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The Barton Aqueduct, opened on 17 July 1761, carried the Bridgewater Canal over the River Irwell at Barton-upon-Irwell in Greater Manchester, England. Designed largely by James Brindley under the direction of John Gilbert, it was the first navigable aqueduct to be built in England, "one of the seven wonders of the canal age" according to industrial archaeologist Mike Nevell. Construction proceeded quickly, but disaster almost struck when the aqueduct was first filled with water and one of its three arches began to buckle under the weight. Remedial work took several months, but the aqueduct was still opened to traffic only 15 months after the enabling Act of Parliament had been passed, on 17 July 1761. It remained in use for more than 100 years, until the construction of the Manchester Ship Canal necessitated its demolition in 1893, replaced by the Barton Swing Aqueduct. ==Background== The original intention was for the Bridgewater Canal to reach Salford from the Duke of Bridgewater's coal mines in Worsley, by remaining on the north bank of the Irwell. Work began in 1759, but it was quickly decided to alter the route by building a masonry aqueduct to carry the waterway over the Irwell at Barton, and terminate instead in Manchester, to the south of the river. A Bill to authorise the new route was presented to parliament on 13 November 1759, and in January the following year Brindley travelled to London to give evidence before a parliamentary committee in support of the proposal. Although a gifted engineer Brindley had no formal education and rarely, if ever, committed his designs to paper. When questioned by the parliamentary committee about the composition of the puddle he frequently referred to in his evidence, he had a mass of clay brought into the committee room. He then formed the clay into a trough and showed how it would only form a watertight seal if it had been worked with water to form puddle. "Thus it is" said Brindley "that I form a watertight-trunk to carry water over rivers and valleys wherever they cross the path of the canal." Later, when asked to produce a drawing of the bridge or aqueduct he proposed to build, he replied that he had no representation of it on paper but would demonstrate his intention by use of a model. He then went out and bought a large round of Cheshire cheese, which he divided into two equal halves saying "Here is my model". Then, to the amusement of the committee, he used the two halves of cheese to represent the semicircular arches and laid a long, rectangular object over the top to demonstrate the position of the river flowing under the aqueduct and the canal flowing over it. Although the duke had seen navigable aqueducts in use on canals when travelling abroad on his Grand Tour, the idea of an such a structure carrying a canal over a river was new to England and was ridiculed by contemporary engineers. One brought in to review the plans, at Brindley's request, commented in a report to the Duke of Bridgewater that "I have often heard of castles in the air, but never before saw where one was to be erected." The necessary Act of Parliament was passed in March 1760, and was quite specific about the form the aqueduct had to take, to protect the viability of the Mersey & Irwell Navigation below. There was already a three-arch road bridge, Barton Bridge, passing over the Irwell, and the aqueduct was required not to restrict traffic on the river any more than the road bridge already did. It had to have the same number of arches, the foundations for which had to be fixed in the river bed, and the arches had to be at least as wide and high as those of the road bridge. 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「Barton Aqueduct」の詳細全文を読む スポンサード リンク
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