Of these unpretending, but attractive-looking places, there are numbers in this neighbourhood; and if ever Washington rises to the importance fondly anticipated by its founders, no city ought to boast more charming environs. Here is no end of sites for country dwellings,--valley and hill, river and rivulet, towering rocks and dark ravines abound in as wild a variety as heart could wish; with land and living both exceedingly cheap. I saw one of the prettiest houses possible, with nearly a hundred acres of land, that had been purchased, a few months before, for five thousand dollars; and, during my stay here, a first-rate house, with stabling, &c. complete, as well situated as any in Washington, and as well built, sold for the same sum. At present, indeed, I should say land about here is of very little value: though admirably calculated for the residence of an independent class of gentry, here is no temptation for the planter or merchant; and but few in this country seek to live a life of leisure or retirement. THE FALLS OF THE POTOMAC. On St. George's day, in company with Captain T----ll, an engineer officer of high standing, and Mr. K----r, I set out on horseback, at an early hour, to view the much talked of, but too rarely visited, Falls of the Potomac. Our way lay along the tow-path of the Chesapeake and Ohio canal, planned to unite the Potomac river with the Ohio below Pittsburg,--one of the greatest works yet contemplated. Its length will be three hundred and forty miles: the locks are of stone, one hundred feet by fifteen; and the amount of lockage designed for the whole line is three thousand two hundred and fifteen feet. Piercing the Alleghany mountains, where the canal attains its highest level, a tunnel is planned, four miles and some yards in length. For upwards of a hundred miles the line is already available; and in this distance are reckoned forty-four locks, and several noble aqueducts, in an ascent of a quarter of a mile. For sixteen miles we followed this magnificent work, which as far as one of the uninitiated may judge, presents a promise of endurance worthy the best days of Rome: the width of the canal here varied, as my companion informed me, from eighty to seventy feet, and the depth from six to seven feet. Independent of this work, in itself so interesting, the scenery is varied and striking. Upon our right lay the canal, to whose course all nature had been subdued,--the forest rooted up, the Potomac bestridden by an aqueduct eighteen hundred feet in length, beds of solid gneiss hewn out fathoms deep, valleys filled up and ramparted with granite against the assaults of the near river; everything on this hand was trimmed and levelled in a workmanlike manner: the labour of man was evident throughout, and the well-trained water stood still, or moved onward or backward, as directed by its master.