Figure wheel of Babbage's difference engine No 2, 1991.

British computing pioneer Charles Babbage (1791-1871) designed Difference Engine No 2 between 1847 and 1849, as part of his attempt to mechanise the production of mathematical tables. The calculating section of the Engine weighs 2.6 tonnes and consists of 4,000 separate parts. Like his other engines, Difference Engine No 2 was never constructed in Babbage's lifetime. Factors cited include his allegedly difficult personality, unconvincing progres, disputes with his engineer, Joseph Clement, political instability, the eventual withdrawal of government funding, and limitations in Victorian machine tool technology. The Science Museum began constructing Difference Engine No 2 in 1985, for the bicentennial of Babbage's birth.