The motions and periodical times of the planets were in general calculated from tables considered the most accurate. Should they differ a little from the statements in other books, it is hoped and believed, they will not be found less near the truth. The tables were calculated for the meridian of Washington City, longitude, as found by Mr. Lambert, 76° 55' 30. 54", west from Greenwich. This seemed most useful to the American student, and consonant with the dignity and importance of the nation. For while we cheerfully pay our tribute of gratitude to the " old world" for its vast discoveries in the celestial regions, and to those noble individuals of Europe, who have dared to tread the milky way, "where the soul grows conscious of her birth celestial, and feels herself at home among the stars ;" we remember not only that we are far removed from the eastern world, but are an independent nation. It illy becomes the United States to move as the satellite of any foreign power. The sentiments of every true American must accord with those of the present Chief Magistrate "While scarcely a year passes over our heads without bringing some new astronomical discovery to light, which we must receive at second hand from Europe, are we not cutting ourselves off from the means of returning light for light, while we have neither observatory nor observer upon our half of the globe, and the earth revolves in perpetual darkness to our unsearching eyes?" : Calculations made for the City of Washington will answer with little variation for the great body of the United States; and, where an allowance must occasionally be made for difference of longitude, with equal ease may it be calculated from the meridian of our own capital, as from that of Greenwich or Paris. No pains has been spared to render the tables not only extensive, but complete and accurate. Being carried through the 19th century, they will save much of the time usually spent in bringing the numbers of the old tables to use at the present time. In the problems worked by the terrestrial globe, calculations are made from the Meridian of Greenwich, longitude on the globe being reckoned from that meridian. For a full understanding of some subjects, it seemed necessary to introduce some trigonometrical calculations, and in a few instances, geometrical demonstrations. For the chapters on eclipses and parallax, the student of leisure and ingenuity would not be satisfied to pass superficially over the principles on which the calculations are founded. Yet there may be many whose time and inclination will not permit them to examine minutely by mathematical computation, and much less by demonstration. The latter class of students may pass over the very small part of the work, which may be thought by a judicious instructor, too abstruse for their investigation. For the convenience of such, the demonstrations in general are printed in a closer type. It is however, highly desirable, that the astronomical student should be well versed in trigonometry. Much of the knowledge of astronomy is founded on this science. Without it the scholar must not only lose much of the satisfaction to be derived from his studies; but can scarcely believe the statements of authors, or that the mathematical results are founded in truth. Questions in our classical books are become fashionable.The author of this would not deny the merits of every book,. in which they are found at large; nor would he detract from the very respectable character of some authors, by whom they have been inserted in our books, or teachers by whom they have been used in our schools. But from his own observation as a teacher, from the natural tendency of inserted questions, and from the information he has received of their use in many of our common schools, he considers their utility as very problematical. Where the questions inserted in the book only, are to be asked, the merest novice may be a teacher; and the answers may be promptly given by the most superficial scholar, with little or no knowledge of the subject. Their principal use undoubtedly is in reviews. But even for these it was not thought they would deserve a place in a work of this nature. In stating the motions of the heavenly bodies, a minute insertion, at least including seconds, was thought necessary, as frequently on these, calculations must be dependant. It is not in all cases, however, requisite, that the student should. commit the minutia. The well informed instructer will easily judge, when the sexigesimals ought to be committed. In many parts of the work, by carrying the calculations forward, and making them for the western hemisphere, the author was forced to explore new regions, "terra incognita." This was particularly the case in the catalogue of eclipses visible in the century. Though he has taken great pains, he cannot hope his work will be free from error. Communications on this subject will be received with gratitude. CONTENTS. PAGE. Explanation of the term, astronomy; advantages of the study; different An explanation of Astronomical terms. The sun; his place in the System; turns on his axis; physical construc- tion of the sun; why cold is intense in elevated regions; Dr. Herschel's by- pothesis of the sun; Dr. Brewster's confirmation; spots on the sun, when Mercury; must have intense heat according to Sir Isaac Newton; differ- ent accounts of Dr. Herschel and Mr. Schroeter respecting spots on Mercury; why important discoveries have not been made in Mercury; elements of Venus; next to the sun and moon, Venus is the most brilliant of the heavenly bodies; she forms our morning and evening star; motion of Venus; must appear more brilliant to the inhabitants of Mercury than to us; the light of Venus remarkably pleasant and bright; Dr. Herschel observed spots on Venus, and concluded she must have an atmosphere; Mr. Schroeter's as- count of her mountains; Dr. Herschel's measurement makes her larger than Mercury and Venus; why these are called inferior planets; their apparent motions explained; Mercury and Venus appear with the phases of the moon ; The Earth; its globular form; circles of the earth; latitude and longitude axis; the celestial sphere appears right, oblique, or parallel; form of the earth's orbit; how the different seasons are produced; the year how reckoned; summer in the northern hemisphere longer than in the southern; motion of the aphelion in the earth's orbit; why the earth's motions are not percepti- ble; why we have the warmest weather when the sun is farthest from the The Moon; her distance from the earth and revolutions; why she always exhibits the same face to the earth; how the earth appears at the moon; com- parative magnitude of the earth and moon; phases of the moon; different parts of the moon have different portions of light; the dark parts of the moon are cavities; Dr. Brewster's account of the lunar irregularities; quantity of the moon's light at the earth; form of the moon's orbit; Dr. Herschel thought he saw volcanoes in the moon; singular appearance of the moon; why the sun and moon appear large near the horizon; how the concavity of the heav- Mars; the atmosphere of this planet causes the remarkable redness of his appearance; Miraldi's view of Mars; brightness at his polar regions; Mars sometimes appears gibbous; appearance of the earth and moon at Mars; Dr. Herschel's account of telescopic appearances at this planet; elements of Mars. Asteroids; Vesta; its light is superior to that of the other Asteroids; Juno; remarkable for the eccentricity of its orbit; Ceres; exhibits a disk surrounded by a dense atmosphere; Pallas; remarkable for the great obliquity of its orbit to the ecliptic; the orbits of the asteroids intersect each other; ar- gument in favour of their being originally one planet not conclusive. some Jupiter; the largest of the planets; surrounded with belts; large spots Saturn; shines with a dim feeble light; the most remarkable phenomenon of Saturn is his ring; the ring appears double; is inclined to the plane of the ecliptic in an angle of 310; the ring illumines one half of the planet; one side shines on the planet for about 15 years, then the other half for the same term in succession; Saturn has dark spots and belts; the heat of the sun at Saturn 90 times less than to us; the spheroidical appearance of this planet is remarka- ble; elements of Saturn; satellites of Saturn; remarkable change in the ap- pearance of one satellite; Dr. Herschel considered his ring and satellites as Herschel, the planet; discovered by Dr. Herschel while viewing the small |