97 
It is known to you all that Biela’s comet, as it is gen- 
erally called, is one of short period, performing its entire 
revolution in about 62 years. It was first seen in 1772, by 
Montaiene, who made three or four imperfect and untrust- 
worthy estimates of position, and it was observed four times, 
quite unsatisfactorily, by Messtrr. In 1806, it was detect- 
ed by Pons; and the general resemblance of its orbit to 
the approximate one deduced for the comet of 1772, at- 
tracted immediate attention. Brsse~ and Gauss computed 
elliptic orbits on the supposition of identity. The latter 
found the apparent path as well represented by an ellipse of 
4? years as by his best parabola, thus suggesting the proba- 
bility that there had been six intermediate returns. . The 
places observed in 1772 were, however, not so well satisfied 
by an ellipse of so short a major axis, and therefore while 
the hypothesis of identity seemed plausible, it could hardly 
be considered probable. It was not until 1826 that the 
comet was seen again. In that year it was independently 
discovered both on the 27th February, by von Brera, an 
Austrian captain, on duty at the fortress of Josephstadt, and 
by Gamparr in Marseilles, ten days later. Upon the first 
Computation of the orbit, each recognized the identity of the 
Comet with that of 1806, and the true length of the period 
became manifest. 
The next return, in 1832, was successfully predicted by 
astronomers ; at the following one in 1839, it was not discov- 
ered; and in the winter of 1845 — 6, a predicted return was 
for the second time observed. But here an unexpected and 
anomalous phenomenon was exhibited. The comet, which 
Was detected at the close of November, was before the end 
of December seen to be double, and the two components be- 
Came apparently farther and farther apart, until, at the end 
of March, their distance from one another amounted to more 
14’, 
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