It will be seen, that, before the discovery of Neptune, the agreement was so close as to indicate that this was an actual law of the distances; but the discovery of this planet completely disproved its existence.
Fig. 304.
283. The Satellite of Neptune.—Neptune is accompanied by at least one moon, whose orbit is shown in Fig. 304. The orbit of this satellite is inclined about thirty degrees to the plane of the ecliptic, and the motion of the satellite is retrograde, or from east to west.
VII. COMETS AND METEORS.
I. COMETS.
General Phenomena of Comets.
284. General Appearance of a Bright Comet.—Comets bright enough to be seen with the naked eye are composed of three parts, which run into each other by insensible gradations. These are the nucleus, the coma, and the tail.
The nucleus is the bright centre of the comet, and appears to the eye as a star or planet.