"Aden," saith old Ibn Batuta of Tangiers, "is situate upon the sea-shore--a large city, without either seed, water, or tree." Five hundred years have elapsed since this graphic account was penned, and the vegetation has in nowise improved. An amphitheatre of dimensions sufficient for the Devil's punch-bowl is formed by two volcanic ranges, once in connection, but obviously rent asunder, heaved outwards, and canted in opposite directions by some violent eruption that has forced an opening to the ocean. A sterility which is not to be surpassed invests the scene with an aspect most repulsive and forbidding. No tree varies the dreary prospect, no shrub relieves the eye, not even a flower lends its aid to enliven the wild and gloomy hollow, the fittest refuge that the imagination could picture for the lawless and the desperate. Fortifications are to be traced on every point either liable to assault or eligible for defence: ruined castles and watch-towers perched on the highest elevations of the precipitous hills stand the now inaccessible guardians of other days; and even the limited view to seaward, where the passing white sail of a small coasting craft, or the catamaran of the amphibious fisherman may occasionally be seen, is partially screened by a triangular rock, which frowns like a great spectre over the inner harbour. Seerah, "the fortified black islet," is said to have been the residence of Cain, "the first born of a woman," after the murder of his brother Abel; and, verily, it would be difficult to devise a more appropriate exile for the banished fratricide. Hurled into the sea by a convulsive shock, it is surrounded by pumice and by currents of obsidian, the products of volcanic emission, strewed among vast undulating waves of cavernous lava, or mingled with black masses of porous rock, which bear evidence of fusion, and yield to the touch a metallic sound. Sterility has indeed claimed this dreary region as her own; and even in the more productive portions of the peninsula, little verdure is derived from the almost leafless Besham, the _Balsamodendron Opobalsamum_, a dwarf shrub, which, according to the Arab tradition, formed a part of the present carried to King Solomon by the Queen of Sheba from the aromatic regions of myrrh and frankincense. Where incisions are made in its stem, the far-famed Balm of Mecca flows copiously, but the volatile oil quickly evaporating, leaves a tasteless insipid gum. Nursed by no periodical shower and by no hidden spring, the precious plant, scorched by a withering blast, derives its only moisture from the mists which envelope the mountain-top, when all is sunshine below.