The Difference Engine – Book Review
Charles Babbage and the Quest to Build the First Computer
Jun 8, 2009
Mathematician Charles Babbage was a man of wide interests and throughout his career he published eighty-six papers and six books on topics such as astronomy, military science, railroads, chess, geology, electricity, lock picking, taxes, and of course mathematics. He once calculated the odds of a person's resurrection at 200,000,000 to 1.
It was 1821, and Babbage was fed up with all the errors in found in mathematical tables of the day. Given that all such tables were generated by human calculators in a mind numbingly tedious process, it was no wonder that they were so unreliable. Babbage wanted to remedy that.
Babbage's Calculating Machines
Charles Babbage's conception and design of calculating machines, beginning with the difference engine and later the analytical engine, ranks as one of the most ingenious and imaginative efforts in the history of technology. The story of his attempt to get these strictly mechanical computers built, a full 150 years before the invention of the first electronic computer, elicits wonder at the potential of the human mind as well as its limitations.
No one could be more qualified to write the story of Babbage and his engines than Doron Swade, PhD, who was curator of computing at the Science Museum, London. He is currently director of the Babbage Project at the Computer History Museum in Mountain View, California.
Swade serves as both biographer and historian as he weaves together the life and work of Babbage. Requiring 25,000 precision machined parts (!) the difference engine tested the limits of what was possible to manufacture in an age when all machines were essentially one-off custom built jobs and no standards existed. One of the craftsmen who worked on the project was Joseph Whitworth, who was perhaps inspired by his experience to go on to develop the first standardized system of screw threads—the British Standard Whitworth thread.
Although thousands of parts were successfully produced, it isn't giving anything away to say that a working machine was never built. Despite decades of work, even carried on for a time after Babbage's death, the complexities, cost overruns and perhaps even Babbage's peculiarities of personality, doomed the concept to failure.
The author does his best to keep the story moving and the first part of the book holds the reader's interest quite well. It lags a bit in the middle as it becomes clear that the engine is not going to work out. That part of Babbage's life and work could probably have been condensed with little loss. But then Swade has an idea.
Bringing a Difference Engine to Life
The later part of the book describes the project to finally build a working difference engine, to be put on display at the museum in time to commemorate the 200th anniversary of Babbage's birth. Swade and his team seem to have almost as trouble as Babbage himself in getting the device built (over a period of six years).
From an engineering and management perspective it's a fascinating project, made more so by having to interpret Babbage's true intentions from less-than-clear drawings, and by the desire to confirm (or not) that the machine could have been built using the technology of the time.
Swade writes well and with authority. His combined knowledge of the history of computing, Babbage's life and work, and his involvement in building a working Babbage engine give him an unparalleled insight into Babbage the mathematician, the inventor and the person. Anyone with an interest in 17th century British history, the development of general purpose computing machines, and early precision engineering will get a lot out of reading The Difference Engine.
References
The Difference Engine: Charles Babbage and the Quest to Build the First Computer, Swade, D., 2000, Viking Press, NY, ISBN 0-670-91020-1
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