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population of most of the other towns has been derived from unofficial publications, and will doubtless be found to differ in some instances from the official statements, which will before long be made public.

Although the Valedictory Address of Washington has been repeatedly printed, yet as "it contains precepts," (to use the words of the present venerable Chief Justice of the United States,) " to which American statesmen cannot too frequently recur," the readers of the American Almanac will not be displeased with having it occupy a few pages of the work. - The article on the Public Lands embraces information that will be interesting and useful to a numerous class of persons.

This volume contains very little matter that is to be found in those which have preceded it, except in relation to such topics as are subject to change from one year to another. The plan adopted with respect to the articles relating to the different states, has left but little room for notices of foreign countries; but these and various other subjects may be expected to receive more particular notice in future volumes.

The information contained in this book has been derived from a great variety of sources. Numerous authorities are referred to in the course of the work; but the volume owes much of its value to gentlemen in the different states, who have been so good as to forward information: to all such the Conductors return their grateful acknowledgments, and respectfully solicit a continuance of their favors.

In a work which treats of such a variety of topics, many of which are subject to frequent change, and respecting many of which authorities differ, errors are unavoidable. It is the wish of the Conductors to present a faithful and impartial exhibition of facts on all the subjects that come within the plan of their work, uninfluenced by local prejudice or party bias; and they will be grateful to any gentleman who may furnish them with the means of rendering it more correct, more complete, and more useful to the public. THE CONDUCTORS.

Cambridge, Oct. 24, 1831.

PRELIMINARY OBSERVATIONS ON THE ASTRONOMI

CAL DEPARTMENT.

ALTHOUGH the year 1832 is not so distinguished as the preceding for phenomena worthy of the notice of our astronomers, yet in the course of it will happen, at least two, deserving very particular attention.

The Transit of Mercury on the 5th of May is the first visible, either wholly or in part, in the United States, for many years. Although, on account of the great distance of this planet from the Earth, its transits are of little importance for determining the parallax of the Sun and the dimensions of the solar system; yet, from the very great precision with which the contacts can be observed, these transits afford the very best opportunity for ascertaining the longitude of a place, an opportunity, perhaps, to be preferred even to a large solar eclipse, on account of the slight change in the parallaxes of the planet in a very considerable extent of territory. In this transit the apparent conjunction will take place at New Orleans only thirtyeight seconds later, in absolute time, than at St. John's, in the island of Newfoundland. Moreover, as this transit will be visible throughout Europe, the observations there will determine the errors of the tables, and will thus render it still more valuable for ascertaining the position of the places in this country where it may be observed. Whether the planet will be visible without the assistance of a telescope, is doubtful; but, seen through this instrument, it will appear as a very small, round, dark body, passing across the Sun.

The Eclipse of the Sun on the 27th of July is the second of the very remarkable series of five large eclipses, visible to us in the short term of seven years; and although in magnitude, in the United States, not to be compared with that of last February, it will be very valuable for the determination of terrestrial longitude, being also visible in the South of Europe. In the Southern States its magnitude will be much more considerable than in the Northern; and in the southeastern part of Cuba, in Great Inagua and Grand Turk's islands, the eclipse will be nearly central, and total for about four minutes; it will also probably be total in the northwest part of Jamaica, near Montego Bay. As it happens, that, at the time of this eclipse, Venus is in Superior Conjunction, those who see the total eclipse may likewise see (what it is supposed never was, nor for ages will again be seen,) this planet on the day of her Superior Conjunction, and only two-thirds of a degree from the Sun.

The Almanac contains a computation of the occultations, for Charleston and Boston, of those stars only whose magnitude is not less than the fifth; which in 1832 will not be numerous. The conjunctions of the Moon with stars of the sixth and seventh magnitudes, which may be occultations in some part of the United States, are marked, in the Calendar pages, with an asterisk instead of the usual symbol for conjunction; in the Almanac for 1833, the occultations of these will likewise be computed.

Those who are in possession of a good telescope, will doubtless notice with attention the appearance of Saturn, between the 29th of September and the 1st of December, during which interval the Rings of this planet cannot be

seen.

a*

In the table of the Latitude and Longitude of the Principal Places in the United States will be found the longitude of a few calculated by the editor from observations on the Annular Eclipse of last February. The observations at Nashville, Washington, Berlin (Maryland), Lowell, &c., were not received in season, and therefore could not be used. Of the longitude of Washington, on the 35th page, it is remarked that 5h. 8' 8" is considered more correct than 5h. 7′ 42′′, the quantity reported by a commission acting under authority of a resolve of Congress, and generally adopted in the construction of the maps of this country; but which, it is believed, has not received the sanction of our astronomers. The former is the longitude deduced by the President of the American Academy of Arts and Sciences, from the observations* of Messrs. Ellicot and Pease on the annular eclipses of 1791 and 1811, viz. 5h. 8′ 4.5" by the former, and 5h. 8′ 11.4" by the latter; and it was most remarkably confirmed by the observations at Washington and at the University of Virginia (1° 29′ 40" West of the Capitol) on the eclipse of February last, by the former of which the position of that building is found to be 5h. 8' 6.7", and by the latter 5h. 8' 6.1". The mean of these four observations (5h. 8′ 7.2'') will hereafter be considered in this work as the longitude of the Capitol in the City of Washington, without regard to the quantity hitherto used.

In the arrangement of the Calendar pages there is no alteration from that in the Almanac for 1831.

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, and the northern extremities of Illinois and Indiana.

The column headed New York, &c. is intended for places situated between latitude 41° 32′ and 39° 48', that is, the southern extremities of New York and Rhode Island, all but the northern third of Pennsylvania, all but the southern extremity of New Jersey, the central parts of Ohio, Illinois, and Indiana, and the northern third of Missouri.

The column 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 extremity of Georgia, Alabama, and Mississippi, 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 latitude 31° 24', that is, all Florida and Texas, the southern half of Louisiana, and the southern extremities of Georgia, Alabama, and Mississippi.

* See "Transactions of the American Academy," Vol. III. p. 269, &c.

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 columns and in other parts of the Almanac, are used to denote Morning and Afternoon.

The time of the Phases of the Moon is computed for the meridian of Washington, 5h. 7′ 42′′, 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 meridian. 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 from 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 time of high water at New York, Charleston, and Boston, was derived from 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 ime of high water along the coast of Maine, New Hampshire, and Massachusetts, as far as Nantucket, is nearly the same as at Boston. 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 30th 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 Berlin, and should be applied according to the direction at the head of the column; but when mean is to be reduced to apparent time, the sign of the equation should be reversed.

Mean time has been generally used in this Almanac; the exceptions being the beginning and end of twilight, the rising and setting of the sun (which could not be expressed in mean time, without occupying too much room), the equation of time and the Sun's Declination.

The Ephemeris of the Sun is taken from the celebrated Almanac of Professor Encke. For the Sun's Right Ascension, in the American Almanac for 1831, the Sidereal time has been substituted; which will be found more convenient for the determination of the time of a star's transit, or of the Right Ascension of the Meridian; its epoch is noon, mean time at Berlin, whilst that of the Sun's Declination and of the Equation of time is noon, apparent time, of the same meridian.

The apparent places of twenty-four stars, as determined by Professor Bessel at Königsberg, will be of great use in ascertaining the time or the latitude. The Declination of some of them will, on comparison with their places in the English Nautical Almanac, be found to differ therefrom more

than was to be expected in the present improved state of astronomical instruments. This difference sometimes amounts to four seconds, and can hardly be altogether ascribed to the use of different tables of refraction.

The Table of Refractions is that computed on principles explained by the late Dr. Thomas Young, and is recommended by its great simplicity; moreover, it is said to agree as closely as any other, with the latest observations nevertheless had not Professor Bessel's new table required a table of logarithms in its use, it would have been preferred, as indeed would any thing recommended by this eminent astronomer.

In the year 1833 there will not be any very important astronomical phenomena in the United States. The Sun will not be eclipsed, and there will not be any occultation of a planet or of a star of the first or second magnitude.

A communication of any observations of the solar eclipse of last February, of the eclipses in 1832, or of any occultations, together with the correct latitude, will be very acceptable; and the longitude of the place of observation will thence be deduced.

R. T. PAINE.

Boston, October 19, 1831.

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