entered into for the construction and completion of the bridge and approaches.

The second section of this act empowered the Secretary of War in his discretion to purchase the Aqueduct Bridge at Georgetown, if, with all its appurtenances, franchises, &c., it could be purchased for a sum not exceeding eighty-five thousand dollars.

Proceedings were had looking to give effect to the provisions of the last-named section, as it was, in my judgment, for the public interest to establish the bridge at the site designated. The parties in interest, however, declined to accept the terms of the act. The fee of the property is in the Alexandria Canal Company, but it is held under a ninetynine years' lease by the Alexandria Canal Railroad and Bridge Company. While the lessees expressed a willingness to treat with the government for a relinquishment of their franchise, the lessors, by a formal resolution, adopted at a stockholders' meeting held in Alexandria May 16, 1881, refused "to accept the act of Congress." In view of this adverse action, it became necessary to determine upon a location for an entirely new structure, and, after due consideration, one was selected at a point of crossing of the Potomac known as the "Three Sisters," above the Aqueduct Bridge.

By my direction specifications were prepared and proposals advertised for to carry out the provisions of the act. The accompanying report of the Chief of Engineers, dated the 7th instant, and papers therewith, to which attention is invited, exhibit the difficulties encountered, and fully explain the impracticability of further action until additional legislation shall have been had. The lowest bid received was for the exact amount of the appropriation, and proposed the construction of a bridge not deemed sufficient in strength. In this connection special attention is invited to the remarks of the Chief of Engineers and his assistant.

A detailed estimate for a substantial bridge at the "Three Sisters," including the cost of proper approaches and necessary inspections and tests of the work, calls for an additional appropriation of $61,000. This estimate is for a "deck bridge," but a "through bridge," which is considered preferable, would, if its construction be decided upon, require a still further appropriation of $19,000.

I have the honor, in view of the foregoing, to recommend that an additional appropriation of $80,000 be made, to give practical effect to the act of February 23, 1881, and that said act be so amended as to permit the payment of necessary expenses previous to the award of the contract and thereafter in supervising its performance.

It is proper to remark as germane to the subject of this communication, that a bill is now pending in Congress (S. 419), providing for a condemnation of the Aqueduct Bridge, and the payment into court of its appraised value, the amount to be held subject to the final determination of the rights of parties in interest, and that in a communication addressed to the Senate Committee on the District of Columbia, by whom the bill had been referred to me, I recommended its enactment with certain modifications and amendments, so as to leave the question of acceptance by the Secretary of War of the bridge at the valuation finally established open to the exercise of his discretion. I believe it advisable that both the legislation contemplated by this bill and the amendments to the act of February 23, 1881, with the additional appropriation herein before recommended, be incorporated into the statutes. In that event the Secretary of War would be in a position to make selection between the two propositions and determine which one it

would be for the best interests of the government and the public service to adopt.

I am, sir, very respectfully, your obedient servant,
ROBERT T. LINCOLN,

Secretary of War.

OFFICE OF THE CHIEF OF ENGINEERS,

UNITED STATES ARMY, Washington, D. C., March 7, 1882.

SIR Referring to your indorsement of August 17, 1881 (on letter of July 28, 1881, from the Engineer Commissioner, District of Columbia), directing the Chief of Engineers "to prepare specifications and advertise" for the construction of a bridge across the Potomac River, near Georgetown, D. C., I have now the honor to submit the inclosed abstracts of bids received in response to advertisement.

It will be seen that the lowest bid, $140,000, is submitted by the "Corrugated Metal Company"; that this bid is for the exact amount of the appropriation made for the bridge by act of February 23, 1881. This proposition is for a bridge which is not deemed sufficient in strength. Several letters have been received from the agents of the Corrugated Metal Company, in which modifications of their plans are proposed, but the offer as first submitted, or as modified by them, is not such as I can recommend for acceptance.

In order to secure satisfactory work in building a bridge by contract, provision must be made for inspection, as the work progresses, in the construction of foundations, piers, and abutments; in manufacture and tests of iron to be used in the bridge, and in the erection of the superstructure. Without this there is no certainty of getting a safe and substantial bridge. Funds must, therefore, be provided to cover such necessary expenses before any contract can properly be made.

A general detailed estimate for a substantial and durable bridge at the Three Sisters, based on the best data so far attainable, including the cost of proper approaches to the bridge and cost of necessary inspection and tests of the work, shows that the bridge can be built for $201,000. Only $140,000 is available. I have, therefore, to recommend

I. That all bids received be declined.

II. That report be made to Congress that an additional appropriation of $61,000 will be required, and that provision should be made for contingencies and advertising, by amending the act of February 13, 1881, so as to permit the payment of necessary expenses previous to the award of the contract.

The above estimate is for a "deck bridge," but a "through bridge" is considered preferable, and, if adopted, the estimated cost will be $19,000 more, making the total cost $220,000.

The investigations in regard to the sufficiency of the bridge were committed to Mr. S. T. Abert, United States civil engineer. Copy of his report, with other papers connected with the subject, is herewith. Very respectfully, your obedient servant,

H. G. WRIGHT,

Chief of Engineers, Brig. and Bvt. Maj. Gen.

Hon. ROBERT T. LINCOLN,
Secretary of War.

REPORT OF MR. S. T. ABERT, UNITED STATES CIVIL ENGINEER, OF MAY 25, 1881.

UNITED STATES ENGINEER OFFICE,

Washington, D. C., May 25, 1881.

GENERAL: I have the honor to submit the following report upon the act referred to in the letter of the Chief of Engineers (of March 17, 1881) entitled "An act to authorize the construction of a bridge across the Potomac River, at or near Georgetown, in the District of Columbia, and for other purposes."

This act consists of three sections. The first section appropriates the sum of $140,000 for building a free bridge and prescribes the conditions upon which it shall be built. The second and third sections are intended as substitutes for the first section in case its provisions cannot be executed; direct the purchase of the piers of the Georgetown Aqueduct over the Potomac River, and prescribe the conditions of the purchase and the character of the bridge which may be erected thereon. The act, however simple in the above statement, presents in its provisions some complexities which can best be unraveled by taking them separately under consideration.

I will therefore state each section separately, and make such comment as seems to be worthy of attention.

FIRST SECTION.

The act begins with a statement of the sum ($140,000) appropriated, and the object, in words as follows:

That the Secretary of War be, and he is hereby, authorized and directed to cause to be constructed across the Potomac River at or near Georgetown, in the District of Columbia, at such point as he may select, a substantial iron and masonry bridge, with approaches; and the sum of one hundred and forty thousand dollars be, and the same is hereby, appropriated out of any money in the Treasury not otherwise appropriated for the construction of said bridge and approaches, the same to be maintained as a free bridge for travel.

This clause requires no comment.

First proviso.

Provided, That the Secretary of War shall construct a bridge upon such plan as shall cost no more than the amount herein appropriated, and which cost shall include the construction of a substantial bridge over the canal, and any and all approaches to the said iron bridge; and no part of this appropriation shall be paid out of the Treasury until contracts shall have been entered into with responsible parties, and with good and sufficient sureties to be approved by the Secretary of War, for the construction and completion of said bridge, including the masonry, iron-work, and approaches, at a cost not to exceed one hundred and forty thousand dollars.

This proviso states that the bridge over the river and canal, and its approaches, shall cost no more than $140,000; that said bridge shall consist of piers of masonry and a superstructure of iron, and that no part of the money appropriated shall be paid out of the Treasury until contracts for the construction and completion of said bridge shall have been made with responsible parties.

Second proviso.

And provided also, That a draw of sufficient width to permit the free passage of vessels navigating that part of the Potomac River shall be constructed in said bridge, unless said bridge shall be constructed upon or by the side of or up the river from the present aqueduct and at the same or greater elevation above the water.

This proviso directs the construction of a draw in the proposed bridge, if it is constructed, at a less elevation above the water than the present aqueduct, that is to say, than the lower chord of the present aqueduct, and does not permit a draw in any other case. This condition may continue a wrong which began with the present aqueduct. Before its construction masted vessels passed up the river above the "Three Sisters," and it may be again desirable to restore the navigation of this part of the river when the present aqueduct shall have been removed. This can be done by placing the bottom chord of the proposed bridge, as the law by inference directs, lower than that of the present aqueduct, and by building a draw if the funds should be found to be sufficient.

Third proviso.

And provided also, That the sum which may be expended under this act shall be treated and regarded as a part of the general expenses of the District of Columbia, and the United States shall be credited with the amount which it may pay under this act for the erection of said bridge upon its fifty per centum of the expenses of the District of Columbia, as provided in the act of June 11, 1878, entitled "An act providing a permanent form of government for the District of Columbia."

This proviso declares what portion of the cost of the bridge shall be borne by the District of Columbia.

Fourth proviso.

Provided further, That the Secretary of War shall, as soon as may be, fix and determine the location of said bridge, and cause a survey of the river to be made at such place of location, determine the length, width, and height of said bridge, and the length of draw, if one is required, and thereupon advertise for plans and price for the construction of such bridge. Such advertisement to be inserted in one or more daily newspapers published in Washington, District of Columbia, New York, Cleveland, Ohio, Detroit, Michigan, Philadelphia, Pennsylvania, and Chicago, Illinois, for the space of one week.

This proviso requires more attentive consideration than those which precede it. It directs

1st. That the Secretary of War shall fix and determine the location of said bridge.

2d. That he shall cause a survey to be made, determine the length, width, and height of said bridge, and the length of draw, if one is required.

3d. And thereupon advertise for plans and price of said bridge. 4th. Specifies the cities in which advertisement shall be made. The location of the bridge can be approximately fixed by consulting the wishes of those interested in the act, who expressed their wishes by petition to Congress, thus fixing the intent of the act.

The location of the bridge is fixed generally by the enacting clause of the act in the following words: "At or near Georgetown."

This is construed to mean at any point between Rock Creek, which separates Washington from Georgetown, and the "Three Sisters," which are several small rocky islands near Georgetown, and about one-half a mile above the aqueduct.

Washington City is excluded by not being expressly mentioned. It would have been mentioned, as being the more important of the two cities, had it been proposed or intended to erect a bridge within its limits.

The Three Sisters" are assumed to be the western limits of the area in which the bridge is directed to be built, these islands being about one-half a mile above Georgetown, affording a suitable foundation for

piers, and having been designated by the movers and petitioners for a free bridge as one of the points to be considered.

In order to determine the best position for the location of the bridge, it will be necessary to consider economy of construction and convenience of situation. The bridge must be built for the sum appropriated, and should afford the shortest and most convenient route to the markets of Georgetown and Washington.

Three positions fall within the general requirements of the act. Taken in the order of succession they may be named as follows: First, the "Three Sisters."

Second, near the aqueduct, either above or below it.

Third, at a point 1,000 feet or more below the aqueduct, and in the limits of Georgetown.

SITE OF THE "THREE SISTERS."

The river is narrowest at the "Three Sisters." The length of a bridge over the river and canal will be about 1,156 feet. The depth to rock at the position of the piers will probably vary from 15 to 28 feet, according to the profile in this office, the accuracy of which is uncertain. But little expense will be required for the approaches at the ends of the bridge. It will be necessary, however, to grade a road from the south end of bridge to the county road which leads into Fairfax County. If the road is carried along the bluff to the south end of the aqueduct, its length will be about 3,500 feet from thence, with a grade of 3 feet to the hundred; to the plateau above the distance will be 6,600 feet. If carried up the ravine just above the north end, the distance will be 6,600 feet to the same plateau.

SITE OF THE AQUEDUCT.

If placed either above or below the aqueduct the length of the bridge will be about 1,705 feet. The approach on the Georgetown side will cost little, but upon the Virginia side the approach will be 250 to 300 feet in length.

The average depth of rock upon which the piers will have to be built will probably vary from 26 to 28 feet.

THE THIRD POSITION.

At 1,000 feet or more below the aqueduct. It would be necessary, in order to bridge the Potomac at this point, to carry the bridge over to Analostan Island, and from there over the old bed of the Potomac to the Virginia shore.

The length would far exceed that at either of the other points. As it would be necessary to build a draw, the cost would largely exceed the cost of a bridge either near the aqueduct or at the "Three Sisters."

From what has been said above, based upon information derived from existing maps, reports, letters, and petitions, it may be inferred that a bridge built at the "Three Sisters" will cost less than at either of the other points mentioned, åând that it will afford the nearest route to market to the largest number of the citizens interested in its construction. Besides the permanent citizens of Fairfax County, the officers and soldiers who are stationed at Fort Myer and the government officials who are stationed at the cemetery at Arlington should also be considered. To them a bridge near the aqueduct would offer the nearest route to Washington City.