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TERRITORY OF COLUMBIA.
THE Territory of Columbia, which formed a part of the States of Virginia and Maryland, became the permanent seat of Government in the year 1801. This territory, extending on both sides of the Potomac, contains a surface of ten miles square, of which the diagonals are north and south, and east and west. Two of the sides run in a direction from north west to south east, and the two others from north east to south west; so that the angles are each towards one of the Cardinal Points. That of the south is at Fort Columbia, situated at Jones's Point, at the mouth of Hunting Creek, on the left bank of the Potomac. From this point the lines of demarcation run each at an angle of 45° to the distance of ten miles, where they take a
direction perpendicular to the first, forming by their intersection the northern corner.
The Potomac takes its rise in that great chain of mountains known by the name of Alleghany, or Apalaches, which separate the western waters from those that run into the Atlantic Ocean. This river traverses the territory of Columbia, from which to its mouth, in the Chesapeak Bay, it is navigable for the largest frigate-a distance, in following its course, of about 200 miles. .
Mr. Jefferson, in his “ Notes on Virginia,” has given the following table of the breadth and depth of this river, at different places:
Embouchure, or mouth. : . 7 miles in breadth.
* This river formas the line of boundary between the States of Virginia and Maryland, to the distance of three , hundred miles.
Mouth · Ö ö i i
7 fathoms: St. George's Island . . . . . . 5 ditto Lower Matchodic . . . . . . . 4, ditto Swan's Point and Alexandria . . . . 3 ditto .. Thence to the falls, 13 miles above Alexandria, 10 feet.
The tide water flows to the distance of three miles beyond Washington city, where the common tide rises to the height of four feet.
The Potomac, in its course, receives several streams. Of these the most considerable is the Shenandoah, which traverses the Limestone Valley, two hundred and fifty miles in length, and joins the Potomac just before their united streams burst through the chain of mountains called the Blue Ridge.
By a survey of the Potomac, made in 1789, 2 it was ascertained, that at the distance of fifteen miles above the city of Washington, this river is a hundred and forty-three feet higher than at tide-water: that from the mouth of Savage River to Cumberland, a distance of thirty-one miles, the descent is four hundred and forty-five feet, or 141 per mile; and from Fort Cumberland to tide-water, a dis
By Messrs. Gilpin and Smith.
tance of a hundred and eighty-seven miles, the descent is seven hundred and fifteen feet, or 3.29 per mile.
By a' survey, made in 1806, at the expence of the Potomac Company, it was ascertained, that the Shenandoah river, from its mouth to Port Republic, has nearly the same breadth during all this distance of two hundred miles, of which the descent is but four hundred and thirty-five feet.
Both these rivers have been lately rendered navigable by means of locks and canals, constructed at very considerable expence. At the great falls of the Potomac, boats pass through a canal one mile in length, six feet deep, and twenty-five feet wide, descending seventy-six feet by means of five locks, each one hundred feet long, and twelve feet wide: on re-entering the Potomac, its course leads to another canal (at the little falls) of the same capacity, and two miles and a half in length, furnished with three other locks, of which the descent is thirty-seven feet to tide-water. The two last locks, at the great falls, cut out of the solid rock, are each a
hundred feet in length, twelve in breadth, and eighteen in depth, containing about 25,200 cubic feet of water. This work was executed in the space of two years, by a hundred workmen. The other three locks are lined with stone, which is found near the river at the distance of ten miles above the falls. The sluice-gates are of cast-iron, and turn on a pivot fixed in the centre, so that the edge of the gate, when open, is directed towards the stream.
The locks of the little falls, three in number, are constructed of wood, and are each a hundred feet in length, and eighteen in breadth. Mr. Gallatin, late Secretary of the Treasury, from whose report we derive our information on this subject, observes, that this breadth, which consumes much water, is unnecessary. It has been proposed to substitute stone in the place of wood..
Three canals, without locks, have also been completed. The first, below Harper's Ferry, at Shenandoah Falls, where the Potomac breaks through the Blue Ridge, is a mile in length. The second, along the Seneca Falls, is three-quarters of a mile. The third, at