POPOCATEPETL (Aztec popocani, “smoking,” tepetl, “mountain”), a burning mountain in Mexico, in 18° 59' 47" N. lat. and 98° 33' 1" W. long., which along with the neighbouring and somewhat lower summit of Ixtaccihuatl (Aztec “White Woman ”) forms the south-eastern limit of the great valley in which the capital is built. As it lies in the province of Puebla, and is the great feature in the view from that city, it is also called the Puebla Volcano. With the single exception of Mount Elias in Alaska, Popocatepetl appears to be the highest peak in North America, rising as it does in a regular snow-covered cone to an altitude of 17,853 feet. The main mass of the mountain consists of andesite, but porphyry, obsidian, trachyte, basalt, and other similar rocks are also represented. Between the pine forest (Pinus occidentalis'), which ceases at a height of 12,544 feet, and the snow limit, 14,960 feet, there lies a tract of loose sand, largely composed of grains of sulphur, which renders the ascent tedious and at times dangerous, though the first 1600 feet can be accomplished on horseback. On the summit is an enormous crater measuring 5000 feet across and with a sheer depth of 2000 feet. The vapours rising from the solfataras, the mixture of sulphur yellow and ash grey in the caldron, the dazzling snow on the edges of the crater walls, and the deep blue of the sky above produce the most indescribable effects of colour. The highest point of the mountain is a softly rounded eminence about 30 feet only from the rim. Sulphur from the crater is regularly worked by a number of Indians who have their huts at the foot of the cone, at a height of 12,000 feet. The material is shot down a slide for a distance of between 2000 and 3000 feet, and the workmen also avail themselves ...