joined together like Siamese twins, look as though they had been set up, side by side, to illustrate the two contending theories of the formation of volcanos. Von Buch and Humboldt might have made Iztaccihuatl on the “upheaval theory,” by a force pushing up from below, without breaking through the crust to form a crater; while Poulett Scrope was building Popocatepetl on the “accumulation theory,” by throwing up lava and volcanic ashes out of an open vent, until he had formed a conical heap some five thousand feet high, with a great crater at the top.
As we toiled slowly up the snow, we took off our veils from time to time, to look more clearly about us. The glare of the sun upon the snow was dazzling, and its intense whiteness contrasted wonderfully with the cloudless dark indigo-blue of the sky. Between twelve and one we reached the edge of the crater, 17,884 feet above the sea. The ridge upon which we stood was only a few feet wide, and covered with snow; but it seemed that there was still heat enough to keep the crater itself clear, for none lay on the bottom, or in clefts on the steep sides.
The crater was oval, full a mile in its longest diameter, and perhaps 700 to 800 feet in depth; and its almost perpendicular walls of basaltic lava are covered with red and yellow patches of sublimed sulphur. We climbed a little way down into it to get protection from the wind, but to descend further unassisted was not possible, so we sat there, with our legs dangling down into the abyss. Part of the malacate, or winder, used by the Indians in descending, was still there; but it was not complete, and even if it had been, so many months had elapsed since it was last used that we should not have cared to try it. It consisted of a rope of hide, descending into the bottom of the crater in a slanting direction; and the sulphur-collectors were lowered and drawn up it by a windlass, in a basket to which another rope was attached. A few years back, the volcano used to send up showers of ashes, and even large stones; but now it has sunk to the condition of a mere solfatara, sending out, from two crevices in the