Strange Engines

If you were wondering what to get mathematician Charles Babbage for his birthday, bad news: you're a hundred odd years late. It's very thoughtful of you, though! And Babbage probably would have very much enjoyed this working prototype of his Difference Engine.

From PhysicsCentral:

Babbage won government support to work on a "difference" engine that could handle calculations that were valuable to navigators; nautical tables at the time were riddled with errors and could lead a ship into disaster. But after one seventh of the machine was built, and 17,000 pounds from government coffers and 6,000 pounds of Babbage's own fortune were poured into the project, the dream of the "difference engine" died.

The tragedy is that Babbage's design would have worked - in 1991 a fully functional version was completed using only materials and techniques available during his lifetime. The 'difference engine' gets its name from the fact that it doesn't do multiplication and division, but instead reduces all such operations to addition and subtraction.

However, Babbage was working on a design for a mechanical device that would be able to handle all kinds of operations - the Analytical Engine. From Wikipedia -

The main difference between the two engines is that the Analytical Engine could be programmed using punch cards. He realized that programs could be put on these cards so the person had only to create the program initially, and then put the cards in the machine and let it run. The analytical engine would have used loops of Jacquard's punched cards to control a mechanical calculator, which could formulate results based on the results of preceding computations. This machine was also intended to employ several features subsequently used in modern computers, including sequential control, branching, and looping, and would have been the first mechanical device to be Turing-complete.

A Turing-complete device would have been the functional equivalent of a modern, digital computer. You read that right. Babbage's machine would have ushered in the Information Age some eighty years early.

Even more fascinating: this mechanical computer had a program designed for it by Ada Lovelace, Lord Byron's daughter, to calculate Bernoulli numbers. This makes Ada the first programmer, although sadly she never had the opportunity to actually run her program.

If you want to read a novel set in a world where Babbage completed his machine, you need look no further than Bill Gibson and Bruce Sterling's Victorian SF novel The Difference Engine.

Turing-completeness does not specifically require digital technology to achieve. Which means that a mathemtician and some determined engineers could have built a functional 'computer' much earlier in history. Interestingly, when modern computers did arise, they were constructed almost simultaneously by a handful of independent organizations. This is why we credit no specific person with the 'invention' of computers.

Maybe history was simply ready for one of humanity's most powerful technologies.

For an even older mechanical calculation device, see The Antikythera Mechanism, a two-thousand-year-old mechanism for calculating the movements of the stars.

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