of these cribs over what would be proper masonry piers is taken from the clear openings of the draw-span. The right rest-pier is of masonry; this opening is 128 feet, while the left opening is but 119 feet. The lowest part of the draw-span is 66 feet above high water. The draw is turned by an engine placed on the truss above the roadway. This was the first draw on the river turned by steam-power.

INFLUENCE UPON NAVIGATION.

Steamboats. From the time of the opening of navigation, March, 1865, considerable delays were experienced by inability to pass it in time of high winds and dark nights. Vessels were compelled to wait during the prevalence of a high wind sometimes as long as two days at a time. Damages to considerable extent were suffered in passing the bridge, and, in consequence of these and the injurious delays, suits were insti tuted or threatened against the bridge company.

The effect of this bridge upon navigation is stated in my letter to the chairman of the Senate Committee on Post-Offices and Post-Roads, dated February 5, 1867, which appears in Chapter V of this report. The subsequent examination made at high water showed that the direction of the current was not essentially different from that at low water, but that the eddy above the bridge near the west shore was much larger and stronger in high water, making the approach to and passage through the draw-opening more difficult.

Several steam saw-mills have been erected on the right bank below the bridge, which, like all mills or furnaces, make at times dense smoke and bright lights, that greatly interfere with the safe navigation of the river in their vicinity, and add to the difficulties in the passage of the bridge.

The difficulties which steamboats encounter in passing this bridge, appertaining especially to it, may be summed up as follows: the narrow draw-opening, 119 feet in the clear; the eddy above the bridge, which makes the course of the current to continually change, and the curve in the main channel where the bridge crosses. These are sufficient to prevent steamboats passing in time of high winds, to which this part of the river is very liable, and in dark nights and thick weather, the effect of which is intensified by the mills located near it.

Rafts. This bridge is now a greater obstruction to the passage of rafts than it was at the time it was legalized in 1867, because of the change which has taken place in the method of rafting. Formerly the rafts were all managed by men using large sweeps, and the passing under the low bridge across the Illinois channel did not interfere with the control of the raft, but now the larger number of the rafts are man aged by means of small steamboats, and they cannot pass under the bridge. The raft has to be dropped near the bridge in the Illinois channel, and the steamboat goes around the head of the island and passes through the draw-opening in the bridge over the Iowa channel. The bridge over this channel does not furnish suitable openings for the pas sage of rafts in its present state, though near low water the rafts are sometimes separated into smaller parts and dropped through this chan uel by the boats.

The spaces between the piers of the bridge over the Illinois channel are not sufficient for rafts, for which this is the usual channel.

The difficulties attending the passage of this bridge by rafts are set forth in detail in the report of the board of engineers on sheer-booms, dated Saint Louis, Mo., February 2, 1877. (See Annual Report Chief of Engineers for 1877, vol. 1, p. 817.)

ALTERATIONS TO LESSEN OBSTRUCTIONS TO NAVIGATION.

Although it is probable that an entirely new and different bridge will be required to meet the wants of navigation if the principle is to be carried out which was enunciated in the report of the House committee in 1858, of which the Hon. E. B. Washburne was chairman, "that any bridge is a material obstruction which is susceptible of being essentially improved," still there are a number of changes that can be made in the present structure that will make it less of an injury to navigation than it now is.

Sheer-booms.-The board of engineers upon sheer-booms, to facilitate the passage of rafts, recommended that a fender be built along the bank above the bridge over the Illinois channel to prevent rafts being drawn into the timber on the bottom at time of high water; that a fixed boom be placed from the upper end of the pivot-rest in prolongation of its east side to the shore above, and that another fixed boom be placed from head of the pier east of the first span east of draw to the head of Little Rock Island. These booms are to be so constructed as not to interfere with steamboat navigation, and it was thought that the boom running from the upper end of the draw-rest to the Iowa shore would facilitate the passage of the bridge by boats.

Straightening the channel.-A further improvement, and one particularly desirable in the present arrangement of the draw-spans, would be cutting off the point of rock above the bridge on the west bank, and filling out the hollow of the bend below so as to destroy the eddy that now makes the passage of the draw difficult. To cut off about 170 feet of the point down to 6 feet depth at low water, requires the removal of about 32,000 cubic yards of rock. The material excavated could be used in making a new bank in the bend below in prolongation of the west restpier. This it is believed would make the west draw-opening available when the obstructions placed below it by mill-owners and others are removed, and make unnecessary the sheer-boom to the Iowa shore recommended by the board of engineers.

Rebuilding east rest-pier.-This could be done by removing it down to 6 feet below low water, and replacing it by a stone pier of the usual di mensions, which would add about 10 feet to the width of the east drawopening. This could be done without interrupting travel over the bridge, and without great expense.

Building new draw with wider openings.-A much greater improvement would be to remove the present draw and the fixed span next east of it, and replace them by a draw having openings of 160 feet in the clear, the same width as has been required in the other bridges on this part of the river, and put a fixed span over the present west draw-opening. To do this would require building a new pivot-pier east of and alongside of the east rest-pier, and a new east rest-pier. This can be done without interrupting navigation, and with but little interruption to the travel over the bridge. This change would make this bridge as good for navigation as any draw-bridge on the river, and would do away with the necessity for the previously suggested changes.

As all of the spans over the Iowa channel, except the draw, are of wood, they must soon be rebuilt; and the piers also are of such nature as to require rebuilding before many years.

HIGH BRIDGE.

At this place a continuous bridge should be about 58 feet above high water, or 77 feet above low water, the natural location for which is at Fulton or Lyons.

S. Ex. 69-7

PROPOSED BRIDGE AT CLINTON, IOWA.

The act approved April 1, 1872, authorized the Chicago and Quincy Railroad Company to build a bridge at this place, and provided in section 4 that it should be available to all railroads desiring to use it, on such terms and conditions as might be prescribed by the Secretary of War. Section 5 made the control of the Secretary of War over this bridge greater than had been defined in any previous act, and defined the reserved authority of Congress in compelling future modifications, if required by the interest of navigation.

The act of Congress approved June 4, 1872, made these requirements applicable to all bridges to be constructed thereafter across the Missis sippi River under any act of Congress. These provisions are copied in full in this report in giving an account of the bridge at La Crosse, Wis. Section 4 of the act approved June 6, 1874, provided that the bridge authorized to be erected across the Mississippi River at the town of Clinton, Iowa, by act approved April 1, 1872, "may be constructed and maintained as a pile and ponton bridge," and on September 29, 1874, the Mississippi Union Bridge Company submitted the plan to the Secretary of War. The Chief of Engineers, on being directed to report upon it, submitted the matter to a Board of Engineers of which Col. J. N. Macomb was president. The Board reported on the 8th of October, 1874. (See Annual Report of the Chief of Engineers for 1875, Part II, pp. 682-684.)

The Board recommended some minor modifications in the proposed bridge, but it has not yet been built.

THE NEW ROCK ISLAND BRIDGE.

(Tested May 8, 1872; opened for railroad travel October 8, 1872.)

This bridge, built by the United States (partly at the expense of the railroad company), presents an anomalous case, and, as far as it is a precedent, deserves more notice in this report than any other. Its location and general design were controlled by a number of important requirements, all of which were known, and being built under officers of the government, there is no consideration which influences the present form of this structure that may not be fully and positively stated. Such is not the case with bridges built by private corporations, where it is impossible to know what relative value was given to considerations of a public and general or of a private and local nature. We will therefore begin with an account of the first steps towards its construction.

PRELIMINARY STEPS.

The old bridge having been shown to be a serious and unnecessary obstruction to navigation, Congress, by act approved June 27, 1866, to establish an arsenal, &c., authorized the preliminary steps to building a new bridge and removing the old one. The questions with regard to the change of the railroad were referred by instructions from the Chief of Ordnance (General Alexander B. Dyer), September 21, 1866, to the commissioners appointed under the acts of April 14, 1864, and June 27, 1866, whose duty was to ascertain the true value of the lands and property rightfully owned by those who would have to be dispossessed in adapting the island to the use of an arsenal. This commission was directed, after hearing the parties in interest and taking the necessary testimony

To suggest the proper change in the location of the railroad and bridge, and the kind of wagon-road that should be established, and the kind of aid that should fairly

and equitably be granted toward effecting these objects.

It is essential that the new location of the railroad should be made on the lower end of the island, as laid down on a plat to be furnished by the commanding officer of Rock Island Arsenal (General T. J. Rodman).

The location, as thus laid down, was nearly that on which the new bridge was built, and its adaptability to the wants of the railroad company indicates that their views were consulted in making it. It was arranged for two spans 375 feet each from end to end over the main channel, with bottom chord 50 feet above high water. The rise from low water to high water was set down as 16 feet, so the gorge high water about 5 feet higher, occurring sometimes at the breaking up of the ice, was not considered. The trusses each side were to be deck trusses, and provided for an inclination of the rails in reaching the higher spans. Alongside the trusses making the railroad approaches to the high spans were other trusses for the wagon-way, allowing of more inclination for the highway than for the railway, but both roadways crossed the high spans on the same grade. This commission consisted of Maj. Gen. J. M. Schofield, Mr. (General) James Barnes, Mr. Selden, and Mr. Church. Their report to the Chief of Ordnance is dated February 4, 1867. It was forwarded by the Chief of Ordnance with recommendations and suggestions February 8, 1867, and is printed as Sen. Ex. Doc. No. 27, Thirty-ninth Congress, second session. During the investigations of the commission, they obtained from Mr. E. H. Johnson, the chief engineer of the Chicago, Rock Island and Pacific Railroad, an estimate of the cost of such a bridge as General Rodman proposed, with the substitution of high spans of 250 feet from centers of piers, instead of 375 feet (the wagon-way to be 17 feet wide and the railroad to have a single track), to cost $1,671,241.81. The commission also obtained an estimate of the cost of a low draw-bridge with the wagon-road above the other, with the provisions regarding the position of piers in the direction of the current, and the position and dimension of spans, provided for in the law for the Quincy bridge. The total cost of this was estimated at $1,296.292.11, and of this sum $1,046,317.58 was for the part over the main river, connecting Rock Island with Davenport. (See Annual Report Chief of Engineers of 1869, pp. 194–199.) The railroad company submitted a proposition setting forth the share of the expense it would take in making the change. When this proposition was afterward considered by the commission, the ordnance officers objected to the width of the wagon-way proposed, which was only 17 feet; and it was thought a much wider wagon-way was necessary, say 26 feet. The railroad company then suggested that the increased width would admit of the railroad being a double track. When this point was reached, the estimates were sent for revision to Mr. Johnson, who thought there was no reason to change his first estimate of cost. It is surprising that such a view should have been entertained. I came in charge in 1869 and made an estimate of the cost of the enlarged bridge, allowing the same prices, and found it would be $1,785,142.67 from Rock Island to Davenport, and including the bridge between the island and Illinois $2,121,526.82. (See Annual Report Chief of Engineers for 1869, pp. 194-199.) Without referring to cost, however, the commission recommended the proposition of the Chicago, Rock Island and Pacific Railroad Company (their assent to the foregoing modification for a wide roadway being duly certified to.)

The essential features in the question of bridging as agreed upon are as follows:

The government to build over the main channel of the river an iron draw-bridge in accordance with the conditions prescribed in the act of Congress of July 25, 1866, the

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frame to be of proper breadth for a double track; the wagon-way to be placed high enough to leave the lower chord for a railroad track; the government to give the company the right of way across this bridge and across the island upon the payment of half the cost of superstructure.

The Chief of Ordnance, in making his report to the Secretary of War, submitting the report and recommendations of the commission, said:

If the bridge is to be built by the government as recommended by the commission, an additional appropriation of $1,000,000 is requested, and it is desirable that it shall be made before the end of the present session.

The words "additional appropriation" undoubtedly referred to an appropriation in addition to estimates previously submitted. It could in no way be regarded as a statement of the estimated final cost of the bridge, as it was afterwards mistaken to be, the mistake causing a serious obstacle eventually to getting to work on the bridge. In the act for the support of the Army, approved March 2, 1867, $200,000 was appropriated towards building the new bridge, according to the recommendation of the Chief of Ordnance. This recommendation was, more properly speaking, that of the commission. The Chief of Ordnance somewhat qualified his approval, and thought the proposal liberal on the part of the United States, and too much so if the railroad company had not already a right of way. The act required, however, the execution of certain papers binding the railroad company to certain conditions, in regard to future preservation and repair, ownership, use, &c., which the company was found unwilling to accede to, and as the act was not compulsory the commencement of the bridge was stopped. The Chief of Ordnance says in his report dated October 19, 1867:

As it is doubtful whether the guarantee which the company is willing to give would fulfill the requirements exacted by Congress of the company in making the appropriation, I would respectfully recommend that the subject be brought to the notice of Congress for such action as may be considered necessary and proper.

A joint resolution was framed to meet the case and was approved July 20, 1868, which gave specific authority to the Secretary of War to allow sixty days after its passage for the railroad company to file an agreement in accordance with it, and if not filed then, he should direct the removal of the existing bridge and proceed with constructing the new one, which the railroad company should not have the use of until it had agreed to and complied with the provisions required of them. This joint resolution contained a proviso that "in no case shall the expenditure on the part of the United States exceed $1,000,000." At the end of section 2 are the words, "all acts or parts of acts inconsistent with these resolutions are hereby repealed." In the complications which followed a due regard was not had to this repeal of parts of former acts inconsistent with this proviso, limiting the cost to $1,000,000.

The act making appropriation for the support of the Army, approved March 3, 1869, appropriated $500,000 towards building the bridge.

The agreement between the United States and the railroad company was signed by General J. M. Schofield (then Acting Secretary of War), and John F. Tracy, president of the company. It has no date, but it was not many days prior to September 10, for on that day the Chief of Ordnance requested authority to commence the work (the agreement as he states having already been signed) and to authorize the employment of a com petent civil engineer to aid in the work.

A marked feature in the agreement signed is the following:

Provided that the aggregate cost of said bridge shall not exceed $1,276,292.11, the estimate of the same made by the commissioners appointed under the act approved June 27, 1866.