Douglas Hartree - Later Life and Work

Later Life and Work

In February 1946, Max Newman (who had been involved in the Colossus computer) submitted an application to the Royal Society for funds to start the task of building a general purpose computer at the University of Manchester. The Royal Society referred the request to Hartree and C.G. Darwin, Direcor of the NPL, to advise them. Hartree recommended the grant but Darwin opposed it on the grounds that Turing's ACE at NPL would be sufficient to serve the needs of the country. But Hartree’s view won the day and the Manchester developments in computing were started.

Hartree did further work in control systems and was involved in the early application of digital computers, advising the U.S. military on the use of ENIAC for calculating ballistics tables. In the summer of 1946 Hartree made his second trip to ENIAC as an evaluation of its applicability to a broad range of science, when he became the first civilian to program it. For this he selected a problem involving the flow of a compressible fluid over a surface, such as air over the surface of a wing travelling faster than the speed of sound.

At the end of 1945 or very early in 1946 Hartree briefed Maurice Wilkes of the University of Cambridge on the developments in computing in the USA which he had seen. Wilkes, then received an invitation from the Moore School of Electrical Engineering (the builders of ENIAC) to attend a course on electronic computers. Before leaving for this, Hartree was able to brief him more fully on ENIAC. It was on the boat home that Wilkes planned the original design of EDSAC, which was to become operational in May 1949. Hartree worked closely with Wilkes in developing use of the machine for a wide range of problems and, most importantly, showed users from a number of areas in the university how they could use it in their research work.

Hartree returned to Cambridge to take up the post of Plummer professor of mathematical physics in 1946. In October he gave an inaugural lecture entitled “Calculating Machines: Recent and Prospective Developments and their impact on Mathematical Physics”. This described ENIAC and the work that Hartree had done on it. Even in 1946, two years before stored programming electronic computing became a reality, Hartree saw the need for the use of sub-routines. His inaugural lecture ended with a look at what computers might do. He said: "..there are, I understand many problems of economic, medical and sociological interest and importance awaiting study which at present cannot be undertaken because of the formidable load of computing involved."

On 7 November 1946 the Daily Telegraph, having interviewed Hartree, quoted him as saying: "The implications of the machine are so vast that we cannot conceive how they will affect our civilisation. Here you have something which is making one field of human activity 1,000 times faster. In the field of transportation, the equivalent to ACE would be the ability to travel from London to Cambridge ... in five seconds as a regular thing. It is almost unimaginable."

Hartree's fourth and final major contribution to British computing started in early 1947 when the catering firm of J. Lyons & Co. in London heard of the ENIAC and sent a small team in the summer of that year to study what was happening in the USA, because they felt that these new computers might be of assistance in the huge amount of administrative and accounting work which the firm had to do. The team met with Col. Herman Goldstine at the Institute for Advanced Study in Princeton who wrote to Hartree telling him of their search. As soon as he received this letter, Hartree wrote and invited representatives of Lyons to come to Cambridge for a meeting with him and Wilkes. This led to the development of a commercial version of EDSAC developed by Lyons, called LEO, the first computer used for commercial business applications. After Hartree’s death, the headquarters of LEO Computers was renamed Hartree House. This illustrates the extent to which Lyons felt that Hartree had contributed to their new venture.

Hartree's last famous contribution to computing was an estimate in 1950 of the potential demand for computers, which was much lower than turned out to be the case: "We have a computer here in Cambridge, one in Manchester and one at the . I suppose there ought to be one in Scotland, but that's about all." Such underestimates of the number of computers that would be required were common at the time.

Hartree's last Ph.D. student at Cambridge, Charlotte Froese Fischer, would become world-famous for the development and implementation of the multi-configuration Hartree–Fock (MCHF) approach to atomic structure calculations and for her theoretical prediction concerning the existence of the negative calcium ion.

He died of heart failure in Addenbrooke's Hospital, Cambridge in Feb. 12, 1958.