151 
Astronomical Society, 
author proceeds to give his own observations on Encke’s comet, at 
the time of its last perihelion passage in 1838, when it appeared 
under circumstances favourable for observing the nebulosity. He 
states that he was able to follow the comet till the evening before 
the perihelion passage ; that he observed it to diminish rapidly, and, 
after being prodigiously reduced, to melt away, as it were, under his 
eyes, disappearing only in consequence of its extreme smallness, in- 
asmuch as its brilliancy should, from its position, have continued to 
increase. The observations are as follows : — 
On the 9th and 10th of October, the nebulosity subtended an an- 
gle of 20', but it diminished continually after that time. On the 
15 th of October, he first remarked it to be elongated in the direction 
of the sun ; and the elongation continued to increase until the 25th 
of October, when the greater diameter appeared to be double the 
smaller, after w^hich it began to diminish. The most luminous part 
was not at the centre, but at the point opposite the sun. On the 
25th of October, the nebulosity was reduced to 15', and the real 
volume was then eighteen times smaller than on the 10th. On the 
6th of November, the nebulosity was 13', and the volume reduced 
to l-40th. On the 13th of November, the nebulosity was 11' ; on 
the 16th, between 8' and 9' ; on the 20th between 6' and 7'; on the 
23rd, 4' ; on the 24th, 3', and the real volume, 826 times less than on 
the 10th of October. On the 29th of November, the comet could 
no longer be seen in the evening twilight, but it reappeared on the 
morning of the 7th of December On the 12th of December it ap- 
peared as a star of the fifth magnitude ; and its diameter w'as less 
than 20", being entirely covered by a wire of that thickness. The 
volume deduced from this apparent magnitude would be 80,242 
times less than on the 10th of October. On the 14th of December 
it appeared feebler, and equal to a star of the sixth magnitude, with 
which it was compared; its diameter was then estimated at 15". 
On the 1 6th the comet appeared as a star of the seventh magnitude, 
and its apparent diameter was from 10" to 12". On the 17th it was 
reduced to the eighth magnitude at most, and its apparent diameter 
was from 7" to 8". On the 18th of December it was entirely invi- 
sible, although stars of the seventh and eighth magnitudes were 
seen in its neighbourhood. From these comparisons it appears that 
the real diameter must have undergone a diminution from the 10th 
of December*, when it was first observed in the morning, until the 
18th, when it finally disappeared. 
A Letter from Professor Schumacher, to Francis Baily, Esq., an- 
nouncing the Discovery of a Comet by M. Galle, assistant in the 
Berlin Observatory. 
The comet was discovered on the 2nd of the present month, 1 7^ 
45*" mean time (Berlin), in the constellation Virgo. Comparing it 
by the great refractor, with a star of the tenth magnitude (which 
star was immediately compared with y Virginis), M. Galle obtained 
the following positions : — 
* There must be some error here in the dates. — E dit. 
