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same," and to state in relation thereto that it was referred to a Board of Engineers, a copy of whose report thereon, together with the accompanying papers, are herewith submitted.

It will be seen that the Board has given the subject full and careful consideration; has studied diligently and with great clearness the characteristics and regimen of each of the rivers concerned, and prepared in great detail a bill to meet the requirements of navigation and commerce and at the same time do justice to the bridge interests.

The Board recommends as follows: That all bridges “over the Missouri River above the mouth of the Platte River shall be high bridges with unbroken spans, all spans over the water way to have a clear channel-way of not less than 300 feet, and a clear head-room of not less than 50 feet above hgh-water mark."

That all bridges “over the Missouri River below the mouth of the Platte River, and above the mouth of the Kaw River, shall be high bridges with unbroken and continuous spans, having at least one channel-span of not less than 400 feet clear channel-way; all other spans over the water way to have a clear channel-way of not less than 300 feet, and all said spans shall have a clear head-room of not less than 50 feet above high-water mark."

All bridges over the Missouri River below the mouth of the Kaw River shall be high bridges with unbroken and continuous spans, all spans to have a clear channel-way of 400 feet, and clear head-room not less than 55 feet above high-water mark.

All high bridges over the Mississippi River above the mouth of the Missouri and over the Illinois and Des Plaines rivers shall have one or more channel-spans, each having not less than 350 feet clear channelway, and not less tban 55 feet clear bead-room above high-water mark, and the clear head-room under other than channel-spans may be less than 55 feet, provided that no part of the superstructure of such spans shall give a less head-room than 10 feet above high-water mark.

All low bridges within the above-mentioned limits shall have two or more draw-openings of not less than 200 feet clear channel-way, and in addition to said draw.openings all said low bridges shall have one or more fixed channel-spans, each having not less than 350 feet clear channel-way, every part of the superstructure of said low bridge to give a clear head-room of not less than 10 feet above high-water mark provided that all spans of both high and low bridges shall be so located as to afford the greatest possible accommodation to river traffic, and the draw-openings of low bridges shall, if practicable, be located next or near shore; provided, also, that in case of a low bridge, if the physical characteristics of the locality so require, and the interests of navigation be not injured thereby, the lengths of the fixed spans or the number of the draw-openings may be reduced; provided, also, that for any two adjacent draw.openings of 200 feet each one draw.opening of 300 feet may be substituted, if the interests of navigation be not injured thereby; provided, further, that in low bridges over the Illinois and Des Plaines rivers two or more draw-openings of not less than 160 feet each may be permitted.

Ponton bridges similar to the ponton railway bridge at Prairie du Chien, Wis., may also be constructed; provided such bridges shall be provided with a ponton draw giving not less than 400 feet clear channelway for each navigable channel of the river, and such other openings for passage of rafts and logs as in the opinion of the Secretary of War may be necessary, etc.

Bridges over the Mississippi River between the mouth of the Missouri and northern limits of the city of Saint Louis shall be high bridges with unbroken and continuous spans having one channel-span not less

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than 500 feet clear channel-way, all other spans to have clear channelway of not less than 400 feet, all spans to have clear head-room of not less than 55 feet above high-water mark.

Bridges between the Eads's Bridge at Saint Louis and northern limit of the city to be high bridges with unbroken and continuous spans, not less than 500 feet clear channel-way and not less than 55 feet clear head-room above high-water mark. The remaining portion, if any, over the river-bed to have not less than 300 feet clear channel-way, and may have such reduced head-room as may be determined by the Board of Engineers elsewhere provided for.

Bridges over the Mississippi River between Eads's Bridge and mouth of the Ohio River to be high bridges with unbroken spans, one channel-span of not less than 650 feet in the clear, other spans to have not less than 500 feet clear channel.way, and all spans not less than 65 feet above high-water mark.

It will be seen that the Board was unable to decide upon the width of channel-spans for bridges between the mouth of the Ohio River and Natchez, Miss.; but recommends that all other spans shall have a clear channel way of not less than 600 feet, and that all spans have a clear head-room of not less than 70 feet above high-water mark.

This office approves the recommendations of the Board so far as they apply to all bridges over the rivers enumerated in the bill, except the portion of the Mississippi River below Cairo.

The Mississippi River Commission, in considering a bill to bridge this river at Natchez, recommended not less than 750 feet for the length of the channel-span, and in a report upon a bridge at Memphis, copy here. with, recommended a channel-span of 1,000 feet at that place, the lengths of these spans being determined by the existing local conditions and the necessities of navigation at the localities. The Commission also recommended that both of these bridges should have a clear headway of 75 feet above high water.

This office is of the opinion that all bridges erected over the Missis. sippi, between the mouth of the Ohio and Natchez, should have at least 75 feet clear headway above high water. As the physical feat. ures of the river and its banks vary materially in this portion, it seems impossible to fix upon a length of channel-span which will be sufficient for navigation at all localities without requiring an unnecessary length at some, which would be an undue hardship upon the companies pro. posing to construct a bridge at these latter places. It is therefore deemed best to leave the length of the channel-span to be required for the consideration and determination, with the approval of the Secretary of War, of the Board of Engineers, provided for in section 19 of the proposed substitute for the bill. It is therefore recommended that section 18 of the same bill be changed to read as follows:

SEC. 18. That all bridges authorized by this act over the Mississippi River between the mouth of the Ohio River and Natcbez, Miss., shall be high bridges with unbroken and continuous spans, having at least one channel-span of the width to be prescribed by the Board of Engineer Officers provided for in the following section (19); all other spans over the water-way to have a clear channel-way of not less than six hundred feet, and all said spans shall have a clear head-room of not less than seventy-five feet above high-water mark.

In view of the importance of this report to the general subject of bridging navigable waters it is respectfully suggested that its printing be recommended. Very respectfully, your obedient servant,

J. C. DUANE, Hon. WILLIAM C. ENDICOTT,

Brig. Gen., Chief of Engineers. Secretary of War.

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LETTER OF TRANSMITTAL.

MISSOURI RIVER COMMISSION,

Saint Louis, Mo., February 23, 1883. Sir: I have the honor to forward herewith the report of the Board of Engineer Officers convened by Special Orders, No. 1, Headquarters Corps of Engineers, dated Washiugton, D. C., January 10, 1888. Very respectfully, your obedient servant,

CHAS. R. SUTER,

Lieut. Col. of Engineers. The COIEF OF ENGINEERS, U. S. A.

REPORT OF BOARD OF ENGINEERS.

SAINT LOUIS, Mo., February 23, 1888. SIR: The Board of Engineer Officers convened by "Special Orders, No. 1,” dated “ Headquarters Corps of Engineers, United States Army, Washington, D.C., January 10, 1888," to consider and report upon Senate bill No. 275, Fiftieth Congress, first session, met in this city on Janu. ary 16, 1888, and remained in session till and including January 21. They then adjourned to allow of the collection of further information. The Board met again on the 27th of January and remained in session till and including January 30, when they adjourned sine die. During this time the Board have gone very carefully over the bill submitted to them for consideration, and have sought from all available sources information to guide them in their final conclusions. The bill under consideration was prepared, in essentially its present shape, in 1882, and during the period which has elapsed since that date much information and experience bave been obtained, not then available, and a good deal of general and special legislation bearing on the general subject has been enacted. The Board have felt that in a general bill, affecting such wide spread and important interests as the one under consideration, all such matter as experience has shown to be of value should be in. cluded. They have, therefore, felt it their duty to recommend many changes in the bill and also to recommend new sections covering points of importance not embraced in the original draught.

The great majority of these changes, at least in the sections noted as "general,” are based upon recent general or special laws affecting bridges, notably the general law for bridges over the Ohio River. In all other cases the changes recommended are such as experience bas shown to be desirable or pecessary. The number of changes and addi. tions recommended has been so great that the Board have rewritten the entire bill, and recommend the inclosed copy as a substitute for the original. In order that the whole matter may be clearly understood, the changes recommended will be noted and explained, section by section, the numbers given referring to the modified bill.

In title.--The upper limit on the Mississippi River, designated as the “port of Saint Paul, in the State of Minnesota," is changed to “ mouth of Minnesota River, in the State of Minnesota.” This gives a more definite limit and includes the Government landing at Fort Snelling, about 4 miles above the steamboat landing at Saint Paul. It is not thought that this extends the limit beyond the port of Saint Paul, and in any case, the 4 miles of river referred to are as navigable in their

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natural condition, and as susceptible of improvement, as many portions of the river below Saint Paul,

"Across the Illinois River, between its mouth and La Salle, in the State of Illinois," is changed to "across the Illinois and Des Plaines rivers, between the mouth of the Illinois and the city of Joliet, in the State of Illinois.” The present project for the improvement of the Illinois River, upon which the United States Government and the State of Illinois have for many years been engaged, contemplates a system of slackwater navigation with locks 350 feet by 75 feet, as high up as Joliet, thence by canal along the most feasible route yet to be determined on to Lake Michigan. The requirements for navigation will, therefore, be the same from La Salle to Joliet as for the other portions of the Illinois River.

In this connection the Board desires to call attention to the fact that the upper limit for the application of this bill on the Missouri River is fixed at the inouth of the Dakota or James River, in Dakota, and near the town of Yankton, while the lower limit on the Mississippi is fixed at the port of Natchez, Miss. The reason for selecting these limits is not apparent. So far as the Missouri River is concerned there is no change of importance in its physical characteristics until the rocky portion of the stream abore Fort Carroll is reached, and the Board are decidedly of the opinion that the provisions laid down for that portion of the stream above the mouth of the Platte should be made applicable as far up as Fort Benton, the head of navigation. With regard to the southern limit on the Mississippi, the Board consider that there is no physical change in the stream of consequence until after Red River is passed, and that the conditions governing bridge construction for the Lower Mississippi would not need modification, at least as far down as Baton Rouge, where the bluffs end, possibly not until New Orleans is reached and ocean shipping met with. Here it is possible that some modification might be necessary or desirable.

Section 1.-In this section has been added, “when public necessity so demands.” The Board consider that all bridges, no matter how carefully located or planned, are more or less obstructions to navigation and while it is doubtless proper that the latter interest should give way to a certain extent when a bridge is a public necessity, yet it does not seem right that this bardship should be imposed unless the general interests imperatively require it. This consideration is of especial im. portance in case of the duplication of bridges at any locality. It is a known fact that in several cases the construction of bridges has been contemplated where such construction was not a public necessity, and where the additional obstruction to the interests of navigation would have been serious, without any compensating advantage to the general public.

There has also been added, "at points where said construction will not materially affect the interests of navigation.” This clause is found in all the recent bridge acts for the Upper Mississippi River, and is an important one. There are some points where the construction of a bridge would be almost a bar to successful navigation, whereas at other points in the vicinity a bridge would not be so serious an obstruction as to prohibit its construction. In such cases it seems proper that the authority to construct shall only apply to the localities where regard for the navigation interest will best justify the construction. An addition has also been made to the description of the portions of the rivers over which the authority under the bill extends by repeating the limits as given in the title of the bill.

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Another addition is as follows, viz, "and hereafter no bridges shall be built over said rivers within said limits, except under said provisions and requirements." Heretofore a number of bridges within the limits contemplated by this act have been erected without the authority of Congress, and no law exists for the prevention of such construction, Many of these bridges have proved serious obstructions to navigation. As the object of the present act is to prevent the unnecessary obstruction of navigation by bridges improperly located or constructed, it would seem proper that such unnecessary obstruction be prevented by pro hibiting the construction of all bridges which do not conform to the requirements of this act. Without this requirement it would result that those who obtain authority for their action will be subject to more restrictions than those who do not, and the act will be practically value. less.

Section 2.-Only such changes are made here as were necessary to make the pumbers correspond to the sections of the bill as amended by the Board.

Section 3. Some few changes have been made in the definitions of terms of frequent occurrence in the bill, which were considered neces. sary for a better understanding of the ideas they were intended to express, or where it was thought the language used might give rise to misunderstanding or controversy. Throughout the bill, as now submitted, many changes have been made in the wording in order to have the phraseology correspond with the definitions given in this section.

Section 4.-This section is section 7 of the original bill. The principal change to be noted is that the provision requiring through-spans is left out, as being unnecessary and sufficiently covered by other provisions in the bill.

Section 5 in the original bill is omitted as unnecessary, as the Board consider draw-spans in high bridges undesirable and generally impracticable. This subject is fully discussed in the special sections where it occurs.

Section 5.-This section is section 6 of the original bill. The prin. cipal change to be noted is that the Board have attempted to do away with the idea of prescribing how the opening or openings through low bridges shall be made. It is sufficient for navigation purposes to know that an opening or openings of the prescribed width will be available when required for the passage of river craft, and the method of effecting such openings should be left, as far as possible, to the judgment of the builders of the bridge, subject to the revision provided for in this act.

The amended section also requires that draw-openings shall be visible for a distance of not less than one mile above the bridge. Safety requires that descending boats or other craft should be able to know certainly whether the draw is open or shut a sufficient time before reaching it, to admit of stopping or landing, should either be necessary. It also requires that so far as practicable, and when in the interests of navigation, all bridges should be located above important landings. The reason for this lies in the fact that, with a bridge located just below a landing, boats coming to or leaving the same would be in great danger of being injured.

It is further provided, that in certain cases where river craft might obstruct the passage through or under the bridge by landing in too close proximity thereto, the right to do so should be extinguished by the owners of the bridge. This provision occurs in the general bridge law for the Ohio River, and seems to the Board a proper one to intro

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