Editing James Brindley (section)

==Early canal engineering==
[[File:Barton aqueduct drawing.jpg|right|thumb|The Barton Aqueduct over the River Irwell, 1807]]
[[File:Barton aqueduct.jpg|thumb|right|Barton Aqueduct, shortly before its demolition, 1891]]
Brindley's reputation brought him to the attention of the [[Francis Egerton, 3rd Duke of Bridgewater|3rd Duke of Bridgewater]], who was looking for a way to improve the transport of coal from his coal mines at [[Worsley]] to [[Manchester]].

In 1759 the Duke commissioned the construction of a [[canal]] to do just that. The resulting [[Bridgewater Canal]], opened in 1761, is often regarded as the first British canal of the modern era (though the [[Sankey Brook Navigation|Sankey Canal]] has a good claim to that title), and was a major technical triumph. Brindley was commissioned as the consulting engineer. However, although Brindley has often been credited as the genius behind the construction of the canal, it is now thought that the main designers were the Duke himself, who had some engineering training, and his land agent and engineer [[John Gilbert (agent)|John Gilbert]]. Brindley was engaged, at the insistence of Gilbert, to assist with particular problems such as the [[Barton Aqueduct]].<ref name=Malet/> This most impressive feature of the canal carried the canal at an elevation of 12 metres (39&nbsp;ft) over the [[River Irwell]] at [[Barton, Salford, Greater Manchester|Barton]].{{efn|In 1893, on the building of the [[Manchester Ship Canal]], the [[navigable aqueduct|aqueduct]] was replaced by the equally impressive [[Barton Swing Aqueduct]].}}

Brindley's technique minimised the amount of earth moving by developing the principle of contouring. He preferred to use a circuitous route that avoided embankments, and tunnels rather than cuttings. Though this recognised the primitive methods of earth-moving available at the time, it meant that his canals were often much longer than a more adventurous approach would have produced. But his greatest contribution was the technique of [[Puddling (engineering)|puddling clay]] to produce a watertight [[clay]]-based material, and its use in lining canals.<ref name=Rolt>{{cite book |title=Navigable Waterways |last=Rolt |first=L.T.C. |author-link=L. T. C. Rolt |year=1969 |publisher=W & J Mackay}}</ref> Puddle clay was used extensively in UK canal construction in the period starting shortly after his death. Starting about 1840 puddle clay was used more widely as the water-retaining element (or core) within [[Embankment dam|earthfill dams]], particularly in the [[Pennines]].<ref>George M. Reeves, Ian Sims, J. C. Cripps Eds., [https://books.google.com/books?id=iDqaIaLe6lkC&pg=PA377&lpg=PA377& Clay Materials Used in Construction], p.377. [[Geological Society of London|Geological Society]], 2006. {{ISBN|978-1-86239-184-0}}</ref>