Alan Turing at Sherborne School

Education and Summary of Turing’s Early Career

Alan Turing was educated at Sherborne School, where, in the Science Sixth he met Christopher Morcom, another outstanding student and enthusiast for science.

Christopher Morcom suddenly died on 13 February 1930. Alan Turing came through the trauma. Somehow he found the strength and won a scholarship to King’s College, Cambridge. He was a Wrangler (that is, he was awarded a first-class degree in Mathematics) at King’s College, Cambridge in 1931, where he became a Fellow in 1935.

From September 1936 to July 1938 Turing worked mostly at the Institute for Advanced Study, Princeton, New Jersey, and gained his Ph.D. there, studying cryptology and he also built three of four stages of an electro-mechanical binary multiplier (an early digital computer).

Turing worked for the British Foreign Office at Bletchley Park during World War II (1939 — 1945) and was awarded the Order of the British Empire (OBE) in 1946. He worked at the National Physical Laboratory, 1945 — 1948 and at the University of Manchester from 1948 to 1954. He became a Fellow of the Royal Society in 1951.

A Summary of His Life

1912 (23^rd June): Birth, Maida Vale, London
1926–31: Sherborne School
1930: Death of friend Christopher Morcom
1931–34: Undergraduate at King’s College, Cambridge University
1932–35: Quantum mechanics, probability, logic
1935: Elected fellow of King’s College, Cambridge
1936: The Turing machine, computability, universal machine
1936–38: Princeton University. Ph.D. Logic, algebra, number theory
1938–39: Return to Cambridge. Introduced to German Enigma cipher machine
1939–40: The Bombe, machine for Enigma decryption
1939–42: Breaking of U-boat Enigma, saving battle of the Atlantic
1943–45: Chief Anglo-American crypto consultant. Electronic work
1945: National Physical Laboratory, London

The official Blue Plaque on Alan Turing’s birthplace unveiled by Andrew Hodges
1946: Computer and software design leading the world
1947–48: Programming, neural nets, and artificial intelligence
1948: Manchester University
1949: First serious mathematical use of a computer
1950: The Turing Test (a test of a machine’s ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human), in his paper Computing Machinery and Intelligence
1951: Elected FRS. Non-linear theory of biological growth
1952: Arrested as a homosexual, loss of security clearance
1953–54: Unfinished work in biology and physics, including Intelligent Machinery (published posthumously in 1969)
1954 (7^th June): Death in Wilmslow, Cheshire from what the medical examiners described as “self-administered potassium cyanide while in a moment of mental imbalance”. Other reasons for his death have surfaced. His mother claimed that he used to experiment with household chemicals, trying to create new substances and became careless. Others claim he was homosexual and killed himself to prevent embarrassment.

Whatever the reason for his death, Turing was truly one of the great forerunners in the field of computers. Today’s computer scientists still refer to his papers. The concept of the algorithm lies at the heart of every computer program for any type of digital computer.

A biography Alan Turing: the enigma by Andrew Hodges was published by Vintage (now Random House) in 1983.

On 23^rd June 1998, Andrew Hodges was asked by English Heritage to unveil the official Blue Plaque on Alan Turing’s birthplace. It would have been his 86^th birthday.

Belatedly, eleven years later, in 2009, the Prime Minister, Gordon Brown, made a full personal statement of recognition, reflection and apology.

On 23^rd February 2012 the Royal Mail released a stamp featuring Turing as part its “Britons of Distinction” series.

Very belatedly, in December 2013 he was granted a “royal pardon” for his conviction (which resulted in his suicide) for consenting homosexual activities.

Alan Turing: A Post Mortem

Foreknowledge of Turing’s Homosexuality

Anthony Cave Brown’s book, “C”: The Secret Life of Sir Stewart Menzies, Spymaster to Winston Churchill, states:

Menzies had known that Turing was a practicing and aggressive homosexual; this had emerged soon after his employment at Bletchley. But since he caused no offence to his colleagues at Bletchley, and since he was perhaps the only man in Menzies’s service who might have been called ‘indispensable,’ his services were retained... Early in 1944 a suspicion arose that he might have been the man responsible for molesting schoolboys at the main public library in Luton, a large industrial town not far from Bletchley. While no proceedings arose, it was decided that the need for good order and discipline required his removal — but not before he had done his finest work.

Gross Indecency

In January 1952, Turing met Arnold Murray outside a cinema in Manchester. After a lunch date, Turing invited Murray to spend the weekend with him at his house, an invitation which Murray accepted although he did not show up. The pair met again in Manchester the following Monday, when Murray agreed to accompany Turing to the latter’s house. A few weeks later Murray visited Turing’s house again, and apparently spent the night there.

After Murray helped an accomplice to break into his house, Turing reported the crime to the police. During the investigation, Turing acknowledged a sexual relationship with Murray. Homosexual acts were illegal in the United Kingdom at that time, and so both were charged with gross indecency under Section 11 of the Criminal Law Amendment Act 1885.

Turing was given a choice between imprisonment or probation conditional on his agreement to undergo hormonal treatment designed to reduce libido. He accepted chemical castration via oestrogen hormone injections.

Turing’s conviction led to the removal of his security clearance, and barred him from continuing with his cryptographic consultancy for GCHQ. At the time, there was acute public anxiety about spies and homosexual entrapment by Soviet agents, because of the recent exposure of the first two members of the Cambridge Five, Guy Burgess and Donald Maclean, as KGB double agents. Turing was never accused of espionage but, as with all who had worked at Bletchley Park, was prevented from discussing his war work.

More about Alan Turing

Science Museum Exhibition;
‘Codebreaker – Alan Turing’s life and legacy’ at the Science Museum – video’;
On bullied “geeks”.

Enigma

Turing’s Rôle in Cracking the Enigma Codes

During World War II, Turing used his knowledge and ideas in the Department of Communications where he used his mathematical skills to decipher the codes the Germans were using to communicate. This was an especially difficult task because the Germans had developed a type of computer called the Enigma. It was able to generate a constantly changing code that was impossible for the code breakers to decipher in a timely fashion.

During his time with the Department of Communications, Turing and his fellow scientists worked with a device called COLOSSUS. The COLOSSUS quickly and efficiently deciphered the German codes created by the Enigma. COLOSSUS was essentially a bunch of servomotors and metal, but it was one of the first steps toward the digital computer.

Alan Turing, the Enigma and the Bombe

Alan Turing had been identified at Cambridge, as a likely candidate for code breaking. He went to the Government Codes & Ciphers School, (GC&CS), in Broadway in London a number of times in early 1938 to be shown what had already been achieved. He was shown the rodding method and some intercepts of German signals enciphered on the German forces’ Enigma which had a plug-board.

The Bombe

In 1939 the only technology available for achieving electrical connections from rapidly changing drum positions was to use small wire brushes on the drums to make contact with fixed contacts on the Test Plate. This was a proven technology from punched card equipment. High speed relays were initially the only reliable devices for sensing the voltages on the interconnections. Thermionic valves were tried but were not reliable enough in 1939. Later, thyratron gas filled valves were used successfully and these were about 100 times faster than the high speed relays.

The British Tabulating Machine Co (BTM) had designed the opened out Enigmas and built the Test Plate. The project to now build a complete search engine, which became known as a Bombe, came under the direction of H H (Doc) Keen. The machine, known as Victory, was completed by March 1940 and delivered to Bletchley Park. It was first installed in one end of Hut 1. Now the work began on finding out how to use this new device. Results at first were not very encouraging. The difficulties in finding cribs meant that when a menu was constructed between intercepted enciphered text and a crib, it usually did not have enough loops to provide good rejection and therefore a large number of incorrect stops resulted.

Read about the Polish Contribution.

Enigma — How it was Operated

There’s an applet on the web; I haven’t tried it myself, but it appears to emulate encoding by an Enigma machine. It’s here: Russell Schwager’s Enigma Machine Applet.

Alan Turing (1912 — 1954)