We were forced to cut our own track across the malpaís. The slope is very steep, and the volcanic blocks slipped under our feet. The rubble on the peak's summit has sharp edges and leaves gaps into which explorers risk falling up to their waists. Unfortunately the laziness and bad temper of our guides made this ascent more difficult. They were despairingly phlegmatic. The night before they had tried to convince us not to pass beyond the limit of the rocks. Every ten minutes they would sit down to rest; they threw away pieces of obsidian and pumice-stone that we had carefully collected. Finally we realized that none of them had ever visited the volcano's summit before.