inches, 63 mean temperature; from 1st to 30th September, twelve days of rain, 3.15 inches, 51° mean temperature; from 1st to 31st October, nine days of rain, 3.19 inches, 44° mean temperature; from 19th July to 31st October, thirty-three days of rain, 13.01 inches. During one hundred and four days, of which thirty-three were rainy, there fell 13.01 inches of rain. The evaporation was 0.10 inch a day, and during the one hundred and four days, 10.40 inches; of course the rain more than supplied the loss of evaporation.

The temperatures marked above are the mean temperatures of the rainy days. The highest temperatures in that valley, during these months, were at midday; in July, 76; in August, 74°; in September, 70°; in October, 72°. The lowest were at 6 in the morning; in July, 53; in August, 44°; in September, 32°; in October, 25°. From these observations it is evident that less evaporation is to be apprehended in the valley of Deep Creek than in regions nearer to the level of the ocean; besides, by raising the dam which forms its reservoir, we might add to it a quantity of water sufficient to supply all the loss of its evaporation and filtration. We will conclude these remarks on the reservoir of Deep Creek by observing that its surface lies below the mouths of its tributaries, and that they might, therefore, at small expense, be turned into reservoirs to preserve the waters of the valley, when (the great reservoir of Deep Creek being full) they would otherwise escape over the dam. For this purpose, the dams of these small streams should have sluice-gates, to distribute their supplies whenever required.

SUMMIT-LEVEL OF THE MIDDLE SECTION.

From these observations it is evident that the eastern and western branches of the middle section possess sufficient supplies to repair their losses from filtrations and evaporation. The first is fifteen, and the second fourteen and three-fourths miles in length; and both, twenty-nine and three-fourths miles. If we subtract this length from that of the whole Deep Creek route, forty-one miles 718 yards, there will remain eleven miles 1,158 yards, or about eleven and three-fourths miles. If we subtract it from the length of the Youghiogheny route, (fifty miles 1,172 yards,) there will remain twenty miles 1,580 yards, or about twenty-one miles. These portions, on either of these routes, may be designated as their summit-levels. On the Youghiogheny route this portion might, perhaps, be dropped below the reservoirs of the Youghiogheny; but its length and expanse of water, which is our present object, would remain the same on either level. We should now examine, first, what means exist to feed these summit-levels; second, what each of these requires to supply all its wants and losses; third, what are the respective advantages of the one and the other, and which is the most advantageous with respect to that question.

The Great and Little Youghiogheny and their upper tributaries are the only streams of any importance which can feed either of these summit-levels. Their levels with respect to the base-mark, and at different points, are as follows:

Feet.

Level of the Great Youghiogheny, at the mouth of Deep Creek below the basemark

250.00

Level of the Great Youghiogheny, at the head of Swallow Falls, below the basemark

140.81

Level of the Great Youghiogheny, one mile above the mouth of Indian Run, below the base-mark

70.50

Level of the Great Youghiogheny, two miles above the mouth of Indian Run, below the base-mark

64.00

Level of the Great Youghiogheny, at the mouth of the Little Youghiogheny, below the base-mark..

53.00

Level of the Great Yonghiogheny, at the mouth of Snow Creek, two miles above the bridge, below the base-mark...

36.69

Level of the Great Youghiogheny, at Charles Glade's Run, below the basemark.

28.72

Level of the Great Youghiogheny, at the mouth of Cherry tree Creek, below the base-mark..

26.18

Level of the Little Youghiogheny, where it is crossed by the State road, below the base-mark....

44.00

These levels being all below the base-mark, proved that whichever summit-level we adopt we must elevate the waters of the two Youghioghenies by throwing great dams across them. The height of these dams would be lower and a less quantity of lockage required if we dropped the summit-level of the Youghiogheny route; but the length of the tunnel from Crabby's Arm, and deep cutting at each of its extremities, would then be proportionably augmented. For the sake of comparison, we have, therefore, supposed those two routes on a level. A passage was sought to open a communication between Deep Creek and the Great Youghiogheny through the opposite valleys of

Indian Run and Cranberry Run. But as the sources of these runs rise 226 feet above the base-mark, and the Youghiogheny at the Indian Run lies 70.50 feet below it, a dam across the Youghiogheny, and tunnel through the Roman Nose Ridge, would both be indispensably required to accomplish this object.

An attempt was also made to lead Muddy Creek, which from the west falls in the Yonghiogheny, to the summit-level of these routes. But to lead it to the summit-level of the Deep Creek route it would be necessary to conduct it by a long aqueduct upward of 140 feet high, and to lead it to that of the Yonghiogheny, to run a feeder upward of thirty miles before it reached the mouth of Indian Rub, and which would absorb by filtrations and evaporation, during its course, most of the water which it would receive. Aqueducts through the ravines which it should wind around would shorten it, but a great number of them would be required, and their construction would be very costly.

To ascertain the relative levels of Pine Swamp (where rise the springs of Muddy Creek of Youghiogheny, and Muddy Creek of Cheat River) and Deep Creek, a level was run to the summit of the ridge which divides the waters of the Youghiogheny and - Cheat Rivers; this ridge, parallel to the Roman Nose Ridge, is called Snaggy Mountain. From this level it appeared that the point from which rise the highest springs of the two Muddy Creeks is 75 feet above Pine Swamp, and 226.77 feet above the basemark. This result, which proved the impossibility of running the canal in this direction from the mouth of Deep Creek, proved also that a reservoir of three or four miles area might be formed in the Pine Swamp, and that being raised at least 150 feet above the base-mark, a feeder might be led from it, following the eastern ridge of Snaggy Mountain, and joining Snowy Creek, after winding around the heads of the tributaries of the Yonghiogheny, from Snowy Creek to Muddy Creek. This feeder would be from eight to twelve miles long, and to form the reservoir a dam might be thrown through Muddy Creek, of the Yonghiogheny, at the gap where it breaks through Snaggy Mountain. This reservoir would afford an important supply, if those of the Little and Great Youghiogheny should prove insufficient to feed the summitlevels. We shall now enumerate and measure the capacity of these several reservoirs, and give all the necessary details of them.

Reservoir No. 1 might be formed in the main branch of the Great Youghiogheny by throwing a dam across it, above the mouth of Cherrytree Creek. It should be 40 feet high to raise the water 6 feet above the summit-level and allow to the feeder a descent of 6 inches per mile; height of its dam, 40 feet, and length of its feeder, to the dam in Deep Creek, sixteen miles. Area of the reservoir exposed to evaporation, 2,894,333 square yards; its prism, or capacity of water above the base-mark, 5,523,370 cubic yards.

No. 2 might be formed in Cherry Creek by throwing a dam across it above its mouth. The dam should be 40 feet high, and the length of its feeder sixteen miles. For this and all the following reservoirs we shall allow the same data, 6 feet water above the base-mark and 6 inches descent per mile for their feeders. Area, 1,752,000 square yards; prism, 3,170,148 cubic yards.

No. 3 might be formed on Youghiogheny, between Cherry and Snowy Creeks, by throwing a dam through it above the mouth of Snowy Creek. Height of the dam, 50 feet; length of the feeder, fourteen miles. Area, 1,475,444 square yards; prism, 2,796,518 cubic yards.

No. 4, receiving Laurel Creek and Snowy Creek, might be formed by throwing a dam across the latter above its mouth. Height of its dam, 50 feet; length of its feeder, fourteen miles. Area, 3,444,444 square yards; prism, 6,536,666 cubic yards.

No. 5 might be formed in the Great Youghiogheny, between Snowy Creek and the Little Youghiogheny, by throwing a dam across it above the month of the Little Youghiogheny. Height of the dam, 67 feet; length of the feeder, ten and a half miles. Area, 2,833,332 square yards; prism, 5,555,555 cubic yards.

No. 6 might be formed in the Little Youghiogheny by throwing a dam across its mouth. Height of the dam, 67 feet; length of the feeder, eleven miles. Area, 53,375 square yards; prism, 106,750 cubic yards.

No. 7 might be formed in Dunker's Lick, by throwing a dam across it, above its mouth. Height of the dam, 75 feet; length of the feeder, nine miles. Area, 1,055,555 square yards; prism, 1,851,851 cubic yards.

No. 8 might be formed in the Great Youghiogheny, between the mouth of the Little Youghiogheny and the ledge, by throwing a dam across the ledge. The height of this dam, 94 feet; length of the feeder, six and a half miles. Area, 2,770,666 square yards; prism, 5,303,555 cubic yards. Area of all the reservoirs, 16,279,149 square yards; prism of all the reservoirs, 30,844,413 cubic yards.

If we dispense with the last two reservoirs, whose dams are the highest and most expensive, the five remaining reservoirs above the mouth of the Little Youghiogheny will contain: Area exposed to evaporation, 12,452,928 square yards, or 4135 square miles, or 2,572.80 acres. Prism of their waters, 6 feet above the base-mark, besides

6 inches allowed per mile of the length of the feeder of each reservoir for its descent. These are all available to supply the summit-level 23,689,007 cubic yards.

These reservoirs are all independent of one another, and the higher ones may pour the surplus of their waters into the lower ones. Those numbered 3 and 5 in the Great Youghiogheny may be regarded as one, to which all the others can contribute when circumstances require it. The dam No. 3 might even be suppressed, which would reduce the number of dams to 5, but the proper location of these dams, as also their number and dimensions, will receive further investigation, which belong to the final project; their number will likely be reduced.

As to the total quantity of water which these basins might hold, if we suppose their mean depth 16 yards, and a middle horizontal section run between the surface and bottom, equal in area to one-half of the upper surface, or to 6.226,464 square yards, (half of 12,452,928 square yards,) it will amount to 99,623,424 cubic yards, or, in round terms, 100,000,000 cubic yards.

As to the time necessary to fill them, from observations taken with care, from 1817 to 1824, inclusive, by Mr. Lewis Brantz, in the vicinity of Baltimore, Md., we have the following results: In the course of eight years, from 1817 to 1824, there fell, on a mean average, yearly, 39.89 inches. In 1822 there fell the smallest quantity. The summer was very dry, vegetation deficient; the crops of grain were short. The quantity of rain which fell that year was 29.20 inches. The greatest quantity which fell was in 1817. It amounted to 48.55 inches. Applying these data to the country round the summit-level, and using only the results of the year 1822, the rain which fell in the first three and last three months of this year amounted to 16.70 inches, while that which fell in the same months of the year 1817 amounted to 18.40 inches. These 16.70 inches are equivalent to 0.465 cubic yards. Thus, during the first three and last months of each year, there will fall at least 0.46 cubic yards of rain on each square yard of the heads of the Youghiogheny, and an area of 217,391,304 square yards would be required to collect water for filling the 100,000,000 cubic yards of the reservoirs. This area amounts to 70.18 square miles; and the area of the valleys of the two Youghioghenies, above their junction, and the surface of the reservoirs amounts to much more. Besides, the heads of Cheat River could, perhaps, be brought to feed the reservoirs. These reservoirs once filled, the mass of waters which lies lower than the head of the feeders will never alter, and the upper part, which feeds the summit-level, will alone require to be renewed every year. We have seen that it contains 23,689,007 cubic yards.

The least quantity of water which the Great Youghiogheny gave in 1824, under the bridge on the road from Mansfield to Morgantown, was on the 21st of September-22.58 feet in a second. The little Youghiogheny gave, on the 23d of September, 1824, at German bridge, 4.30 feet. Total given by those two streams in a second, at their lowest stage, 26.88 feet.

This is the minimum which they can give to supply the reservoirs. In one month it would amount to 2,580,480 cubic yards, and supposing, what is most. unlikely, that the two Youghioghenies and their tributaries should remain in this state, and give no more for six months, from May to October, it would supply the reservoirs with 15,482,8-0 cubic yards; and as during the six preceding months they would have received much more, they would be full at the opening of navigation, and receive every month at least 2,580,480 cubic yards as regular tribute.

We do not consider in this calculation the loss by filtration and evaporation, for by raising the dams of the reservoirs, a quantity of water would be added to them, which would overbalance it.

We must now compare those supplies, the minimum of what the heads of the two Youghioghenies can furnish, with the maximum of what either of the two summit-levels will require.

They will both require the same expense of water for lockage. We know that two lockfuls is the maximum expense for raising or lowering a boat, and eight minutes are required for its passage through a lock of 30 yards in length, 54 yards in breadth, and 2 yards in lift. Such a lock will contain 426.66 cubic yards, without deducting from it the draught of water of the boat, and its passage (at the maximum) will thus consume 853.32 cubic yards, or 854 cubic yards at most. Now, if the canal is navigated nine months, or two hundred and seventy days a year, at ten hours a day, and that the locks of the summit-level be kept in constant operation all that time, they might pass, allowing eight minutes for each boat, 20,250 boats, at an expense of water equal to 17,293,500 cubic yards for the nine months, or 1,921,500 cubic yards a month. This maximum of water for the expense of lockage is 658,980 cubic yards less than the minimum which the reservoirs will receive during that time.

The expense of water for lockage being 17,293,500 cubic yards, and the reservoirs containing 23,689,007 cubic yards, there will remain in reserve to supply the losses of the summit-level from filtrations and evaporation, 6,395,507 cubic yards.

The summit-level of Deep Creek, extending eleven and three-quarter miles in length, will require 413,600 cubic yards to fill it; and supposing that it loses by filtrations

and evaporation the value of its prism every month, or nine times in the year, it will expend 3,722,400 cubic yards. The profile of its feeder having a supposed area of 10 square yards, and a length of ten and one-half miles, it will consume, at the same rate, 1,663,200 cubic yards. Total consumption for nine months, 5,385,600 cubic yards. Retrenching this quantity from the surplus mass of the reservoirs, there will still remain 1,009,907 cubic yards, which, after supplying all the waste of lockage and the losses of the summit-level from filtrations and evaporation, will serve as an additional supply to repair those of the eastern and western branches of the middle section.

The Youghiogheny summit-level, extending twenty-one miles in length, will lose, from filtrations and evaporation, on the same principle, 739,200 cubic yards a month, (the value of its prism,) and 6,652,800 cubic yards in nine months. It would thus absorb the whole surplus mass of the reservoirs, after the waste of lockage, and require a much greater expenditure of water than the Deep Creek summit-level.

Thus the important advantages of a greater supply of water, of a length shorter by nine miles, of a tunnel shorter by two and a half miles, render the Deep Creek route superior to the other; though the final surveys only can settle that point, yet at this stage of our operations we would recommend that route in preference. However, the analysis which we have just concluded is a convincing proof that a canal by either of those routes over the chain of the Alleghanies, between the mouths of Savage River and Bear Creek, is perfectly practicable. The total distance from the mouth of Savage River to that of Bear Creek will be forty-one miles at least; the rise from the mouth of Savage River to the base-mark, 1,432 feet; and the fall from the base-mark to the mouth of Bear Creek, 956.35 feet; total of lockage, 2,388.35 feet.

The preparatory surveys executed on this middle section were performed by Captain McNeill, of the United States Topographical Engineers, and Mr. Shriver, assistant civil engineer, employed by the United States. The talents and activity displayed by these gentlemen and their assistants enabled the board to collect the facts on which they rest their opinion of the practicability of this middle section, and of the best direction through which its route can be directed.

Captain McNeill was assisted in these labors by Messrs. De Russy, Cook, Trimble, Hazard, Dillahunty, Fessenden, and Williams, lieutenants of artillery, whose scientific education, imbibed in the Academy at West Point, was thus made valuable in the most efficient and useful manner to their country and to themselves. Mr. Shriver was assisted by Messrs. Jonathan Knight, John S. Williams, Freeman Lewis, and Joseph Shriver. The memoirs, surveys, and maps of these gentlemen accompany this report. Before we conclude the article relating to this middle section, we should give an analysis of two other routes which have been proposed for leading the canal over the Alleghany; the one by ascending Will's Creek, (a stream which falls in the Potomac at Cumberland,) and descending to the Youghiogheny by the valley of Casselman's River; the other by passing from the valley of the Potomac to that of Cheat River, and thus descending to the Monongahela.

First. Two of the head springs of Will's Creek rise very near Flaugherty Creek, which falls in Casselman's River, below Salisbury; the eastern is called Laurel Run and the other Shock's Run. The shortest distance between Laurel Run and Flaugherty Creek is one mile 756 yards. It was measured from Wilhelm's saw-mill, on Laurel Run, to Engle's saw-mill, on Flaugherty Creek. The first is 156 feet lower than the second. A deep cut of 333 yards long and 35 feet deep, in the highest part of it, on the side of Engle's saw-mill, a tunnel of 1,483 yards, and another deep cut 700 yards long and of the same depth as the former, on the side of Laurel Run, would be required to unite those two streams. The greatest height of the ridge above the bed of the tunnel would be 156 feet. This route offers great advantages if we only considered the shortness of the distance and tunnel; but as to the essential condition of a sufficient supply of water, it is absolutely out of the question. Flaugherty's Creek, at Engle's mill, gives only 0.415 cubic foot in a second, and Laurel Run, at Wilhelm's mill, 0.600 cubic foot, (at their lowest stage in 1824.) They would only give, together, 1.015 cubic feet per second to feed the whole summit-level. The details, which we have already given in analyzing the Deep Creek route and summit-level, are sufficient to show the impracticability of running a canal by the route of Flaugherty's Creek with so small a supply of water.

As to the route between Shock's Fork and Flaugherty's Creek, the season was too advanced to measure accurately its length, or the tunnel and deep cuts which it would require.

Their profile will be surveyed next season. This route would be longer than the other, and its summit-level should be fed by the waters of Castleman's River above Salisbury, led by a feeder to the western extremity of the tunnel. This feeder, following the eastern side of Castleman's Valley, would receive the waters of its tributaries between Salisbury and Flaugherty's Creek. At their lowest stage these tributaries gave, Itogether, 5 fe t in a second, and Castleman's River, above Salisbury, 15.33 cubic feet; total, 20.33 cubic feet to feed the summit-level. This quantity is not considerable when we consider that, on a length of thirty miles from the summit-level to Cumber

land, the canal would have to draw most of its water from Castleman's River, for Will's Creek is a torrent, which, in the greatest part of its course, gives but little water in summer. The length of this summit-level, and of the route which the canal would thus trace, are less than by Deep Creek. As to their comparative heights, no survey was made in the season of 1824 to ascertain the difference. We shall now expose the reasons why the western branch of the canal was not led through the valley of the Monongahela, (before concluding this part of our report.)

We have already seen that the valley of Cheat River, through which it would be necessary to pass to the Monongahela, is divided from the Upper Youghiogheny by a ridge whose greatest depression, at the head of the two Muddy Creeks, is 226.77 feet above the level of the base-mark. A tunnel would, therefore, be necessary to pass from the valley of the Youghiogheny to that of Cheat River.

A single inspection of the map will show that the route of the canal would be very much lengthened by running its summit-level from the heads of the North Branch of the Potomac to those of Cheat River, and that it should be raised to a much higher level than on the route of Deep Creek. There is every reason to believe that the bed of Cheat River has a more rapid descent than that of the Youghiogheny; and that where it forces through the Laurel Hill, it is already nearly on a level with the Youghiogheny at Connellsville, for at this gap and a little above Furnace Run it begins to be navigable. Its bed is here about 150 yards wide. The highest floods in Cheat River do not rise above eight or ten feet at Furnace Run, and at its lowest stage in August and September it is very low at this place, and often fordable. Indeed, Cheat River to its junction with the Monongahela receives no stream of any importance but the Big Sandy, whose supply is constant, but in the summer is very trifling, even toward its mouth and in the lower part of its course. After descending along a rocky and very precipitous bed, Cheat River mingles its clear and limped waters with the muddy stream of the Monongahela, whose bed and shores are all formed of alluvial soil.

The Monongahela has absolutely the same features as the Ohio; its shores are flat, but raised perpendicularly along both sides of the river to the height of 15 or 25 feet above the line of water, formed of a rich alluvial soil. They are covered by the current, and when the river rises they crumble into it and render its waters muddy. The floods of the Monongahela are considerable. At Brownsville it rises 38 feet, while at its lowest stage its depth is only from 12 to 15 inches on its highest bars. The two banks present all along a succession of flats and bluffs. The flats of one bank are generally opposite to the bluffs of the other, and the former are found where the river expands, while the latter close on its banks where it narrows. The chief tributaries of the Monongahela are on its right shore: George's Creek, below Mr. Gallatin's residence; Big Redstone, below Brownsville; and on the left, Ten-Mile Creek. These streams flow constantly, but in summer give but a small quantity of water; an observation which is also applicable to many of the tributaries of the Youghiogheny.

If the western section of the Chesapeake and Ohio Canal cannot be led to the Monongahela, it will at least embranch with it at McKeesport, and perhaps, when a denser population will render it desirable, a line of junction may be drawn between Cheat River and the Valley of Youghiogheny. It would be fed by a reservoir above the gap of Cheat River and the constant springs which run from the western ridge of Laurel Hill.

WESTERN SECTION.

This section begins at the mouth of Bear Creek and ends at Pittsburgh, descending the valleys of the Youghiogheny and Monongahela to the Ohio.

From the mouth of Bear Creek to that of Castleman's River the Yonghiogheny runs in a very winding course between a succession of flats and bluffs, the flats of one shore being generally opposed to the bluffs of the other; the banks high and rugged where they wind in, and flat where they wind out. The two banks present nearly the same difficulties. The right shore, however, seems the best. The distance between those points, following the winding of the river, is about sixteen and a half miles.

Castleman's River is about one hundred yards wide at its mouth. It is a fine river, and will give a great deal of water to the canal. At the driest season it offers from 8 inches to 1 foot in depth. Before joining the Youghiogheny it receives Laurel Hill Creek.

From the mouth of Castleman's River till you reach two or three miles above Connellsville, the Youghiogheny forces through Briery Mountain and Laurel Hill, and its bed is very deep. The left bank is very high and rugged, the right somewhat less. In this space of abont twenty-eight and a half-miles the canal must be frequently cut in a shelf on the sides of the valley, or run on embankments supported by a wall. The river has a fall of about 16 feet at Ohiopyle Falls; it is here about 150 yards wide. Connellsville is considered as the head of navigation in the Youghiogheny. In the driest season it has here from 8 inches to 1 foot in depth.

From Connellsville to Robstown the river winds during twenty-four or twenty-five