Jeremy Thacker was a possibly apocryphal 18th-century writer and watchmaker, who for a long time was believed to be the first to have coined the word "

chronometer A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and the ...

" for precise clocks designed to find

longitude Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...

at sea, though an earlier reference by

William Derham William Derham FRS (26 November 16575 April 1735)Smolenaars, Marja.Derham, William (1657–1735), ''Oxford Dictionary of National Biography'', Oxford University Press, 2004. Accessed 26 May 2007. was an English clergyman, natural theologian, na ...

has now been found. Thacker is credited with writing ''The Longitudes Examin'd'', published in London in 1714, in which the term 'chronometer' appears. In the work, the claim is made that Thacker created and extensively tested a

marine chronometer A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT), or in the modern ...

positioned on

gimbal A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of ...

s and within a vacuum, and that sea trials would take place. It has been concluded by others that such tests must have resulted in failure. The idea of a vacuum for a marine clock had already been proposed by the Italian clockmaker Antimo Tempera in 1668. Slightly later,

John Harrison John Harrison ( – 24 March 1776) was a self-educated English Carpentry, carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the History of longitude, problem of calculating longitude while at s ...

would successfully build marine timekeepers from 1730.''Old Ironsides: eagle of the sea : the story of the USS Constitution'' David G. Fitz-Enz p.9

/ref>

Question of authenticity

According to an article published in the ''

Times Literary Supplement ''The Times Literary Supplement'' (''TLS'') is a weekly literary review published in London by News UK, a subsidiary of News Corp. History The ''TLS'' first appeared in 1902 as a supplement to ''The Times'' but became a separate publication ...

'' in November 2008, Pat Rogers argued that "Thacker may never have existed and his proposal now emerges possibly as a hoax?". Rogers argues Thacker was an invention of

John Arbuthnot John Arbuthnot FRS (''baptised'' 29 April 1667 – 27 February 1735), often known simply as Dr Arbuthnot, was a Scottish physician, satirist and polymath in London. He is best remembered for his contributions to mathematics, his membersh ...

, and that ''The Longitudes Examined'' fell within the major tradition for

satire Satire is a genre of the visual, literary, and performing arts, usually in the form of fiction and less frequently non-fiction, in which vices, follies, abuses, and shortcomings are held up to ridicule, often with the intent of shaming ...

, and that it was designed to send-up ambitious

projects. This view met with opposition from

Jonathan Betts Jonathan Betts Order of the British Empire, MBE (born January 1955) is Curator Emeritus at the Royal Observatory, Greenwich, Royal Observatory (National Maritime Museum), Greenwich, a horological scholar and author, and an expert on the first marin ...

and Andrew King, both noted Harrisonians, who argued that, as Rogers acknowledged, there were in fact "convincing reasons for accepting the traditional view that some good science is dropped into the project".

Notes

{{DEFAULTSORT:Thacker, Jeremy English clockmakers 18th-century English writers 18th-century English male writers 18th-century British people

Question of authenticity

Further reading

Notes