Percy Edwin Ludgate (2 August 1883 – 16 October 1922) was an

Irish Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit ...

amateur scientist who designed the second analytical engine (general-purpose

Turing-complete In computability theory, a system of data-manipulation rules (such as a computer's instruction set, a programming language, or a cellular automaton) is said to be Turing-complete or computationally universal if it can be used to simulate any ...

computer) in history.

Life

Ludgate was born on 2 August 1883 in

Skibbereen Skibbereen (; ) is a town in County Cork, Ireland. It is located in West Cork on the N71 national secondary road. The name "Skibbereen" (sometimes shortened to "Skibb") means "little boat harbour". The River Ilen runs through the town; it reac ...

County Cork County Cork ( ga, Contae Chorcaí) is the largest and the southernmost county of Ireland, named after the city of Cork, the state's second-largest city. It is in the province of Munster and the Southern Region. Its largest market towns a ...

, to Michael Ludgate and Mary McMahon. In the 1901 census, he is listed as Civil Servant National Education (Boy Copyist) in

Dublin Dublin (; , or ) is the capital and largest city of Ireland. On a bay at the mouth of the River Liffey, it is in the province of Leinster, bordered on the south by the Dublin Mountains, a part of the Wicklow Mountains range. At the 2016 c ...

. In the 1911 census, he is also in Dublin, as a Commercial Clerk (Corn Merchant). He studied accountancy at Rathmines College of Commerce, earning a gold medal based on the results his final examinations in 1917. At some date before or after then, he joined Kevans & Son, accountants.

Work on analytical engine

It seems that Ludgate worked as a clerk for an unknown corn merchants, in Dublin, and pursued his interest in calculating machines at night. Charles Babbage in 1843 and Ludgate in 1909 designed the only two mechanical analytical engines before the electromechanical analytical engine of

Leonardo Torres y Quevedo Leonardo Torres y Quevedo (; 28 December 1852 – 18 December 1936) was a Spanish civil engineer and mathematician of the late nineteenth and early twentieth centuries. Torres was a pioneer in the development of the radio control and automated ...

of 1920 and its few successors, and the six first-generation

electronic Electronic may refer to: *Electronics, the science of how to control electric energy in semiconductor * ''Electronics'' (magazine), a defunct American trade journal *Electronic storage, the storage of data using an electronic device *Electronic co ...

analytical engines of 1949. Working alone, Ludgate designed an analytical engine while unaware of Babbage's designs, although he later went on to write about Babbage's machine. Ludgate's engine used multiplication as its base mechanism (unlike Babbage's which used addition). It incorporated the first multiplier-accumulator, and was the first to exploit a multiplier-accumulator to perform division, using multiplication seeded by reciprocal, via the convergent series . Ludgate's engine also used a mechanism similar to slide rules, but employing his unique discrete Logarithmic Indexes (now known as Irish logarithms), and provided a very novel memory using concentric cylinders, storing numbers as displacements of rods in shuttles. His design featured several other novel features, including for program control (e.g., preemption and subroutines – or microcode, depending on viewpoint). The design is so different from Babbage's as to be a second type of analytical engine, preceding the third (

electromechanical In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...

) and fourth (

) types. The engine's precise mechanism is unknown as the only written accounts which survive do not detail its workings, although he stated in 1914 that " mplete descriptive drawings of the machine exist, as well as a description in manuscript" – these have never been found. Ludgate was one of a few independent workers in the field of science and mathematics. His inventions were worked on outside a lab. He worked on them only part-time, often until the early hours of the morning. Many publications refer to him as an accountant, but that came eight years after his 1909 analytical engine paper. Little is known about his personal life, as his only records are his scientific writings. Until 2016 the best source of information about Ludgate and his significance lie in the work of Professor

Brian Randell Brian Randell (born 1936) is a British computer scientist, and Emeritus Professor at the School of Computing, Newcastle University, United Kingdom. He specialises in research into software fault tolerance and dependability, and is a noted aut ...

. As from then, a further investigation is underway at Trinity College, Dublin under the auspices of the

John Gabriel Byrne Computer Science Collection John is a common English name and surname: * John (given name) * John (surname) John may also refer to: New Testament Works * Gospel of John, a title often shortened to John * First Epistle of John, often shortened to 1 John * Second ...

. Ludgate died of

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severi ...

in 19 October 1922, and is buried in Mount Jerome Cemetery in Dublin.

Legacy

In 1991, a prize for the best final-year project in the Moderatorship in

computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includi ...

course at Trinity College, Dublin – the Ludgate Prize – was instituted in his honour, and in 2016 the Ludgate Hub e-business incubation centre was opened in

, where he was born. In October 2022, a plaque from the National Committee for Commemorative Plaques in Science and Technology was unveiled at Ludgate's home in Drumcondra by the Provost of Trinity College, Linda Doyle.

References

Bibliography

* Available on-line at:
Fano.co.UK
* * (A subscription to the journal or payment on a per-article basis is required to view this article) �
full version
* * * (extensive background and research document), and . In: online catalog of The John Gabriel Byrne Computer Science Collection * Brian Coghlan (2019) "An exploration of the life of Percy Ludgate": and , presented at the West Cork History Festival 2019, Skibbereen, Ireland * (see als

* (see als

* online catalog * Mobile-friendly Ludgate folder of the above catalog * (see Book Depositor

also see BookFinde

{{DEFAULTSORT:Ludgate, Percy 1883 births 1922 deaths People from Skibbereen 20th-century Irish businesspeople 20th-century Irish scientists Irish inventors Businesspeople from Dublin (city) Scientists from Dublin (city) Computer designers Deaths from pneumonia in the Republic of Ireland Burials at Mount Jerome Cemetery and Crematorium