1804. It is enclosed on the landward sides by a brick wall, the fourth side fronting the Anacostia river. Entering the yard through a handsome gateway, designed by Benjamin Latrobe, the visitor is greeted with the sight of trophies of naval warfare. These consist of cannon captured by our gallant seamen, not the least interesting amongst them being the two whose history is recorded in the inscription borne by one of them: "On the 3d day of August, 1804, Captain Stephen Decatur, in command of an American gun-boat off Tripoli, boarded and captured in succession two Tripolitan gun-boats, armed with this and the adjacent gun." The Navy Yard covers about thirty-seven acres of land; and, besides the workshops, contains the officers' quarters. The main building is 432 feet in length on the east and west fronts, and 265 feet in length on the north and south fronts; it contains the boiler-shop, machine-shop, pattern-shop, smithery, and erecting-shop. Another large building is situated eastward of the main building; it contains the forge-shop,in which may be seen in operation a steam-hammer weighing, five tons, the anchor and faggoting shops. The business of the latter is to convert the scrap-iron collected from various Navy Yards into blooms, from which the heaviest anchors are forged. Northward of the firstmentioned building is the iron-foundry, 265 feet long and 65 feet wide, in which all the castings are made for the machinery of government ships, and the shot and shells for the Ordnance Department are cast. The new Ordnance building, which is about the same size, is seen to the westward. The Dahlgren guns, howitzers, carriages, Minie balls, and various forms of cartridges, are here manufactured, under careful supervision. Besides these,

there are various other buildings for offices, carpenters, blockmakers, pyrotechnists, riggers, copper-rolling mill, navy stores, brass-foundry, camboose-shop, and tankshop. In the southeast corner of the yard is the shiphouse and marine railway.

UNITED

STATES COAST SURVEY.

The office of this important enterprise is situated on New Jersey avenue. Although the service of surveying the Atlantic, Gulf, and Pacific coasts of the United States is legally under the control of the Treasury Department, its duties are discharged by officers of the army and navy, with the assistance of scientific civilians. The work of survey is divided into nine sections, each of which commences by measuring a base-line five or ten miles in length; this is performed by using a compensating baseapparatus, and requires the greatest care and exactness. After this a series of stations is established, and by computing the triangulation of these from the principal base, a centre is obtained for all subsequent measurements. The topography being completed, the hydrographer commences to take soundings. When the field-work is finished, the results thus obtained are forwarded to the office in Washington, where the drawings are reduced, engraved, electrotyped and printed.

NATIONAL OBSERVATORY.

The National Observatory is situated southwest of the Executive Mansion, upon an elevated site, commanding a beautiful view of the noble Potomac river, and in full sight of the two cities of Washington and Georgetown. It was originally designed and used for a hydrographical

office. The preparation of wind and current charts, the regulation of chronometers, and the other branches of hydrographical research still occupy the principal care of the Observatory, in which astronomical investigation is made a secondary consideration. In the west wing of the building is placed the transit instrument, under a slit twenty inches wide, extending across the roof, and down the wall of the apartment on each side to within four or five feet of the floor.

The transit instrument is a seven-foot achromatic with a clear aperture of 5.3 inches, and was made by Ertel & Son, of Munich; the mounting consists of two granite piers, seven feet high, each formed of a solid block of that stone, let down below the floor and imbedded in a stone foundation eight feet deep, and completely isolated from the building. Midway between the piers, and running north and south, is the artificial horizon, composed of a slab of granite ten feet long, nineteen inches deep, and thirteen inches broad; it rests on the foundation, and is isolated from the floor, with the level of which the top of it is even, with a space all around it of half an inch; in the middle of this slab, and in the nadir of the telescope, there is a mortise, nine inches square and ten inches deep, in which the artificial horizon is placed to protect it from the wind during the adjustment for collimation, or the determination of the error of collimation of level, and the adjustment for stellar focus, verticality of wires, and the other uses of the collimating eye-piece. Besides this delicate instrument, and connected with its uses, there is an astronomical clock to denote sidereal time, the electric chronograph, invented by Professor John Locke. In the south wing of the building is the prime vertical transit,

and the photograph-room. A very fine library of astronomical works, and a normal clock, made by Kessels, of Altona, are in the room of the Superintendent. The clock has a gridiron pendulum, and its annual variation is less than eleven seconds. In the east wing is the mural circle. Here also is the meridian circle; the telescope tube is 56 inches in length, the object-glass has 4.5 inches of clear aperture, and 58.2 of focal length. The electric clock, by which chronometers are regulated, is worthy of observation, as well as the valuable collection of charts. In the library, amongst many other rare works, are to be found a number of star charts, and a daily record of the barometer, thermometer, state of the winds and of the heavens, compiled by Le Verrier, from observations extending from Algiers to St. Petersburg in latitude, and from Constantinople to Paris in longitude. The large equatorial in the dome was constructed by Merz & Mahler, of Munich, and is a counterpart of the instruments at Dorpat and Berlin. The object-glass of this instrument has a clear aperture of 9.65 inches, and a focal length of 14 feet 4.3 inches; its magnifying power ranges from 80 to 600, although the higher power is seldom attained, owing to the fact that the slightest tremor of the building throws the object out of the focal plane. When required, a clockwork motion is attached to compensate for the revolution of the earth upon its axis. An electric chronograph is also connected with it when it is used as a transit instrument. The observatory is open to visitors every day between the hours of 9 A. M. and 3 P. M., and a courteous officer renders all necessary assistance, and furnishes all needful information.

THE WASHINGTON NATIONAL MONUMENT.

The subject of erecting a national monument to Washington was mooted by the Continental Congress, as early as 1783, when a resolution was passed ordering a statue to be erected "in honor of George Washington, the illustrious Commander-in-chief of the United States of America during the war which vindicated and secured their liberty, sovereignty, and independence." The commissioners who laid out the city set apart the present site of the monument, but for want of funds, the statue was not ordered. The ground selected by the commissioners was marked on the plan of the city submitted to Congress by Washington in 1793, and Washington died in the belief that on that spot he would be commemorated.

In 1799, Congress passed a resolution authorizing President Adams to correspond with Mrs. Washington, asking her consent to the removal and interment of her husband's remains beneath a monument to be erected by the government in the Capitol. Mrs. Washington consented, in the following beautiful and concise letter:

Taught, by the great example I have so long had before me, never to oppose my private wishes to the public will, I must consent to the request of Congress which you had the goodness to transmit to me; and, in doing this, I need not-I cannot say what a sacrifice of individual feeling I make to a sense of public duty.

The monument was not erected, and Washington's remains were therefore not removed.

In 1800, a bill passed one house of Congress, for erecting a "mausoleum of American granite and marble, in a pyramidal form, one hundred feet square at the base, and