Difference engine
The difference engine was an early computer designed by Charles Babbage in the early 19th century. It was a complex clockwork device made of bras and steel cogs which which could perform complex calculations (PROSE: The Book of the War) such as solving quadratic equations (TV: Spyfall) by computing differences between numbers. (PROSE: The Book of the War)
In 1822, Babbage brought the designs for the machine to the Star Chamber in a request for funding. He built a partial version of the machine to demonstrate during evening soirees at his home in London. (PROSE: The Book of the War) The Thirteenth Doctor and Ada Gordon examined the machine in Babbage's house in 1834. (TV: Spyfall)
However, before the machine could be fully completed, Babbage designed a more advanced version, the analytical engine, which the Star Chamber funded and built. (PROSE: The Book of the War)
In the 1880s, Joseph Montague's Difference Golems were named after the difference engine. (AUDIO: Children of Steel)
