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The Difference Engine: Charles Babbage and the Quest to Build the First Computer

Penguin (Non-Classics)

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Same book as "The Cogwheel Brain"

This is a terrific book. Beyond that, I have nothing to add to the previous excellent reviews, except to note that it seems to be precisely the same book as Doron Swade's The Cogwheel Brain. I nearly bought both until I checked the tables of contents...

One of the great accomplishments of the 19th century

Charles Babbage and John Herschel, the astronomer, were preparing tables for the astronomical society. They needed to check the work of computations by humans, by different computers. The need for tables was particulary important for navigators. The source of error in the tables was clear, human fallibility. The manual production of tables, calculation, transcription, typesetting, and proofreading created opportunities for error. The engine of change in 1821 was the steam engine. Charles Babbage wanted to produce a machine to produce error-free tables.

Babbage entered Trinity in 1810. He studied on his own the work of the French mathematicians. His father was a well-to-do London banker. Charles married and received from his father an allowance of three hundred pounds. In London he established himself in scientific circles. By the spring of 1822 he had a small working model of his first design. Computing devices of the time required manipulation and were limited as to the size of the numbers the devices could handle. Babbit first used the method of differences, addition, in his design. He sent a brief announcement to the Astronomical Society about his invention. He received a mandate from the government and was prepared to build a new machine. He hired Joseph Clement for precision engineering work. Clement and Babbage devised new tools and modified machines. There was a need to produce large numbers of similar parts. Babbage conceived of his machine when manufacturing was in transition. By 1826 Babbage was wholly absorbed in the design of his Difference Engine. The machine was eight feet by seven feet by three feet.

In 1826 Babbage published a book on life assurance. While traveling in Europe following the death of his wife, he learned of his election as Lucasian Professor of Mathematics. He never resided in Cambridge and gave no lectures. Babbage expressed a view on the decline of science In England. Undoubtedly science was more professional in Prussia and France. Babbage's position alienated some of his supporters. In 1832 part of the engine was put on display in his drawing room. Clement was to leave the project. Work was not resumed. The Treasury Department spent more than seventeen thousand pounds on it.

There is a curious affinity between mathematics, mind, and computing. After the break with Clement, Babbage moved from the Difference Engine to the Analytical Engine. He devised the first automatic mechanisms for multiplication and division. He had in fact designed a general purpose four function calculator. In 1836 he opted for punch cards to control the engine. The Analytical Engine was never built. Babbage worked in isolation. With the Analytical Engine Babbage was seduced by the intellectual quest.

After twenty years the Treasury axed the Difference Engine and wrote off the expense. Between 1846 and 1849 Babbage designed Difference Engine No. 2. Maurice Wilkins believed the Analytical Engine was one of the great accomplishments of the 19th century. The Science Museum in Britain built a version of the Difference Engine No. 2 for an exhibit on Babbage.

Wonderful Engines

This book has 2 basic parts. First, is the discussion of Babbage's life and his computing engines. Second, is the author's modern-day story of attempting to complete Babbage's Difference Engine, a feat which Babbage himself was unable to do. I picked up this book for the first part. I wanted to learn about Babbage and how his engines worked. While the author gives a wonderful account of Babbage's life and methodology, he does not clearly describe HOW these engines function. I realize that the engines are extremely complex, but a chapter on the functioning of the Difference Engine trial piece and some diagrams on its operations would have been much appreciated. Unfortunately, as were Babbage's contemporaries, we are left mainly in dark as to how simply turning a crank can produce the necessary additions. The author also never fully explains the "method of finite differences" upon which the function of the difference engine is based.

The most amazing part of the book is the overview of Babbage's design for the Analytical Engine- the first programmable computer. It is amazingly similar in concept to today's modern computers, but it uses motion through metal gears and cams, instead of electricity through logic gates and wires. I expected to be bored by the modern-day story, but I actually was interested in the process of reconstructing this 19th century machine. It was enlightening to see how the same problems Babbage faced 150 years before troubled engineers today.

Overall, I recommend this book for those curious about Babbage and his engines. However, the writing seems jerky and unorganized in parts, and there is little technical description of the engines' functionality.

Doron Swade's Quest to Build a Difference Engine

This is the first book I've read on Charles Babbage, but I imagine that there are others that are better. First, this book seems to assume you've already read a book or two about Babbage before. It almost has an apologetic tone and seems to be an answer to what, I assume, have been slights against Babbage and his work. Second, this book is as much about the author and his quest to build a Difference Engine as it is about Babbage himself. If you want to hear about dealing with office politics in an British museum, you may find this interesting.

All in all, this is a fairly dry read. It was interesting at points, but I certainly wouldn't recommend it for your first book on Babbage.

History - What a story

I enjoyed this book very much. It was refreshing to step away from the technical library and read more about the people, machines, trials, and triumphs that occured as far back as the early 1800's.

Though it all you learn about a man who had such vision. His execution could be faulted for many reasons. But in the end the machine works! I can not wait to see the Difference Engine myself someday.