and is such as would be shown by the sun if it moved uniformly in the equinoctial. Equation of time.-The equation of time is the difference be tween apparent and mean time, is found in the Nautical Almana for each day, and is used for reducing apparent time to mear time. Zenith distance. The zenith distance is the distance a celes tial object is from the zenith, or the point overhead. The British league, or three times our geographical mile of & to a degree, or 2025 yards, is 6075 yards. The Brabant league 2 6096 yards. The Danish and Hamburg league is 8244 yar the German league is 8101 yards; the long German league 10126 yards; the short German league is 6859 yards; the Pur: guese league is 6760 yards; the Spanish league is 7416 yards the Swedish league is 11700 yards. All of them are parts of degree, but made before the length of a degree was accurat determined. Length of Days in Different Countries. At London, England, and Bremen, Prussia, the longest day 16 hours. At Stockholm, in Sweden, the longest day has. hours. At Hamburg in Germany, and Dantzic in Russia, the longest day is 18 hours, and the shortest is 7. At St. Petersburg in Russia, and Tobolsk in Siberia, the longest day has 19 hours, and the shortest, 5. At Tornea, in Finland, the longest day has 24 hours, and the shortest is a half-hour. At Wardbuys in Norway, the longest day lasts from the 1st of May to the 22d of July without interruption; and at Spitzbergen the longest day is three months and a half. At New York the longest day has 15 hours and 56 minutes; and at Montreal 151⁄2 hours. TABLE OF SAILING DISTANCES FROM NEW YORK TO DIFFERENT PARTS OF THE WORLD, IN GEOGRAPHICAL MILES. TABLE OF MILES AND KNOTS, KNOTS AND MILES. The decimals of miles in this table are repeaters, and when four is used, the last figure should be increased by one. While it must be admitted that we have made great improve ent in the design and construction not only of the hulls of stea ips, but also of the machinery and all other appliances c |