When Computers Were Human (8 page)

When he began work on his calculating machine, Babbage was following a path that was already well marked. Inventors in both England and the United States had built machines based upon Adam Smith's example of the divided labor in pin manufacture. Their machines followed each step that Smith had identified in
The Wealth of Nations
. They cut a roll of wire into fixed lengths, sharpened one end of each wire segment, affixed a head to the other, and placed the finished pin in a paper holder. Babbage took the opportunity to study one of these pin-making machines and reported that “it is highly ingenious in point of contrivance,” especially interesting “in respect to its economical principles.”
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Babbage designed a machine that might be considered more flexible than the pin-making machines. Rather than analyze the equations that had been used to create a specific table, such as the decimal trigonometry tables, he considered a single computational technique that could be applied to many kinds of calculation. The technique that he chose was a process of mathematical interpolation known as the finite difference method. The finite difference method is one way of computing intermediate values of a table, such as the intermediate positions of the moon that Nevil Maskelyne's computers prepared for the British
Nautical Almanac
. It is especially amenable to the division of labor because it reduces the entire process into the simple operation of addition. A simple application of this method can compute a list of the squared integers (4, 9, 16, etc.) without performing a single multiplication. First, one computes a list of the odd integers: 1, 3, 5, 7, 9, etc. This can be done by starting with the number 1 and successively adding 2: 1 + 2 = 3, 3 + 2 = 5, 5 + 2 = 7. Once this has been completed, one can sum the list of odd integers to get the list of squares: 1 + 3 = 4, 4 + 5 = 9, 9 + 7 = 16, and so on.

Though Babbage's machine would be far more complicated than the pin-making device, it was simpler in one respect. The pin machine needed to perform four different fundamental operations. Babbage's machine would only need to do one: addition. Babbage started with a geared adding mechanism originally developed by Blaise Pascal (1623–1662) in 1642,
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improved the design, and cascaded the devices so that the results of one addition would be fed to the next. To create a list of squared integers, one mechanism would repeatedly sum the number 2 to create new odd numbers. The next mechanism would sum the odd numbers to create the squares. By the spring of 1822, Babbage had completed a demonstration model of his machine, which he named the “Difference Engine.”

The London of 1822 was wholly unprepared for Babbage's machine. It was a world of gaslights and horse-drawn carriages, of servants and walking sticks. Most residents had not yet seen a steam locomotive, as the city's first railroads were still under construction.
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Though the idea of the adding machine was one hundred and eighty years old, there was
none to be bought or sold. The first commercial machine, which would be produced in France, existed only as a crude prototype.
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Babbage anticipated that his machine might be met with disbelief or even opposition. He cautiously approached the Royal Society, recognizing that the organization might be able to help him promote his machine. His letter to the society president made conservative claims and acknowledged that Royal Society members might not believe it possible to create a machine that
could handle such complex calculations without supervision. He tried to disarm potential criticism by invoking Jonathan Swift: “I am aware that the statements contained in this Letter may perhaps be viewed as something more than utopian, and that the philosophers of Laputa may be called up to dispute my claim to originality.”
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6. Difference engine constructed from the original plans of Charles Babbage

The Laputian philosopher that Babbage wished to avoid was not the computing tailor but an inventor who lived on the flying island. This inventor claimed to have a computing machine whereby “the most ignorant person, at a reasonable charge, and with a little bodily labour, might write books in philosophy, poetry, politics, laws, mathematics, and theology, without the least assistance from genius or study.”
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The machine was a silly device, a box of shafts and gears that spun through every possible combination of words, but it was a symbol of Jonathan Swift's mockery of the Royal Society. Babbage, though he shared some of Swift's reservations about the society, desired to avoid any comparison to the mythical device. He carefully described his invention in the context of de Prony's computing organization. He explained how the computers prepared their tables and then analyzed “what portion of this labour might be dispensed with.” By his count, de Prony had employed ninety-six individuals to produce seven hundred computations a day. Babbage claimed that his machine could replace all of the human computers and most of the mathematicians. Of the original staff, all that would remain would be the ten planners and one mathematician, “or at the utmost two,” to direct the work.
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Though the Royal Society was in no hurry to pass judgment upon Babbage's proposal, the Astronomical Society rushed to give the idea uncritical praise. Based upon what they observed of the crude prototype, they offered Babbage a gold medal for his contribution to astronomy.
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“The labour of computing equations with the pen would be immense, and liable to innumerable errors,” wrote one member of the Astronomical Society, “but with the assistance of [Babbage's] machine, they are all deduced with equal facility and safety.” He made a special effort to emphasize the general use of the machine, arguing that “astronomical tables of every kind are reducible to the same general mode of computation” and that the machine could even be applied to commercial tasks, such as the preparation of “Interest, Annuities, &c, &c, all of which are reducible to the same general principles.”
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The Royal Society eventually endorsed the Difference Engine, and the English government offered to finance the construction of the machine. Eager to devote his entire energies to the project, Babbage resigned his office with the Astronomical Society in 1823. The work progressed more slowly than he would have wished, as both he and his mechanic needed to refine his design and improve their metalworking skills. The project
was interrupted by the death of Babbage's wife, Georgiana, an event that disrupted his life in a way that nothing else could have. The loss “left Babbage a changed man,” observed biographer Anthony Hyman. There was “an ‘inner emptiness' to the man, who had only recently seen so much potential in his life.” In “his public controversies, there was a new note of bitterness of which there was no trace while Georgiana was alive.” Babbage left England for a Continental tour in 1827, leaving the engine unfinished.
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In later years, Babbage recognized that he had been naive in his attempt to build the Difference Engine. Without referring to himself directly, he confessed that a novice engineer could be “dazzled with the beauty of some, perhaps, really original contrivance,” and would rush into its construction “with as little suspicion that previous instruction, that thought and painful labour, are necessary to its successful exercise.”
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Babbage worked on the Difference Engine for ten years. During this time, he was engaged in other projects, such as computing life insurance tables, forming two new scientific societies, and writing a book about manufacturing. Even accounting for these other projects, the work on the Difference Engine took longer than Babbage had anticipated, and it encountered unforeseen problems. The English government eventually grew impatient with Babbage's progress. Concluding that they would see no return on their investment, they withdrew their financial support in 1834, forcing Babbage to terminate the project.

Undeterred by his failure to complete the Difference Engine, Babbage moved to design a second, more ambitious device. He never even attempted to construct this machine, which he called the Analytical Engine. Modern writers have generally viewed the machine as an important intellectual step toward the stored-program electronic computer. One historian has gone so far as to claim that it was “a general purpose computer, very nearly in the modern sense.”
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The drawings of this machine show how Babbage anticipated the features of a modern computer, though his design used gears and levers rather than chips and circuit boards. The Analytical Engine had a means of storing numbers, a central processor, and an elementary programming mechanism. Unlike the Difference Engine, this machine was not restricted to a single mathematical method, such as the method of finite differences. The programming mechanism, which read instructions from a string of punched cards, controlled the order of operations. One observer, the daughter of the poet Lord Byron, Ada Lovelace (1815–1852), called the Analytical Engine the “material and mechanical representative of analysis,” a triumph of the division of mathematical labor. Lovelace herself illustrated the nature of the machine by writing a sample program for it.
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Babbage would spend almost fifteen years designing the Analytical Engine.
He left nearly three hundred detailed engineering drawings of his proposed machine.
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As he worked over these drawings, he recognized that the Europe of the early nineteenth century might not be able to support large computing organizations or computing machines based upon the division of labor. The “most perfect system of the division of labour is to be observed,” he wrote, “only in countries which have attained a high degree of civilization, and in articles in which there is a great competition amongst the producers.”
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As the early nineteenth century saw little competition for scientific computation, it offered little opportunity for the sophisticated division of labor espoused by Babbage and de Prony.

CHAPTER THREE

The Celestial Factory: Halley's Comet 1835

I
N HIS NOVEL
Hard Times
, Charles Dickens described an astronomical observatory “made without any windows” and an astronomer who “should arrange the starry universe solely by pen, ink, and paper.” He used this description, which sounded more like the computing room of the
Nautical Almanac
than the staff of an observatory, as a metaphor for a factory. In this factory, the director “had no need to cast an eye upon the teeming myriads of human beings around him,” just as the director of almanac computations had no need to watch the stars each night, “but could settle all their destinies on a slate, and wipe out all their tears with one dirty little bit of sponge.” When Dickens used this metaphor, both the Royal Observatory at Greenwich and the British Nautical Almanac Office had adopted the basic elements of factory production, elements that included a central facility and a standard schedule of operations or, as Dickens described them, “a stern room, with a deadly statistical clock in it, which measured every second with a beat like a rap upon a coffinlid.”
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Both the almanac and the observatory consciously accepted such methods around the time of the 1835 return of Halley's comet. Neither organization had seen much innovation since the days of Nevil Maskelyne. Through the middle part of his career, Maskelyne had been an active leader of both organizations, acquiring new equipment for the observatory and developing new methods for the almanac. At some point in the 1780s or 1790s, he had settled into a comfortable routine and had watched innovations occur elsewhere. The major astronomical discovery of the late eighteenth century, the planet Uranus, had been accomplished by an independent observer, William Herschel, not by the observatory staff. The radical division of labor came from Gaspard de Prony. A second periodic comet, the first to be discovered after Halley's, was identified by at least four individuals, none of whom was associated with Greenwich. This comet was ultimately named for a German astronomer, Johann Franz Encke (1761–1865), who calculated the object's orbit.
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Following the death of Nevil Maskelyne in 1811, the British Admiralty made only a few improvements to the almanac and the observatory. The new Astronomer Royal apparently spent little time at the observatory and acquired a reputation for hiring unimaginative assistants, “indefatigable, hard-working, and, above all, obedient drudges.” A critic of the observatory argued that “Men who had the spirit of ‘drudges,' to whom observation was a mere ‘mechanical act,' and calculation a ‘dull process,' were not likely to maintain the honour of the Observatory.”
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Such assistants had not sustained the honor of the
Nautical Almanac
. In 1818 the Admiralty removed the publication from the observatory and appointed an independent supervisor.
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