COMET 1840 (II.).—In Astronomische Nachrichten, No. 2,079, Dr. Kowalczyk, of Warsaw, publishes his investigation of a definitive orbit for the comet discovered Berlin, by Prof. Galle, the present Director of the Observatory at Breslau, on the 25th of January, 1840. This comet, which was last observed at Kremsmunster on the ist of April, had already been made the subject of extensive calculation by Professors Plantamour and Loomis. The former, in 1843, discussing his own series of careful observations taken at Geneva, found (Astroti. Nach., No. 476) that a parabolic orbit represented the comet's course within the probable limits of error of observation; on including the series taken at Berlin he found the most probable orbit to be an ellipse, but of great excentricity to which little weight was considered to attach. Loomis, on his side, taking into account the effect of planetary perturbation during the interval of the comet's visibility, also found an ellipse, but with a more moderate excentricity, the period of revolution being about 2,420 years; the sum of the squares of the errors in the ellipse is diminished to one-third of the amount with the best determinable parabola. Loomis's investigation will be found in the “Transactions of the American Academy,” vol. viii.; his orbits are not included in the extensive collection in Dr. Carl's “Repertorium der Cometeu-Astronomie,” a work which, notwithstanding its great utility to the student of this branch of the science, is yet not complete or free from numerical errors.