The finest and most appropriate place to form a lake, is in the bottom of a small valley, rather broad in proportion to its length. The soil there will probably be found rather clayey and retentive of moisture; and the rill or brook, if not already running through it, could doubtless be easily diverted thither. There, by damming up the lower part of the valley with a head of greater or less height, the water may be thrown back so as to form the whole body of the lake.