OBITUARY : John Herivel

22 Jan 2011

OBITUARY : John Herivel
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John Herivel, who has died aged 92, was one of the leading Bletchley Park 
codebreakers working on the German Enigma machine cipher during the Second 
World War.

Herivel was one of a number of bright young mathematicians recruited from 
Cambridge by Gordon Welchman when he set up Hut 6 to break German army and 
air force Enigma ciphers in January 1940, and he arrived at Bletchley on 
January 29 1940. Aged only 21, he had been one of Welchman's students at 
Sidney Sussex College.

After being trained on how to break Enigma by Alan Turing, Herivel was put 
to work, and soon proved his worth by finding an imaginative way of 
breaking the Enigma ciphers by hand - this became known as the Herivel 
Tip, or "herivelismus", and relied on lazy operators setting up their 
machines in the morning according to the daily keys and carelessly doing 
as little as possible before sending their first message.

The codebreakers had broken the "Red" Enigma cipher used for liaison 
between the Luftwaffe and ground forces in late January 1940. Later, the 
Enigma ciphers would be broken using electromechanical devices called the 
Bombes, but at this stage they were all broken by hand, and the Red cipher 
could be broken only intermittently.

"When I came to Hut 6, we were doing very badly in breaking into the Red," 
Herivel later recalled. "Every evening, I would sit down in front of the 
fire and put my feet up and think of some method of breaking into the Red. 
I was very young and very confident, and I said I'm going to find some way 
to break into it. Then, one evening, I remember vividly suddenly finding 
myself thinking about the other end of the story, the German 
operators"...../snip/


.....The full importance of the break using the Herivel Tip was not 
appreciated at the time. But it continued to be used to break into Enigma 
for another three months, until Hut 6 started using the Bombes. Welchman 
later suggested that, without Herivel, Bletchley might not have broken the 
Red cipher during the period from May to August 1940, with potentially 
disastrous consequences.

"If Herivel had not been recruited in January 1940, who would have thought 
of the Herivel tip ?" Welchman asked. "Let there be no misconceptions... 
Loss of continuity would, at all stages, have been very serious, if not 
disastrous."

John William Herivel was born in Belfast on August 29 1918 and educated at 
Methodist College. In 1937 he won a scholarship to study Mathematics at 
Cambridge.

At Bletchley, Herivel moved from Hut 6 to the "Newmanry", the section 
working on the German "Fish" teleprinter ciphers which were solved using 
Colossus, the first semi-programmable computer.

After the war, he worked initially as a teacher but struggled to control 
the boys. Instead he took a post as a lecturer in the History and 
Philosophy of Science at Queen's University, Belfast. He retired to 
Oxford, where he was a Fellow of All Souls, in 1978.

John Herivel published a number of books, including Joseph Fourier: The 
Man and the Physicist ( 1975 ); The Background to Newton's Principia, a 
Study of Newton's Dynamical Researches in the Years 1664-84 ( 1965 );
and Herivelismus and the German Military Enigma ( 2008 ).

He married, in 1947, Elizabeth Maude Jones. She died in 2005, and he is 
survived by two daughters.


http://www.telegraph.co.uk/news/obituaries/military-obituaries/special-forces-obituaries/8275117/John-Herivel.html

http://i.telegraph.co.uk/multimedia/archive/01808/herivel_1808731f.jpg