"The Marriage of Figaro," by Mozart, was performed at the Karnthnerthor Theatre to-night, and this favorite opera of the Viennese had attracted so large an audience that not a seat was vacant, and the baron had to elbow his way with no little difficulty through the crowd filling the pit, in order to reach a point where he might be able to see every part of the house, and discover him for whose sake he had come. At length he had succeeded in advancing so far that, leaning against one of the pillars supporting the upper tiers of boxes, he was able to survey the lower part of the house. But all faces were averted from it, all eyes were fixed on the stage. The opera had just reached the scene where Count Almaviva lifts the carpet from the chair and finds Cherubino under it. A loud outburst of laughter resounded from the pit to the upper gallery. But in the midst of the din, a loud and angry voice exclaimed: "Ah, you young good-for- nothing, if I had you here I would show you how to behave!" And a threatening fist and vigorous arm was raised in the midst of the orchestra-stalls. "Good heavens! that is really Andreas Hofer," murmured Baron von Hormayr, concealing himself anxiously behind the pillar. A renewed shout of laughter greeted Hofer's words, and all eyes turned toward the side where they had been uttered. And there sat the good Andreas Hofer, in his handsome national costume, with his long black beard, and his florid, kind-hearted face. There he sat, quite regardless of the gaze which the audience fixed upon him, utterly unaware of the fact that he was the observed of all observers, and quite engrossed in looking at the stage, where proceeded the well-known scene between Cherubino, the count, and Figaro. He followed the progress of the action with rapt attention, and when Cherubino tried to prove his innocence by all sorts of plausible and improbable falsehoods, Hofer's brow became clouded. He averted his eyes from the stage, and turned to his neighbor. "Why," he said, loudly and indignantly, "that boy is as great a liar as though he were Bonaparte himself!" Now the merriment of the audience knew no longer any bounds. They applauded, they shouted, "Bravo! bravo!" They forgot the scene on the stage entirely, and devoted their exclusive attention to the queer, bearded stranger in the orchestra-stall, on whom all eyes and opera-glasses were fixed. Baron von Hormayr behind his pillar wiped the perspiration from his forehead, and cast furious glances on Andreas Hofer, who, however, was utterly unaware of his presence, and from whose breast, protected as it was by his beard and crucifix, rebounded all such glances like blunted arrows.