A collection of nearly 150 letters to and by Alan Turing has been found in a neglected filing cabinet in a storeroom at Manchester University. Turing worked at the university from May 1948, when he was appointed Deputy Director of the university’s Computing Machine Laboratory. There was no Director as such, but the Head of the Mathematics Department was Professor Max Newman, a distinguished mathematician who had been a Bletchley Park codebreaker during the war. Newman’s influence on Turing went back to the 1930s, when his lectures at Cambridge had inspired Turing to work on the Entscheidungsproblem, and this led to Turing’s seminal 1936 paper ‘On Computable Numbers’.
The papers which have just surfaced cover the period from March 1949 to 2 June 1954, and thus run right up to Turing’s death on 7 June. I have not yet been to Manchester to see the originals, but I have read the archivist’s synopsis of every one. Despite there being numerous items written after Turing’s trial and conviction for ‘gross indecency’ in March 1952, no reference is made to any of the problems he faced at this time: his trial, the verdict, the hormone injections and psychiatric analysis, the loss of his Security Clearance, etc. In fact, they shed little light on Turing the man, although he does make some admissions as to his dislike of the USA, his lack of skill as a reviewer, and the gap between his writing and speaking styles.
The subject matter of many of the letters testifies to his growing success and reputation as a mathematician. He receives many requests to write papers and books, to speak at conferences, to review papers, to advise other academics and students on research, to supply copies of his own papers (we’re talking here not just pre-internet days, but pre-photocopier, too), and to permit the Manchester University computer to be used to do work for others. Although none of the letters is outstandingly important, their sheer number and diversity demonstrate clearly that Turing was a highly respected mathematician, right at the forefront of the newly emerging computer revolution, whose views were sought by other eminent mathematicians across the world.
The first Manchester computer, the one Turing used, was called ‘The Baby’, but it was superseded by a series of ‘Atlas’ machines, which remained in use into the late 1960s. It is here that I can reveal a connection from my own past. In the 1960s, I was working for a firm of consulting civil engineers, and we wished to design some large asymmetrical suspended road slabs as part of Newcastle’s Central Motorway East. Computer analysis was the best way forward, so we commissioned Manchester University to run our analyses overnight (day-times were reserved for in-house use). Now comes the bit that anyone under 50 will find incredible. We sent our inputs to Manchester, as punched paper tapes, on the train – and the stacks of fanfold computer paper with the Atlas results came back by train the next day. This was the highest of high-tech in the 1960s!
Of course, in those days, I knew nothing of Turing. Having been researching his achievements during the last twenty years, I am now often asked to speak about Turing and his work. In August, it was the Turing Fest in Edinburgh, and in October I am contributing to a 2-day study tour about Alan Turing, organised by the New Scientist.