A mysterious balloon, with two men in it, passed over this city about 5 o'clock this afternoon, from west to east, at a great heighth [sic]. The sensationists have it that it was in the service of the traitors, and that it had C.S.A. [Confederate States of America] conspicuously painted on its sides; others say, which is more probable, that it was one of Prof. LOWE's, which had parted its fastenings and started off on its own hook.