We arrived at Aix at 3 P. M., and having taken a place for an evening ride to Liege, and had my passport _vised_ at the Hotel de Ville, the next thing was to visit the cathedral containing the bones of the great CHARLEMAGNE. His tomb is under the floor, in the centre of the church, and is covered by a plain marble slab, on which is inscribed in _lofty_ simplicity, 'CAROLUS MAGNO.' After looking at the throne of the 'grand monarque,' and at the immense windows of the choir, (remarkable for the lightness and elegance of their frames,) we were conducted by a priest to a closet, or _sanctum sanctorum_, to see the famous cabinet of precious relics.[12] I send you a printed account of these veritable relics, and as to their authenticity, it is to be hoped your bump of marvelousness is too large to permit you to doubt. Will you not look upon me with a 'thrilling interest,' when I tell you that I have seen and touched them with my bodily hands? They gravely tell you how the 'sacred' articles were obtained, and how they were presented to Charlemagne by the patriarch of Jerusalem. I doubt not they really find them _precious_ articles of speculation, and would be grieved to hear a suspicion of their being genuine. The linens worn by the virgin when Christ was born, are among those too sacred for common eyes, and are only shown in seven years, with much 'pomp and circumstance.' By the way, I saw also the splendid crown of Isabella of Castile and Arragon, (the patron of Columbus,) of pure gold, covered with diamonds. And in London I forgot to tell you of Charlemagne's Bible, a magnificent folio MSS., on parchment, richly illuminated, etc. It had intrinsic and unquestioned evidence of being executed for the emperor by Eginhard, the historian of that period. It was 'bought in' at auction, for £1500, ($7,500,) but finally sold to the British Museum. But you must be tired of relics. * * * * * LIEGE, SEPTEMBER 16.--Last evening I reconnoitred the town of Aix la Chapelle, heard two acts of the 'Marriage of Figaro' admirably sung in the Grecian Opera-House, and then stepped into the 'Schnell-Post.' On the frontiers of Belgium, about midnight, we were stopped at a 'Bureau de Police,' our luggage was all taken off and searched, and our passports examined, during which operations we all 'kept our patience,' save a poor Frenchman, who had to pay duty on a couple of boxes of cologne, snugly stowed in his trunk. After rewarding the worthy gentlemen for their politeness, we were suffered to proceed.