Steam Powered Computing

by Nicholas Mee on October 31, 2012

Charles Babbage was born on 26 December 1791. He would become one of the leading mathematicians and inventors of his day. From 1828 to 1839 he was Lucasian Professor of Mathematics at Cambridge University – a position held by Isaac Newton in the 17th century and more recently Stephen Hawking.

Charles Babbage

Industrial Mathematics

Babbage is famous as a pioneer of computing. Until the 20th century scientists and engineers, indeed anyone who needed to perform a complicated calculation, had to rely on printed mathematical tables, but these tables were compiled by hand, because there were no mechanical aids available. The result was that they were riddled with errors and that this was a serious problem. Babbage was painfully aware of this and his solution was to mechanize calculation. He designed a machine that would perform the calculations and then print out the resulting tables. By automating the process this would remove the sources of error and produce the first error-free tables. His name for this invention was the Difference Engine. His original design required the engineering of around 25,000 precision metal parts and would have weighed around 15 tonnes. He was given government funding of £17,500 to complete the task – an enormous sum, the equivalent of the cost of a couple of battleships. But the Difference Engine was never completed.

The Difference Engine operated by Doron Swade

Not until 1991 that is. In that year the Science Museum in London held an exhibition marking the bicentenary of Babbage’s birth at which they unveiled the Difference Engine No.2. It had been constructed from a refined design that Babbage devised between 1847-1849.

The Poet’s Daughter

Ada Lovelace Byron was born 10 December 1815, the daughter of the romantic poet Lord Byron. Her parents separated when she was very young and Byron left England four months later. He died in Greece in 1823 and Ada never met him. Ada’s mother intended that she should be as unlike her reckless and passionate father as possible so Ada was tutored in mathematics and science and grew to love these subjects. While still a child she said: ‘I love mathematics-it has answers. Every time I solve a maths problem, it makes a lovely shape in my head.’ In 1833, at the age of 17 Ada was introduced to Babbage and became a life-long friend.

The Analytical Engine

With his first machine still unfinished, in 1834 Babbage conceived of a much more ambitious machine – a steam-driven programmable computer, that he named The Analytical Engine. It is this machine rather than the Difference Engine that shows the originality and depth of Babbage’s ideas. All the components of a modern computer are contained in Babbage’s plans. The Analytical engine was designed to have a memory and to follow a program that would include logical instructions and proceed down pathways determined by intermediate steps in the calculation, just like a modern computer program. However, not surprisingly the British government were reluctant to provide even more money for the scheme.

The World’s First Computer Programmer

Ada Lovelace Byron, the world’s first computer programmer

With support for his plans hard for find, Babbage was encouraged when an Italian mathematician Louis Menebrea wrote an article about the Analytical Engine in French. Babbage asked Ada to translate it into English. For nine months in 1842-43 she worked feverishly not only translating the report but also adding her own notes and observations – her additions were longer and more significant than the original report. Ada realised that the machine’s potential was not only as a general purpose calculator, but that it could be adapted to perform practical scientific tasks and even compose music and produce images. She went on to devise a set of instructions that would instruct the Analytical Engine to calculate a series of numbers known to mathematicians as The Bernouilli Numbers. She had, in effect, written the first computer program for the world’s first programmable computer. In 1980 a programming language developed in the United States was named ‘Ada’ in her honour.

Ada died in 1852 at the age of just 36. At her request, she was buried next to Lord Byron – the poet father she had never known.

The Masterplan

Despite lavish funding from the British government none of Babbage’s machines were completed during his lifetime. But a new project has just been launched with the aim of finally bringing the Analytical Engine to life. Thousands of pages of Babbage’s handwritten notes and plans are stored by the Science Museum in London. The most detailed design for the Analytical Engine is on Plan 28 and this is the name that has been adopted for the project. Plan 28 will cost £250,000 and will take three years. The end result will be a steam powered machine the size of a steam locomotive.


Further Information

The Code Book on CD-ROM by Simon Singh and Nicholas Mee includes material about Babbage and his excursions into cryptography.

The Computer History Museum gives background information about Babbage and an explanation of how the Difference Engine works.

The Difference Engine in Action. The following link shows a video of Doron Swade explaining how the Difference Engine works.

Details about the project to build the Analytical Engine are given on the official website at:


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