_Occultation of a Star._—An occultation of the 7th mag. star 4 Geminorum by Jupiter took place on Nov. 7, 1882, and it was observed by Prof. Pritchett, of Glasgow, Missouri, with a 12-1/4-inch equatoreal, power 200. “The images of both planet and star were very steady. The margin of Jupiter’s disk was very sharply defined. The immersion was very near the N. border of the broad S. equatoreal belt. At 11^h 28^m 10^s·65 local mean time the star was _apparently_ within the dark outline of the disk, apparent geometric contact having occurred at 11^h 20^m 24^s·49. For a moment the star seemed to disappear, but a moment later was plainly seen, as if through a well-defined notch in the otherwise _continuously even_ margin. This notch lasted 46^s·26, and at 11^h 28^m 56^s·91 it _vanished_, and the light of the star was _entirely extinguished_.” The emersion of the star could not be observed, as clouds supervened. FOOTNOTES: [33] The question of periodicity is an extremely interesting one as affecting the disposition, form, and colours of the markings on Jupiter. Certain features visible in 1869-70 were unmistakably reproduced in 1880, and it has been suspected that the cycle of these changes accords with the length of the Jovian year. Future observations must be compared with old drawings and records for the identification of similar features if they are recurrent. [34] On the morning of Dec. 5, 1887, I made a drawing of Saturn, the image of the planet being remarkably well defined, though the Moon was only 1° distant. [35] Amongst the first observers of these dark transits were Cassini (Sept. 2, 1665), Romer (1677), and Maraldi (1707). CHAPTER XII. _SATURN._ Apparent lustre.—Grand spectacle afforded by the Rings.—Period &c.—“Square-shouldered” aspect.—Early Observations.—Belts and Spots on the Planet.—Rotation-Period.—The Rings.—Divisions in the outer Ring.—The transparent or Crape-ring.—Discordant Observations.—Eccentric position of the Rings.—Aspect.—Further Observations required.—Occultations of Saturn.—The Satellites.—Occultations of Stars by Saturn. “Muse, raise thy voice, mysterious truth to sing, How o’er the copious orb a lucid ring, Opaque and broad, is seen its arch to spread Round the big globe, at stated periods led.” This planet shines brighter than an ordinary first-magnitude star, and is a pretty conspicuous object, though less luminous than either Venus, Jupiter, or Mars. He emits a dull yellowish light, steadier than the sparkling lustre of Mercury or Venus.