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the volume, yet it is less full than was intended : other useful matter has also been omitted for want of room.
It is impossible to give a complete enumeration of the sources from which information has been derived; some of the principal ones, relating to foreign countries, are the English Royal Kalendar, the Englishman's Almanac, the British Almanac and Companion, the Almanach de Gotha, the Genealogischer-Historischerund-Statistischer Almanach, published at Weimar, and various journals ; relating to our own country, the Laws of the United States, the Journal of the Executive Proceedings of the Senate, Official Documents of the General Government, the Register of Officers and Agents in the Service of the United States, the Directory of the Twenty-first Congress, the National Calendar, the Constitutions of the several states, the American, Historical, Chronological, and Geographical Atlas, works on the History and Geography of the different states, the Quarterly Journal of the American Education Society, Hazard's Register of Pennsylvania, Nilés’s Reg. ister, the State Registers of Maine, New Hampshire, Vermont, Connecticut, and New York, a variety of journals and other publications, together with private correspondence with gentlemen of every state in the Union. To those who have been so good as to communicate information, the Conductors return their grateful acknowledgments.
A full view of the Fifth Census of the United States will form an important article in the next volume. Though our own country must hold a prominent place in every number, yet copious details respecting foreign countries may be occasionally expected; also essays on interesting subjects of a scientific and practical nature; notices of important discoveries and useful inventions ; views of the state and progress of education; and accounts of the proceedings of benevolent societies and associations for promoting religion, learning, philanthropy, and moral civilization. The Conductors take the liberty to request the purchasers of this volume to preserve it, as belonging to a series of volumes which, should they be able to execute their design, will be diversified in their contents, and embody such a variety of valuable matter as to form a library of useful knowledge, exhibiting the most important facts of contemporary history, the statistics of the globe, views of the state and progress of society, and miscellaneous information on the different departments of human knowledge and active life. Cambridge, Nov. 15, 1830.
PRELIMINARY OBSERVATIONS ON THE ASTRONOMI
THE .year 1831 is peculiarly distinguished for phenomena worthy of the attention of the astronomers of the United States.
The eclipse on the twelfth of February is the first of a very remarkable series of five large eclipses of the sun, visible to us in the short term of seven years. The others happen as follows; the first on the 27th of July, 1832, total in Cuba ; the second on the 30th of November, 1834, total in Charleston, Beaufort, &c., in South Carolina; the third on the 15th of May, 1836, annular near Cuba; and the fourth on the 18th of September, 1838, apnular in three fifths of the States of the Union.
The eclipse of the present year, taking place near noon, will of course attract great attention. Should the sky be clear, at the time of the nearest approach of the centres of the Sun and Moon, much diminution of the light is not to be expected, probably not enough to render visible the planet Venus, then about 13 degrees east of the Sun ; but a very considerable effect on the thermometer will doubtless be noticed; and, for half an hour, the power of a lens to produce combustion, by refracting the solar rays, will be entirely destroyed. "If the day should be cloudy, the darkness will probably be complete.
În the fourth page there is a representation of the appearance of the sun, at those places where he will be eclipsed centrally, and where about 11) digits on his south limb; by inverting the volune, the lower figure becomes a representation of his appearance at those places (New Orleans, Mobile, Savannah, Charleston, &c.) where the eclipse will be of about the same magnitude on the north.
The passage of the eclipse over the United States only, is represented in the map prefixed to the title-page; but a representation of the entire eclipse for the whole Earth may be easily obtained, by marking on a map of America and the contiguous oceans, the points passed over by the paths of the different digits, and connecting them by curve lines.
After the second sheet had been printed, it was discovered that the phases of the eclipse at the city of Mobile, in the state of Alabama, had been omitted; they are therefore inserted here, viz.
Latitude, 30° 40' North ; Latitude reduced, 30° 29' 57'' North.
S. D. not corrected. S. D. corrected.
Mean time Apparent conjunction 11 27 19.4 11 27 19.4 End of the eclipse 1 7 16.2 A.
1 6 59.3 A. Duration of the eclipse 3 17 12.2 3 16 39.4 Digits eclipsed, 11° 35' 31" on Sun's north limb. At greatest obscuration, moon north 48.06''; at apparent o 48.08. Point first touched at the beginning, 68° 59' from the vertex of the Sun. The occultations this year are uncommonly numerous; and several
h. m. sec.
h. m. sec.
years must elapse before as many eclipses of stars of the first magnitude, and of the principal planets, can again be expected.
Particular mention has already been made of the most important use to which observations of eclipses of the sun, planets, and stars may be applied, viz. the determination of terrestrial longitude, which cannot be settled with equal precision, within the same space of time, in any other way. In the Almanac for 1832, all the occultations will be computed for Charleston, Washington and Boston.
The catalogue of those eclipses of the satellites of Jupiter, which are visi. ble in some part of the United States, has been continued, for the purpose of affording an easy inethod of determining the longitude, with a very considerable degree of precision. On the 37th page a recent discovery respecting these eclipses is noticed, viz. that they might be observed at sea with sufficient accuracy for nautical purposes. The discoverer remarks, “ that as it is difficult to follow the satellite when the ship has much motion, it will be advisable for the observer to limit his attention to the times when the vessel is at the extremity of her roll or pitch. An attendant, with a watch, should note the time when the observer is certain he does see the satellite previous to immersion, and certain that he does not see it after immersion; the mean oi these times should be taken for the true time. The power applied to the telescope should be about 45." As the number of transit telescopes in the United States is very limited, the insertion of a catalogue of Moon-culininating stars was considered inexpedient at this time, but it may appear in the next number, should the insertion be recomieuded.
In the arrangement of the Calendar pages, there is but little alteration from that of the last year. The Equatorial Parallax and Semidiameter of the Moon have, however, been placed in the Appendix, and the beginning and end of twilight for every eighth day, and the distance of the centre of the Moon from the centre of the Earth, at each apogee and perigee, substituted.
The beginning and end of twilight, and the rising and setting of the Sun and Moon, are given for five places in the United States, situated in different latitudes ; the Almanac is thus adapted to the inhabitants of every part of the country, as these particulars depend simply on the latitude, and are wholly independent of the longitude.
The column headed Boston, &c. will answer for all places north of latitude 41° 32', that is, British Continental North America, Maine, New Hampshire, Vermont, Massachusetts, and Michigan; all but the southern extremity of New York and Rhode Island, the northern half of Connecticut, the northern third of Pennsylvania, the Connecticut Reserve in Ohio, ard the northern extremities of Illinois and Indiana.
The column headed New York, &c. is intended for places situated be. tween latitude 41° 32' and 39° 48', that is, the southern extremities of New York and Rhode Island, all but the northern third of Pennsylvanian, all but the southern extremity of New Jersey, the central parts of Ohio, Illinois, and Indiana, and the northern third of Missouri.
The colump headed Washington, &c. may be used between latitude 39° 48' and 35° 52', that is, throughout Maryland, Virginia, Delaware, the District of Columbia, and Kentucky, the northern half of Tennessee, the southern extremity of New Jersey, the southern third of Ohio and Indiana, the southern half of Illinois, all but the northern third of Missouri, and the northern third of North Carolina and Arkansas.
The column headed Charleston &c. is suited to places between latitude 35° 52' and 31° 24', that is, South Carolina, all but the southern extrem
ity of Georgia, Alabama, and Mi«sissippi, all but the northern third of North Carolina and Arkansas; the southern half of Tennessee ; the northern half of Louisiana.
The column headed New Orleans &c. is adapted to places south of lat. itude 31° 24', that is, all Florida and Texas, the southern half of Louisiana, and the southern extremities of Georgia, Alabama, and Mississippi.
The setting of the Moon is given from new moon to full, and the rising from full moon to new; the letters M. A. m. a , to be found in these columps and in other parts of the Almanac, are used to denote Morning and Mfternoon.
The time of the Phases of the Moon is computed for the meridian of Washington, but may be readily reduced to that for any other meridian, by adding or subtracting the difference of the longitude, according as the same is east or west of that city. The time of the moon's southing is computed for the same ineridian. The variation, however, even in a remote part of the United States, will be inconsiderable.
The time of High Water is corrected for the difference of the Right Ascension of the Sun and Moon, and the distance of the Moon from the Earth. The small corrections depending on their declinations and our distance froin the Sun, have been neglected as unimportant; indeed it has been ascertained, from a series of several hundred observations, that the corrections we have introduced will, in calm weather, give the time of high water within fifteen minutes, and, generally, much nearer. The difference between the titne of high water at New York, Charleston, and Boston, was derived froin the best authorities; but perhaps it has not been ascertained with the degree of accuracy that is to be desired. If our authorities are correct, the time of high water along the coast of Maine, New Hampshire, and Massachusetts, as far as Nantucket, is nearly the same as at Bos. ton. Moreover, when it is high water in New York, it is nearly so in Long Island Sound, along the coast of New Jersey, Delaware, Maryland, Virginia, and North Carolina, as far as Cape Lookout, (with the exception of Sandy Hook and the entrance of Chesapeake Bay;) whilst along the coast of the southern part of North Carolina, of South Carolina, Georgia, and Florida, at Sandy Hook and the entrance of the Chesapeake, the time agrees very nearly with that in the column for Charleston ; when greater accuracy is desired, reference should be had to the Tide Table on the 15th page. The time of the tide immediately preceding the southing of the moon, only, having been given, it should be corrected by the addition of half the difference when the time of the other tide is required.
The Planets are placed in the order in which they pass the meridian on the first day of each month, and their declinations are computed for the moment of their passage over the meridian of Washington.
The equation of time is the correction by which apparent is reduced to mean time. It is computed for apparent noon at Greenwich, and is to be applied with the actual sign; but when it is desired to reduce mean to apparent time, the sign of the equation should be reversed.
Apparent time has been generally used in this Almanac; the only exception being in what relates to eclipses, occultations, and their elements, the rising and setting of the Moon, the passage of the Moon and planets over the meridian, and the time of high water. The beginning and end of twilight, and the rising and setting of the Sun, could not be given in mean time, as was to be desired, without occupying too much room.
The Appendix is intended to answer all the essential purposes of a Nautical Almanac, and the insertion therein of the distances of the Moon from the planets, and of the proportional logarithm of the difference between the
distances, it is hoped, will be found an improvement on any Almanac hitherto published. The difficulty of measuring the altitude of stars at sea is so great, that the insertion of the Moon's distance from them is rendered nearly useless. Indeed it has been asserted, that it could be more accurately measured on a celestial globe, than by any instrument of reflection whatever. But the planets are so much more brilliant, that their distance from the Moon, and altitude, can generally be determined with great accuracy, in the twilight, and before the horizon becomes invisible. The insertion of the proportional logarithm not only very considerably facilitates the computation, but affords an opportunity of correcting a typographical error, should any exist.
The whole of the Ephemeris of the Sun was calculated from the celebrated Almanac of Professor Encke. It was reduced with great care, and with corrections for the second and higher orders of differences, from the meridian of Berlin to that of Greenwich. As Bessel's corrections of Carlini's Solar Tables were introduced by Encke into his Ephemeris, the place of the Sun, both with respect to the ecliptic and the equator, as well as his distance from the Moon, as given in the Appendix to this Almanac, will always be found to differ very considerably from the English Nautical Almanac, in the computation of which, these corrections were wholly unnoticed.
The places of six stars of the first magnitude, as determined at Konigsberg, are given for every fifteenth day; they afford an opportunity to those possessed of a transit telescope, of determining the time with the greatest precision; or if the time has been otherwise accurately ascertained, of adjusting the telescope to the meridian. The stars selected are situated as nearly equidistant as possible.
The most important astronomical phenomena visible in the United States, in 1832, are a transit of Mercury on the 5th of May, an eclipse of the Sun on the 27th of July, three occultations of Saturn, two of Uranus, one of Mercury, one of Venus, one of Mars, two of Aldebaran, besides many of the smaller stars.
The year 1832 will be rendered memorable, also, by the return to the perihelion of two of the three comets, whose orbits have been discovered to be elliptical, viz. that known as Encke's, whose period is about 1212 days, which will pass the perihelion about the 7th of May; and that known as Biela's, whose period is about 2460 days, which will pass the perihelion on the 27th of November, and the perigee on the 22d of October, when it will be distant from the earth about 51 millions of miles. The latter, when nearest the Sun, will have an elongation of about 120°, and be about 30° nearer the elevated pole than the Sun, and will, consequently, be in a very favorable situation for observation. The former, it is believed, will have, when brightest, a great southern declination, and will, if this supposition is correct, be wholly invisible throughout the United States.
R. T. PAINE, Boston, November 12, 1830.