The Difference Engine, designed in the 1820s by the English mathematician and inventor Charles Babbage , was intended to automatically compute mathematical tables which, until that time, had been tediously calculated by hand and were prone to error. Babbage saw an opportunity to revolutionize the field.
With good political contacts and the ear of Prime Ministers, Babbage was able to acquire initial funding for the construction of his machine, a task expected to last 3 years. The project turned into a nightmare, however, as setbacks piled up. In 1827, family tragedies, including the death of his wife, led Babbage to escape in travels to the Continent. When he returned and eventually secured further funding, a personality clash with his head engineer, Joseph Clement, saw construction of the engine halted. In the meantime, Babbage had designed a general-purpose computer, the Analytical Engine. He sought funds to either complete the Difference Engine or commence his new Analytical Engine. By this stage, the 1840's, times were hard and a government which had already spent as much as 17,000 English pounds with little reward declined to continue financing his plans.
According to Babbage's design, the Difference Engine was to be steam-powered and as large as a locomotive. The Difference Engine was eventually built in 1991, the bicentennial of Babbage's birth, using the technology of the era as proof that Babbage's designs were valid. A working model resides today in the Science Museum in London.