John Smeaton

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John Smeaton by George Romney, 1779 (detail), National Portrait Gallery, London

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

He was associated with the Lunar Society.

Law and physics

Smeaton was born in Austhorpe, Leeds, England. After studying at Leeds Grammar School he joined his father's law firm, but 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"[1] addressed the relationship between pressure and velocity for objects moving in air (Smeaton noted that the table doing so was actually contributed by "my friend Mr Rouse" "an ingenious gentleman of Harborough, Leicestershire" and calculated on the basis of Rouse's experiments), and his concepts were subsequently developed to devise the 'Smeaton Coefficient'.[2] Smeaton's water wheel experiments were conducted on a small scale model with which he tested various configurations over a period of seven years.[3] The resulting increasing efficiency in water power contributed to the Industrial Revolution.

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.

Civil engineering

Smeaton's Lighthouse

Recommended by the Royal Society, Smeaton designed the third Eddystone Lighthouse (1755–59). He pioneered the use of 'hydraulic lime' (a form of mortar that 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 the rock underlying the structure's foundations had begun to erode; it was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeaton's Tower. 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. Portland cement led to the re-emergence of concrete as a modern building material, largely due to Smeaton's influence.

Cross section of the Eddystone Lighthouse showing the method of dovetailing
Perth Bridge, over the Tay

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

The impounded harbour at Charlestown, Cornwall

Because of his expertise in engineering, Smeaton was called to testify in 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.[7]

Mechanical engineer

Chimney Mill, Newcastle upon Tyne, now converted into a clubhouse

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 with 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 engine, erecting one at Chacewater mine, Wheal Busy, 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.[8][9] This bell, built for the Hexham bridge project, was not intended for underwater work, but in 1790 the design was updated to enable it to be used underwater on the breakwater at Ramsgate Harbour.[9] Smeaton is also credited with explaining the fundamental differences and benefits of overshot versus undershot water wheels.

Smeaton experimented with the Newcomen steam engine and made marked improvements around the time James Watt was building his first engines (ca. late 1770s).[10]

Legacy

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. The Society was a forerunner of the Institution of Civil Engineers, established in 1818, and was renamed the Smeatonian Society of Civil Engineers in 1830.

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.

Signs on the John Smeaton Viaduct

John Smeaton Academy, a secondary school in the suburbs of Leeds adjacent to the Pendas Fields estate near Austhorpe, is named after Smeaton. He is also commemorated at the University of Plymouth, where the Mathematics and Technology Department is housed in a building named after him. A viaduct in the final stage of the Leeds Inner Ring Road, opened in 2008, was named after him.

He is 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.

Smeaton coefficient

The lift equation used by the Wright brothers was due to John Smeaton. It has the form:[11]

${\displaystyle L=kV^{2}AC_{l}\,}$

where:

${\displaystyle L}$ is the lift
${\displaystyle k}$ is the Smeaton coefficient- 0.005 (the drag in pounds weight of a Template:Convert plate at 1 mph) was the value as determined by Smeaton,[12] later corrected to 0.0033 by the Wright brothers
${\displaystyle C_{l}}$ is the lift coefficient (the lift relative to the drag of a plate of the same area)
${\displaystyle A}$ 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.[13] In modern analysis, the Lift coefficient is normalised by the dynamic pressure instead of the Smeaton coefficient.

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References

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6. "The Greenwich Hospital Smelt Mill at Langley, Northumberland 1768-1780" by F. J. Monkhouse, Transactions of the Institution of Mining and Metallurgy vol. 49, 1940. It is a Scheduled Ancient Monument.
7. Rye Museum website
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9. {{#invoke:Citation/CS1|citation |CitationClass=journal }}
10. John Smeaton- Engineering Timeline
11. Template:Cite web
12. probably, strictly speaking, Rouse
13. {{#invoke:Citation/CS1|citation |CitationClass=journal }}