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What is a Volcano

A vulcano is an opening in the surface of the earth, or in a mountain, from which are ejected smoke, flames, stones, lava, &c. Beneath the outer crust of the earth inflammable materials appear to exist, which different causes excite into combustion. Volcanoes are supposed to owe their origin to the metals and minerals which form the basis of earths and alkalies; and which, when ignited, expand, — shake the rocky foundations, — and sometimes, bursting through, produce all the destructive effects of earthquakes.

They break forth under the sea, as well as the land, and throw up mountains which rise above the level of the water. During an eruption of Vesuvius, A.D. 79, 3 cities in Italy: Herculaneum, Pompeii, and Stabiae, were overwhelmed, and lay buried beneath the matter ejected from the volcano until within a few years, when excavations were made and many relics discovered; — streets, houses, papyri, (manuscripts,) grain, fruit, bread, medicines, all in a remarkable state of preservation, have been found just as they were left by the terrified inhabitants at the time of the eruption!

There are more than 200 volcanoes in the world; more than one half of them are in America and Oceanica The most noted volcanoes in America are Cotopaxi (the highest in the world), near Quito; Popocatapetl, in Mexico; Cosiguina, and the Water Volcano, in Guatemala. In France, Spain, Portugal, and many other countries, there are districts which show the former existence of volcanoes, which have long been extinct; near Naples, in an area of 200 square miles, there are sixty craters, some of them larger than Vesuvius; in one of these, the town of Cumea has stood for 3,000 years.

Many examples of new islands rising out of the sea by volcanic action are on record. Some of them are permanent, but others, after a time, disappear. Teneriffe, Iceland, Sicily, St. Helena; part of Sumatra, Java, Japan; and the Sandwich Islands, seem to have been upheaved by volcanic agency; Hawaii, the largest of the last-named group, contains an area of 4,000 square miles, and rises 18,000 feet above the ocean.