Cortes reached Tlascala in safety, and at once began to prepare his revenge on the Mexicans, aided by reinforcements of a few Spaniards from Vera Cruz. Gunpowder had also to be manufactured, and a cavalier named Francio Montano undertook the perilous task of obtaining sulphur for the purpose from the terrible volcano of Popocatepetl. He set out with four comrades, and after some days journeying, they reached the dense forest which covered the base of the mountain, and forcing their way upward, came by degrees to a more open region. As they neared the top the track ended, and they had to climb as best they could over the black glazed surface of the lava, which, having issued from the crater in a boiling flood, had risen into a thousand odd forms wherever it met with any obstacle, and continually impeded their progress. After this they arrived at the region of perpetual snow, which increased their difficulties, the treacherous ice giving way at every step, so that many times they narrowly escaped falling into the frozen chasms that yawned all round them. At last, however, they reached the mouth of the crater, and, crawling cautiously to the very edge, peered down into its gloomy depths. At the bottom of the abyss, which seemed to them to go down into the very heart of the earth, a lurid flame burned sullenly, sending up a sulphureous steam, which cooling as it rose, fell again in showers upon the sides of the cavity. Into this one of the brave explorers had to descend, and when they had cast lots the choice fell upon Montano himself. His preparations were soon made, and his companions lowered him in a basket into the horrible chasm to a depth of four hundred feet, and there as he hung, he scraped the sulphur from the sides of the crater, descending again and again until he had procured enough for the wants of the army, with which they returned triumphantly to Tlascala. Meanwhile the construction of the ships went forward prosperously, and by Christmas, in the year 1520, there was no longer any reason to delay the march to Mexico. [Illustration]