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The movement of freights between the East and the West, by the lines of transportation already established, shows that the freights eastward are greatly in excess of the freights westward, in the proportion of about 6 to 1. This indicates that about six loaded boats would go eastward to one loaded westward, tbat five-sixths of the boats going westward would be empty, and all going eastward would be loaded, consequently we may presume that of twelve boats passing the summit-level of the canal seven may be considered as loaded and five may be considered as empty. By the system of locks each boat passing the summit-level will have an average expenditure of 18,000 cubic feet of water, or 216,000 cubic feet for the twelve boats, but by the system of inclined planes the seven loaded boats will expend 108,129 cubic feet and the five empty boats will expend 27,125 cubic feet of water, a total of 135,254 cubic feet, an average of 11,271 cubic feet for each boat, or only 62 per cent. of the expenditure by locks. Upon this hypothesis of the movement of boats Ioaded and empty, the quantity of water required for operating the inclined planes may be determined definitely for any given number of boats, and generally the quantity of supply of feed-water at the summit may be determined upon the basis of tonnage per annum; 100 boats would carry (58 being loaded and 42 empty) 6,960 tons, and expend 1,127,117 cubic feet of water, about 162 cubic feet per ton, varying as the tonnage; whereas, on the contrary, by the lock-system the 100 boats passing the summit would expend equal quantities of water whether loaded or empty.

It may be further remarked that by the system of planes the loss by leakage at the locks would be entirely obviated at the summit-level, an insignificant quantity probably, but yet worthy of being noted.

Referring again to the comparison of quantities of water expended at planes and at locks in the eastern slope of the canal, and applying the hypothesis of non-balance of freights eastward and westward, we find that six loaded boats passing eastward, and one loaded and five empty ones passing westward, will expend 52,357 cubic feet of water, and by the same movement of boats through a lock by the favorable condition of three eastward boats, finding full locks, there will be expended 7:3,357 cubic feet of water, nearly one-half more than the quantity expended by the inclined plane. This feature of the comparison, together with the absence of leakage at the summit-locks, shows that, in the system of inclined planes, the storage water in the sunimit-level is under better control in the matter of its distribution down the slope of the canal, saving in the last case 33 per cent. of the water expended by the system of locks, under the same condition of tonnage. This feature gives great weight to the system of inclined planes.

The local conditions in regard to these comparisons are, on the Savage River section of the canal, especially favorable to the system of inclined planes.

EFFECT ON THE TONNAGE CAPACITY OF THE CANAL. It was shown in my former report that the tonnage capacity of the canal is dependent on the facility for passing boats at the restricted points as at the locks, and was equal, under ordinary circumstances, to about eight boats per hour, and 192 per day. Upon the basis of movements of freights eastward and westward, given above, seventwelfths of these-12 boats-are loaded, aggregating a tonuage of 4,032,000 tonnage for a season of 300 days. In the case of the inclined planes, boats can be passed up (and down) over a distance of 950 feet in 4.4 minutes, allowing for time to get into the carriage, say ten boats per hour, increasing the capacity 25 per cent. With regard to the convenience of passing boats at a plane, it may be readily shown that they can be passed over the plane in one-half of the time, or in any other ratio, by the same expenditure of water, by increasing the power of the turbine motor.

If double-track planes were applied to the canal at the increased cost of 50 per cent., the capacity is to some extent unlimited, and ten boats could be passed in each direction in each hour, doubling the capacity last stated, which would give 480 boats per day, and 144,000 boats, 17,280,000 tons, per annum of a season of 300 days.

ECONOMY OF TIME IN TRANSPORTATION. To determine the time of transit over a canal operated by locks, the time taken up in slowing up the boat to enter the lock, and the time taken up in getting under way again at the visual speed, must be taken into the account as the means of determining the time lost by retardation of speed, as well as the time required in locking throngh. A like amount of retardation takes place in passing a plane, as the boat must come very nearly to a dead stop in entering the carriage, but by good management the boat may be made to leave the carriage with the communicated velocity acquired in passing over the plane-24 miles per hour.

[This is the practice on the Morris Canal.]

To determine the time consumed at locks in retardation and locking, we may take the operations on the completed canal as a basis. Under the most favorable conditions of the lock being open to an approaching boat, the tow-line is cast off at the distance of 350 feet from the lock, and the boat comes to a stop when in the lock, and we will assume that an equal distance is required to get under way again at the usual speed.

The lock for this purpose is taken to be 120 feet long; and the distance occnpied in slowing up, locking, and getting under way again is therefore 820 feet at each lock. The usual speed acquired over the canal between locks is two miles per hour, rarely faster. Loaded boats make the trip from Cumberland to Georgetown, a distance of 184.5 miles, in 41 days, passiug through 74 locks, making an average speed of 1.7 miles per hour.

The total distances taken to slow up, lock, and get under way are, for 74 locks, 60,680 feet, leaving 913,480 feet, over which the speed of two miles per hour is made, requiring 864 hours of time, and the time remaining of 41 days, 21 hours, is taken up at the locks in retardation and locking, equal to 17 to minutes at each lock, in passing over 820 feet of distance. To render this case somewhat more favorable, we will assume that but 15 minutes' time are taken up in slowing up, locking, and getting under way.

In applying these measures of time to the portion of the canal between Cumberland and Connellsville, via the Savage River route, we will consider it in characteristic section. Connellsville to mouth of Piney Run, 68 miles, with 134 locks; Piney Run to month of Savage River, twenty-eight miles, with 156 locks; and Savage River to Cumberland, thirty -one miles, with 42 locks.

In passing over the first section of 68 miles, a boat will take up 33.5 hours in passing 134 locks and 109,880 feet, leaving 249,160 feet to be passed over at the rate of two miles per hour, requiring 23.6 hours, a total of 57.1 hours for this section. On the middle section, deducting the tunnel summit-level of 5 miles length, which will be passed iv 2.5 bours, 39 hours will be taken to pass 156 locks and 127.920 feet of distance, equal to 24.23 miles, 1.23 miles more than the distance to be passed over on this section, exclusive of the tunnel. The reason for this result is that the distances between the locks average about 600 feet, 40 feet less than is assumed to be taken up in getting under way, and slowing up to enter the next lock, and the boat does not get the speed of two miles per hour, as assumed, but in the half distance between locks will acquire a speed of 1.89 miles per hour. [As we have assumed nearly 24 minutes less time at locks than was found by the basis of times on the portion of canal in operation, we may disregard this saving of a fraction of a minute.] The whole time on this section is 41.5 hours. The time occupied in passing over the section from the mouth of Savage River to Cumberland, we have 10.5 hours to 42 locks, and 34,440 feet of distance and 12.24 hours to pass over the remaining 129,240 feet or 24.48 miles, making for this section 22.74 hours, and for the whole distance between Cumberland and Connellsville, 121.34 hours, a rate of 1.05 miles per hour. If the 17.4 minutes found to be occupied at each lock had been used in these calculations the time would have been found to have been 13.28 hours more, or 134.62 hours.

BY SYSTEM OF INCLINED PLANES. The time regnired for the passage of boats along the canal where inclined planes are used is to be determined in the same manner as for the system of locks. Equal times and distances are taken up in slowing up to enter the carriage, as in the case of locks, but no time is lost in retardation in getting under way again. If a boat, moving at the rate of two miles per hour, comes to a stop in 350 feet when the propelling power is stopped, the average rate of speed has been one mile per hour for the 350 feet of distance and the time 4 minutes, quite nearly. In the calculations for determining the expenditure of water in passing the plane, the rate of two and one-half miles per hour was assumed, and to pass from the upper to the lower pool, or vice versa, a distance of, say, 990 feet, the time will be 44 minutes, making 8. minutes for the time taken at each plane to pass over a distance of 1,340 feet.

Considering tirst the section between the mouth of Piney Run and the mouth of Savage River, a distance of twenty-eight miles, with 20 planes, we have for the time occupied at planes, 2.83 hours and 26,800 feet of distance, and the remaining distance 22.92 miles is passed over in 11.46 hours, and the section is passed in 14.33 hours, sa saving in time of 27.2 hours on this section,) with a rate of two miles per hour, quite Dearly, the section being passed as if it were one continuous unobstructed level.

The saving of time at the other points named would be, at the mouth of Castleman River, difference between 2 hours occupied at the eight locks in going over 6,520 feet and P4 minutes and 29.4 minutes (37.9 minutes) to pass the same distance by the plane, a saving of 1.37 bours.

At the Ohio Pyle Falls, a plane of 96 feet lift would give a distance of 1,310 feet to be passed in 6 minutes, and 1,660 feet in 10 minutes ; 12 locks would require 3 hours of time to 9,810 feet of distance, while in passing this distance with the plane but 564 minutes would be taken, saving here 2.06 hours ; and the whole time that would be saved between Connellsville and Cumberland is 30 hours and 38 minutes, (equal to a shortening of the canal by 61.26 miles,) making the time from Connellsville to Cumberland 94 hours, only four days, and the average speed 1.35 miles per hour. If the time of passing locks as found by the operations of the canal in use, had been used, the saving in time would have been almost 44 days.

It is quite probable that planes could be introduced at other places on the canal, but the surveys are not made in such detail as to determine this.

From the above discussion of planes and locks it is apparent that if planes of higlier lift could be used, the economy of time and cost would be greater yet; and that were the canal operated to its full capacity with planes, the planes could be double-tracked at an increased cost not exceeding 46 per cent. of the cost of the single-track planes, which would establish a double line of boats moving in opposite directions as fast as two miles per hour over the mountain section; nor would the double-track planes expend as much water in operating the turbines as wonld the single-track planes, because the load to be moved up or down the plane would be counterbalanced by 35 tons, or 60 tons, or 185 tons; and in all cases 33 per cent. of a saving in work would take place; and in the case of the movement of two boats at the same time, one or the other of the boats might be said to have been moved without any expenditure of water; and for the case of six loaded boats down, or eastward, and one loaded boat and five empty ones westward, on the Savage River section, if the boats could be moved over the planes in pairs, the expenditure of water would be for the five empty boats up, and the one loaded ove, 36,204 cubic feet, or an average of 2,901 cubic feet for each boat as compared with 4,363 cubic feet for each boat as found for the single-track plane, a sav. ing, again, of nearly one-half of the quantity estimated for the operation of singletrack planes.

In the operations of the double-track plane, when two boats were to be moved at the same time, double work would have to be done in moving the boats over the length of the upper plane, and for this purpose a turbine of double the power figured for the single-track plane would be required with double the expenditure of water for that time, and this double expenditure is considered in the calculation of the last average quantity of 2,901 cubic feet. Fixed caissons carrying water in which the boats may be floated while passing over the plane, have been used, as noted in the beginning of this report. Such an arrangement would add the weight of caisson to the load to be moved and also the weight of water required to float the boat, which would be an additional load of about 115 tons, and would require an additional expenditure of water in the same ratio for like movements of boats. In the case of a double-track plane with caissous, the same increase in expenditure of water would be necessitated; but in the case under discussion, that system of arrangement must be established that expends the least quantity of water.

In whatever manner the comparison may be made between the lock-system and the inclined-plane system, either of single locks and single-track planes, or of double locks and double-track planes, the economy in construction and in the expenditure of water is pre-eminently in favor of the inclined planes.

Stationary steam-engines could be substituted for the turbine motors, but their cost would be $15,000 additional at each plane. They would be more liable to accident, and require skilled superintendence and the constant expense of fuel, while, on the contrary, they would avoid the expenditure of water needed to operate the turbines.

EFFECT ON COST OF TRANSPORTATION. Taking the operations of the completed canal between Cumberland and Georgetown as a basis of cost, a careful analysis of the cost of transporting coal shows a cost of 0.4 cent per ton per mile, exclusive of tolls, when the rate of transportation is 1.7 miles per hour, or at the rate of 0.68 cent per hour of time, and conseqnently a saving of 301 hours' time works a saving of 20.8 cents per ton between Connellsville and Cumberland, an equated saving of fifty-two miles in distance by the system of inclined planes, in comparison with the system of lift-locks as herein compared. Very respectfully,

THOMAS S. SEDGWICK. Maj. WM. E. MERRILL,

U. S. Engineers, Brevet Colonel, U. S. A.

N 9.

SURVEY OF THE YOUGHIOGHENY RIVER, PENNSYLVANIA.

UNITED STATES ENGINEER OFFICE,

Cincinnati, Ohio, August 14, 1874. GENERAL: I have the honor to forward herewith Lieutenant Mahan's report on the survey of the Youghiogheny River, as ordered by the act of March 3, 1873.

The cause of the delay in getting this report before Congress is explained in the report itself.

Having no special instructions as to the limits of the survey I directed Lieutenant Mañan to commence at West Newton and work down stream to the mouth of the river. I selected West Newton as the starting point because I understood tbat the wishes of those at whose instance this survey was ordered were to have an extension of the Monongahela slack-water system up the Youghiogheny; and therefore I thought it best to limit the survey to a length of river that could be examined thovoughly, and not to go above a point that could be reached by three dams of 10 feet lift each, believing that there would be ample time to continue the survey after these dams were built. I had no instructions to make this survey a part of the examination for the extension of the Chesapeake aud Ohio Canal route, and therefore treated the question as a purely local one.

After the estimate for an improvement by permanent dams had been made, I directed Lieutenant Mahan to make another estimate for the construction of movable dams, on the model of that across the Seine at Port-à-l'Anglais. I did not expect that this system could be advantageously applied to the Youghiogheny, but I thought that it would be a valuable study for similar work on the Ohio.

The mouth of the Youghiogheny is in the second pool of the Monongahela, and, therefore, boats descending the former stream must pass two locks before reaching free navigation in the Ohio.

For this reason, and for its increased cost, I would not recommend an improvement on the Youghiogheny by movable dams.

The most serious question in improving this river comes from the scantiness of its water-supply in summer. On this account the estimate for lock-foundations is particularly large in order to reduce leakage to the minimum.

The estimated cost of slack-water to West Newton, by three locks and dams of 10 feet lift each, is $688,023.21. This is a larger estimate than is usual for suchi locks and dams, but it will be seen on examination that the increase of cost arises from the defective character of the foundations.

Accompanying this report are fourteen sheets of maps, giving the plat of the part of river surveyed on the scale of 1 inch to 200 feet, its longitudinal profile, and various cross-sections. There is also a sheet on which is shown, on a small scale, the kind of movable dam on which the estimate was based. The movable parts are Chanoine wickets, and the arrangement is similar to that adopted at Port-à-l'Anglais on the Seine just above Paris. Respectfully, your obedient servant,

WM. E. MERRILL,

Major of Engineers, U.S.A. Brig. Gen. A. A. HUMPHREYS,

Chief of Engineers, U.S.A.

Report of Lieut. F. A. Mahan, Corps of Engineers.

UNITED STATES ENGINEER OFFICE,

Cincinnati, July 28, 1874. Sir: I have the honor to submit the following report of the survey of the Youghiogheny River from West Newton to McKeesport:

Having been ordered for temporary duty to the Atlantic coast just two weeks after my return to this office, and not having had with me any maps or other data from which a report could be prepared, I have been compelled to wait until the present

time before completing it, as upon my return I found that certain additions had to be made to the maps, the data for which were to be found only in my own note-book.

The act of Congress approved March 3, 1873, reads as follows, in so far as it concerns this work:

** Sec. 2. That the Secretary of War is hereby directed to cause examinations or surveys, or both, to be made at the following points, namely : * The Youghiogheny River, Pennsylvania.”

Your orders, given to me verbally, were that the survey should extend from McKeesport, at the month of the river, to West Newton, about twenty miles up; consequently nothing was done outside of these limits.

The Yonghiogheny rises near the boundary-line of the States of Maryland and West Virginia. Its course is about due north as far as Contluence, where its direction changes to west-northwest, preserving this general direction unchanged until it joins the Monongabela at McKeesport. A few small, unimportant streais empty into it above Contluence, at which point it is joined by its two most prominent tributaries, Castleman's River and Laurel Hill Creek. Below Confluence three other streams flow into it, but they are also very small. The Youghiogheny runs very nearly parallel with the Monongabela ; just below its head-waters it is crossed by the Baltimore and Ohio Railroad. At Contluence the Pittsburgh, Washington and Baltimore Railroad comes on its right bank, which it follows thence to McKeesport. The Pittsburgh, Wheeling and Baltimore Railroad is a branch of the Baltimore and Ohio Railroad, which it joins at Cumberland, Md.

There are no towns of any importance between McKeesport and West Newton. The distances of the principal villages from Pittsburgh are as follows:

Miles. McKeesport, on the right bank.

15.7 Boston, on the left bank

19.4 Osceola, on the right bank.

21.7 Alpsville, on the right bank

22.5 Shaner's, on the right bank

26.2 Buena Vista, on the left bank

27.7 Armstrong's, on the right bauk.

27,7 Moore's, on the right bank ..

28.8 West Newton, on the right bank

34.5 In times of very high-water steamboats could go up to West Newton, and perhaps even farther, were it not for the bridge that here crosses the river, and is about 10 feet above high-water.

I could not tind any data for determining an average high-water at West Newton, as no one seemed to take any particular notice of the river. The highest water there known occurred on the 7th of February, 1868, and stood at 23. 94 feet above low-water. This rise was caused by an ice-gorge in the river below.

The river in times past has been slack-watered, but I have so far been unable to obtain any satisfactory information about its history or its work. I could only find traces of two locks and dams, one about a mile below Osceola, the other at Buena Vista, but they had long been lying in ruins, the dams completely broken through, and the locks almost totally destroyed. Nothing of them is now standing save small portions of the chamber-walls. So far as I could learn from conversation with persons living in the neighborhood of the river, the great cause of failure was in the dams having been built too high. What this height was exactly I could not learn, but the lift from pool to pool was about 13 feet.

The survey was made in August, September, and October of 1873. The force at first consisted of Mr. Hoag, myselt, and tire men, the number of whom was afterward increased to seven. Considerable delay was caused by the difficulty of obtaining suitable transportation for the party and instruments, but work was finally begun on Augnst 11 and continued until November 1.

The party was divided into two sections. The first, under Mr. Hoag, took in the topographical and hydrographical parts, while the second, under my own supervision, attended to the leveling. The topography was conducted by the ordinary methods of courses and bearings. A system of diagonal time-soundings was made from West Newton to McKeesport, and at all marked shoals lines of triangulated soundings, 200 feet apart, were run perpendicularly to the shore.

The leveling was conducted with the special object of determining the difference of level between the water-surface at West Newton and the water-surface in the second pool of the Morongahela slack-water system. Eleven bench-marks in all were established. They are all cut on rocks and in the form of a Greek cross, the center of the cross being the point at which the rod should be held. The following description of the bench-marks may be useful for future reference:

No. 1. On top of a sandstone guard-post, situated at the intersection of the curbs on

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