Page:The story of the comets.djvu/76

42 {| align="center" cellpadding="5" cellspacing="0"
 * | Name.
 * | Mean Distance from the Sun in Radii of Earth's orbit.
 * | Encke's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 4.09
 * | Tempel's Second (1873, ii.) &hellip;&hellip;&hellip;
 * | 4.76
 * | Tempel's First (1867, ii.) &hellip;&hellip;&hellip;&hellip;
 * | 4.89
 * | JUPITER &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 4.9 to 5.5
 * | Tempel-Swift (1869, iii., 1880, v.) &hellip;&hellip;
 * | 5.17
 * | Winnecke's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.58
 * | Wolf's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.60
 * | Brorsen's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.61
 * | D'Arrest's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.77
 * | Faye's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.97
 * | Finlay's (1886, vii.) &hellip;&hellip;&hellip;&hellip;&hellip;
 * | 6.06
 * | Biela's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 6.16
 * }
 * | D'Arrest's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.77
 * | Faye's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 5.97
 * | Finlay's (1886, vii.) &hellip;&hellip;&hellip;&hellip;&hellip;
 * | 6.06
 * | Biela's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 6.16
 * }
 * | Biela's &hellip;&hellip;&hellip;&hellip;&hellip;&hellip;&hellip;
 * | 6.16
 * }
 * }
 * }

It has been pointed out by W. W. Payne that there is a manifest tendency with the Jupiter comets for their perihelions to gather towards one particular region lying in the general direction of the vernal equinox. Jupiter's absolute motion in the region of the opposite, or autumnal equinox, must approximately equal his mean motion plus that of the "Sun's Way" (so-called). "Jupiter therefore would overtake or meet more comets in that part of its orbit than in others, and so the possibility of disturbing influence in that region would be greater than elsewhere."

It may be remarked that great as is the attractive power of Jupiter in drawing comets into its own sphere of influence it does not follow that a comet moving in a parabolic orbit can be captured at one effort of disturbance. Thus, Brooks's Comet of 1889 (v.), now moving in an orbit of 7 years, had up to 1886 an orbit requiring 27 years for its journey round the Sun.

The idea that certain comets are associated with particular planets, or perhaps as a better way of putting it, that certain planets have certain comets in groups attached to them, is a somewhat modern one, started by Laplace, who put forth the