Another pleasant sail of 133 miles carries us from Luxor to Syené, or As-souan (Coptic, _souan_, the opening), Egypt’s extremest boundary, where Juvenal pined in exile, where the first cataracts burst through the gates of Egypt, and where those grand quarries are stationed which have supplied the whole of the roseate granite obelisks of Egypt. We have already had occasion to mention the existence, in these quarries, of an unfinished obelisk not yet reft from the parent rock, but bearing the traces of the artificers’ hands, as though they had unexpectedly been summoned from their work. The dimensions of the Syené obelisk have been variously stated: for example, 100 feet by 11 feet 2 inches; and 95 feet by 11 feet: and a flaw was discovered in the shaft, which has suggested an excuse for its abandonment; while others are of opinion that the flaw is an accident of subsequent occurrence. The excellence of the quality of the granite of Syené, and its property of splitting under the application of suitable force, permitted the separation from the native rock of a single piece of sixty, seventy, and sometimes more than a hundred feet in length. The unfinished obelisk exhibits the contrivance by which these immense stones were severed from the solid rock. In the course of the line which marks the boundary of the obelisk, is a sharply cut groove; and all along this groove, at short intervals, are holes which are intended for the reception of wedges or plugs of dry wood; when the wedges were driven firmly into the holes, the groove was filled with water; the dry wedges gradually imbibed the water and swelled, and the force created by their swelling along a line of considerable length, was sufficient to crack the granite throughout the whole extent of the groove. We are but too familiar with this force in the instance of water congealed into ice; a small fissure or opening of any kind becomes filled with water in the winter-time; the water freezes; frozen water expands, and under the force of that expansion the fissure is doubled in extent. It is this process which is so destructive to the face of buildings constructed of laminated stone; it is this which produces the slide of mountains and the fall of cliffs; and the same force the agriculturist utilises by ploughing, for the purpose of breaking up the clods of his land and pulverising the soil. It has been supposed that the Egyptians sometimes had recourse to another method, which is thus described by our old friend, Charles Knight, in the “Pictorial Gallery of Arts.”