level canal of four hundred and seventy-three miles, which would require 189 hours to be traveled from one end to the other.

The 40-foot canal having 600 feet of lockage in a distance of three hundred and fortyone and a half miles, is equivalent, as to time, to a single level canal of three hundred and sixty-seven miles, and which would be traveled in 146 hours from one end to the other. But it has been shown that on the first canal the amount of transportation being expressed by 130, it will be 100 on the 40-foot canal—the velocity and towing power remaining the same in both cases. Comparing, now, this ratio of 130 to 100 with that of the time employed to travel respectively each canal, viz, 189 hours to 146, it is found that these ratios are equal Therefore, on either of these canals, and notwithstanding a difference of 2,558 feet lockage, an equal weight will be transported during the same time, and with an equal towing power-a result entirely due to a larger transverse section having been assigned to the canal whose lockage is greater.

With a view to augment still more the amount of transportation without increasing the expense attending it, the boat might have received a length of at least eight times its breadth; but it would have required a length of lock of 118 feet, (between the hollow quoins,) which, on account of the great number of locks, would have caused too great an expense. The necessity of conciliating economy with the object to be expected from the work has, therefore, obliged us to limit the length of the boat to seven times its breadth, 13 feet-that is to say, to 94 feet about; this length varying, however, from 90 to 94 feet, according to the mode of constructing the boat. With a draught of 3 feet, such a boat, if rectangular, would displace about 100 tons weight of water, or, on account of deviation from this form, about 90 tons only, it will carry a burden of 60 tons. Respecting the locks destined to admit this boat, they must have at least 102 feet between the hoflow quoius, and 14 feet breadth in the clear. In the estimate, they are nearly all supposed to be of 8 feet lift, though in the framing of a final plan they should vary according to considerations not immediately connected with the object of the present report.

The sheet No. 3 exhibits the plan and sections of the lock upon which has been made the estimate of this article of expense. The main walls are built of common rangework masonry, (No. 18;) their facing only is laid with water-line cement. Hewn stone has been used exclusively for the hollow quoins, mitre-sills, abutments, and recesses of gates. The blocks do not exceed 9 cubic feet, (Nos. 27 and 28.) The bottom of the chamber consists chiefly of a reversed arch, built of brick, with water-line cement. The estimate amounts to $13,069.80. But we must take into consideration that a number of locks will have their foundation upon solid rock, and will therefore require less masonry; and also that owing to the necessary declination, which, in the final plan, the bottom of the canal will receive, the amount of lockage will be less than it is in this general plan. Under these impressions, $12,000 has been deemed a fair average cost of a lock on the whole line of canal.

Respecting the aqueducts, they are to be built of masonry, and their lengths calculated to afford a free passage to the streams at the time of freshets; they are generally to be connected with the sides of the valley by means of embankments carefully made.

We now pass to the description of the canal.

EASTERN SECTION.

[Omitted.]

MIDDLE SECTION.

This section includes the summit-level, and extends from Cumberland (or rather from the western end of the eastern section) to the mouth of Castleman's River, in the Youghiogheny. Its length is seventy miles 1,010 yards; but a lockage of 1,961 feet and a tunnel of four miles 80 yards long, under a ridge of 856 feet elevation, will make this section extraordinarily expensive.

This section will, besides, require the erection of dams across the valleys through which it passes, and more especially in the bed of Will's Creek. This stream, in fact, affords, in summer and fall, a too small supply of water toward its sources to rely altogether upon it; the summit-level must feed, therefore, the upper portions, while frequent dams erected across the valley will make available the water delivered by the stream.

The valleys of Will's Creek and Castleman's River being formed of a succession of flats and bluffs, the canal will often require to be supported by walls whose height should place the work out of reach of the freshets. These freshets rise in Will's Creek from 7 to 10 feet, and from 12 to 16 feet in Castleman's.

In planning this section, care has been taken to avoid, as much as practicable, expensive aqueducts, and none is to be erected over Castleman's River. The canal will

follow. constantly, the right side of the valley, whose southern exposure will procure an earlier navigation in spring and later in autumn. Respecting Will's Creek, its valley is so narrow at some places, and the height of freshets so inconsiderable, that four crossings have been made to take advantage of the most favorable ground, and thus lessen the expense. It must be observed that these two streams are not navigable, and will, therefore, require no peculiar work to accommodate their trade and navigation.

The execution of the tunnel will be not only very expensive, but also long and difficult; all the geological appearances lead to the conclusion that the excavation will have to be made through sandstone rock. The estimate has been calculated for three different kinds of ground, hard clay, sandstone, granite, and unstratified limestone. The hypothesis of sandstone being admitted here, the estimate relating to this kind of ground accompanies the present report. (See sheet No. 5.) The tunnel will require to be lined with masonry, experience having shown that this precaution is indispensable. Brick masonry has been adopted in the estimate as the most convenient to fulfill the object. The dimensions of the interior of the tunnel are, 22 feet in width, 7 feet under the water-line and 164 feet above the same line, which form 234 feet from the bottom to the top of the arch. The tow-path is 4 feet wide. The shafts destined to facilitate the excavation, and to air the tunnel, are proposed to be sunk 180 yards apart from center to center. Their diameter will be 6 feet within the lining of brick masonry. A gallery, lateral and parallel to the tunnel, corresponds with the shafts. This gallery, or heading, is destined to drain the tunnel during its excavation; its width is 3 feet, and its height 63 feet; it is lined with brick masonry, and communicates with the tunnel by means of arcades or side-headings, which correspond to the points at which the shafts terminate into the heading. The sheet No. 4, herewith annexed, exhibits all the draughts relating to this tunnel, and to the deep cuts at its ends.

The deep cut at the western end is 1,060 yards long; that at the eastern, 140 yards; each opens into a basin having 880 yards in length and 64 yards in width. The tunnel, the deep cuts, and the basins, form together the summit-level, whose length will be 5 miles 1,280 yards; a lock is located at each end, and where each basin terminates.

Let us now examine the resources upon which we can rely to supply with water this summit-level, and the portions of canal contiguous to it. The stream upon which we have chiefly to depend is Castleman's; it yielded in 1825 and 1826 the following results:

We have admitted, in the former part of the present report, 18 cubic feet per second as the minimum of water yielded by Castleman's River; and we have also pointed out two reservoirs, one at Pleucher's farm and the other at Forney's mill, containing together 22,000,000 cubic yards. These are the resources afforded by the localities to feed the summit-level and supply its lockage and also portions of canal contiguous to the summit-level.

The reservoirs are to be filled in winter, during the interruption of the navigation— an interruption which, considering the elevation of the summit-level above the ocean, 1,903 (?) feet, cannot be supposed less than four months, viz.: from the 1st of December to the 1st of April. By adopting 98 cubic feet per second as the mean supply afforded in winter by Castleman's River, at Pleucher's farm, we find that in less than seventy-two days both reservoirs would be filled up.

However, to remove any doubt on the subject, we will take an area of thirty-six square miles of ground whose rain-water supplies Castleman's River, and make a computation of what such an area would yield; we will suppose it to be formed of two strips of land, each of eighteen miles long and one mile wide, and stretching along the banks of Casselman's River above Forney's mill.

From observations made from 1817 to 1824, inclusively, by Mr. Lewis Brantz, in the vicinity of Baltimore, we have the following results: In the course of these eight years there fell, on a mean average, yearly, 39.89 inches of rain; in 1822 there fell the smallest quantity, which was 29.20 inches; the greatest quantity fell in 1817-it amounted to 48.55 inches.

Adopting these data for the country round the summit-level, and using only the results of the year 1822, we find that the rain which fell in the three first and three last months of said year amounted to 16.70 inches, and for the six other months to 12 inches.

Cubic yards.

0.463

0.347

The whole, or 29.20 inches, are equivalent per square-yard surface to.....

0.810

These 16.70 inches are equivalent per square-yard surface to..
The 12 inches are equivalent per square yard surface to

Applying now these last results to the area of thirty-six square miles above mentioned, we find that they will receive at the minimum:

During the fall and winter....
During the spring and summer
The whole year round....

Cubic yards. 51, 630, 796.80

38, 695, 219.20 90.326, 016, 00

From which it will be seen, first, that the two-thirds of the first quantity, or 34,420,531 cubic yards, would be about one-third more than will be necessary to fill up the reservoirs in four months; second, that 44 cubic feet per second would make up, during six months, the two-thirds of the second quantity, and might, therefore, be deemed the mean discharge per second of Castleman's River during spring and summer, instead of 18 cubic feet, assumed in the present report; third, that this surplus will partly replenish the reservoirs during the time of navigation.

If to these considerations we add that, instead of thirty-six square miles, we might easily have taken double, we may conclude that, the filtratious and evaporations of rain-water being taken into the most liberal account, the portion of Castleman's Valley above Forney's mill will convey to the bed of this river more water than we have admitted; we believe, therefore, that the minimum supply of the summit-level will consist of, first, a reservoir of 22,000,000 cubic yards; second, 18 cubic feet per second of running water. And, since the navigation is supposed to be opened during eight months, the monthly resources will be 2,750,000 cubic yards from the reservoirs, 1,728,000 cubic yards from the river itself; total, 4,478,000 cubic yards per month. Let us see now how the use of this monthly supply will be regulated. Taking into consideration the unavoidable delays at the end of the summit-level, the impediments at the debouches of the tunnel and through the deep cuts, and, finally, the greater resistance the boats will meet through the tunnel, we cannot suppose less than 3 hours and 25 minutes for a boat to pass from one end of the summit-level to the other, which comes to one and two-thirds miles per hour. But the passage is to be effected in fleets or trains, on account of economy both of time and water; and we adopt thirty boats for each train-a number which in the present case seems to us favorable to combine the time of passage with the supply of water during the same time. These thirty boats, moving in train, will meet with more delay than would a single boat, and instead of 3 hours and 25 minutes, as before stated, we assign 4 hours to the train to pass from one end to the other of the summit-level.

We suppose, also, that a fleet of thirty boats, descending the eastern lock of the summit-level, and (through the same lock) passing an ascending fleet of the same number of boats, will effectuate this cross-passage in eight hours, under the plausible supposition that 16 minutes will be required for the cross-passage of a boat ascending and one descending. A similar cross-passage is supposed to take place at the western lock of the summit-level, and at the same time.

Now, a first fleet leaving the eastern lock will arrive four hours afterward at the western lock, and meet there a fleet coming from the west, and ready to proceed eastward. This second fleet will reach in four hours the eastern lock, and find here a third fleet, having ascended the lock during the passage of the first and second fleets. This third fleet will proceed westward, and arrive four hours after at the western lock, where it will find a fourth fleet, having ascended the lock during the passage of the second and third fleets. Lastly, this fourth fleet will move eastward and reach in four hours the eastern lock, meeting there with a fleet from the east, having ascended the eastern lock during the passage of the third and fourth fleets.

The passages of these four fleets, forming together 120 boats, and requiring four hours each, may be considered, as will be seen just now, the maximum of trade which the supply of water can admit. At this rate of 120 boats a day, 3,600 might pass per month, and 28,800 during the eight months of open navigation.

Let us now compute the expanse of water which the lockage of these boats will require. Admitting, as in fact will be the case, that, at each lock, one ascending boat alternates with a descending one, each boat will draw, from the summit-level, but one lockful, viz., half a lockful at each end. However, in order to provide for contingencies and unforeseen cases, we adopt one lockful and a half for the passage of each boat through the summit-level. One lockful and a half containing 623 cubic yards, the 3,600 boats passing during one month will require 2,242,500 cubic yards of water, which, being taken out of the monthly supply, amounting to 4,478,000 cubic yards, will leave 2,235,200 cubic yards. This last quantity is destined to feed the canal itself, exclusive of lockage, on a length of 18 miles and at a rate of 120,000 cubic yards per mile and per month, absorption, filtration, and evaporation being taken into account. These eighteen miles comprehend the summit-level, a portion of six miles in Will's Creek, and a similar of also six miles in Castleman's Valley. The remainder of the canal down Will's Creek will be supplied by this stream, while Castleman's River will feed the remainder of the canal descending its valley.

The estimated cost of the summit-level, just described, is as follows: The tunnel

The details relating to the estimate of the tunnel are exhibited in the sheet No. 5, annexed to this report. As to the basins and deep-cuts, their detailed estimates have been carried into those belonging to the eastern and western portions of this middle section. We shall now present successively the description of these portions: the eastern, commencing at the eastern end of the summit-level and terminating below Cumberland; the western, beginning at the western end of the summit-level, and debouching into the Youghiogheny below the mouth of Castleman's River.

EASTERN PORTION.

Subdivision 1.-From the eastern end of the summit-level to the mouth of Little Will's Creek :

Distance, 15 miles 460 yards; descent, 1,016 feet; 127 locks.

The canal follows for 84 miles the left side of the valley of Will's Creek; it then crosses the stream to descend for two miles along the right bank; crossing again the creek it remains on the left side as far down as the fourteenth mile; it then crosses a third time, to follow the right side of the valley as far down as opposite the mouth of Little Will's Creek.

The considerable descent in so short a distance, the contracted breadth of the valley, the steepness of its sides, the great quantity of excavation in rocky ground, will concur together to render this subdivision very expensive in proportion to its extent. The distance between the heads of two consecutive locks will not be less than 180 yards. The first six miles will be fed, as stated before, by the summit-level; the remainder will be supplied by Will's Creek. To that effect dams, erected at suitable places, will afford the means of taking into the canal not only the waters of the creek, but also those of its tributaries.

The estimate of this subdivision amounts to (the eastern basin and deep-cut excluded) $2,300,859.28.

Subdivision 2.-From the mouth of Little Will's Creek to the western end of the eastern section, below Cumberland:

Distance, 13 miles; descent, 309 feet; 39 locks. From the summit-level, twentynine miles 240 yards; descent, 1,325 feet; 166 locks.

At the commencement of this subdivision the line of canal takes a sudden change of direction from nearly east and west to almost north and south. The valley also changes its character, becoming broader, more level, and less rapid in its descent.

The canal continues for ten and one-half miles on the right bank of the stream, passing alternately along steep and rocky hill-sides and through meadow-land, but even in the latter requiring a large quantity of excavation of rock. It then passes over to the left bank, and continues for more than half a mile on favorable ground, when it enters the defile formed by the breaking of Will's Creek through the mountain of the

same name.

The difficulties of this passage are great, and continue for more than a mile. The ground then becomes favorable, permitting the canal to pass at the outskirts of Cumberland, to join with the eastern section.

Provision is made for taking in a supply of water immediat ly below the junction of Great and Little Will's Creeks, and also at several points below. Adjoining Cumberland, the canal will receive a feeder from the Potomac for a supply below, and more especially to complete what is necessary in relation to the first subdivision of the eastern section.

This feeder is proposed to be made navigable, in order to accommodate the trade of the Potomac above Cumberland. Its length is one mile; its width, at the waterline, 30 feet; its depth, 4 feet. At its point of departure from the Potomac a basin is formed in the bed of the river, by means of a dam erected at the first ledge above.

The

Cumberland. This basin, comprehending an extent of about eight miles, will afford a constant supply of water, and also accommodate the coal-trade of the Potomac. levees around the basin, the dam, the guard-lock of the feeder, the feeder and its aqueduct over Will's Creek, are included in the estimate of this subdivision.

A basin is contemplated at Cumberland, and adapted to the probable wants of the place; it will be provided with locks to communicate with the Potomac.

The estimate of this subdivision amounts to $1,555,764.32. The estimate of the eastern portion amounts to $3,856,623.60.

WESTERN PORTION.

Subdivision 1.-From the western end of the summit-level to the mouth of Middle Fork Creek:

Distance, 163 miles; descent, 216 feet; 27 locks.

This subdivision commences at the western end of the basin formed in the valley of Flaugherty's Creek, and into which is introduced the feeder from the reservoirs in the valley of Casselman's. Having already stated all the details relating to this appendage of the summit-level, we find ourselves dispensed from entering into further expla nation upon the subject.

The canal for this subdivision is on the right bank of Casselman's River. On this distance, although no very formidable difficulties are presented, yet the amount of excavation of rock, as also the great quantity of walling, will render the work very expensive. The first six miles are to be fed by the summit-level, as it has been stated; as to the remainder, provision has been made, at several places, for taking from Casselman's River additional supplies.

It is to be observed that this upper subdivision of Cassel man's River has a descent less rapid than that of the lower; the reverse takes place in the valley of Will's Creek.

The estimate of this subdivision amounts to (the western basin and deep cut excluded,) $1,240,215.32.

Subdivision 2.-From the mouth of Middle Fork Creek to the mouth of Casselman's River:

Distance, 19 miles 1,030 yards; descent, 420 feet; 53 locks. From the western end of the summit-level, 35 miles 1,250 yards; descent, 636 feet; 80 locks.

This subdivision keeps on the right bank of Casselman's River, as far down as 440 yards below its mouth. The nature of the ground through which it passes resembles that of the subdivision above, except in the vicinity of the Youghiogheny, when it becomes much more favorable, offering more earth and less rock for excavation than above. Occasional resorts to the stream will secure to the canal a competent supply of water. And at the end of this subdivision, two feeders, one from Casselman's River and the other from Laurel Hill Run, are introduced for the supply of the section descending the valley of the Youghiogheny.

According to the documents hereto annexed, the estimate of this subdivision amounts to $1,459,316.93. And the estimate of the western portion amounts to $2,699,532.25. We close the description of the present middle section by offering the following summary of the main facts relating to it:

This section commences 440 yards below the junction of Casselman's River with the Youghiogheny; it follows the right side of the valley to the Monongahela, and hence to Pittsburg, along the right bank of this stream.

The ground on the left of the Youghiogheny is nearly of the same kind as that on the right; the distance and descent the same for either bank; however, the right bank deserves the preference on account of exposure, and of its receiving the main tributaries of the stream; it will not require, across the Youghiogheny, two aqueducts, which would otherwise become indispensable, should the canal follow the left side of the valley.