Rensselaer Republican, Volume 27, Number 22, Rensselaer, Jasper County, 30 January 1896 — SCIENCE AND VOLCANOES. [ARTICLE]

SCIENCE AND VOLCANOES.

Ck|>ei of the Eruptions Have Not Yet Been Definitely Ascertained. It was formerly believed apd taught that a volcano is a mountain sending forth fire, smoke and lava, tills being the sense of the definitions in geographies which are by no means antiquated. Modern investigations haye, howqyer. changed this definition, eliminating the word mountain and adding to the list of substances ejected the very important one, steam, for steam is an active worker and can by no means be overlooked. There is aii apparent reason for assuming volcanoes to be mountains, since they generally' build up andTafff, retaining a central chimney for the ejection of fresh volcanic material. A volcano may he an orifice in the surface of a plain, like a geyser, although the latter are not classed with true volcanoes. They are Comparatively local In their nature, the water being heated very near the point of ejection, while the volcanoes have an origin for their lava at very much greater depths below the earth’s surface. Then, again, the word' mountain has itself received a modified definition, and even a conical peak with steam issuing from its apex may not be a mountain in the strict seflse of the word. Mountain, according to the larest authorities, is dependent upon geological structure, and not on height, and our Blue hills are as truly mountains, although their summits are hut GOO feet above the sea, as the Himalayas or the Andes, with forty or fifty times the height. A mountain is no longer simply an elevation of land to 2,000 feet or more, as was formerly taught, but is "the record of a certain geological process. In his “Story of Our Planet,” Prof. T. C. Bonney devotes quite a little space to the consideration of the volcano. “That a volcano is reared practically by one architect,” he writes, “that the tyhole cone and the mountain proper are formed-by the.ejected material, is now generally admitted. But this opinion is not always favorably regarded. Before the days of Scrope and Lyell the ejected materials were generally supposed to play a subordinate part and a volcanic mountain was held to be largely due to the upheaval of the strata- of the earth’s crust in a conical form around the orifice. In this hypothesis obvious difficulties existed, such as understanding how the beds thus uplifted could maintain their position when the imprisoned vapors and lava had escaped from, beneath.”*Happy Thoughts.