A restless Victorian mathematician
Charles Babbage was born in London in 1791 and died there in 1871. He studied at Cambridge, where he was frustrated by the way mathematics was taught, and with a few friends he helped start a society to promote the more modern notation then used on the European continent. Later he held the Lucasian professorship of mathematics at Cambridge, the chair once held by Isaac Newton, though by most accounts he was not an active teacher in that role.
His interests ranged widely. He took part in founding scientific societies, wrote about how factories organize work, argued about the state of science funding in Britain, and became known as a combative and sometimes difficult public figure. His book on the economy of machinery and manufactures looked at how tasks could be divided and mechanized, a theme that connects naturally to his later machines.
The Difference Engine
Babbage’s best-known early project grew out of a practical problem. Mathematical tables of logarithms and other functions were needed for navigation, engineering and astronomy, and they were calculated by people working by hand, then typeset by others. Errors could creep in at every stage. Babbage proposed a machine that would calculate the values mechanically and prepare them for printing, using a method of repeated addition that avoids multiplication.
In the 1820s he obtained support from the British government, and work began on a large engine built from precisely machined parts. The project was slowed by the difficulty of manufacturing so many accurate components, by disagreements with the engineer in charge of construction, and by questions over cost. It was eventually abandoned without a complete machine. Parts of a small demonstration section were assembled and survive.
The idea itself did not die. In the 1850s a Swedish father and son, Georg and Edvard Scheutz, built a working difference engine based on a published description of Babbage’s concept. Babbage also designed an improved version, now called Difference Engine No. 2, in the late 1840s. More than a century later, the Science Museum in London built one from his drawings, finishing the calculating section in 1991. It worked, which is usually taken as evidence that his plans were sound, though it was built with modern care about tolerances.
The Analytical Engine
In the 1830s Babbage turned to a more ambitious idea. Instead of a machine that performed one method, he imagined one that could be given different instructions on punched cards, borrowing the technique from the Jacquard loom used in weaving. The design had a store for holding numbers and a mill for doing arithmetic, together with the ability to choose between paths and repeat steps. This was the Analytical Engine, described in more detail in the longer account of his vision for the first computer.
Ada Lovelace’s notes of 1843 on the engine have kept his name connected with the idea of programming. Babbage continued revising the design for the rest of his life. A later attempt by his son Henry to assemble part of the mill, using his father’s drawings, produced a small working portion, but the full engine was never constructed.
Why “father of the computer” is a simplification
The phrase appears in many books and museum labels, and it has some justice. Babbage’s plans contained a clear separation of memory from processing, a program held on cards, conditional steps and printed output, which is a recognizable outline of a general-purpose computer.
But the label hides several complications.
- It was a design, not a working machine. The Analytical Engine was never completed, so it did not calculate anything in its full form.
- Later pioneers mostly did not build on it. The electronic machines of the 1930s and 1940s were developed in a different technical world, and many of their builders were unaware of his work or arrived at ideas independently. His reputation as a precursor grew as historians reread his papers.
- Computers have many ancestors. Mechanical calculators, punched-card tabulating equipment, telegraph and telephone switching, mathematical logic and electronics all contributed. The work of Alan Turing, for example, supplied a theoretical framework that was independent of Babbage’s.
- Fatherhood is a human story, not a legal one. Nearly every major technology involves many people, and the search for a single computer inventor tends to flatten a long, shared effort into a myth.
A more careful phrase might be that Babbage was one of the most important early visionaries of programmable computing. That statement keeps what is distinctive about him without crediting him with achievements that belong to later engineers.
Legacy
Babbage’s reputation in his own lifetime was mixed. Admirers saw an ingenious thinker; critics saw someone who consumed public money without delivering a machine. Posthumously, he has become a symbol of the gap that can exist between an idea and the technology available to realize it.
His work also remains a useful starting point for understanding computers in general. A device that fetches numbers from a store, processes them and returns the results under the control of a sequence of instructions captures the structure behind many later designs, though in his version it was made of brass wheels rather than electronic circuits.