 and the comet I, 1861, to which Prof, 
Kirkwood, of the State University in Indiana, U.S., has 
lately added the interesting observation that the earliest 
records of this meteor shower, as well as of a con- 
spicuous star-shower annually visible about October 18- 
20, indicate a periodic time in their maximum returns, 
which corresponds, like that of the November meteor 
system and its attendant comets, to an ellipse whose 
major axis is very nearly the mean distance of 
the planet Uranus from the sun. The time has 
thus arrived when systematic observations of meteor 
showers may be regarded as an important auxiliary 
to astronomers in certain cases where the orbits 
of comets are intersected by the earth’s path, by vying 
with the telescope in detecting the hidden courses of such 
comets as, by comminution or disbanding of their sub- 
stance, have so lost their brightness, as at length com- 
pletely to elude their search. 
The probability that the orbit of Biela’s comet is 
marked by a considerable meteor stream was first shown, 
almost simultaneously, by the two eminent directors of 
the national observatories at Vienna and Copenhagen, 
Drs. Weiss and D’Arrest. The meteor stream to which 
the comet appears in this instance to have given rise, was 
principally observed in Germany, France, Belgium, and 
the United States of America, in the yearse1798, and 
1838, occurring on December 6 and 7 in those years ; 
and again by the astronomer of Miinster, Dr. Heis, at Aix- 
la-Chapelle, on December 6, 1847. Either of the perio- 
dical returns of the comets, 1818, I., or of Biela’s comets, it 
was found by Weiss and D’Arrest, would perfectly account 
for the dates of appearance of these meteor-showers, and 
for the observed direction of their radiation from a point 
of divergence between Cassiopeia and Andromeda. The 
situation of this meteor stream is such that the meteors 
enter the earth’s atmosphere with almost the least pos- 
sible speed, of about eleven miles per second, that 
meteors can have; while the Leonides, or meteors of 
November 14, penetrate it with a velocity which is about 
four times greater, The position of the orbit is also such 
that it undergoes very rapid changes by the attractions of 
the planets ; so that, while encountering the earth on 
December 7 in 1798, the meteor particles, at the last 
visible return of the comet in 1852, must have extended 
across that point in the earth’s course which it passed on 
November 28 in that year. A few meteors from the 
same radiant point were seen by the late Signor 
Zezioli, of Urbino, the most zealous contributor of 
shooting-star observations to Prof. Schiaparelli, on 
November 30, 1867, diverging from the indicated place. 
The probability that the shower formerly witnessed on 
December 6 and 7 has thus advanced with the node of 
F 
