Slashdot Mirror
The Difference Engine
London�s Science Museum to build a working Difference Engine
Overview
The book was first published in 2000 by Little, Brown and Company as The Cogwheel Brain: Charles Babbage and the Quest to Build the First Computer to coincide with the unveiling of the printing part of the Science Museum's Difference Engine. A paperback was also released by Abacus. The book I reviewed is an American edition that published in hardcover format by Viking and Penguin in September 2001. It's the same book, just a different title.
The Difference Engine is arranged chronologically, in three parts. Part I is titled "The Difference Engine" and describes Babbage's work to build his Difference Engine, an automatic calculating machine. Part II is about an improved machine he designed, The Analytical Engine. A Modern Sequel (Part III) tells the story of the London Science Museum's project to build a working Difference Engine.
The Difference Engine In the 19th century, a "computer" was a person who performed calculations by hand, not a machine. Mass production techniques hadn't been developed yet, and making precision parts was a craft rather than an industry, where the screws one maker produced for you would all have a thread slightly different from that of screws you bought from someone else.
Swade describes Babbage's life from his early years, when he was expelled from Cambridge after presenting a formal thesis that was deemed blasphemous, and quarrelling with his father about his marriage. At age 29, sitting with his friend the astronomer John Herschel checking math tables, Babbage exclaimed "I wish to God these calculations had been executed by steam!" So Babbage's quest began -- to build a machine to perform calculations automatically so that they would be less error-prone, leaving humans to think instead of labor. He wrote to Sir Humphrey Davy, the President of the Royal Society, the society for the scientific elite at the time (Babbage was himself a member), as well as to other influential friends and colleagues to try and raise interest in his project. The Society liked the proposal of this "engine" and awarded him a gold medal and funding. But after five years of work (with his component builder Joseph Clements) and no engine, people began criticising Babbage, claiming he had been unable to finish the project and was concealing this so he could keep getting paid. The Society checked up on him, decided his progress was acceptable, and kept funding him.
Babbage then wrote a controversial book criticising the decline of science in England and suggesting an overhaul of the Royal Society, which didn't win him much support. Clements went on strike over a pay and ownership of tools dispute, then finally quit. Babbage had a portion of his Difference Engine built, which he showed off at the elaborate parties he threw, and he managed to get a lot of people excited about his ideas, including his belief that miracles were just the effect of God's laws which we weren't privy to; that God is basically a programmer.
The Analytical Engine
Whereas the Difference Engine was the equivalent of a calculator and quite limited in its capabilities, the Analytical Engine was more like the modern computer. Ideas were borrowed from the looms used in the textile industry -- ideas that are now famously part of modern computers; the Mill (CPU), Store (Storage) and an input facility (punched cards). Babbage designed his own Mechanical Notation to describe the engine's design. He wasn't actively looking for funding, but rather just working on his designs. He wrote to the Duke of Wellington, complaining about how the Government has treated him, and mentioned working on a new machine. In a letter to the Prime Minister Robert Peel, he asked that the Government decide; should he continue work on the old machine or start on the Analytical Engine?
Babbage was a man with many interests and for a while during his occasional exchanges with government officials he worked as an unofficial consultant for five months working to settle the railway "gauge war" -- e.g. work out whether a broader or narrower gauge was better. Babbage believed his work was more acknowledged overseas than in England, and he was suitably encouraged when he was invited to speak about his Analytical Engine at a conference in Turin, Italy. This encouraged him to campaign for funding for it, both in England and also overseas. The first published description appeared in a Swiss journal in 1842.
Robert Peel sought a way to fob off Babbage and was given this in the form of a advice from George Biddell Airy, the Astronomer Royal. After 20 years of work, Babbage finally got a letter saying his work would no longer be funded, but that the government was withdrawing it's claim to the finished work. Babbage politely refused, but somehow interpreted the letter to mean that the government was at least keen on his Analytical Engine and should fund it, else he'd go overseas for funding. With this letter Babbage scored an audience with the Prime Minister, which didn't go very well, ending with him storming out of the interview.
Augusta Ada, the Countess of Lovelace and daughter of Lord Byron, met Babbage at a party when she was 17 and the two became friends. He gladly taught her about his work, and she translated the article from a Swiss journal on the Analytical Engine to English, adding her own comments and getting it published in a journal. Babbage wanted her article "Sketch of an Analytical Engine" to include an anonymous note describing his disputes with the Government, which he attempted to get the publishers to include without her knowledge. When they refused, Babbage asked Ada to withdraw the article, at which point she became upset, realising he was trying to use her article as a political tool. There is then some discussion about how much Ada really contributed to Babbage's work, citing Bruce Collier's notes that she is "the most overrated figure in the history of computing", and either mad or seemingly that way because of her drug abuse. Swade explains that it is not so much Ada who Collier is taking fault with, but the historians who exaggerate her contribution to celebrate her as a woman who succeeded in an area dominated by men at the time (mathematics). He also points out that some of the ideas she expressed in her article were not ideas Babbage had expressed before, and that it is a great pity she died so young, with her ideas never fully made known.
Babbage met up with Georg Scheutz and his son Edvard in 1855. They were visiting London from Sweden to display a machine they'd built, similar to the Difference Engine. Babbage welcomed the two, showed them his workshop and later helped them sell one of their machines to the Dudley Observatory in Albany, NY. Their machine caused Airy to change his mind about the usefulness of calculating machines, although ultimately the invention didn't do the Scheutzs much good; they both died bankrupt.
After 10 years break, Babbage at age 70 began working on his Analytical Engine again, finally deciding on the specifications. He also began a public attack on "vile and discordant music", which resulted in organ-grinders deliberately baiting him etc. (His autopsy revealed he had degeneration of the inner ear due to an arterial disease, so he wasn't just a party-pooper; the music really caused him some distress). Babbage died just before the age of 80, a bitter man plagued to the end by the organ-grinders' music and no working Analytical Engine.
A Modern Sequel
In 1985 Australian computer scientist Dr Allan Bromley approached London's Science Museum with the idea to build a working Difference Engine by 26 December 1991, to celebrate the bicentenary of Babbage's birth. It is an interesting story, with several unforeseen setbacks of a technical nature as well as more mundane ones like funding troubles, contractors going bankrupt and building the machine in the machine with public scrutiny. Swade was the person who ran the project, with the work and advice of several others, like Michael Wright, Neil Cossons and John Reid, also of the Museum, as well as Rhoden Partners and their design engineers Reg Crick and Barrie Holloway.
The deadline was shifted forward to June, rather than December, as part of the deal through which the final funding was made. A demonstration was "faked" to the press, after a worried Swade explained that the machine was almost ready, but they didn't want to risk breaking parts by running a real calculation at that date. The pressure was on.
The final chapter discusses whether Babbage's title of "the father of modern computing" is really very accurate. Not so much the fact that his machines weren't fully built in his time, but that they relied on the decimal system, not the binary number system. There is also a brief discussion of similar machines that were invented around the time, around the world.
The book is a comprehensive work on Charles Babbage and his work in general, so while the title is not totally accurate, it is apt, since the Difference Engine is the common link between the beginning and end parts of the book. It's also of note that the printing section of the Difference Engine is also part of the Analytical Engine, so by completing this, the Science Museum have validated not just Babbage's work on the Difference Engine, but also some of his work on the Analytical Engine. Hopefully someone will write another book or revision that details work done on the printing section; Swade actually seems to hint at this in the book ("But that is another tale for another day").
The diagrams and illustrations at the end of the book are great, but it might have been better to put them at the relevant parts of the book. For example, the pictures of Countess Lovelace in the chapter about her.
Conclusion
One review I saw states that this book is best for informed readers. I think "interested" readers would be more accurate. The book doesn't presume existing knowledge of Babbage, but if you are interested in the history of science, computing and the Difference Engine, you'll get a lot more out of it. The book is technical in parts but not overly so. It is generally more than readable, although I found the politics, both in Babbage's day and more recently, a bit tedious at times.
A common theme in the book is the set of difficulties both Babbage and Swade faced, not just technically, but also with funding, publicity and staffing. Many companies in modern times can relate to these, I'm sure! It is a sad story, because for all his brilliance and vision, Charles Babbage never lived to see his machines work and receive the accolades he deserved. That his Difference Engine has been successfully built today fittingly fulfills Babbage's vision.
Related Links
- Science Museum's Exhibit
- Printing Mechanism
- More on the Printing Mechanism
- Babbage's papers and Analytical Engine emulator
You can purchase this book at Fatbrain.
Eventually, sadly, Turing committed suicide by injecting cyanide into an apple & eating it. The original version of Apple's logo was, it is said, Turing's apple, with a bite out of one side and the stripes of the gay pride flag.
Like I say, apparently this is just a coincidence and Apple was paying no such homage to Turing, but I still think it fits pretty well, & wish it were true. Oh well...
DO NOT LEAVE IT IS NOT REAL