These baths were built in the last great days of Rome, and one reads the last stages of national corruption and, perhaps, the secret of her fall, in the character of these ornamented walls. They breathe the very spirit of voluptuousness. Naked female figures fill every plafond, and fauns and satyrs, with the most licentious passions in their faces, support the festoons and hold together the intricate ornament of the frescoes. The statues, the pictures, the object of the place itself, inspired the wish for indulgence, and the history of the private lives of the emperors and wealthier Romans shows the effect in its deepest colors. We went on to the baths of Caracalla, the largest ruins of Rome. They are just below the palaces of the Cesars, and ten minutes' walk from the Coliseum. It is one labyrinth of gigantic arches and ruined halls, the ivy growing and clinging wherever it can fasten its root, and the whole as fine a picture of decay as imagination could create. This was the favorite haunt of Shelley, and here he wrote his fine tragedy of Prometheus. He could not have selected a more fitting spot for solitary thought. A herd of goats were climbing over one of the walls, and the idle boy who tended them lay asleep in the sun, and every footstep echoed loud through the place. We passed two or three hours rambling about, and regained the populous streets of Rome in the last light of the sunset. LETTER LVII. SUMMER WEATHER IN MARCH--BATHS OF CARACALLA--BEGINNING OF THE APPIAN WAY--TOMB OF THE SCIPIOS--CATACOMBS--CHURCH OF SAN SEBASTIANO--YOUNG CAPUCHIN FRIAR--TOMBS OF THE EARLY CHRISTIAN MARTYRS--CHAMBER WHERE THE APOSTLES WORSHIPPED--TOMB OF CECILIA METELLA--THE CAMPAGNA--CIRCUS OF CARACALLA OR ROMULUS--TEMPLE DEDICATED TO RIDICULE--KEATS'S GRAVE--FOUNTAIN OF EGERIA--THE WOOD WHERE NUMA MET THE NYMPH--HOLY WEEK. The last days of March have come, clothed in sunshine and summer. The grass is tall in the Campagna, the fruit-trees are in blossom, the roses and myrtles are in full flower, the shrubs are in full leaf, the whole country about breathes of June. We left Rome this morning on an excursion to the "Fountain of Egeria." A more heavenly day never broke. The gigantic baths of Caracalla turned us aside once more, and we stopped for an hour in the shade of their romantic arches, admiring the works, while we execrated the character of their ferocious builder.