officers and employees of the United States, including the light-house keeper, can pass on the land along the pier or on the latter only by sufferance of those who have taken possession of the pier built by the United States at a cost of many thousand dollars, and of the land which it has formed.

During the year the steamer C. Wall and the schooner Augusta collided, the former against the light-house pier extension and the latter against the westerly shore return of the outer breakwater at Oswego, N. Y., but as it was not certain who, if any one, was to blame for the collisions, no steps were taken to collect the cost of repairs, which was small in both cases.

There is no other occupancy of piers in this district, and no other injury has occurred to them by collisions during the fiscal year ending June 30, 1897.

Very respectfully, your obedient servant,

Brig. Gen. JOHN M. WILSON,

W. S. STANTON, Major, Corps of Engineers.

Chief of Engineers, U. S. A.

APPENDIX Z Z.

REPAIR OF THE AQUEDUCT BRIDGE ACROSS THE POTOMAC RIVER AT WASHINGTON, D. C.

REPORT OF LIEUT. COL. CHAS. J. ALLEN, CORPS OF ENGINEERS, OFFICER IN charge, FOR THE FISCAL YEAR ENDING JUNE 30, 1897.

UNITED STATES ENGINEER OFFICE,

Washington, D. C., July 19, 1897. GENERAL: I have the honor to forward herewith my annual report for the year ending June 30, 1897, for repairs to the Aqueduct Bridge,

*

Very respectfully, your obedient servant,

Brig. Gen. JOHN M. WILSON,

CHAS. J. ALLEN,

Lieut. Col., Corps of Engineers.

Chief of Engineers, U. S. A.

REPAIR OF THE AQUEDUCT BRIDGE ACROSS THE POTOMAC RIVER AT WASHINGTON, D. C.

SKETCH OF THE WORK.

In compliance with a resolution of the United States Senate of January 21, 1893, an examination of the piers of the Aqueduct Bridge was made May 2 to 20, 1893, with the aid of a diver.

On June 21, 1893, a report in detail was made of the examination, and on July 17, 1893, an estimate of the cost of the repairs, amounting to $51,070, was submitted. It was proposed to repair Pier No. 4 by means of a cofferdam, within which the defective masonry was to be rebuilt, and to repair the remaining piers with Portland cement concrete in bags put in place by a diver. (Report of the Chief of Engi neers for 1895, pp. 4085-4091.)

WORK DONE.

On August 7, 1894, an appropriation of $51,070 was made in the District of Columbia appropriation act for the fiscal year ending June 30, 1895, for the repair of the bridge, as follows:

For the repair of the Aqueduct Bridge, fifty-one thousand and seventy dollars, said sum to be expended by, and the work to be done under, the direction of the Chief of Engineers of the Army, by contract or otherwise, and by the purchase of material in open market, in order to prevent delay in the prosecution of the work.

On September 29, 1894, a contract was entered into with the Shailer & Schniglau Company, of Chicago, Ill., for the repair of Piers Nos. 2, 3, 5, 6, 7, and 8 by Portland cement concrete in bags put in place by a diver, and for the repair of Pier No. 4 by means of a cofferdam within which new masonry was to be laid in the eroded cavity, the bridge spans resting on Pier No. 4 to be supported on false work during the repairs to provide against any possible further failure of the pier when the water was pumped out of the cofferdam and the effective weight of the overhanging masonry of the upstream end thereby increased.

After the cofferdam had been pumped out and débris disposed of, the overhanging masonry of the ice breaker was removed in order that the reconstruction of this part of the pier might be safely prosecuted. This masonry, which was just above the eroded cavity, was found to be well laid in lime mortar and was removed with some difficulty. The removal of the débris below the eroded cavity was next undertaken, the excava tion being carried down to solid rock and as far downstream as the first line of cross braces of the original cofferdam of 1838, which timbers, 21 in number, had been left in place and built into the masonry of the pier. As this work went on, it was found that the old masonry had not been started from solid rock, and part of it was of poor quality.

The Acting Secretary of War and the Chief of Engineers made an inspection of the work on June 24, 1895, and in view of the poor quality of the masonry at the base of the pier it was decided that after the completion of the present contract (for the upstream end of the pier) it would be necessary in the near future to remove the defective masonry in the remainder of the pier and replace it by masonry of proper quality founded on the solid rock. The existing appropriation was insufficient for this purpose, and it was therefore necessary to ask a further appropriation from Congress. The cofferdam would be needed for the proposed work, and the contract was therefore modified June 27, 1895, so as to provide for the purchase of the cofferdam from the contractors for the sum of $3,000 in lieu of its removal by them, for which last they were to be paid $1,500 and were to have the timber.

The work of repairs under the appropriation of August 7, 1894, was completed in August, 1895. The total expenditure, including contract work, hired labor, purchase of materials and cofferdam, superintendence, inspection, etc., was $46,379.70, leaving a balance of $4,690.30, which reverted to the United States Treasury.

Full reports of the work of repairs to the bridge piers will be found in Appendix A A A to the annual reports of the Chief of Engineers for 1895 and 1896.

A complete report and estimate of the cost of reconstruction of pier No. 4 will be found in the report dated November 30, 1895, of the officer then in charge, and published as Document No. 158, House of Representatives, Fifty-fourth Congress, first session. The estimated cost of reconstruction of the pier was $65,000, which sum was appropriated as follows, by the act of Congress of June 8, 1896:

Repairs to Aqueduct Bridge: For reconstruction of pier numbered four of the Aqueduct Bridge across the Potomac River at Georgetown, District of Columbia, to be available until expended, sixty-five thousand dollars.

A contract for the work of reconstruction of the pier was made May 17, 1897, with the Houston Construction Company, of Philadelphia, Pa. The contract was approved May 28, 1897. The work to be completed November 1, 1897. Amount of contract, $30,000.

The contractors commenced work on the 28th of May, and by the close of the fiscal year had most of their plant in position on the coffer

dam; had made some progress in quarrying stone at their quarry, which is on the east bank of the Potomac, and about 3 miles above Georgetown; and had done some work toward putting in repair the false work for supporting the spans adjoining pier 4, and also the cofferdam.

Other work during the fiscal year ended June 30, 1897, consisted in some slight necessary repairs by hired labor to the cofferdam.

Amount expended during fiscal year ended June 30, 1897, $1,446.43.

July 1, 1897, outstanding liabilities.

$136.00

July 1, 1897, amount covered by uncompleted contracts..

July 1, 1897, balance available

33, 117.57

Abstract of proposals for reconstruction of pier No. 4 of the Aqueduct Bridge, District of Columbia, opened by Lieut. Col. Chas. J. Allen, Corps of Engineers, March 22, 1897.

All the above proposals were rejected and the work was readvertised under date of

April 10, 1897.

Abstract of proposals for reconstruction of Pier No. 4 of the Aqueduct Bridge, District of Columbia, opened by Lieut. Col. Chas. J. Allen, Corps of Engineers, April 30, 1897.

NOTE.-The bid of R. H. Hood was not made in accordance with printed form.

The contract was awarded to the Houston Construction Company, the lowest bidder. Date of contract, May 17; approved May 28, 1897. Date of commencement, on or before May 30; date of completion November 1, 1897.