Long before computers became handy and electronic, they were first very mechanical, consisting of large gears, long rods, columns of discs, levers, springs, and metal frames, and were powered by cranking a handle. Widely regarded as “the father of computers,” [1] Charles Babbage, an English mathematical genius and philosopher, invented what is known today as the Babbage Engine, also known as the Difference Engine.Built to eliminate errors and to automate and speed up the mathematical computation of polynomial functions, Charles Babbage designed three versions of the Babbage Engine, each an enhanced and improved version of its predecessor. Babbage employed the mathematical method known as the method of finite differences, both to power and to name the calculating machine.
The Birth of Difference Engine
In 1820, the Royal Astronomical Society assigned a task to Babbage and his friend John Herschel to improve the numerical tables in the navigational book Nautical Almanac.[2] After formulating the equations, Babbage and Herschel assigned clerks to perform the computations. To reduce errors, they had another set of clerks perform the arithmetic. Despite this, they still found a lot of discrepancies in the results. This spurred Babbage to design a machine that could produce error-free results in a shorter period. He began constructing a small engine, referred to as Difference Engine 0, and it was completed in 1822.[3] The machine consisted of 18 wheels and 3 axes and produced accurate results at a rate of 33 digits per minute.[4] Babbage presented the prototype to the Royal Astronomical Society and proposed a larger-scale model that could be used by the government for nautical and astronomical calculations. Impressed by the accuracy of the engine, the government agreed to fund his project, which gave way to the construction of Difference Engine 1.
The Mishaps of Difference Engine 1
In 1823, the Chancellor of Exchequer agreed to fund Babbage’s Difference Engine project and granted him £1700[5] to get started. The engine has two sections, the calculating section, and the printing section, with a total of 25,000 parts and dimensions of 260 cm high, 230 cm broad, and 100 cm deep.[6] In 1824, Babbage began constructing the machine in the two rooms of his house, but later realized he needed a bigger space and some competent workers to finish the project. He hired an engineer, Joseph Clement, to take charge of the mechanical work. Clement hired more workers and used his workshop for the project.
However, the construction took much longer than Babbage and the government had anticipated. In 1830, Clement’s workers had fabricated all the parts, but most of the sections had not yet been assembled. Because the project was taking so long, Babbage and the government decided to pull the project out of Clement’s workshop. By that time, Babbage had a building in his property set aside for building the Difference Engine. Clement’s resistance, however, made things difficult for Babbage. Clement now insisted that the engine belonged to him, based on the trade practices of the time. In 1832, Clement assembled a portion of the calculating mechanism and Babbage presented it to the government for demonstration [2]. This was only one-seventh of the whole calculating section but was a working model. Construction of the engine continued, and the calculating section was close to completion, but the printing section was left untouched. Work on the project stopped in 1833, but it was only in 1834 that Clement agreed to transfer the engine to Babbage’s workshop when both had parted ways. This urged the government to stop funding the project, considering that more funds would be needed to reorganize the engine in Babbage’s workshop. By this time, the government already spent £17,000.[7]
Because of these unfortunate events, Babbage had lost the motivation to continue with the project. Instead, he shifted his focus to a more ambitious engine, the Analytical Engine, which he believed could do all the things that the Difference Engine could do and much more.
Abandoned but Not Forgotten
Babbage spent most of his years designing the Analytical Engine after the failure of the Difference Engine, but it was the very development of the Analytical Engine that provoked Babbage to turn back to the Difference Engine. In 1947, using the arithmetic mechanisms of the Analytical Engine, he redesigned the Difference Engine, refining the original design with simpler mechanisms and fewer parts. The new version, which he called Difference Engine 2, only had a third of the parts of the original [8] and could calculate more quickly than the previous one. He completed the design in 1849 and presented it to the British government. Due to the previous failure of Difference Engine 1, the government declined to support the project. Babbage passed on the design and the surviving sections of Difference Engine 1 to his son, Major-General Henry Prevost Babbage, who showed great interest in his father’s work [2]. After his father died in 1871, Henry Babbage continued to work on and publicize his father’s work. Difference Engine 2, however, was never constructed to completion.
Difference Engine, In Modern Times
In the 1980s, more than 100 years after Babbage’s death, Allan Broomley, an associate professor at the University of Sydney, took interest in the original drawings of the Babbage Engine at the Science Museum Library in London. His studies caught the attention of the Museum’s then Curator of Computing, Doron Swade, who led the construction of the Difference Engine 2 calculating section from 1985-1991. Nathan Myhrvold, former Chief Technology Officer at Microsoft, then commissioned the construction of the printing section of the engine. The first complete version of the Difference Engine 2 was finally completed in 2002,[9] and it works just as Babbage had designed. After the successful completion of the first Difference Engine 2, Myhrvold also funded the construction of its clone, which was completed in 2008.
Today, the original Difference Engine 2 is on display at the Science Museum in London, and its clone is sitting inside Intellectual Ventures in Seattle. Babbage’s pioneering work in automatic computing has become the foundation of the subsequent computer technologies that were developed over time. He may never have seen his masterpiece in its full glory, but the Babbage Engine is undoubtedly one of the most brilliant and founding inventions in the history of computer technology.
Sources:
[1] “Charles Babbage”, N.d., https://history-computer.com/People/BabbageBio.html Accessed 29 September 2020
[2] “Differential Engine”, N.d., https://history-computer.com/Babbage/DifferentialEngine.html Accessed 29 September 2020
[3] Wikipedia. “Difference Engine”, N.d., https://en.wikipedia.org/wiki/Difference_engine Accessed 29 September 2020
[4] “Differential Engine”, N.d., https://history-computer.com/Babbage/DifferentialEngine.html Accessed 29 September 2020
[5] Wikipedia. “Difference Engine”, N.d., https://en.wikipedia.org/wiki/Difference_engine Accessed 29 September 2020
[6] “Differential Engine”, N.d., https://history-computer.com/Babbage/DifferentialEngine.html Accessed 29 September 2020
[7] “Differential Engine”, N.d., https://history-computer.com/Babbage/DifferentialEngine.html Accessed 29 September 2020
[8] “The Babbage Engine”, N.d., https://www.computerhistory.org/babbage/ Accessed 29 September 2020
[9] “The Babbage Engine”, N.d., https://www.computerhistory.org/babbage/ Accessed 29 September 2020
