The Difference Engine aimed to mechanise the process of calculation. Composed of thousands of cogs, springs, brackets and other moving parts, it was designed to perform a multitude of calculations, as opposed to a single sum, surpassing anything that had gone before it. It was designed by Charles Babbage (1791-1871), who dreamed of creating an automatic, error-free, calculating machine. A machine, which today, would be recognised as a computer.

Difference Engine No.1 was far from a complete device. It showcased only a small section of what Babbage had envisioned. By 1834 he had designed a new and more complex machine – the Analytical Engine. Like modern computers, this machine could be ‘programmed’ through a series of punched cards, which ‘told’ the machine which calculations to perform and in which order (an idea inspired by the Jacquard Loom, which used punched cards to produce different textile designs).

Babbage went on to design his final calculating machine – Difference Engine number 2, creating a series of intricate, detailed drawings and instructions to show how it would work. But like most of his designs, he never actually built it. It wasn’t until 2002 that the first complete Babbage Engine was finally assembled. It took seventeen years to complete, constructed by modern day specialists at the Science Museum in London using Babbage’s detailed designs. With thousands of moving parts, the machine is a whopping two metres tall, over three metres long and weighs as much as a large hippopotamus! And it works just as Babbage predicted it would in his designs made over 150 years before.

He dreamed of creating an automatic, error free, programmable machine, which revolutionised complex problem solving, and in so doing he pre-empted the progression from the mere calculator to computers of the future. The Difference Engine had the capability to store information, temporarily holding data that could be used for later processing. Today, different software can make relatively simple numbers and calculations model just about anything, from games and music to landing on the moon!


Did you know..?

Ada Lovelace (1815-1852), self-styled as an “Analyst (& Metaphysician)” and the daughter of the famous poet Lord Byron, worked for a time with Babbage on the designs. She published her own notes proposing ways to develop the machine’s programmable features, which foresaw more fully than anyone else the wider impact that software could have for human society.

Sources & acknowledgements

This object description and its related educational resources were researched and written by our team of historians and education specialists. For further information see the item’s home museum, gallery or archive, listed above. 

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