As you might expect from its name, the "Difference Engine" is a strangely difficult object to describe. You might start by imagining the side of a large crib with uprights ringed by small metal wheels ...

Give money to have the world's first computer, Charles Babbage's Analytical Engine, built, and in return you might get your name engraved on one of the thousands of brass cogs that comprise the ...

But it wasn’t an engraving. It was a sheet of finely woven silk – a thousand threads to the inch – so subtle and detailed ...