Difference Engine Serial 2

This is one of two constructions of the Difference Engine, designed by Charles Babbage in the 1800s, both built over a hundred years later. This particular construction was spending its last weekend in the Computer History Museum in Mountain View, as it was to be moved to the living room of one of the benefactors that funded its construction. As such I came to the museum on an emergency visit. The other construction is in the Science Museum in London, where it is to remain. The Difference Engine sounds in concept to be an example of the Steampunk concept, but to see it in person, it really evokes the fantasy in a way I did not expect. It is quite breathtaking to see in operation. It's almost fantastical watching the shafts disengage gears on one half cycle, allowing addition operands to be reset, and the double helixes spin on the other half of each cycle, carrying overflows from addition operations up to the next digit. On one side of the machine, a man turns a crank. It must be done by hand, because if at any point the machine stalls, it should be stopped immediately or it may be damaged. On the other side, no joke, is a printer, feeding out the results of the operation. We are told that Babbage's design worked as conceived (which was not to be known for sure until it was built), though there were two small modifications made for practicality: the crank needed a ¼ gear ratio to be able to be powered by a human, and one of the counterweights needed to be adjusted so it wouldn't need to dip through the floor. I highly recommend looking up better videos than the ones I took. I was not positioned to take very good shots, as it was a crowded room.