Page:Encyclopædia Britannica, Ninth Edition, v. 6.djvu/221

Rh COMET 193 Discovered by M. F;iye at Paris, 1843, Nov. 22, and period deter mined at this appearance. M. Leverrier has made very extensive researches respecting the previous motions of this comet, which he considers to have been revolving in an orbit of the above limited dimensions since the year 1747, when it may have passed so near to the planet Jupiter as to have its orbit completely changed. The calculations relating to this comet have for many years been in the hands of l)r Axel-Mbller of Lund, the results of whose masterly com putation of the perturbations will be found in various volumes of the Astronomiche Nachrichtcn. Observations have been made at every return to perihelion since 1843. XIII. Peters s Comet. ...1846, June 1-2124 it 240 7 35 & 200 28 59 i... .. 30 24 24 1846-0 1846 (V.) e 0721339 a 5-48558 Period... 12 85 years. Discovered at Naples by Dr Peters, now director of the Observatory of Clinton, U.S., 1846, June 26, and not observed elsewhere, ex cept at Some on July 2. The period of revolution is uncertain to 1 &quot;6 years, according to Peteps s last discussion of the observations of 1846, since which year the comet has not been found, though there appears to be no doubt of the great deviation of the orbit from a parabola. XIV. Tuttle s Comet, .1871, December 1 7974. IT 116 4 35 a 269 17 12 i .. 54 17 1870 e 0-821054 o 5-75652 Period. ..13 81 years. Direct. Periodicity discovered in 1858, when the comet was detected by Mr Tuttle at Cambridge, U.S. (January 4). It was soon found to present a great similarity of elements to those of the second comet of 1790, which was found by Mechain at Paris on January 9, and further investigation established the identity of the comets, five revolutions having been performed between 1790 and 1858. The two appearances have been connected by the calculation of the per turbations in the interval by Clausen and Tischler. GHOTJP B. I. Comet 1866 1. T 1866, January 11-1339 .. 60 28 .231 26 .. 17 18 (Tempel.) e 0-905420 a 10-32479 1866 Period. ..33 18 years. Retrograde. This body is widely known as the &quot;comet of the November meteors, 1 which have been found to move in an orbit that is almost identical. It was discovered by Tempel, 1865, Dec. 19 ; the best determination of the elliptical elements is due to Prof. Oppblzer. The ensuing return to perihelion will be looked for in 1899. in which year a repetition of tho grand meteoric display of 1866 may also be expected. IT. Stephan s Comet, 1867, 1. T 1867, January 19-8606 c 849055 a 10-41762 Period.. ^33 -62 years. i 18 12 35 .75 52 16, 18fi7. .78 35 45 f 1867 Direct. Discovered by Stephan at Marseilles, 1867, Jan. 27. The elliptical orbit which represents the whole course of observation very closely is due to Mr Searle of Cambridge, U.S. This comet appears to make a very close approach to the orbits of Mars and Uranus, and it is likely the actual form of orbit may be owing to an encounter with the latter planet near the aphelion. III. Wcstphal s Comet. 1852. T ...... 1852, Oct. 127628 e .......... 0-918463 . 43 14 8 .346 9 49 . 40 54 28 a 15-3315 1852 Q Period. ...60 03 years. Direct. Discovered by Westphal at Gbttingen, 1852, July 24. The ellip tical character of the orbit was first established by Marth in the same year. Elements, in the calculation of which the effect of planetary attraction during the period of observation is included, have been published both by the discoverer and by Dr Axel Mbller, whose elaborate investigations relating to Faye s comet have been alrea.dy mentioned. IV. Poms Comet. 1812.. T 1812, Sept. 15-3136 c 0-954541 IT,. & . i... . 92 18 44 .253 1 2 . 73 57 3 17-0955 1812 Period 70 69 years. Direct. Detected by Pons at Marseilles, 1812, July 20, and independently at a later date by Wisniewsky at Novo-Tcherkask. To Eacke is due the discovery of the periodicity, but it is doubtful if the length of revolution can be inferred from the observations, within several months, so that although another perihelion passage is approach ing, no reliable prediction of the track in the heavens is at present practicable. V. De Vico s Comet. 1846, III. T......1846, March 5-5454 e 0-962089 . - // o 17-5072 H d3 3&amp;lt;3 i Direct. i 85 5 42 Discovered by De Vico at Rome, 184(i s Feb. 20, and in a few weeks recognized as a periodical comet,, ellipses having been calculated by Breen, Hind, and Peirce. The most reliable orbit, which is given above, is by Van Galen. This comet makes a near approach to the orbit of the planet Venus. VI. Olbers s Comet. 1815. T 1815, April 25-9922 e 0-931220 a.... 17-6338 i 44 29 55 Discovered by Olbers at Bremen 1815, March 6. The elements transcribed were calculated by Bessel upon the whole course of observation ; very similar ellipses were also found by Gauss, Nieo- lai, and Nicollet. Bessel computed the effect of planetary attrac tion upon the motion of the comet in the actual revolution, and as, signed the next perihelion passage to 1887, Feb. 9 ; but unfortunately this date is not to be relied upon within anything like nariow Limits. VII. Brorsen s Comet. 1847, V. T -- 1847, Sept. 9 5427, 79 12 6 309 48 49 19 8 25 e 0-972560 o 17-7795 Period 74-97 years. Direct. Discovered by Brorsen at Altona, 1847, July 20. While there appears to be no doubt of the ellipticity, the period is yet open to considerable uncertainty, Dr Gould (the present director of the Observatory of Cordova) having inferred a revolution of 81 05 years. 1 1 is one of those comets which yet require a more minute calcu lation. VIII. Halley s Comet. lu the case of this celebrated body we shall content ourselves with reproducing the elements for the appearance of 1835-36, as elaborately worked out by Westphalen, and the elements assigned for the next return in the year 1910 by the late Count de PoL .tc5- coulant. Elements of 1835-36. T Nov. 15-9082 ir -....304 31 32 8, 55 9 59 i 17 45 5 1835-0 c 0-967371 a 17-9879 Period 76 30 years Eetrograde. Elements 0/1910. T May 23-86 c 0-961733 a. 17-9555 TT 305 38 14 & ... 57 10 33 i 17 46 51 1910 Period. ...76 - 08 years. Eetrograde. It would be useless to attempt to present a history of Halley s comet within the space to which this article must be limited. With regard to its history previous to the year 1456, the earliest visit known to Halley, the reader may refer to a paper on &quot;The Past History of the Comet of Halley,&quot; Hind in Monthly Notices of the Royal Astronomical Society, vol. x., in which the appearances of the comet are traced back with a greater or less degree of proba bility to the year B.C. 12, chiefly by aid of the details preserved to us in the Chinese annals ; also to a remarkable memoir by the late Dr Angstrom of Upsala, Sur deux inegalites d une grandeur rz- marquable dans les apparitions de la comete de Halley, Upsala, 186?, which is corroborative of the conclusions in the first-mentione I paper. (J. R. H.) VI. - 25
 * * I* j ( 1846 Period 73 25 years.