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The original Ferris Wheel, sometimes also referred to as the Chicago Wheel, was the centerpiece of the 1893 World's Columbian Exposition in Chicago, Illinois. Intended to rival the 1889 Paris Exposition's Eiffel Tower, the Ferris Wheel was the Columbian Exposition's largest attraction, with a height of . The Ferris Wheel was dismantled then rebuilt in Lincoln Park, Chicago, in 1895, and dismantled and rebuilt a third and final time for the 1904 World's Fair in St. Louis, Missouri. It was demolished there in 1906. thumb ==Design and construction== The Ferris Wheel was designed and constructed by George Washington Gale Ferris, Jr., a graduate of Rensselaer Polytechnic Institute. He was a Pittsburgh, Pennsylvania, bridge-builder. He began his career in the railroad industry and then pursued an interest in bridge building. Ferris understood the growing need for structural steel and founded G.W.G. Ferris & Co. in Pittsburgh, a firm that tested and inspected metals for railroads and bridge builders. Dynamite was used to break through three-feet of frozen ground, to create a foundation for the wheel, during the construction of the wheel in Jackson Park during the winter of 1892-3. Jets of steam were used by workers to thaw dirt and prevent poured concrete from freezing. Piles of timber were driven thirty-two feet into the ground, on top of which was laid a grillage of steel, filled with concrete.〔The Devil in the White City, Erik Larson, pg. 193.〕 The wheel rotated on a 71-ton, 45.5-foot axle comprising what was at that time the world's largest hollow forging, manufactured in Pittsburgh by the Bethlehem Iron Company and weighing 89,320 pounds, together with two cast-iron spiders weighing 53,031 pounds.〔 There were 36 passenger cars, each fitted with 40 revolving chairs and able to accommodate up to 60 people, giving a total capacity of 2,160.〔 On June 9, 1893, the wheel was primed for a test run with great anticipation and a good deal of anxiety. The engine that would activate the wheel was fueled by steam boilers whose underground mains rushed steam to propel the pistons of its thousand-horsepower engines. Upon first seeing the wheel which towered over everything in its vicinity, Julian Hawthorne, son of the author Nathaniel, was amazed that anything of such a size "continues to keep itself erect...it has no visible means of support—none that appear adequate. The spokes look like cobwebs; they are after the fashion of those on the newest make of bicycles".〔Larson (2003), p. 258〕 Both Ferris and his associate W. F. Gronau also recognized the engineering marvel the wheel represented, as a giant wheel that would turn slowly and smoothly without structural failure had never before been attempted.〔Larson (2003), pp. 258-259〕 For its inaugural run, no cars had yet been attached. The workmen however, climbed the structure and settled themselves on the spokes to the accompaniment of cheers from an audience of fair employees who had gathered to watch the momentous event. After the wheel had completed its first rotation, Gronau deemed the test a success. "I could have yelled out loud for joy".〔Larson (2003), p. 260〕 Ferris himself had not been able to attend the launching of his invention, and that evening received a telegram: "The last coupling and final adjustment was made and steam turned on at six o’clock this evening one complete revolution of the big wheel was made everything working satisfactory twenty minutes time was taken for the revolution—I congratulate you upon its complete success midway is wildly enthusiastic".〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ferris Wheel」の詳細全文を読む スポンサード リンク
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