THE Great Falls of the Potomac, some fourteen miles above Washington, possess an indescribable grandeur. The Potomac rises in a spur of the Alleghany Mountains, and several streams are combined with it in its downward course. Forty-seven miles below the gap at Harper’s Ferry, where the river bursts through the mountains, are the Great Falls, formed by the waters impetuously forcing a passage through a stupendous ridge of granite which here restrains the cur-rent from side to side. The river gradually narrows as it approaches the barrier, until it is only about three hundred feet wide, and then with a mighty effort rushes over the granite walls, making a descent of forty feet into hollow rocks. It then continues its course with amazing velocity, dropping foot by foot in a series of cascades, until its ” perpendicular pitch ” is eighty feet in a distance of about two miles. On the Virginia shore huge masses of rock stretch upward for seventy feet, and on the Maryland shore are ledges and boulders, over which the waters dash in great billows of foam. Ten miles below the Great Falls are the Little Falls, a succession of rapids with a total descent of twenty feet. Leaving these rapids, the river glides calmly toward Washington with nothing to obstruct its passage. The scenery around the Great Falls and Little Falls is very wild and picturesque. Cabin John Bridge, a notable example of bridge building, crosses the river between the two series of falls. It conveys the aqueduct of the Washington Water Works. It is four hundred and twenty feet long, and has an arch of two hundred and twenty feet, which is said to be the largest in the world. The bridge is constructed of massive granite blocks, and cost $237,000.
THE Chesapeake and Ohio Canal, by means of which immense quantities of coal are brought to Georgetown from the mines of West Virginia and Maryland, and grain and produce from the West, ex-tends to Cumberland, Md., a distance of one hundred and eighty-four miles. For the first fifty miles from Georgetown, it is sixty feet in width ; then it has an average width of fifty feet to its terminus, with a depth of six feet. On its course are seventy-five capacious locks, eleven aqueducts, and nearly two hundred culverts. Water is supplied to it from the Potomac by numerous dams. The canal was first chartered in 1784, and constructed as far as the Great Falls. In 1828 another charter was obtained from Congress, with the intention of extending the course to Pittsburg, a total distance of three hundred and sixty miles. Work upon the extension was continued until 1841, when Cumberland was reached, and, for various reasons, it was made the terminus. The construction was exceedingly difficult, and cost $13,000,000. Congress appropriated $1,000,000 for the great enterprise, and Washington subscribed $1,000,000, Mary-land, $5,000,000, and Alexandria and Georgetown, $250,000 each. From Georgetown a considerable part of the coal and produce received by the canal is shipped to Southern cities.
At the Georgetown canal terminus is an aqueduct bridge, 1,446 feet long, connecting with the Virginia shore, which carries the Alexandria Canal across the Potomac. The bridge is constructed on huge granite piers of sufficient strength to resist the shock of the masses of ice which come sweeping down the river in the early spring. The canal was incorporated in 1830.