The Executive Mansion, or official residence of the president of the United States, occupies the centre of a plat of 20 acres, at the opposite extremity of Pennsylvania avenue from the capitol. It is a handsome building two stories high, with a lofty basement,-170 feet long by 35 feet wide. In convenient proximity to the mansion are four spacious and commodious edifices, known as the State, the Treasury, tho Navy, and the War Departments ; a fifth building, the Department of the Interior, is as yet unfinished: these, as their names imply, contain the offices of the principal executive departments. The General Post Office is built of white marble, in the Corinthian order ; it is 204 feet long, 102 feet deep, and three stories high. The building is sur rounded by an ample lawn. At the home office are shown the auto graphs of all potentates who are or have been in alliance with the Union, and the presents made by foreign courts to American ambas sadors, with several relics of General Washington ; Franklin's printing press; various objects of interest obtained by Wilkes in the United States Exploring Expedition, &c. At the office for Indian affairs are the portraits of all chiefs who have from time to time came to negotiate with the president. This quarter of the city contains many elegant private dwellings, most of which are occupied by the foreign ministers.
The Navy Yard, and the Arsenal immediately to the north of it, are situated on the Anacostia, just below the long bridge which spans the Potomac and connects the Columbian and the Virginian shore of the river. To the navy yard are attached the marine barracks, and to the arsenal very extensive publio manufactories of arms and military stores. The works at the navy yard are on a very important scale, and in the anchor and chain cable manufactories, machine shops, &c., every approved contrivance for assisting human labour has been intro duced. The slips and ship houses are very spacious and well arranged. The river, on arriving at Washington, makes a beautiful sweep, forming a bay, on which the city stands. The navy yard and arsenal follow the curve.
The National Observatory occupies an elevated site ou the Potomac, between the president's house and Georgetown. Its exact site is 33' 53' N. lat., 77' 2' 48' W. long., and from it is measured the first meridian of American geographers. It contains a very extensive and valuable collection of instruments, and ranks among the first institutions of the kind in existence : it is now under the direction of Lieut. M. F. Maury, U.S.N., so well known by his investigations of oceanic wind? and currents. As at Greenwich the observatory announces mean time daily by the fall of a large ball.
One of the most striking of the public buildings of the city is the Washington Monument, which Mande on the Mall, between the presi dent's house and the Potomac. It is a vast circular structure 250 feet In diameter, and 100 feet high, surmounted With an obelisk 70 feet at the base, and 500 feet high. The building is surrounded by a colon nade of 30 pillars, each 12 feet in diameter and 45 feet high, and is elevated upon a base 20 feet high, and 300 feet /square. The pediment of the front portico has a triumphal car, with a statue of Washington; another statue of Washington stands opposite the principal entrance; and around the building are statues of the ' Fathers of the Revo lution,' and of the signers of the Declaration of Independence; with sculptured representations of some of the principal events in Wash ington's career, emblematical designs, &c. The centre is to be occu
pied by the tomb of Washington, a sculptural structure of unusual magnitude and very ambitious design, which has been for several years in process of execution, and which will comprise a large number of statues of heroic size. Statues of Jefferson, Jackson, &c., and one or two monumental erections are tho only other specimens of the sculptor'a art which adorn the public places of the city.
The remaining public buildings in Washington are a city-hall, several market-houses, a penitentiary, nearly 40 churches, some of them very costly edifices ; an orphan asylum, almshousea, &c. Columbian College, which was incorporated by Congress in 1821, is a spacious brick building situated a little to the north of the city ; it has 10 instructors, 55 students, and a library of 6000 volumes. The National Medical College, previous to 1840, formed the medical department of this college. The public and private schools and academies are very numerous, and bear a high character. Among literary institutions the first place is due to the Smithsonian Institution, which was founded under the will of an Englishman named Smithson, who bequeathed above half a million dollars for the purpose. The build ing stands on the Mall, in the midst of extensive grounds. It is Romanesque in design, is 450 feet long, 140 feet wide, and has 9 towers, ranging from 75 to 150 feet in height. It contains a spacious library, museum, gallery for works of art, a lecture room, capable of accommodating 1200 persons, a chemical laboratory, &c. The National institute holds its meetings at the patent-office. There are several other literary and numerous benevolent institutions.
Washington is neither a commercial nor a manufacturing city, and the legislative sessions and the residence of the executive have failed to attract the wealthy to it as a place of permanent abode. The population of Washington consists of members of the legislature and of the executive departments of state and of foreign diplomatists., with the addition of such professional, trading, mechenical, and menial perwans as are required to tniointer to their comfort The tone of society, as might b anticipated from this eironmetance, differs con siderably from that which prevails in other parts of the Union.
Owiug to the iuflueuce of the example of the foreign diplomatists, it approaches more nearly in some respects to that of Europe. In external appearance and the arrangements of dementia and social intercourse*, Washington reminds the European of a second-rate Continental capital; in its business habits, political claims Rnd govern ment and parliamentary offices, of Westminster. There is nothing nsholsatio or commercial In Its character : that consists rather of mixture of politics and pleasure. The highest intellects, the best oduestea, and most influential gentlemen of America are to be met with In the circles of Washiugton. The fashionable amusements are as in Europe—balle, soirdes, dinner parties, &e., which in costliness are on a level with those of the moat courtly cities of the Old World. The city affords every accommodation to the temporary residents. The boarding-houses of Washington form quite a feature of the city; and the hotels are numerous and on a scale of great magnitude and splendour. Some have marble fronts of considerable architectural pretensions.