THE SCIENTIFIC AMERICAN DIGEST
extraordinary specimen of lodestone, weighing more than 400 pounds, and possessing unusually powerful magnetic strength, has been placed on exhibition in the department of geology at Field Mu· seum of Natural History. The huge natural The average boy who likes to mys· tify his friends would give his...
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Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.363.9262 http://www.nature.com/scientificamerican/journal/v143/n6/pdf/scientificamerican1230-466.pdf |
Summary: | extraordinary specimen of lodestone, weighing more than 400 pounds, and possessing unusually powerful magnetic strength, has been placed on exhibition in the department of geology at Field Mu· seum of Natural History. The huge natural The average boy who likes to mys· tify his friends would give his last cent for a small piece of this 400· pound natural magnet from Utah magnet comes from the Wasatch Mountains in Utah. Lodestone led to the invention of the magnetic compass by the Chinese in the 12th Century. It is one variety of the mineral magnetite which has the property of attracting iron and other metals. A steel needle placed in contact with a lode· stone will in a short while become so mag· netized that, if free to move, it will point toward the north pole. It was observance of this fact that suggested the compass. The attraction of the lodestone for iron was known hundreds of years before the polarity of the mineral was discovered, ac· cording to Dr. Oliver C. Farrington, curator of geology at the museum. "Thales of Miletus (630-550 B.C.) men· tions this power of lodestone as do a num· ber of the later Grecian sages, " states Dr. Farrington. "There is a fable that the dis· covery of the lodestone was made by a Cretan shepherd who noticed that his iron· pegged sandals and iron-shod crook clung to the earth. Digging into the ground he found lodestone. "In classical times and during the middle ages, extravagant tales based upon a miscon· ception of the power of lodestone were cur· rent. There were stories of magnetic domes which held statues of iron and even of |
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