JUPITER
“Speaks for himself” every evening this month. On the 1st, he rises at 10:34 a. m., and on the 2d sets at 12:06 a. m.; on the 16th, rises at 9:50 a. m., and sets at 11:16 p. m.; and on the 30th, rises at 9:03 a. m., and sets at 10:23 p. m. He has a direct motion of 4° 2′ 31″; and his diameter decreases from 34″ to 31.6″. On the 17th, at 9:44 a. m., he is 3° 44′ north of the moon. It may interest the general reader to know that while he is admiring, night after night, this beautiful body making its way through the “lesser lights” of the heavens, that the astronomer is laboring diligently to discover its properties and learn with exactness its motions. From the last report of Prof. G. W. Hough, Director of the Dearborn Observatory, Chicago, we find that “the disk of Jupiter was observed on every favorable occasion, and micrometric measures made on the principal spots and markings, including the great red spot first remarked in 1878.” These observations were made principally with a view to obtaining the time of revolution of the planet on its axis; and the result of the observations from September 12, 1883, to June 11, 1884, a period during which the planet made 660 revolutions, was a mean of 9h. 55m. 38.5s., which differs from the mean of five years’ observation by 1.5s.; the former mean being that much greater than the latter.