_Occultations of Mercury._—There was an occultation of Mercury by the Moon on April 25, 1838. It occurred on the day of the planet’s greatest elongation E., and at a time in the evening when it might have been most suitably witnessed, but cloudy skies appear to have frustrated the hopes of intending observers. There was a repetition of the event on the morning of May 2, 1867, and it occurred, curiously enough, less than 24 hours after an occultation of Venus. FOOTNOTES: [27] Chambers, in his ‘Descriptive Astronomy,’ 4th edition, 1889, devotes a chapter to the discussion of facts having reference to Vulcan; and the reader desiring full information will find it here. CHAPTER VIII. _VENUS._ Beauty of Venus.—Brilliancy.—Period &c.—Venus as a telescopic object.—Surface-markings on the planet.—Rotation-period.—Faintness of the markings.—Twilight on Venus.—Alleged Satellite.—Further observations required.—Transits of Venus.—Occultations of Venus. “Friend to mankind, she glitters from afar,— Now the bright evening, now the morning star.” _Beauty of Venus._—This planet has an expressive name, and it naturally leads us to expect that the object to which it is applied is a beautiful one. The observer will not be disappointed in this anticipation: he will find Venus the most attractive planet of our system. No such difficulties are encountered in finding Venus as in detecting Mercury; for the former recedes to a distance of 47° from the Sun, and sometimes remains visible 4½ hours after sunset, as in February 1889. But Venus owes her beauty not so much to favourable position as to surpassing lustre. None of the other planets can compare with her in respect to brilliancy. The giant planet Jupiter is pale beside her, and offers no parallel. Ruddy Mars looks faint in her presence, and does not assume to rivalry. This planet alternately adorns the morning and evening sky, as she reaches her W. and E. elongations from the Sun. The ancients styled her _Lucifer_ (“the harbinger of day”) when a morning star and _Hesperus_ when an evening star.