Babbage's Difference Engine No 2 on display at the Science Museum.
© Science Museum / Science & Society Picture Library
This engine was constructed by the Science Museum in London from designs made by the British computing pioneer Charles Babbage (1791-1871) between 1847 and 1849. Reg Crick and Barrie Holloway, shown here working on the display, were engineers who asisted with the building of the engine. The main part of the engine was completed in 1991 for the bicentennial year of Babbage's birth, and the printing mechanism was completed in 2000. Babbage conceived the engine to calculate a series of numerical values and automatically print the results. Difference Engine No 2 was never constructed in his lifetime.