William Gravatt

William Gravatt FRS (14 July 1806 – 30 May 1866), was a noted English civil engineer and scientific instrument maker.

Apprenticed as a mechanical engineer in London from aged 15, after interview he worked with Sir Marc Isambard Brunel on the Thames Tunnel, and then designed bridges for the Calder and Hebble Navigation. Whilst surveying the route for the South Eastern Railway to Dover, he devised the more transportable dumpy level, which is now universally employed. He then supervised the northern engineering team under Isambard Kingdom Brunel on the Bristol and Exeter Railway, where the deployment of his "curve of sines" theorem speeded construction. Dismissed from the project in 1841, after losing money during the railway mania period, Gravatt helped to construct both the Craig telescope and a copy of the Difference machine, distinguishing himself in a number of papers submitted to the Institution of Civil Engineers. He died after being accidentally poisoned by an overdose of morphine by his nurse.

Born in Gravesend, Kent on 14 July 1806, he was the son of Colonel William Gravatt, the Assistant Inspector of the Royal Military Academy, Woolwich. At age 15, his father negotiated an apprenticeship to mechanical engineer Bryan Donkin. During this period he met and became friends with John Smeaton, Edward Troughton and Dr. George Wollaston.

Gravatt joined the Institution of Civil Engineers as an Associate in 1826, and in 1828 was elected a member, following his proposal based on the "curve of sines" for use on defining track transition curves on railways. In 1832 he became a FelIow of the Royal Society, and a Fellow of the Royal Astronomical Society.

Before he finished his apprenticeship, Gravatt successfully interviewed with Sir Marc Isambard Brunel, and was given a job as a supervisor on the Thames Tunnel.

On 27 June 1827, after the tunnel flooded, Isambard Kingdom Brunel forbade anyone from entering the workings. However, company directors Robert Marten and Richard Harris insisted Gravatt take them in to inspect the damage, accompanied by two miners as crew for a dinghy. Whilst in the workings, Marten attempted to move forward in the dinghy, and after striking his head on the tunnel, tipped the boat over in 12 feet (3.7 m) of water. Only Gravatt and miner Dowling could swim, and after rescuing Marten and Harris, Gravatt was joined by Brunel in the search underwater for the second miner Richardson. Joined by officials from the Humane Society, they eventually recovered the body with a drag-line. On 5 March 1828, silver medals were voted by the Royal Humane Society to Brunel and Gravatt "for having hazarded their own lives to preserve those of their fellow-creatures."

In 1832 during a break in work on the Thames Tunnel due to water ingress, Donkin recommended Gravatt as Engineer to the Calder and Hebble Navigation. Gravatt resultantly designed the arches for several bridges, using a solid iron-plate inverted arched chain above the platform, creating the forerunner of the suspension bridge. However, early in the start of construction Gravatt was dismissed on grounds of experience. He was replaced by William Bull.

Commissioned by Mr. H.R. Palmer in examining the original scheme for the South Eastern Railway's route from London to Dover, during the works Gravatt devised the more transportable dumpy level, which is now universally employed.