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POPULAR SCIENCE REVIEW. 
lias ably calculated the great changes in the orbit of the comet produced by 
the attraction of this giant planet, the principal being a change in the mean 
anomaly of nearly two degrees in the vectorial angle or eccentricity of a 
degree, and in the inclination of about two degrees. He also calculates the 
form of the orbit in which the comet must have moved prior to its close 
approach to Jupiter, and shows that the elements resemble those of a comet 
discovered by Messier in 1798. He does not think it likely, however, that 
the two comets are the same. Herr Harzer thinks that there is reason to 
believe that the orbit of the comet would have suffered similar great changes 
in 1760, and may undergo similar changes in its near approach in 1937. 
On November 20, 1880, Mr. J. Birmingham observed the star 
B D + 2°, 97 quite close to the planet Jupiter, being distant only by 4"*05, 
and giving to the planet all the appearance of having five satellites. The 
light of the star was, however, very different from that of the satellites; 
and, though it is a 7 ‘7 th magnitude star, it shone only like a 10 th magnitude 
star, owing to its proximity to the bright planet. 
Swift's Comet = Comet e, 1880. — The later observations which have been 
made of this comet have seemed to materially alter the earlier impression 
about its orbit. Instead of having a period of eleven years, it seems that 
there can be no doubt that its period is really only half of this, or about five 
and a half years ; but owing to the position of its orbit the comet is invisible 
at every other return to perihelion. The latest and best orbit seems to be 
that by Mr. Winslow Upton of Washing-ton. He finds as follows : — 
Epoch 1880, Oct. 25*5, Washington mean time. 
r M = 357 48 49 '3 = Mean Anomaly at Epoch. 
1880 J a = ^96 41 55-4 = Longitude of Ascending Node. 
J W = 106 18 13*8 = Distance of perihelion for Ascending Node. 
\ i — 5 31 3*5 = Inclination of orbit. 
e = 0*67594 = Eccentricity. 
a = 3*29942 = Semi-major axis, 
ju = 592"*0373 = Mean Motion. 
From these figures we learn that the comet passed through its perihelion 
on November 7*79433 Washington mean time, and has a period of 2189*1 
days, or only 2*4 days short of six years. This result is in close accord 
with that calculated by Prof. Frisby from less perfect data. The period of 
this comet is so nearly equal to half that of the planet Jupiter, and its orbit 
approaches so close to that planet, at a time when that planet is not far dis- 
tant, that the comet must undergo considerable perturbation in its motion. 
Pechule's Comet = Comet f, 1880. — On Dec. 16, 1880, Herr Pechiile dis- 
covered a comet not far from the place of Hartwig’s comet. It was small, 
and at the time of its discovery pretty bright. It soon grew faint, however. 
According to Prof. Young this comet had two tails, the upper and brighter 
one was directed towards the Sun, and about 40' in length ; the other, or 
fainter, tail was only about two-thirds as long. They were too faint to be 
seen after the 22nd. From the observations Mr. C. S. Chandler has computed 
an orbit. The elements he obtained were : — 
