Dr. Arnold Lynch




The Times February 01, 2005

Arnold Lynch
Engineer who made a crucial contribution to wartime codebreaking

AT THE Post Office Research Station in Dollis Hill, North London, from 1936 to 1974, Arnold Lynch specialised in the measurement of the electrical and magnetic properties of materials. Both during and after the war his work greatly assisted the drive towards miniaturisation of radio and radar sets. It was also crucial to one of the most complicated codebreaking sagas of the war the cracking of the Fish code, an exceptionally complex teleprinter cypher used by the German High Command.
Lynchs work on the development of an optical tape reader was essential to the construction of the Colossus machine which was used to break Fish. The Colossus has a serious claim, too, to be considered the first programmable electronic computer.

Arnold Lynch was born in Tottenham, North London, in 1914. His father was headmaster of West Green School and both parents were very active in the Labour Party. He won a scholarship to Dame Alice Owens School in Islington, before going up to Emmanuel College, Cambridge. Shortly after graduating he entered the Post Office by competitive examination.

In 1943 he was studying photocells. Unknown to him, his boss at Dollis Hill, Tommy Flowers, was working to develop a machine that would break Fish manual decoding was so slow that any coherent material it yielded was already hopelessly out of date. Thanks in large part to Lynchs work on optical tape readers, the Colossus could read punched tape at 5,000 characters per second, five times faster than previous designs.

After the war he continued to research dielectric loss. He felt it was a great professional achievement when this work led to the choice of British polyethylene in preference to American in the first transatlantic telephone cable laid in the mid-1950s.

When he retired in 1974, he returned to the lab work. At City University he developed the measurement technique now used to meter electricity flowing in the high-voltage link between the British and French national grids. He worked in the electrical engineering department of University College London, using open resonators for millimetre-wave measurements. He also worked on a new free-space method of measuring ferrites. A paper on the subject, with several co-authors, won the Maxwell Premium of the Institution of Electrical Engineers.

Lynchs major work in retirement was at the National Physical Laboratory in Teddington, again on precise electrical measurement. He developed a non-contact method of measuring the electrical resistivity of metals, which greatly facilitates the testing of aircraft components for correct heat-treatment and is also used to identify coins in coin-operated machines.

One of his great interests was the history of technology, and he was a member of the archives committee of the Institution of Electrical Engineers for some 25 years. He took a great interest in the project, begun in 1994, to rebuild Colossus at the Bletchley Park Museum.

He married Edith Taylor in 1953. She died last year, and he is survived by a son and a daughter. Another daughter died in infancy.

Arnold Lynch, electrical engineer, was born on June 3, 1914. He died on November 13, 2004, aged 90.


A Difficulty in Electromagnetic Theory . The Lynch-Catt article.





[The obituary below was given in the USA in the IEEE]


Arnold Charles Lynch BSc MS PhD CEng FIEE (1914-2004)

J Patrick Wilson.

Arnold Lynch was a founder member of the Science, Education and Technology Division of the IEE, an active member of the Archives Committee and instrumental in setting up the annual weekend meetings on the History of Electrical Engineering, most of which he attended. In addition he was a lively contributor to discussions, a most helpful and informative correspondent with many colleagues, and a popular after-dinner speaker. He was an avid reader of the ‘Dipole’ column in IEE News and solver of its puzzles. He received at least six IEE premiums for lectures or papers. Arnold was born in Tottenham, North London, on 3 June 1914, where his father was a headmaster. His parents, who were active in the Labour party, named him after Matthew Arnold. He won a scholarship to Dame Alice Owen’s School in Islington and from there went to Emmanuel College Cambridge where he studied under Rutherford and G F Searle, and attended a rather dated lecture course given by the ageing J J Thomson. In 1936, after a short spell making amplifiers, he entered the Post Office by competitive examination and worked at their Research Station at Dollis Hill until his retirement in 1974. During this time he gained a BSc in psychology through evening classes at Birkbeck College and, shortly before his retirement, Cambridge University awarded him a PhD for his contributions to electrical engineers. At Dollis Hill he was involved in a wide variety of research projects including measurements of permeability and permittivity of magnetic and dielectric materials and the measurement and application of piezo-electric devices. He developed many new measuring techniques, such as that for the capacitance between conductors in a multiway cable so that crosstalk and interference could be minimised over long distances. During the war a variety of secret projects arose whose purpose was not disclosed although Arnold admitted he made his own guesses. One problem for him was whether it was possible for the enemy to detect magnetic compasses secreted in RAF uniform buttons. When the war was over he was sent to Germany to interview scientists, including Heisenberg, about their work. In 1974 he took up retirement work, first at City University, where he developed high voltagetechniques to measure the flow of electricity in the power link between France and England. Atthe Polytechnic of the South Bank he investigated the breakdown of insulators at high voltages, and at University College London he worked on open resonators at millimetric wavelengths for free-space measurement of ferrites. His major retirement work was at NPL where he developed non-contact methods for measuring resistivity which found application in checking the heat-treatment of aircraft components and in identifying coins in slot-machines. He also taught mathematics at Open University summer schools for about ten years, and was involved in the rebuilding of Colossus, providing many technical details from memory. His hobby interests included classical music, skiing, sailing, cycling and motor cycling, an old Rolls-Royce, bridge and local history. 6
Page 7
Arnold married Edith Taylor in 1953 and they settled in Potter’s Bar. She was a teacher of the deaf and enjoyed accompanying him on many of the weekend meetings. She died in February and he in November 2004, at the age of 90. They are survived by a son and a daughter, their younger daughter died in infancy. He made many contributions to the history of electrical engineering, including lectures at Savoy Place on J J Thomson’s discovery of the electron, ‘Half the electron’ and ‘Blumlein’s transformerbridge network’. These were later published in ESEJ as well as a paper on ‘Four pioneer deep-sea cables’. His sixteen contributions to the IEE History weekends covered several recurring themes as well asmiscellaneous subjects such as the ether (1981) and electromagnetic theory (1998), biographies of Fleeming Jenkin (1986) and Heaviside (1988) and the Variac (1997). Four concerned computers as Arnold had been involved in what is now regarded as the world’s first digital computer. This was Colossus and its prototype Heath Robinson, used for deciphering the German teleprinter-based Lorentz machines and the Geheimschreiber. Arnold’s contribution to the project (vide 1978 paper) was an optical reader for the punched tape output, which used crescent-shaped windows so that the circular punched hole would produce a rectangular pulse from the photocell. Interestingly, his optical reader was a derivative of the Post Office speaking clock (1990). The camera for this was later used in a number of WW2 projects to record the sounds of planes, helicopters and tanks for training purposes, as well as the Auto-Teller for RAF Fighter CommandHQ. This was a crude form of speech synthesiser in which sequences from a limited vocabulary of words recorded on a glass disc could be selected by a code sent on a narrow-band telegraph line. In his third computer paper (1984), Arnold discussed mechanical and electromechanical systemsof data storage: punched tape; thermionic valves; capacitors; cathode ray tubes; mercury and quartz delay lines; magnetic techniques; semiconductors; and the threaded magnetic core storesthat he was involved with. His fourth paper (1999) was a tribute to the late T H Flowers who wasthe leader of the Colossus project and whose involvement stemmed from the use of indirectly-heated thermionic valves in telephone exchanges. Arnold contributed several papers on the history of measuring techniques (1993, 2001), units, material standards (1980, 1982, 1983) and in his last paper (2003) he described himself as ‘almost retired’! He also had a great interest in submarine cables: both the pioneering telegraph ones andthe first telephone cable (TAT1) in which he was personally involved (1995). This was a joint UK/UK/Canadian venture requiring a series of amplifiers and a much better coaxial cable, usingpolythene insulation, a British invention. Unfortunately US polythene appeared to behave differently under pressure from that measured by Arnold. Fortunately he was able to convincethem that this was due to the measuring techniques, thus avoiding foreign payments for‘American’ polythene. Over the years Arnold Lynch worked on a wide variety of interesting topics and we are fortunate in having this legacy of recorded information as well as happy memories of a friend and colleague. Thanks are due to Arnold’s family and former colleagues, and to the IET Archives for much of the above information. 7