The Code Book by Simon Singh Page B

statistics, and as a diversion he drew up a set of mortality tables, a basic tool for today’s insurance industry.
    Babbage did not restrict himself to tackling scientific and engineering problems. The cost of sending a letter used to depend on the distance the letter had to travel, but Babbage pointed out that the cost of the labor required to calculate the price for each letter was more than the cost of the postage. Instead, he proposed the system we still use today—a single price for all letters, regardless of where in the country the addressee lives. He was also interested in politics and social issues, and toward the end of his life he began a campaign to get rid of the organ grinders and street musicians who roamed London. He complained that the music “not infrequently gives rise to a dance by little ragged urchins, and sometimes half-intoxicated men, who occasionally accompany the noise with their own discordant voices. Another class who are great supporters of street music consists of ladies of elastic virtue and cosmopolitan tendencies, to whom it affords a decent excuse for displaying their fascinations at their open windows.” Unfortunately for Babbage, the musicians fought back by gathering in large groups around his house and playing as loud as possible.
    The turning point in Babbage’s scientific career came in 1821, when he and the astronomer John Herschel were examining a set of mathematical tables, the sort used as the basis for astronomical, engineering and navigational calculations. The two men were disgusted by the number of errors in the tables, which in turn would generate flaws in important calculations. One set of tables, the Nautical Ephemeris for Finding Latitude and Longitude at Sea , contained over a thousand errors. Indeed, many shipwrecks and engineering disasters were blamed on faulty tables.
    These mathematical tables were calculated by hand, and the mistakes were simply the result of human error. This caused Babbage to exclaim, “I wish to God these calculations had been executed by steam!” This marked the beginning of an extraordinary endeavor to build a machine capable of faultlessly calculating the tables to a high degree of accuracy. In 1823 Babbage designed “Difference Engine No. 1,” a magnificent calculator consisting of 25,000 precision parts, to be built with government funding. Although Babbage was a brilliant innovator, he was not a great implementer. After ten years of toil, he abandoned “Difference Engine No. 1,” cooked up an entirely new design, and set to work building “Difference Engine No. 2.”
    When Babbage abandoned his first machine, the government lost confidence in him and decided to cut its losses by withdrawing from the project—it had already spent £17,470, enough to build a pair of battleships. It was probably this withdrawal of support that later prompted Babbage to make the following complaint: “Propose to an Englishman any principle, or any instrument, however admirable, and you will observe that the whole effort of the English mind is directed to find a difficulty, a defect, or an impossibility in it. If you speak to him of a machine for peeling a potato, he will pronounce it impossible: if you peel a potato with it before his eyes, he will declare it useless, because it will not slice a pineapple.”
    Lack of government funding meant that Babbage never completed Difference Engine No. 2. The scientific tragedy was that Babbage’s machine would have been a stepping-stone to the Analytical Engine, which would have been programmable. Rather than merely calculating a specific set of tables, the Analytical Engine would have been able to solve a variety of mathematical problems depending on the instructions that it was given. In fact, the Analytical Engine provided the template for modern computers. The design included a “store” (memory) and a “mill” (processor), which would allow it to make decisions and repeat instructions, which are