ephemeris

, or nautical almanac.

This in its wide sense, and recognizing its value to navigators and astronomers, must be pronounced one of the most useful of publications. How Drake and Magellan got on is matter of marvel, for sailors were not especially administered to till 1675, when the Kalendarium Nauticum, by Henry Seaman, Mariner, appeared; it comprised the usual matter of annual almanacs, and was enriched with such precepts and rules in the practice of navigation and traffic as are in daily use. But in 1767 our nautical almanac, a tabular statement of the geocentric planetary positions, which may be said to have created a new era in voyaging, was published; and this book, with certain alterations, was in force up to 1830, when a commission of the Royal Society and astronomers established the present Ephemeris, now so much valued. It is published annually, but computed to four years in advance, to accommodate those proceeding on long voyages. Attempts have been made in other countries to publish The Nautical Almanac, improved and corrected, but they are mere copies, corrected by the errata furnished annually in advance.