They observed that most of the stones which were thrown up in the eruptions, fell within the crater, the rest fell over the south side. The dull sound which was constantly heard within increased from time to time, and terminated with an explosion, at which time stones, sand, and ashes were thrown up. Those eruptions were frequent--some stronger than others. From various places in the interior and near the edge of the crater, arose small columns of smoke, the principal of which were three on the east side, and at a considerable depth within the crater. The crater itself has the appearance of a large funnel, whose sides are but little inclined, and the bottom of which is not visible. The sides are furrowed by numerous gulleys which descend from around the mouth of the crater, having the appearance of the radii of a circle towards the centre. There are three distinct rings, or excavations, which divide the crater into four zones of different dimensions, the largest being that nearest the mouth, and which is of solid rock, the others appear to be composed of sand. The snow occupies only the exterior part of the summit, and that part of the interior of the crater which faces to the north, where its limits cannot be discovered. The mouth of the volcano is nearly circular, about a mile in diameter, and appears much lower on the eastern than on the western side. The lip of the southern side is very thin, and so broken that it seems impossible to walk on it, while the northern part, on the contrary, is broad and more even. On account of a thick stratum of mist by which they were surrounded, the intrepid travellers could only see the summit of the peak of Orizaba, and the neighboring snow-capped mountains to the north. Having completed the observations, and night approaching, they descended by the same way towards the place where they had left the servant, with the intention of passing the night there and returning to the summit next morning; but finding the man in a high fever with a violent pulse and headache, they resolved on descending. To relieve him, he was carried over the most difficult places, and finding it impossible to descend by the same path by which they had ascended in the day, they took at once that bend of the mountain which is called "de los Neveros;" and which, although very steep, is composed of loose sand through which they descended very rapidly. It was after night when they arrived at the limit of vegetation, but having taken a different direction, they did not strike the place where they expected to meet the Indians. They made a large fire as a signal, but the Indians did not make their appearance; and on the following morning, the 21st of April, separating to the right and left, and after shouting, they soon rallied the Indians. The reunited party descended to the rancho de la Vaqueria, and from this they passed through the village of Atlauca; at eight in the evening reached Ameco, and on the 23d of April returned to Mexico.