Exhibit of stone purchased in "open market" of Messrs. Wells, Timberman & Co.

Exhibit of cement purchased in "open market" of Mr. James Clark.

For middle-lock sluice:

2,100 barrels, (300 pounds each,) $2.48..

$11,363 45

2,482 20

1,208 45

15, 054 10

$20,340 88

$5, 208 00

For lower-lock sluice:

230 barrels, (300 pounds each,) $2.48.

694 40

The amount of funds available for this work at the beginning of the fiscal year

was

Balance from last year's appropriation...

Appropriated by act approved March 3, 1873...

$66,300 88 400, 000 00

There has been expended....

Remaining at the end of the year..

Amount appropriated by act of Congress approved June 23, 1874..........

Amount available for fiscal year ending June 30, 1875..............

Amount required beyond appropriation for completing the work, about.

The sum of $480,000 could be advantageously used daring the fiscal year ending June 30, 1876, and I would earnestly recommend that an appropriation of that amount be made as soon as possible to finish the work.

During the present year it is proposed to finish the work embraced in the contract of Kittle & Co., finish the sluices, prolong the bridges over the creeks which empty into canal, build the riprap wall as far as material can be fouud for it, and build the entire guard-lock, if possible.

In conclusion, I have to bear witness to the faithful manner in which the gentlemen connected with the engineer force have performed the various duties assigned them. Very respectfully, your most obedient servant,

Col. J. N. MACOMB,

AMOS STICKNEY,

Captain of Engineers and Brevet Major, U. S. A.

Corps of Engineers, U. S. A.

Number.

I 3.

IMPROVING ROCK ISLAND RAPIDS, MISSISSIPPI RIVER.

The work of excavation at Rock Island Rapids, done in the fiscal year 1872-1873, under contract with Dull and Williams, was finished before the 1st July, 1873, but the closing of the contract by a final estimate had to be deferred to September 15, 1873, as the high water prevented a thorough resurvey of the places at Winnebago chain and some patches between St. Louis chain and Campbell's chain. At Winnebago chain, 2,144 cubic yards, and at the latter places, 220 cubic yards of rock had been removed. For the fiscal year ending June 30, 1874, an appropriation of $50,000 was made. At the letting of the work on 5th June, 1873, Mr. Geo. Williams was the only responsible bidder, and I was authorized to enter into contract with him; and by his energy and skill the work of excavation, by means of chisel and dredge, has been pushed with each success that by 24th October, 1873, I settled his final estimate under that contract, which embraced in all 1,801 cubic yards of rock excavation.

There remain to be excavated 7,199 cubic yards to complete the improvement of Rock Island Rapids under the approved scheme. I expect to excavate about 3,300 cubic yards at lower chain, and at scattering patches during the fiscal year ending June 30, 1870, by means of the $50,000 appropriated on 23d June, 1874. There would then remain about 4,000 cubic yards of rock to be removed, chiefly at foot of Moline chain, and at scattering patches, and as this remaining work can only be done by means of chisel and dredge, under all the difficulties of a very strong river-current and the liability of frequent interruptions from passing rafts and steamers, the price of $16 a cubic yard is not estimating the cost too high; and I, therefore, most earnestly recommend that the sum of $80,000 may be appropriated for completing the improvement.

For any information more in detail in regard to this work, I beg leave to refer to the report of Assistant E. F. Hoffman, who has so ably conducted the operations from the beginning.

Financial statement.

Balance in Treasury of United States July 1, 1873..

Amount in hands of officer, and subject to his check, (including $2,999 per

$50,000 00

centage due on contracts not yet completed).

4,034 74

Amount appropriated by act approved June 23, 1874

50,000 00

Amount expended during the fiscal year ending June 30, 1874.

51,694 04

Amount available July 1, 1874

52,340 70

Amount required for the fiscal year ending June 30, 1876

80,000 00

Report of Mr. E. F. Hoffman, Assistant Engineer.

UNITED STATES ENGINEER OFFICE,

Rock Island, Ill., July 1, 1874.

COLONEL: I have the honor to submit my annual report of operations for the improvement of the Rock Island Rapids, during the fiscal year ending June 30, 1874. The work of excavation done under the contract by Messrs. Dull & Williams, for the fiscal year 1872 to 1873, which could not be closed by a final estimate before July 1, 1873, on account of the high stage of water, making a thorough hydrographic survey and revision inconvenient, was finally reported to you as being executed satisfactorily in conformity with the contract, whereupon the relations with the firm of Messrs. Dull & Williams on the part of the Government were declared to be ended, and the following final estimate was drawn up on September 15, 1873, and duly signed by both parties.

Final estimate of work done by Dull & Williams, under their contract for the improvement of the Rock Island Rapids of the Mississippi River, commencing September 28, 1872, and ending September 15, 1873.

For the work of excavation at these rapids, Congress had appropriated the sum of $50,000 for the fiscal year 1873-1874.

Previous to the letting of the work, the subject was considered by the Chief of Engineers if the work of excavation by means of chisel and dredge could not be carried on more advantageously at the remaining scattered patches by the Govern

ment.

You were directed to report upon this subject, and, after mature consideration, the fact appeared in figures that, as the purchase of the necessary implements was out of question on account of the small appropriation, the excavation per cubic yard, even by hiring machinery, would reach the price of $16.50. If, at the commencement of the improvement of these rapids, the requisite machinery in chisel, dredge, steamer, flat and dump boats could have been built or bought by the Government, I am confident a great saving of money would have been the result, and the quality of work superior. At the present advanced state of the work, even if the means for purchase of machinery were at hand, no pecuniary advantage would be gained.

Excavation by means of chisel and dredge is a difficult kind of work and a precarious one, if the engineering and superintending are not carried on with all zeal and fidelity. It should but be used when coffer damming is utterly impossible on account of scattered patches.

In relation to work of excavation done by means of coffer-damming on the part of contractors and on the part of Government, I can exhibit an interesting comparison obtained at this place.

The work of coffer damming and excavating at these rapids has been done by contract. The within table exhibits place, amount of rock-excavation, running feet of coffer-dam, and ratio between excavation and running feet of coffer-dam. Coffer-dam work at the Rock Island Rapids.

Eastern channel.

In the year of 1872 it became necessary to excavate the eastern channel of the drawpier of the new Government bridge at this place, situated at the foot of the rapids. This work was done by the Government under the head of Rock Island bridge appropriation.

The within table contains the cost per cubic yard of excavated rock at that place and the ratio between amount of cubic yards and amount of running feet of cofferdam. The information was obtained from the maps and records in the office.

Rock-excavation in the pit of the coffer-dam erected in the eastern channel of the draw of Rock Island Government bridge.

In comparing the results in both exhibits it will be seen that the average cost-price per cubic yard obtained by contract-work is not much higher than the price for which Government did the work of coffer-damming and excavating. If, furthermore, it is taken into consideration that the erection of coffer-dams, such as are at Sycamore, Moline, and Smith's chain, was done in a current of the river running with a velocity from 6 to 8 feet per second-meanwhile the Government coffer-dam at the bridge was set in nearly calm water-the comparison in regard to cheapness stands for this instant in favor of contract-work. Even the ratio between amount of cubic yards excavated to the amount of running feet of coffer-dam is in advantage of contract-work, as can be readily seen from the above exhibits.

In laying the above before you I state that I confine myself for making this comparison only for this locality under the mentioned circumstances, having no doubt that other results in favor of Government work can be and are obtained.

In consequence of your report to the Chief of Engineers, showing the price for excavating a cubic yard of rock by means of hired implements to be $16.50, you were authorized to advertise the work, and on the 5th of June, 1873, bids in relation to the work were opened. Mr. George Williams, of Keokuk, Iowa, was the only bidder, and you were empowered to enter into contract with him for the work of excavation at Duck Creek chain, at the price of $18 per cubic yard; lower chain, at the price of $16 per cubic yard; foot of Moline chain, at the price of $12 per cubic yard: various places on the rapids, at the price of $14 per cubic yard.

The contractor, Mr. George Williams, was notified to commence work, and Mr. C. H. Benck and Mr. John F. Wallace, civil-engineer assistants, were intrusted with the superintending in the field. They lived on a small quarter-boat with their parties during the season, right at the place of the work, and, as ever, performed the duties assigned to them with ability and faithfulness.

I submit here an extract from their joint report in reference to the work of excavation during the fiscal year 1873-1874:

The excavation during the past season was carried on under a contract with Mr. George Williams, of Keokuk, Iowa, who used four chisel-boats and two dredges in the prosecution of the work, and excavated 800 cubic yards of rock at the head of Duck Creek chain, 680 cubic yards at lower chain, 296 cubic yards at foot of Campbell's chain and a crib containing 25 cubic yards below lower chain.

Owing to the high stage of water the commencement of the work was delayed until about the 15th of July, 1873, at which time work was commenced with two chisel-boats at the head of Duck Creek chain. On the 23d of July the two other boats commenced operations at lower chain, and the work was carried forward on the part of the contractors with great diligence until its completion.

On the 28th of August, one chisel-boat, having finished its work at Duck Creek chain, was transferred to the foot of Campbell's chain.

The following table will show the number of days that the chisel and dredge boats worked at each locality. From which we find that

The dredge removed on an average at Duck Creek chain 26 cubic yards per day. Lower chain, 212 cubic yards per day.

Amount paid.