Charles Babbage's Difference Engine No1, c 1830s.
© Science Museum / Science & Society Picture Library
Impression from a woodcut by B H Babbage. Charles Babbage (1791-1871) first conceived the idea of an advanced calculating machine to calculate and print mathematical tables in 1812, as he wanted to eliminate all the sources of inaccuracy associated with compiling mathematical tables by hand. The engine was begun in 1824 and assembled in 1832 by Joseph Clement, a skilled toolmaker and draughtsman. It was a decimal digital machine - the value of a number represented by the positions of toothed wheels marked with decimal numbers.