Immediately in front of Washington city the Potomac expands into a broad, lake-like body of water, a mile and a quarter wide and at least eighteen feet deep. The Anacostia River, at its mouth, is almost the same width and fully as deep. Improving the navigation of the Potomac and the construction of a canal to the head waters of the Ohio River, were enterprises that began with the founding of the National Capital.

In 1872, Congress appointed a board of officers with a view to the improvement of the channel of the river and water fronts of Washington and Georgetown, for commercial purposes, as well as the reclamation of the malaria-infected marshes opposite the city. These improvements will necessitate the rebuilding of Long Bridge for railroad and ordinary traveling purposes, and reclaim more than a thousand acres of valuable land. It is proposed to remove the National Observatory and use the earth for filling up the marshes.

The Navy Yard Bridge crosses the Anacostia River, at the foot of Eleventh street, having supplanted the wooden structure built in 1819, over which Booth made his escape after the assassination of Lincoln.

The various buildings occupied by the Executive and Legislative branches of the Government are worthy of especial notice. The Capitol is considered one of the largest and finest edifices of the kind in the world, and in point of durability of structure and costliness of material, it certainly has no superior. It stands on the west side of Capitol Hill, very near the centre of the city, and one mile distant from the Potomac River. The main or central building is three hundred and fifty two feet in length, with two wings or extensions, each having a front of one hundred and forty-three feet on the east and west, and a depth of two hundred and thirty-nine feet along the north and south façades, exclusive of the porticoes. The entire length of this great edifice is seven hundred and fifty feet; its greatest depth three hundred and twenty-four feet; the ground plan covering three and a half acres.

The central and original Capitol building is of freestone, taken from the Government quarries at Aquia Creek, forty miles below the city, which were purchased for that purpose, by the Commissioners, in 1791. This building is now painted white, to correspond with the extensions, columns and porticoes of white marble. From the centre rises the great dome, designed by Walter, to replace the original one removed in 1856, after the additions to the building had rendered it out of proportion. The apex is surmounted by a lantern fifty feet high, surrounded by a peristyle, and crowned by the bronze statue of Freedom executed by Crawford in 1865. The height from the base line to the crest of this statue is three hundred and eight feet, making the dome of the Capitol rank fifth in height with the greatest structures of the kind in Europe.

The great dome is visible from every elevated point in the District for miles around, and from its windows, as far as the eye can reach, is extended a panorama of wooded hills, beautiful valleys, with the majestic cloud-capped spurs of the Blue Ridge raising their lofty heads in the distance. The eastern façade of the building looks out upon the extended plain of Capitol Hill, with its background of green hills reaching far beyond the Anacostia. On the north a broad valley extends, until it unites with the encircling hills of the city; on the south the majestic Potomac and Anacostia rivers are seen to meet and mingle their placid waters; while from the west are beheld the lawns and groves of the Botanic Garden, the Mall, and handsome grounds of the President's house, with Georgetown Heights and the glittering domes of the Observatory in the distance.

EAST FRONT OF CAPITOL AT WASHINGTON.

The main entrance, from the grand portico into the rotunda is filled by the celebrated bronze door modeled by Rogers, in Rome, 1858, and cast in bronze at Munich, by Miller, in 1860. On the panels of this door are portrayed, in alto relievo, the principal events in the life of Christopher Columbus, and the discovery of America. The key of the arch is adorned with a fine head of the great navigator; in the four corners of the casing are statuettes, representing Asia, Africa, Europe and America, with a border in relief of ancient armor, banners and heraldic designs emblematic of navigation and conquest. Bordering each leaf on the door are statuettes, sixteen in number, of his patrons and contemporaries; the nine panels bear alto relievo illustrations of the principal events in his life; while between the panels are a series of heads, representing the historians of the great discoverer and his followers. Altogether, this justly celebrated bronze door, besides being wonderful as a work of art, constitutes in itself a small volume of the most interesting and important events belonging to the history of our country.

The rotunda into which the door leads is embellished with eight large historical paintings, by different artists. Four of these were executed by Trumbell, who served as aid-de-camp to Washington in 1775, and reproduced in his figures the likenesses of the actors in the scenes portrayed. In arranging the characters for the "Declaration of Independence," in which the Congress of 1776 is represented in the act of signing that great instrument of American liberty, the artist conferred with Jefferson, the Author of the Declaration, and John Adams, both of whom were present and signers. The individual costumes, the furniture, and the hall itself, are represented with scrupulous fidelity, all of which tends to increase the interest inspired by this painting.