“We started from the city of San Miguel on the afternoon of the 7th of December, 1848, directing our course towards the western border of the plain where rises the dark bulk of the volcano. At eleven o’clock at night we reached the foot of the mountain, distant four leagues from the town. Although the moon shone with extraordinary brilliancy and the night was one of serenest beauty, yet we considered it safer to take shelter in an Indian hut for the remainder of the night than trust ourselves among the fissures of the mountain in the treacherous moonlight. At four in the morning, with the earliest dawn of day, we commenced our ascent on horseback. We however soon found our course so much impeded by masses of lava, over which it was difficult to force the animals, that we were compelled to dismount and pursue our journey on foot. About half way up the mountain the dikes of lava became less frequent, and the ground more firm and open, and, although quite precipitous, yet not difficult of ascent. This open belt, however, does not extend to the summit, and long before we reached it we were again driven upon the beds of sharp, rough, and unsteady lava. “Our course now lay through a deep channel formed between two vast currents of lava, composed of enormous crags, which in 1844 had flowed out from fissures in the side of the volcano. We had not proceeded far between these walls of rock when we found the scoriæ beneath our feet so yielding and unsteady that we could scarcely retain our foothold. Frequently we slid back three or four yards, thus losing in a moment the advance which it had cost us great labor to accomplish. Nevertheless, after many efforts and through much exertion, and after having suffered several severe falls, we succeeded in reaching the throat of the mountain. Here the lava was solid and the scoriæ firm; and though the slope was very steep and dangerous, yet we found it easier to proceed here than over the soft and yielding ashes below. “About mid-day we reached the summit proper of the mountain and stood on the edge of the great crater, which is surrounded by a wall of immense rocks, irregular in height, and having a circuit of a mile and a half. The area within these strange bulwarks is level; but on descending, we found with alarm that it was traversed in every direction by profound fissures, varying from one foot to five yards in width, from which escaped dense clouds of sulphurous smoke. About in the centre of this area was the yawning, active crater, or mouth of the crater, or mouth of the volcano. Our guide peremptorily refused to advance farther, insisting that we were liable at any moment to sink into some one of the numerous fissures which yawned beneath the superficial crust. He added further that in the neighborhood of the crater the gases were so pungent and the sulphurous odor so overwhelming that we could not escape suffocation.