WASHINGTON, the capital of the United States of North America, is pleasantly situated on the left bank of the Potomac river, at its junction with a tributary called the Eastern Branch, 38, 136, and 226 miles S.W. from Baltimore, Philadelphia, and New York respectively. The observatory from which American geographers generally reckon their meridians is in lat. 38. 53. 39. N., and long. 77. 2. 48. W. from Greenwich. The district of Columbia, in which Washington is situated, was formed by Act of Congress in 1790, the States of Virginia and Maryland having each ceded a portion of their territory for that purpose. The two portions formed a square of 10 miles, or an area of 100 square miles. In 1846, however, the portion ceded by Virginia was restored to that state, so that the present district comprises only the Washington-portion lying on the Maryland side of the Potomac, and has an area of about 60 square miles. This district is independent of any of the states, and is solely under the government of Congress. The city of Washington was founded in 1793; and in 1800 the government, which had hitherto had its seat in Philadelphia, was transferred thither. Its site, which has a general elevation of about 40 feet above the river, is diversified by irregular elevations, which give a pleasant variety to the city, and furnish commanding positions for its principal buildings. It has on the south the Eastern Branch, and on the north it is separated from Georgetown by a stream called the Rock Creek, while a small stream, the Tiber Creek, flows through the town. At a little distance, it is surrounded by an amphitheatre of wooded hills of moderate elevation, commanding extensive and picturesque views, and affording eligible sites for suburban villas. The city is regularly laid out, and traversed by streets from 70 to 100 feet wide, running east and west, and north and south. Besides these, there are fifteen avenues, from 130 to 160 feet wide, named after the fifteen states which at the time of its formation constituted the Union, and extending from several centres in the direction of these states. It is about 4\frac{1}{2} miles in length from N.W. to S.E., and about 2\frac{1}{2} in breadth from N.E. to S.W.; but only a small portion of this area has yet been built upon, and hence Washington has not incorrectly been termed a "city of magnificent distances." The two great centres of the city, standing about a mile apart, are the Capitol and the President's House, from which most of the avenues diverge. The Capitol, in which the National Congress hold their sittings occupies a commanding position 72 feet above the water-level of the Potomac. It was commenced in 1793, but operations were subsequently suspended in consequence of the war, and much that had been done was destroyed by the British in 1814; so that the whole edifice was recommenced in 1815, and was not entirely finished till 1828. In 1851 the foundation stone of two additional wings was laid; and including these and the space between the wings, the whole building will occupy an area of about 4\frac{1}{2} acres. The original building, consisting of a centre and two wings, has a length of 352 feet, a depth at the wings of 121, and is crowned by a magnificent central dome, 145 feet in height from the ground, each of the wings being also surmounted by a flat dome. The exterior presents a rusticated basement of the height of the first story; the two others are comprised in a Corinthian elevation of columns and pilasters; and the whole building is surrounded by a balustrade of stone. The eastern and principal front, including the steps, projects 65 feet, and is embellished with a magnificent portico of eighteen columns 30 feet high, forming a colonnade 160 feet in length, the centre of which is crowned by a pediment of 80 feet span. The western front has a receding portico 100 feet in length, with ten columns. The two additional wings, not yet completed, are to be each 238 feet in length by 140 in width, surrounded on three sides by colonnades, and to communicate with the main building on the fourth by corridors 44 feet long and 50 wide. Within the Capitol are the Senate Chamber, Hall of Representatives, Rotunda, Congressional Library, the Chamber of the Supreme Courts, and numerous offices. The grounds, extending to about thirty acres, are enclosed by an iron railing, and are very tastefully laid out and planted, forming one of the pleasantest promenades in the city. Near the western entrance of the Capitol stands a monument erected by the officers of the navy, in memory of their brother officers, who fell in the war of Tripoli. It consists of a column of marble springing from a large square base, to the height of 40 feet, and surmounted by an eagle. On the abutments of the eastern front are two interesting groups representing "Columbus" and "Civilisation." In front of the Capitol is also a much admired colossal statue of Washington in a sitting posture, by Greenough, bearing the simple and appropriate inscription of "First in war, First in peace, First in the hearts of his countrymen." The President's House, the White House, or Executive Mansion, stands in the centre of a beautiful plot of ground of twenty acres, 44 feet above the Potomac, tastefully laid out and adorned with trees and shrubbery. The edifice, which is of white freestone, is two stories in height, crowned by a balustrade; and extends 170 feet in front and 86 feet in depth. The north front has a lofty portico ornamented with four Ionic columns. The interior arrangements are elegant and well adapted to the various purposes for which the building is designed. In the centre of a small square in front is a bronze statue of Jefferson, and across Pennsylvania Avenue in the centre of Lafayette Square, is a bronze equestrian statue of General Jackson. In the same square with the President's House are buildings for the state, treasury, war, and navy departments. The state department occupies a plain brick edifice to the N.E. of the President's House. It is 160 feet long by 55 wide, and is two stories in height. In this building all the diplomatic business of the country is transacted, and it also contains a large library of books, maps, &c. Immediately south of this is the treasury department, occupying an imposing stone building of three stories, 340 feet long by 170 wide, exclusive of the north and south wings. The eastern front has a magnificent colonnade of forty-two Ionic columns. The building of the War Department occupies the north-west corner of the square, and is precisely similar in design to the State Department buildings. The buildings occupied by the Navy Department lie directly west of the President's Mansion, and behind the War Office buildings. One of the finest structures in Washington is the General Post-Office. It is of white marble, in the Corinthian order, three stories in height, 204 feet long, and 102 deep, containing in all eighty-one rooms. Near the post-office is the Patent-Office, a magnificent building, partly of freestone and partly of marble, three stories in height, having an elegant central portico, with eight Doric columns in front. It has several magnificent halls, one of which, designated the National Gallery, contains cabinets of natural history, relics of Washington and Franklin, &c. The City Hall is an elegant stuccoed building, 200 feet in length. One of the noblest institutions and finest structures in Washington is the Smithsonian Institution, situated on a gently rising ground, west of the Capitol, and surrounded by extensive grounds, laid out in gardens, &c. It originated in a bequest of more than half a million of dollars left by an Englishman, named Smithson, "to found at Washington, under the name of the Smithsonian Institution, an establishment for the increase and diffusion of knowledge among men." The building, which is of a reddish freestone, is Romanesque in style, and is 450 feet in length by 140 in width, and has nine towers, varying in height from 75 to 150 feet. It consists of a central compartment, 205 feet by 55, two connecting ranges of 60 feet, and two wings. It has a lecture-room capable of containing nearly 2000 persons, a museum for objects of natural history, 200 feet in length, a library capable of containing 100,000 volumes, a gallery for painting and statuary, 120 feet long, and one of the best-furnished laboratories in the United States. The Washington monument on the Mall, between the president's house and the river, will, when completed, be a magnificent structure. It comprises a grand circular colonnaded building, 250 feet in diameter and 100 feet high, from the centre of which springs an obelisk shaft 70 feet square at the base, and 500 feet high, making a total elevation of 600 feet. The vast rotunda, forming the base of the monument, is surrounded by thirty massive columns, each 12 feet in diameter and 45 feet high, elevated