To afford an idea of what has been done in the manufacture of these instruments we mention the following: Of refractors, the one in the United States Naval Observatory at Washington has an object glass twenty-six inches in diameter; that of Mr. R. S. Newall, Gateshead, England, an object glass of twenty-five inches; Observatory of Harvard College, Cambridge, Mass., fifteen inches; Allegheny Observatory, connected with the Western University of Pennsylvania, at Allegheny, Pa., thirteen inches; Michigan University, at Ann Arbor, Mich., twelve and five-tenths inches; Middletown University, Connecticut, eleven inches. Of reflectors, the one constructed by the Earl of Rosse, at Parsontown, Ireland, has a mirror six feet in diameter; the Observatory of Melbourne, Australia, four feet; and Mr. S. Lassell, Marblehead, England, two feet in diameter.
During this month makes us his shortest visit. This he does on the 21st, making his stay about 9h. 16m. in length. Winter begins theoretically the same day at 4:51 a. m., when the sun stands still before he starts on his northern journey, and the astronomers say that the sun enters _Libra_. On the 24th at 2:00 p. m., sun is 90° east of Uranus, that is, is quartile with this planet; on the 12th, at 2:00 a. m., he is 180° from Jupiter, that is, in opposition; on the 31st, at 11:00 p. m., nearest the earth; on the 1st, 16th and 30th he rises at 7:05, 7:18 and 7:24 a. m., and sets at 4:34, 4:35 and 4:44 p. m., respectively. Twilight ends on the 16th at 6:17 p. m.
Presents the ordinary phenomena of its changes as follows: Full on the 2d, at 1:51 p. m.; last quarter on the 9th, at 6:22 a. m.; new on the 17th, at 8:16 a. m.; first quarter on the 25th, at 8:13 a. m. It rises on the 15th, at 6:08 a. m., and sets on the 1st and 30th, at 5:21 a. m. and 5:13 a. m. respectively. Is nearest the earth on the 2d, at 9:30 p. m., and again on the 31st, at 10:48 a. m. Is farthest away from the earth on the 16th, at 11:06 p. m. Runs highest on the 4th, on which date its altitude equals 68° 1′ 33″; and on the 31st, when its altitude amounts to 68° 1′ 56″. It runs lowest on the 17th, when the elevation is 30° 56′ 19″ in latitude 41° 30′ north.
Presents us this month with an unusual number of phenomena, none of which, however, are of a striking character. He rises on the 1st at 8:28 a. m.; on the 16th, at 8:55 a. m.; on the 31st, at 7:48 a. m.; sets on the corresponding days at 5:16, 5:53 and 5:20 p. m.; that is, during the entire month setting from one-half hour to one and one-third hours later than the sun; and thus being visible to a careful observer for perhaps ten or twelve days both before and after the 17th, the day on which he reaches his greatest distance (20° 12′) east of the sun. His motion during the first seventeen days is 30° 33′ 44″ direct, and for the remaining fourteen 5° 9′ 55.5″ retrograde. Diameter increases from 5.2″ to 9.6″. At 3:00 p. m. on the 4th he is 1° 26′ south of Mars; on the 19th, at 6:34 a. m., 6° 27′ south of the moon; on the 25th, at 10:00 a. m., stationary; at midnight on the 29th, 2° 25′ north of Mars; and on the 30th, at 5:00 a. m., reaches its nearest point to the sun.