William Hamilton Shortt (1881-1971) was a railway engineer and noted horologist, responsible for the design of the Shortt-Synchronome free pendulum clock, a widely used

time standard A time standard is a specification for measuring time: either the rate at which time passes or points in time or both. In modern times, several time specifications have been officially recognized as standards, where formerly they were matters o ...

, employed internationally in

observatories An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. His ...

in the period between the two World Wars. His deep involvement in precision timekeeping, as a colleague of

Frank Hope-Jones Frank Hope-Jones (1867–1950) was a British horologist. He was born the son of William Hope-Jones in Eastham, Wirral Peninsula and educated at Birkenhead School. His brother was Robert Hope-Jones, the electric organ designer. His parents were ...

and director of the Synchronome Company, derived from work on the safety of train travel and the accurate measurement of train speeds, following investigations into a serious train derailment of a

LSWR The London and South Western Railway (LSWR, sometimes written L&SWR) was a railway company in England from 1838 to 1922. Originating as the London and Southampton Railway, its network extended to Dorchester and Weymouth, to Salisbury, Exeter ...

train at Salisbury Station in 1906, when twenty-eight people died. Shortt was born in September 1881 in Wimbledon, Surrey, only son to Charles Henry Shortt, a civil engineer, and Fanny (née Dobson) who was sister to the poet

Henry Austin Dobson Henry Austin Dobson (18 January 1840 – 2 September 1921), commonly Austin Dobson, was an English poet and essayist. Life He was born at Plymouth, the eldest son of George Clarisse Dobson, a civil engineer, of French descent. When he w ...

. He worked at the LSWR from 1902, starting as an articled pupil. He became an associate of the

Institution of Civil Engineers The Institution of Civil Engineers (ICE) is an independent professional association for civil engineers and a charitable body in the United Kingdom. Based in London, ICE has over 92,000 members, of whom three-quarters are located in the UK, whi ...

in 1907. Shortt met Hope-Jones in 1910, and began collaborating in the design of master clocks from 1912, joining the Synchronome Company as a shareholder and director. He produced a series of designs involving new forms of escapement, attempting to optimise the delivery of energy to the pendulum, while taking account of variations in external factors such as temperature and atmospheric pressure. Shortt's experiments continued until 1916, when he was released from duties with the LSWR to serve as a captain in the Royal Engineers in France. In 1919, having been demobilised from the army, he returned to his experimental work, producing a series of clocks in which he continued to try new ways of delivering an impulse to the pendulum, while attempting to make the pendulum do as little work as possible. The theoretical ideal was a pendulum operating freely in a vacuum and doing no work. Some of the best performances to date had been achieved by clocks housed in vacuum tanks, using a Riefler escapement. Shortt's breakthrough in 1920 came with the development of a clock system, inspired by the work of R.J. Rudd of Croydon, championed by Hope-Jones, in which the task (each thirty seconds) of unlocking the impulse to an otherwise free pendulum was taken on by a separate

slave clock In telecommunication and horology, a slave clock is a clock that depends on another clock, the master clock. Modern clocks are synchronized through the Internet or by radio time signals, to Coordinated Universal Time. UTC is based on a network ...

, which in turn was corrected (as part of the same operating cycle) by a synchronising pulse derived from the

master clock Master or masters may refer to: Ranks or titles * Ascended master, a term used in the Theosophical religious tradition to refer to spiritually enlightened beings who in past incarnations were ordinary humans *Grandmaster (chess), National Master ...

, containing the free pendulum. This system therefore utilised a mechanical

phase-locked loop A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal. There are several different types; the simplest is an electronic circuit consisting of a ...

. Championed by the Astronomer Royal of Scotland,

Ralph Allan Sampson Ralph Allan (or Allen) Sampson FRS FRSE LLD (25 June 1866 – 7 November 1939) was a British astronomer. Life Sampson was born in Schull, County Cork in Ireland, then part of the UK. He was the fourth of five children to James Sampson, a Corn ...

, Shortt's free pendulum clock was rapidly adopted worldwide by many observatories as a time standard, and remained as such until the widespread adoption of

quartz clock Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks and watches are at least a ...

s from the Second World War onwards. Shortt was honoured for his work in horology and precision timekeeping with the Gold Medal from the

British Horological Institute The British Horological Institute (BHI) is the representative body of the horological industry in the United Kingdom. It was founded by a group of clockmakers in 1858, and has its current premises at Upton Hall in Nottinghamshire, which include ...

in 1931 and its Fellowship in 1932, the

John Price Wetherill Medal The John Price Wetherill Medal was an award of the Franklin Institute. It was established with a bequest given by the family of John Price Wetherill (1844–1906) on April 3, 1917. On June 10, 1925, the Board of Managers voted to create a silver ...

from the

Franklin Institute The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memori ...

in 1935, and the Tompion Medal of the

Worshipful Company of Clockmakers The Worshipful Company of Clockmakers was established under a royal charter granted by King Charles I in 1631. It ranks sixty-first among the livery companies of the City of London, and comes under the jurisdiction of the Privy Council. The c ...

in 1954. He was made a liveryman of the Company in 1931 and served as Master in 1950.Shortt, Obituary.

References

Extra reading

*Frank Hope-Jones, ''Electrical Timekeeping'' (NAG: London, 1940) *R.H. Miles, ''Synchronome - Masters of Electrical Timekeeping'' (AHS: London, 2019), pp. 27–30, chapters 8 and 9. {{DEFAULTSORT:Shortt, William Hamilton 1881 births 1971 deaths Horology