THE AMERICAN EPHEMERIS AND NAUTICAL ALMANAC. FOR THE YEAR 1856. PUBLISHED BY AUTHORITY OF THE SECRETARY OF THE NAVY. WASHINGTON. PREFACE TO THE FIRST VOLUME. THE preparation of this work was begun in the latter part of the year 1849, in accordance with an act of Congress, approved on the 3d of March of that year. An account of this preparation, its details, the values of the constants adopted, and the means employed in various parts of the work to secure additional accuracy or greater convenience, will be found in the article "ON THE CONSTRUCTION OF THE EPHEMERIS," contained in the Appendix to this volume. An article" ON THE ARRANGEMENT AND USE OF THE TABLES" will also be found in this volume, to which the student is referred for instruction. The theoretical department of the work has been placed under the special direction of Professor Benjamin Peirce, LL.D., and most of the calculations have passed under his final revision. It is due to the memory of the late Nathaniel Bowditch, LL.D., the illustrious commentator of La Place, to say, that his zeal in enriching the library of the University at Cambridge, that of the American Academy of Arts and Sciences, and his private library, still preserved and accessible to students, with the best works in astronomical science, and his influence in promoting and diffusing in America a love for this branch of knowledge, have greatly facilitated the labor of preparing the American Ephemeris for publication in its present form. |