Allan G. Bromley
Allan George Bromley | |
---|---|
Born | |
Died | 16 August 2002 New South Wales, Australia | (aged 55)
Nationality | Australian |
Alma mater | University of Sydney |
Known for | Understanding of Charles Babbage's calculating engines. |
Scientific career | |
Fields | History of computing |
Institutions | University of Sydney; Science Museum, London |
Allan George Bromley (1 February 1947 – 16 August 2002) was an Australian historian of computing who became a world authority on many aspects of early computing and was one of the most avid collectors of mechanical calculators.[1][2]
The work on understanding Charles Babbage's calculating engines is Allan Bromley's greatest legacy. The October–December 2000 issue of the IEEE Annals of the History of Computing was dedicated to him for the quality of his research on this subject.[1][3] His studies of the
Bromley was an
Biography
Bromley was born on 1 February 1947 and named after his uncle Allan, who was killed in New Guinea during World War II, and his father George, who died on 8 August 1962.[citation needed] Bromley grew up on a 30-acre (12 ha) property at Freeman's Reach, on the Hawkesbury River, in New South Wales, Australia, in an historic home, "Sunny Corner". He completed his secondary education at Richmond High School and in 1964, at the age of 17, his academic ability earned him a scholarship to study science at the University of Sydney.[citation needed] He had been awarded the Nuclear Research Foundation Medal, University of Sydney, Summer Science School, 1963.[citation needed]
Bromley graduated in 1967, with first-class honours in
Bromley had an amateur interest in the history of mechanical inventions, and was aware of the ancestral figure of
After Babbage's engines, Bromley moved on to other historical computing artefacts. He made a ground-breaking study of the
In 1998, after a long spell of illness, he was diagnosed with
Collections
Bromley started collecting mechanical calculators in 1979. A year later he already had sixty pieces.
His collection included some rare pieces. The pride of place was taken by four mechanical anti-aircraft gun predictors developed and built by the British government after World War I. The machines, weighing about half a tonne, marked the height of mechanical computation; they were first used in the Spanish Civil War and extensively during World War II. They performed in real-time and were capable of predicting the firing angle to explode a shell within 10 metres of a plane at anything up to 10,000 metres.[9]
Charles Babbage's computing engines
Most discussions of the history of computing start with Charles Babbage, and what we know about Charles Babbage's Difference and Analytical engines really starts with the scholarship of Allan Bromley.
— Tim Berguin, Editor-in-chief, IEEE Annals of the History of Computing, Volume 22, number 4, October–December 2000, p.2
Part of Allan Bromley's scholarship was his study, at the
During several visits to London beginning in 1979, Allan G. Bromley of the University of Sydney in Australia examined Babbage's drawings and notebooks in the Science Museum Library and became convinced that Difference Engine No. 2 could be built and would work. I had independently read of Babbage's hapless fate and become deeply puzzled as to why no one had tried to resolve the issue of Babbage's failures by actually building his engine.
In 1985, shortly after my appointment as curator of computing, Bromley appeared at the science museum carrying a two-page proposal to do just that. He suggested that the museum attempt to complete the machine by 1991, the bicentenary of Babbage's birth. Bromley's proposal marked the start of a six years project that became something of a personal crusade for me.— Doron D. Swade, Scientific American, February 1993, p.89
Antikythera mechanism
Bromley built a partial reconstruction of the Antikythera mechanism, one of the oldest (surviving) geared mechanisms known. Working with Frank Percival, a Sydney clockmaker, he improved on an earlier reconstruction by Derek J. de Solla Price.[13] Having tested Price's theory using Meccano parts, Bromley found that the mechanism was unworkable. Working with Percival, he improved the device by altering the function of the handle so that one complete rotation would correspond to a single day, which he considered to be the most obvious astronomical unit. Bromley worked with the same set of parts as Price, but suspected that a gap in the mechanism was originally home to several extra gears.[14]
Another breakthrough by Bromley concerned a train of gearing which appeared to have 15 and 63 teeth, for which Price had been unable to discover a purpose. Price considered these numbers to be too difficult to work with, and assumed that they should be corrected to 16 and 64, theorising that it could have operated a four-year cycle on the device. Bromley worked with the original count of 15 and 63 teeth, discovering that the train's cycle was four and a half years; four of such cycles equalled 18 years, a duration equal to the cycle of eclipses. With this gearing, the mechanism worked correctly, with the pointer moving into a new square for each new moon, as the handle is turned, meaning that each square on a dial represented one month. Over 223 months, or 18 years, the complete cycle is shown.[14]
The model was acquired by the
References
- ^ a b Graeme Philipson, Allan Bromley: historian, eccentric, gem, 27 August 2002.
- .
- .
- ^ The University of Sydney News, 29 March 1988, p.39
- ^ Received from Anne Bromley, Allan Bromley's widow, 22 September 2012.
- ^ The last of the first, Biography of Allan Bromley, p.160 (2000)
- ^ Kingston, Jeff (11 September 2002). "Obituary". Sydney Morning Herald. Retrieved 20 December 2015.
- ^ The Gazette, May 1980, p.24
- ^ Omega Science Digest, Nov–Dec 1983
- S2CID 2285332.
- ISBN 978-0-8138-0047-9.
- ^ Swade, Doron David (2003). Calculation and Tabulation in the Nineteenth Century: Airy versus Babbage (Ph.D.). University College London. p. 16.
- ^ Comments on "Decoding the Heavens", many details about Bromley's involvement in the Antikythera Mechanism research.
- ^ a b "Article". The University of Sydney News. 29 March 1988. p. 39.
- ^ "Bromley's model of the Antikythera Mechanism". Inside the Collection. Museum of Applied Arts & Sciences. Retrieved 27 February 2021.
Sources
- McCann, Doug; Thorne, Peter (2000). The last of the first, CSIRAC: Australia's first computer. Victoria, Australia: The University of Melbourne. ISBN 978-0-7340-2024-6.