feet in the clear, and the remainder of the structure built on piers of masonry 200 feet apart.

At the first meeting of the board it was to a bridge of this form that the arguments of the railroad companies were directed, however their opinions or policy may have been altered by subsequent investigation. The cost of such a structure they fix at $2,451,000 for Detroit, and it would be about the same for the other crossings.

The nature and magnitude of the commerce which would thus be forced through these narrow passages has already been described and compared with that of the largest sea-ports of the lakes and oceans. If the right of way were given to vessels passing through a draw, it would subject the railroad-trains to as severe a blockade as they have ever suffered heretofore from insufficient ferriage; thus, in the single month of June, 1873, as appears from the records kept by the board, there were three hundred and sixty-one times when the draw would have had to be kept open for 20 minutes or more; ninety-three times, for 30 minutes or more; twenty times, for 45 minutes or more, and once, for an hour and a quarter, to make way for vessels passing in one direction only. This is based on the belief that 12 minutes must be allowed for closing the draw, passing a train, and opening again. If it took 14 minutes to do this, there was one instance where the draw would have been kept open for two hours and a half; but the vessels passing in the opposite direction might keep open the other draw after the one just considered was closed, and thus still longer delay the passing of trains. Details may be seen in the graphic representation of passing vessels, accompanying this report.

The president of the Michigan Central Railroad proposed that the draw should be closed thirty times a day for a space of 10 minutes each, thus giving time for the transfer of all their trains, and throwing all the delay upon the vessels; but the wind and current will not permit the latter to remain long in a position to pass; and, for safety, at least 6 minutes must, on this account, be added to the time when the draw is actually closed or in motion, making 16 minutes in 48, or onethird of the day; thus stopping in their course, during the season of navigation, about 9,000 vessels, an obstruction altogether inadmissible. But even if there were no stoppage, there would yet be great difficulty to tows, rafts, and sailing-vessels in passing draws.

The 8,500 steamers must slacken their speed, and the 3,500 sailingvessels, which annually pass, must often come to anchor to wait for a tug to tow them through, or be drifted by the wind and current against the bridge. Of the 4,500 tows many must break up, especially under cross-winds, and be taken through in parts. Rafts might, perhaps, usually pass in safety with the aid of additional tugs, but would sometimes be wrecked by the operation, and the damage that would inevitably result from this and other apparent causes would soon reach a large amount.

The

Some of the statistics of a draw-bridge at Chicago have been furnished to the board by the railroad companies, as evidence that a draw could readily pass the shipping of the Detroit River. They show that 43,735 vessels passed during the season of navigation of 1868. detailed records for some months in 1873 show that more than half the entire number were tugs, and about half the remainder scows and canalboats. A tug rarely takes through more than one vessel at a time. Two tugs are often required for one vessel. The current is almost imperceptible, the banks are only about 120 feet apart, are built up with docks on both sides, which serve as fenders and guides, the draw is not

more than about one-third the length of that proposed for the Detroit River and can be swung round very readily. For these reasons, no adequate comparison can be made between the Chicago draw-bridge and a draw-bridge over the Detroit River.

During the past season of navigation about 250 vessels ran aground in the old channel at St. Clair Flats. If a small fraction of this number were to strike the piers of the bridge proposed across the waterway, as the vessels would in some cases sink, the loss would be serious. When it is considered that all these difficulties are largely multiplied by the increase of traffic on the river, and again by the increase of traffic over the bridge, the board is of the opinion that no bridge with draws alone for the passage of vessels should be tolerated across this waterway at any point.

3d. The board having suggested a bridge which should be continuous during the winter, when the railroads need the bridge, and during the season of navigation have a portion removed so as to give a clear way for navigation, a plan and estimate was made by Mr. Pope for such a structure.

The plan gives two movable portions, each 400 feet long. Each portion is made of two spans, the abutting ends being supported by a ponton, and the extreme ends resting on permanent piers of the bridge; during the season of navigation the pontons and spans resting on them to be removed from the channel. The estimated cost was $1,966,500.

In discussing this plan the board changed it by substituting for the pontons movable caisson-piers, resting on permanent foundations at least 18 feet below the lowest known stage of water, the caissons being floated to their foundations, loaded and sunk at the close of navigation, and the trusses placed upon them. Two such piers to be used with three spans resting on them; the removal of the caisson part of the two piers and the three supported spans, at the opening of navigation, to give a clear water-way of 700 feet, measured at right angles to the current. Bridge to have 30 feet clear headway, the rest of it to have 300foot spans, and with a pivot-draw with two openings of 100 feet each in the clear, near the American shore; this draw being kept constantly open during the season of navigation. The 700-foot opening to be, if practicable, in American waters. Such a bridge gives to navigation during the season a clear water-way 700 feet wide, while at Sarnia the river is only 800 feet wide, and at the Lime Kilns practically much less, for heavy vessels. To the railroads it gives a bridge during the winter months, when alone the need of a bridge is imperative.

The board deem a water-way 700 feet wide during the season of navigation sufficient to accommodate the commerce in question without serious inconvenience, and they therefore think the bridge just described admissible, so far as the interests of navigation are concerned, without being so costly as practically to prohibit its construction to a railroad company. But while it suffices for the needs of the railroad, it requires the ferry system to be kept up, and is a bridge useless to it for eight months in the year; while it is not a grave obstacle to navigation, it yet cramps a noble navigable river, which if it had been formed by art would have been held as of priceless value; it diminishes its width by twothirds and places in it permanent obstacles to navigation.

CONCLUSIONS.

The conclusions to which the board has arrived are, then

1st. That a bridge giving a clear headway of 150 feet, and clear spans

of 400 feet, would not seriously injure navigation, but would be very expensive, involving long and in some places inconvenient approaches. 2d. That no bridge giving passage to vessels by draws alone, with draw-spans at present practicable, can be permitted without serious injury to navigation.

3d. That a bridge giving a clear opening of 700 feet from April 1 to December 1, with two draw-openings 100 feet in the clear, and with the permanent foundations of its movable piers 18 feet below lowest stage of water, will not be a serious obstacle to navigation.

4th. For the reasons heretofore given, although the question has not been directly referred to it, the board deem the crossing of the river by tunnels the only unobjectionable method; and from all the information they have obtained, think a tunnel at Detroit or Stony Island is by no meads impracticable, at a cost not so great as to debar its construction. Finally, the board would remark that at no place between Lakes Huron and Erie should a bridge be permitted which would give less facilities to navigation than the one already discussed, having 700 feet clear opening; that no construction should be commenced without prior approval of the plan and location by the Secretary of War; that, under his direction, the construction should be so carried on as during its progress to give least obstacle to navigation; that the opening of 700 feet should be kept clear to navigation from April 1 to December 1 of each year under severe penalties; that as a portion of the opening might be in Canadian waters, to control this portion so far as the interests of American commerce are concerned the United States should reserve the right at any time to stop the running of trains across the American portion of the bridge.

All of which is respectfully submitted.

G. K. WARREN,

Major of Engineers and Bvt. Major-Gen.
C. B. COMSTOCK,

Major of Engineers and Bvt. Brig. Gen.
G. WEITZEL,

Major of Engineers and Bet. Major-Gen., U. S. A.

Brig. Gen. A. A. HUMPHREYS,

W. E. MERRILL,

Major of Engineers and Brt. Colonel.

W. R. LIVERMORE,

Captain of Engineers, Recorder.

Chief of Engineers, U. S. A.

The following papers are herewith transmitted to accompany the report:

I. Report of James F. Joy, president Michigan Central Railroad Company, to the Board of Engineers, concerning the interests of the railroad companies in bridging Detroit River.

II. Statement of G. W. Bissell and Robert J. Hackett.

III. Opinion of Franklin Moore, Inmber-dealer, on the proposed scheme for bridging Detroit River.

IV. Opinion of R. A. Alger on the same.

V. Opinion of R. W. Gillett on same, and statements of facts concerning the commerce of the lakes.

VI. Opinion of Mitchell B. Kean, tug-owner, of effect on vessels of a bridge over Detroit River.

VII. Opinion of Allen Sheldon, wholesale dry-goods merchant; W. B. Dickerson,

REPORT OF THE CHIEF OF ENGINEERS.

produce merchant; and Duncan Stewart, (J. S. Hurd & Co.,) grain merchant, concerning bridging Detroit River.

VIII. Statement of Willard S. Pope, civil engineer, concerning bridging Detroit River.

IX. Statement of same concerning relative merits of high and low bridges over Detroit River.

X. Proposal by A. B. Maynard and E. W. Meddaugh on behalf of Michigan Central Railroad and Canadian Southern Railroad to accept a grant from the Government allowing said roads to build winter bridges across Detroit River, with two openings of 400 feet each, and a draw of 166 feet to each bridge.

XI. Report of paper read by E. S. Chesebrough on Detroit River tunnel, before Civil Engineers' Society of Louisville.

XII. Answers by F. N. Finney, Chief Engineer Canada Southern Railway, to questions proposed by Board of Engineers to railroad and bridge companies.

XIII. Statement of W. R. Clinton, master ferry-boat Victoria, in favor of ferrying cars across Detroit River.

XIV. Statement of Joseph Nicholson, vessel-captain, against bridging Detroit River.

The following drawings are herewith transmitted, to accompany the report:

I. Vessels passing Detroit, Mich., (No. 37.)

II. Diagram showing traffic on Detroit River, from record kept at Grosse Isle by Canada Southern Railroad.

III. Diagram showing number of cars ferried weekly at Windsor by steamers Great Western, Transit, and Saginaw, from 1869 to 1873.

IV. Map of crossing of Canada Southern Railroad, &c., furnished by Canada Southern Railroad Company.

V. Plan showing Canada Southern Railway crossing St. Clair River.

VI. Plan showing Canada Southern Railway crossing Detroit River.

VII. Chart of Detroit River, showing railway connections, currents, &c.

VIII. Profile of Detroit tunnel.

IX. Profile of Detroit River, lines A, H, P, R.

X. Plan showing draw and fixed spans across main channel, Detroit River, furnished by Canada Southern Railroad.

XI. Detroit bridge, Plans Nos. 1, 2, 3, furnished by Willard S. Pope, for Michigan Central Railroad.

I.-REPORT OF MR. JAMES F. JOY, PRESIDENT MICHIGAN CENTRAL RAILROAD COM

PANY.

To the Board of Engineers appointed to investigate and report as to bridging the Detroit River:

There are invested in the railroads whose outletting point is Detroit, and whose business crosses the river at that point from the west, including the Michigan Central and roads tributary to it, (the Detroit and Milwaukee, Detroit and Bay City Road).......

In the Great Western, now in and to go in this year..

$65, 000, 000

35, 000, 000 100, 000, 000

The main portion of this capital is invested in roads whose chief business is the transportation of the productions of the country, and merchandise and passengers, between the East and the West. This investment has been made as the necessities of the country have required, and must continue to increase as the country becomes populous and expands, and none can estimate the limit to which it will reach, provided a passage of the river by means of a bridge can be effected.

The expense of transportation has been so much diminished of late years that the grains of the West, as well as other productions, are rapidly changing from water to transportation by rail; and especially during the five months during which navigation is closed, the trains of all the roads are overburdened by the immense volume of this kind of business. The extent of it may, to some extent, be estimated from a statement made by the Chicago Board of Trade, in a petition to Congress for a new road especially for freight, a copy of which is appended hereto.

Many millions of bushels of grain are annually locked up each winter at Chicago and other lake-ports for want of transportation, and the distress is so great that efforts are actually being made to induce Congress to grant the money necessary to build a new double or fourfold track all the way from Chicago to the seaboard for the relief of the country from this annual stoppage of this immense business. Consider for a moment the necessities of the millions of people whose productions are thus stopped on their way to market some months in every year, and the expense also to which they are subject for storage, loss of interest, and other charges to which they are compelled to submit. Though it is not easy to state the amount of loss, or damage, or expense caused to the agricultural community by reason of this cause, yet it is not difficult to see that really it will take the damage and loss of not many winters to amount to all the value of all the shipping afloat upon the lakes.

In the latter part of January, 1865, after the winter's blockade, and the rivers were opened, and before the ice passed from the lakes and the Straits of Mackinac, the business of the West was moving eastward upon the railways in a large volume. The price of all kinds of produce was ruling very high, as well as of beef and pork. Just at that time a flood in the Genesee River swept away the New York Central bridge at Rochester, and all the business finding its way out by that avenue, by the roads both north and south of Lake Erie, was brought to a stand. All depots, and trains upon side-tracks, on both lines, as far back as Chicago, were filled with valuable property which could not move, as were all the store-houses in the lake cities. It was nearly four weeks before the bridge was restored and the trains could freely move, and about as much longer before the cars going East could return and be employed in the regular business. In the mean time prices fell off, perishable property was much injured, and the losses were very large. Indeed, it was estimated that the losses to the shippers of western productions to the seaboard and to the agricultural portion of the West in that year, from this cause alone-the stoppage of the movement of produce East for only four to six weeks-was enough in amount to have built another road such as the New York Central Road was at that time.

It is safe to say that with uninterrupted trains, and with a bridge across the Detroit River, three or four or five, and perhaps ten times as much property would pass the river every winter in the same period of time as was then stopped by that calamity. For the business which will pass by rail through Detroit is not to be measured at all by the past, when it could not move sometimes at all, and never with facility during the winter months, but by the ability of a double-track road between Chicage and New Eugland and New York, moving across the river by a bridge, and therefore not subject to interruption, upon which road full trains may be as they are now moving on the New York Central Road, both ways at the same time, and not more than twenty minutes apart from each other. Estimating the capacity of the roads by that standard, and with such frequent trains and constantly moving, and it will be difficult to even value the amount of business to be done or the immense relief it will be to the whole West during the four or five months when the navigation is usually closed, and with four or five such roads north and south of the lake constantly at work, night and day, for that time, the relief given by property reaching market and sales, by saving interest, cost of storage, and other charges occasioned by delay, will be of the most incalculable value to all the West. It will be felt upon every farm, and by every business man, in fact by every inhabitant of the great Northwest, and through all the arteries and channels through which business of any kind moves and money circulates through the whole western country.

It would not only be a relief of such incalculable importance, but it would affect the price of transportation by water all the rest of the year. The store-houses of the West would be continually drained during the winter. There could be no such accumulation as now takes place of many millions of bushels of grain at a single point in a single winter. The flow of produce East would be constant, and spring would open with little or no surplus at the shipping-points, and when at last navigation should open, there being no large accumulation, the price of freights would not be from 15 to 20 cents between Chicago and Buffalo, as they were nearly all last year, and at the opening of this season, but from 2 to 5, and the effect would be felt all the summer through. In this way the saving to the West would each year be simply enormous. There might not be, it is true, so many vessels upon the lakes, and the width of the draws of bridges possibly might not be considered so important as vessel-owners seem now to consider them. There might not be a vessel of some sort every five or ten minutes passing up and down the river, but the gain to the people of the West in every aspect of the case would be almost incalculable.

Now the time during which the Straits of Mackinac are closed and navigation is obstructed was last winter five months, and is rarely less than four, and will probably average from four to five, more than a third of the whole year by considerable. Shall trade and transportation stop during that time to suit the vessel-owners and enable them to reap a richer harvest from the millions who earn their bread by the sweat of their brows during the rest of the year—and they do not hesitate always to take all they can