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XLII. 
ELEMENTS OF THE ORBIT OF THE COMET OF sit. 
BY NATHANIEL BOWDITCH. 
—=: Be 
THIS memoir contains the geocentric longitudes and latitudes 
of the comet of 1811, with an abstract of the calculations of the ele- 
ments of its orbit, from a combination of all the observations, made at 
Cambridge, Nantucket, and Salem, in such manner as was supposed 
would produce the most accurate result. 
The comet was seen in France before its conjunction with the sun, 
as early as the 25th of March, and continued visible till the end of 
May. It was observed about the same time at the Cape of Good 
Hope, and at other places south of the equator. It was also visible at 
Chilicothe in the month of May. No correct observations were how- 
ever made in this part of the country till after the conjunction, about 
the 6th of September, when it was seen for the first time in most 
parts of New England. It was then near the feet of the Great Bear. 
Its apparent motion was direct, passing in succession through the 
northern parts of the constellations Bootes and Hercules, the middle 
of the Eagle and the south of the Dolphin. It disappeared near the 
northern part of the Water-Bearer about the 16th of January 1812. 
The apparent velocity when first observed in September was about a 
degree per day: it increased gradually till the middle of October, and 
was then 13°; after which it continually decreased, and was about half 
a degree per day, at the time it ceased to be visible. The whole ap- 
parent path described by the comet was nearly a great circle about 
140° in length. The comet was at its greatest north declination, 493°, 
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