Meanwhile the young Moslem and his companion in misfortune, who had been brought prisoners to Gradiska, were confined in one of the massive towers which flanked the castle.  They had arrived not long before the comencement of the festival, and when going under guard along a corridor in the east wing, Ibrahim passed the open door of an apartment in which Strasolda was adjusting the rich jewels of the counsellor’s lady before her appearance in the ball-room.  Startled by the approaching tramp of armed men, the Uzcoque maiden raised her eyes, and beheld the noble and well-remembered features of the young Turk, whose captive she had been, and whose image had so strangely reappeared to her through the flitting cloud of smoke in the cavern.  “Mother of Heaven!” she exclaimed, covering her eyes with her hands; “do I again behold that Moslem youth, ever appearing when least expected?” Again she gazed; but the prisoners, hurried onward by their guards, had proceeded to the end of the corridor, where a narrow winding staircase, fashioned in the immense thickness of the tower wall, led to their appointed prison, a large square apartment, the sides of which were panneled to a considerable height, and imperfectly lighted by small windows, or rather embrasures, perforating a wall many feet in thickness.  Here they were left to their reflections, and to what comfort they could derive fron a lamp and a supply of provisions.  Hassan, wearied with his journey, hastily swallowed his supper, and, stretching himself upon a paillasse, soon forgot his calamities in sound repose.  Ibrahim, more vigilant and less apprehensive of future evil, as the Turks and Austrians were then at peace, paced awhile along the floor of his spacious prison, musing on the peerless charms of the Uzcoque maiden.  From time to time he gazed upon the walls and windows as if calculating the chances of escape, when gradually the peculiar and regular design of the panneling caught and fixed his attention.  It was divided by prominent mouldings into oblong squares, from the centres of which projected large diamond-shaped bosses of carved oak.  This peculiarity at length roused into action some reminiscences of the early life and adventures of his beloved patron, the pacha of Bosnia, to the recital of which he had often, in his boyhood, listened with eager delight.  These recollections, at first shadowy and indistinct, became gradually more vivid and accurate, until finally the full conviction flashed upon him that his benefactor, when taken prisoner in his youth by the Austrians, had been confined in this very tower and room, and, by a singular discovery, had been enabled to liberate himself and his fellow-prisoners.  The pacha, then a subordinate in rank, in endeavouring to reach the level of one of the embrasures, had mounted upon the shoulders of a comrade, and was supporting himself by a firm grasp of the large boss in the centre of the pannel, when suddenly he felt it turning round in his hand.  Surprised to find it not a fixture,