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 the district resumed its former stability, though it still remained far too hot to be habitable. In 1780, twenty years after the outburst, the heat of the hornitos was still so great that a cigar could readily be lighted by plunging it two or three inches into one of the lateral cracks. When Humboldt visited Jorullo in 1803, forty-three years after the eruption, he found around the base of the great cone a mass of matter, of convex form, about 500 feet high, near the cone, but sloping gradually as it receded from it; this mass, which covered to the extent of four square miles, was then still in a heated state. And twenty-two years later, in 1825, Mr. Bullock found the cones still smoking.

Previous to the outburst, two purling streams had watered the plain of Malpays, the Cutimbo, and the San Pedro. These two rivers ran into the crater, and lost themselves below at the eastern limit of the plain, but reappeared afterwards on the western limit as hot springs.

Among the productions of volcanoes, emitted or ejected through their craters and vents, may be enumerated various gases—such as hydrochloric acid gas, carbonic acid, hydrosulphuric acid, and gases formed by the several combinations of sulphur with oxygen; aqueous vapour, lava, minerals, cinders, stones, sand, water, mud, and ashes—which latter probably consist simply of pulverized lava.

The quantity of ashes discharged by volcanoes