The musical theatres go on languidly. Mercadante's opera, Il Giura- mento,-the revival of which was lately attempted without success at Drury Lane,-was produced on Saturday :at Covent Garden. It was splendidly put upon the stage and admirably performed by Grisi, Mario, Didiee, and Graziani ; but nothing could make up for the inanity of the drama and the weakness of the music. The house was thin, and the audience cold notwithstanding the heat of the weather. At Drury Lane there was a performance on Monday for the benefit of Balfe. The piece was the Italian version of The Bohemian Girl, his daughter appearing in the part of the heroine. She sang and acted charmingly, and was enthu- siastically applauded by a crowded house.