about finished ready for pumping. The embankment for the Davenport wagon-approach was nearly finished, and its slopes were protected by a dry wall. This wall had not been carried up to its full height, however, and the extreme high water of April, 1870, overflowed it, causing a slight wash in the embankment and settling of the wall.

During the year the following work has been done: Piers Nos. 1, 2, 3, 4, upper starling, lower starling, and pivot masonry of draw-pier, have been entirely built. The Davenport railroad abutment has been built up to the street grade, and the island railroad abutment has been entirely built, with the exception of the coping and step-stones of the wing-walls. The dry slope-wall of the Davenport wagon-approach has been relaid, and a slight excavation has been made for the island wagon-approach.

The timber protection connecting the three detached pieces of masonry of the draw-pier has been entirely built.

Amount of masonry laid in the river during the year.

Pier No. 1, 512 cubic yards; built by Harvey & Livesey.
Pier No. 2, 685 cubic yards; built by Government.
Pier No. 3, 539 cubic yards; built by Government.
Pier No. 4, 647 cubic yards; built by Government.

Upper starling and rest-wall of draw-pier, 1,263 cubic yards; built by Government, with the exception of 58 cubic yards, built by Harvey & Livesey.

Lower starling and rest-wall of draw-pier, 488 cubic yards; built by Harvey & Livesey.

Pivot masonry of draw-pier, 1,010 cubic yards; built by Harvey & Livesey.

Amount of masonry laid on land during the year.

Davenport railroad abutment, 347 cubic yards; built by Harvey & Livesey.

Island railroad abutment, 214 cubic yards; built by Harvey & Livesey.

Dry-slope wall laid.

Davenport approach, 397 yards; built by Government.

Earth embankment.

Davenport approach, 996 yards; built by Government.

Earth excavation.

Island approach, 679 yards; made by Government.

Timber and crib work.

Draw-pier, 469,360 feet timber, board measure; built by Government.

Materials received during the year.

2,118 cubic yards of stone.

2.393 barrels cement.

1,104 cubic yards sand.

469, 360 feet timber, board measure.

23,160 pounds iron for sheathing piers.

41, 387 pounds iron for doweling, tie-rods, washers, bolts, &c., for crib of draw-pier.

276 cubic yards of rubble and macadam stone.

201.3 cubic yards riprap in lower starling of draw-pier. 495.3 cubic yards riprap in upper starling of draw-pier. 696.6 total in starlings.

1,668 cubic yards in the crib of draw.

2,364.6 total cubic yards of riprap in draw-pier.

The contractors for building the piers, Messrs. Harvey & Livesey, showed great want of energy or capacity in carrying on their work, and it was finally found necessary to take it out of their hands, which was done on the 8th of October, 1870.

From the beginning of the year up to that time, they had put only three pieces of masonry in the river, viz: Pier No. 1, and the pivot masonry and lower starling of draw-pier. On land they had partially built the two railroad abutments. On the 8th of October we took the work in our hands, and on December 10 had built piers Nos. 2, 3, 4, and the upper starling of draw-pier, all of which stand in deeper water and. on much more difficult foundations than any the contractors had built. A coffer-dam for the last pier, No. 5, was also constructed and pumped out, but owing to the existence of a thick bed of boulders and gravel at the site of this pier, the presence of which was not known, the coffer-dam was badly broken in pumping, and the lateness of the season, December 13, rendered its abandonment necessary. The river was full of ice the next day.

In order to facilitate the washing away of the dams no longer needed, the tie-rods in the upper stringers were removed about the last of December.

I hoped and expected that the moving ice and swift current during the high water of the spring would carry the dams away entirely. This was especially desirable at No. 5, as it is necessary to get this dam out clean before constructing another one. Unfortunately this dam held fast, while most of the others were washed away.

A steam-dredge is now at work removing it, and I hope in a few days to commence the construction of the new one.

About the time of taking the work out of the hands of Messrs. Harvey & Livesey, they presented to you a paper protesting against your action, and making certain statements about the work. This paper is full of misrepresentations. Soon after they presented to the Secretary of War a petition asking to be reimbursed in the sum of about $240, 000, claiming it was due for their work and the damage they had sustained at the hands of the Government. This petition was referred to me, and I was directed to prepare copies of all papers relating to the dealings of this office with Messrs. Harvey & Livesey, and also to make a statement of facts in the case. These papers were made out and forwarded. I was called upon, together with yourself and several assistants in the office, to give our testimony before a United States commissioner in a suit which Messrs. Harvey & Livesey had brought against the Government to recover damages.

It is unnecessary here to say more than that the claims of Messrs. Harvey & Livesey are outrageous and unwarranted.

RECAPITULATION.

All the masonry work of the bridge has been completed, with the exception of pier No. 5, and about 365 cubic yards to finish the four abutments.

The timber protection of the draw-pier has been finished, and also the main part of the approaches.

The work was much delayed during the year, principally by the tardiness of the contractors, but it was taken out of their hands on the 8th of October, 1870, since which time it has progressed much more rapidly.

Very respectfully, your most obedient servant,

Colonel J. N. MACOMB,

AMOS STICKNEY, Captain of Engineers,. U. S. A.

Corps of Engineers, U. S. A., Rock Island, Illinois.

UNITED STATES ENGINEER OFFICE,

Rock Island, Illinois, August 28, 1871. COLONEL: In obedience to your instructions, I have the honor to make the following report upon the progress made in the construction of the superstructure of the Rock Island bridge, up to June 30, 1871.

General specifications for the superstructure of the bridge having been issued in May, 1870, bids were received for the same on the 6th of July, 1870, from the following firms:

The drawings, strain-sheets, statements of weights, &c., accompanying the bids were carefully examined and considered, and a report made thereon by me, recommending the adoption of the design as proposed by the Baltimore Bridge Company. This report, together with one from General Warren, to whom the subject had been referred, was sent to the Secretary of War, who, on the 23d of September, approved of the recommendation that the contract be awarded to the Baltimore Bridge Company for $459,784. A contract was accordingly entered into for three spans, one 366-foot draw, one 260-foot span, and one 220-foot span, that being about the amount of work that could be carried on with the available funds then on hand.

The work upon the two fixed spans and part of the draw was carried on at Phoenixville, Pennsylvania. The turn-table, engine, and hydraulic jacks, for supporting and turning the draws, were in course of construction at St. Louis. On the 30th of June all the iron for the 260-foot span, and part of the 220-foot, had been fabricated, examined, and tested, and was then being shipped. The machinery for the draw was nearly all finished.

On account of the heavy masses of material, novel shapes, and nicer workmanship required for the spans of this bridge, it has taken much longer to get the material out than had at first been estimated. The coutract with the Bridge Company was accordingly extended until the

15th of October, when it is expected that the three spans mentioned above will be completed.

There will then be left five spans (three double-deck, and two singledeck) to be erected. It is confidently expected that the entire bridge will be finished by the first of March, 1872.

Very respectfully, your obedient servant,

Colonel J. N. MACOMB,

W. H. H. BENYAURD,

United States Corps of Engineers,

Captain of Engineers.

General Superintendent Rock Island Bridge.

Н 8.

ROCK ISLAND, ILLINOIS, May 15, 1871. GENERAL: I send to you to-day by express a box containing the maps and report of Mr. Gorham P. Low, jr., civil engineer, assistant in charge of the survey for a ship-canal from Hennepin, on the Illinois River, to Watertown, on the Mississippi River, some eight miles above here, showing a length for the canal some sixty-five miles, and a feeder some thirtyeight miles. This report was completed by Mr. Low, and presented at my office during my absence on a tour of duty to Phoenixville, or it should have been forwarded at an earlier day.

I cannot say that I agree with Mr. Low in the conclusion that, in case of the construction of the canal, "the counties and cities immediately benefited by the work would relieve the Government from any expenditure for damages," but the great cost of the ship-canal will probably prevent the Government from immediately undertaking the work, especially in view of the good water communication between the lakes and the Mississippi by the Illinois River improvement now in progress. That part of the report giving estimates for a commercial canal between Hennepin and the Mississippi River will be of interest to the canal commissioners of the State of Illinois, and to that part of the community whose interests would be promoted by such a line of communication; and as the ship-canal survey afforded the data for such an estimate, I authorized it to be appended to the report upon the shipcanal survey.

The box now sent by express contains the following papers: Mr. Low's manuscript report to me, XXII pages, and the tabular statements, and six sheets of maps mentioned in the report.

All of which is respectfully submitted by your most obedient servant, J. N. MACOMB,

Colonel of Engineers, United States Army.

Brigadier General A. A. HUMPHREYS,

Chief of Engineers, United States Army, Washington, D. C.

Report on a canal route between the Illinois River, near Hennepin, and the Mississippi River, near Rock Island, with a navigable feeder from the Rock River, at Dixon, April 10, 1871.

ROCK ISLAND, ILLINOIS, April 10, 1871. COLONEL: I have the honor to submit the following report upon the examinations and surveys of a route for a ship-canal between the Illinois River, near Hennepin, and

the Mississippi River, near Rock Island, with a navigable feeder from the Rock River at Dixon.

The party having taken the field September 5, 1870, I took charge of the surveys on the 19th of that month, by order of Brevet Major General Wilson, United States Army. Early in December the field-work having been completed, most of the party were discharged, and the remainder have since been engaged in preparing the accompanying drawings and estimates. I was ably assisted upon the surveys and office-work by Mr. Albert Millet, civil engineer, in charge of the transit party, and Mr. Lovell Swisher, civil engineer, in charge of the leveling.

The drawings submitted are as follows:

Sheet A.-Map and profile of proposed route from the Illinois River to Devil's Slough. Sheet B.-Map and profile of proposed route from Devil's Slough to the Mississippi River.

Sheet C.-Map and profile of proposed route for feeder.
Sheet D.-General map of proposed canal and feeder.
Sheet E.-Proposed lock for ship-canal.

Sheet F.-Proposed lock for commercial canal.

It will be observed from the maps that the main line of survey differs in many places from the proposed line of canal. In such cases cross-sections and side-levels were taken, sufficient to furnish data for profiles on both lines. According to original instructions all calculations and estimates for excavation, locks, &c., were to be based on the dimensions recommended for the enlarged Illinois and Michigan Canal I have, therefore, estimated for a ship-canal section 160 feet in width at the water-line, and 7 feet deep, with slopes of 2 to 1; and for locks 350 feet long and 75 feet wide. I also submit estimates for a commercial canal of smaller dimensions. At various portions of the line it is proposed to reduce the width of the ship-canal section in deep cutting to 100 feet on water-surface. This width will allow the passage of tows of barges as large as can enter the locks, while the reaches thus narrowed are not long enough to seriously delay them when meeting each other. The cost of widening at any time will be no greater, and probably less, than at first construction. The estimates have been made accordingly. To protect the banks of the ship-canal from the action of waves from passing steamers, I have proposed the construction of low retaining-walls, to be built into the slopes and extending 1 foot below and 18 inches above the surface of the water, as being more economical in respect to material than riprapping. As such a wall would be built only after the opening of the canal to navigation, I have estimated it at $5 per cubic yard, laid without cement.

In the design for ship-caual locks shown on sheet E, the gates are similar to those designed by General Wilson for the locks at Keokuk. The water is admitted into the lock through a valve-platform and archways in the upper miter-sill wall, and is discharged through valve-openings in the lower gates. As the transportation of stone and other material to the sites of most of the locks will be very expensive, this plan of construction is proposed as requiring the smallest amount of masonry. As a rule, the foundations of the locks will not be expensive, and probably only locks Nos. 1, 2, and 3 will need bearing-piles. Lock-masonry is estimated at $1 per cubic yard. As the canal is designed for the passage of steamers of large size, estimates have been made for swing-bridges of 75 feet openings, and placed high enough to allow the passage under them of ordinary barges and horses. On the feeder, no protecting walls, and only ordinary bridges, have been estimated for.

The eastern division of the work, extending from the Illinois River to the junction with the feeder at Devil's Slough, will be 25.86 miles in length; will contain nineteen locks of an aggregate lift of 207 feet; will require three railroad and thirteen common drawbridges, and sixteen culverts. It will be the most expensive portion of the line to construct, and is estimated to cost $5,779,277 24, or $223,483 26 per mile.

The dam across the Illinois River at Henry, in process of construction by the State of Illinois, will form a pool extending to the southern terminus of the Illinois and Michigan Canal. By reference to sheet A, it will be seen that, starting from this pool in the Illinois River opposite Hennepin with two locks of 8-foot lift each, the proposed line runs across the bottom-land to the Bureau Valley Mills, where it crosses the Peoria branch of the Chicago, Rock Island and Pacific Railroad, and continues up the southerly side of the valleys of Bureau and West Bureau Creeks, a great portion of the way being under the bluffs and requiring the construction of only one bank. On the seventh mile, counting from the Illinois River, the line becomes parallel with the Chicago, Rock Island and Pacific Railroad, and continues between that road and the bluffs to the crossing of the Chicago, Burlington and Quincy road on the eighteenth mile and Bear Pond Creek Station." It there passes under both roads and runs over the summitlevel to the junction with the feeder-line at Devil's Slough, about three miles north of Sheffield. Between locks Nos. 15 and 17 it will be difficult to make room for an independent channel for Pond Creek, and it might be advisable to construct ponds and weirs instead of the regular canal-section, thus forming a common channel for canal