Charles Babbage builds his Difference Engine, a mechanical computer that produces mathematical tables. Babbage never built a complete version of the mechanical computer, but the largest part he built is now on display at the London Science Museum. A complete version of Difference Engine No. 2 was built in 1990, strictly following his original design. It works and is also on display at the London Science Museum. Difference Engine No. 1 consisted of 25,000 precision parts and, by the time it was cancelled, had already cost Her Majesty’s Government a whopping £17,470, which at the time was enough to build two good battleships.
