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John Smeaton

Portrait of John Smeaton, with the Eddystone Lighthouse in the background
Born 8 June 1724 (1724-06-08)
Austhorpe, Leeds, England
Died 28 October 1792 (1792-10-29) (aged 68)
Austhorpe, Leeds, England
Nationality British
Occupation Civil engineer

John Smeaton, FRS, (8 June 1724 – 28 October 1792) was an English civil engineer – often regarded as the "father of civil engineering" – responsible for the design of bridges, canals, harbours and lighthouses. He was also a more than capable mechanical engineer and an eminent physicist. He was associated with the Lunar Society. He was the first self-proclaimed civil engineer.

Contents

Law and physics

He was born in Austhorpe, Leeds, England. After studying at Leeds Grammar School, he joined his father's law firm, but then left to become a mathematical instrument maker (working with Henry Hindley), developing, among other instruments, a pyrometer to study material expansion and a whirling speculum or horizontal top (a maritime navigation aid).

He was elected a Fellow of the Royal Society in 1753, and in 1759 won the Copley Medal for his research into the mechanics of waterwheels and windmills. His 1759 paper "An Experimental Enquiry Concerning the Natural Powers of Water and Wind to Turn Mills and Other Machines Depending on Circular Motion" addressed the relationship between pressure and velocity for objects moving in air, and his concepts were subsequently developed to devise the 'Smeaton Coefficient'.[1]

However, over the period 1759-1782, he performed a series of further experiments and measurements on waterwheels that led him to support and champion the vis viva theory of German Gottfried Leibniz, an early formulation of conservation of energy. This led him into conflict with members of the academic establishment who rejected Leibniz's theory, believing it inconsistent with Sir Isaac Newton's conservation of momentum. The debate was sadly marred by unfortunate nationalistic sentiments on the establishment's part.

Civil engineering

Recommended by the Royal Society, Smeaton designed the third Eddystone Lighthouse (1755-59). He pioneered the use of 'hydraulic lime' (a form of mortar which will set under water) and developed a technique involving dovetailed blocks of granite in the building of the lighthouse. His lighthouse remained in use until 1877 when - with the rock underlying the structure's foundations beginning to erode - it was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeaton's Tower [1]. He is important in the history, rediscovery of, and development of modern cement, because he identified the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to the invention of Portland cement.

Deciding that he wanted to focus on the lucrative field of civil engineering, he commenced an extensive series of commissions, including:

Because of his expertise in engineering, Smeaton was called to testify in a court for a case related to the silting-up of the harbour at Wells-next-the-Sea in Norfolk in 1782. He is considered to be the first expert witness to appear in an English court. He also acted as a consultant on the disastrous 63-year-long New Harbour at Rye, designed to combat the silting of the port of Winchelsea. The project is now known informally as "Smeaton's Harbour", but despite the name his involvement was limited and occurred more than 30 years after work on the harbour commenced[4].

Mechanical engineer

Employing his skills as a mechanical engineer, he devised a water engine for the Royal Botanic Gardens at Kew in 1761 and a watermill at Alston, Cumbria in 1767 (he is credited by some for inventing the cast iron axle shaft for waterwheels). In 1782 he built the Chimney Mill at Spital Tongues in Newcastle upon Tyne, the first 5-sailed smock mill in Britain. He also improved Thomas Newcomen's atmospheric steam engine, erecting one at Chasewater mine in Cornwall in 1775.

In 1789, Smeaton applied an idea by Denis Papin, by using a force pump to maintain the pressure and fresh air inside a diving bell.[5][6] This bell, built for the Hexham bridge project, was not intended for underwater work. In 1790 the design was updated to enable it to be used underwater on the breakwater at Ramsgate Harbour.[6]

Legacy

Boltzmann's-equation.jpg To understand the significance of Smeaton's work in the context of the development of thermodynamics, see timeline Edit

Highly regarded by other engineers, he contributed to the Lunar Society and founded the Society of Civil Engineers in 1771. He coined the term civil engineers to distinguish them from military engineers graduating from the Royal Military Academy at Woolwich. After his death, the Society was renamed the Smeatonian Society, and was a forerunner of the Institution of Civil Engineers, established in 1818.

His pupils included canal engineer William Jessop and architect and engineer Benjamin Latrobe.

He died after suffering a stroke while walking in the garden of his family home at Austhorpe, and was buried in the parish church at Whitkirk, West Yorkshire.

John Smeaton lends his name to John Smeaton Community College, a secondary school in the suburbs of Leeds, adjacent to the Pendas Fields estate near Austhorpe. He is also mentioned in the song "I Predict a Riot" (as a symbol of a more dignified and peaceful epoch in Leeds history; and in reference to a Junior School House at Leeds Grammar School, which lead singer Ricky Wilson attended) by the indie rock band Kaiser Chiefs, who are natives of Leeds. He is also commemorated at the University of Plymouth, where the Mathematics and Technology Department is housed in a building named after him.

He also has a viaduct named after him, which forms an important piece of Leeds' new £50m inner ring road.

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Smeaton coefficient

The lift equation used by the Wright brothers was due to John Smeaton. It has the form:[7]

L = k V^2 A C_l \,

where:

L is the lift
k is the Smeaton coefficient- 0.005 (the drag of a 1-square-foot (0.093 m2) plate at 1 mph) was the value as determined by Smeaton, later corrected to 0.0033 by the Wright brothers
Cl is the lift coefficient (the lift relative to the drag of a plate of the same area)
A is the area in square feet

The Wright brothers determined with wind tunnels that the Smeaton coefficient was incorrect and should have been 0.0033.[8] In modern analysis, the Lift coefficient is normalized by the dynamic pressure instead of the Smeaton coefficient.

See also

References

External links

Awards and achievements
Preceded by
John Dollond
Copley Medal
1759
Succeeded by
Benjamin Wilson

1911 encyclopedia

Up to date as of January 14, 2010
(Redirected to Database error article)

From LoveToKnow 1911

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