Babbage's first attempt at a mechanical computing device, the Difference Engine, was a special-purpose machine designed to tabulate logarithms and trigonometric functions by evaluating finite differences to create approximating

Babbage is not known to have written down an explicit set of instructions for the engine in the manner of a modern processor manual. Instead he showed his programs as lists of states during their execution, showing what operator was run at each step with little

If the Analytical Engine had been built, it would have been digital, programmable and Turing-complete. It would, however, have been very slow. Luigi Federico Menabrea reported in Sketch of the Analytical Engine: "Mr. Babbage believes he can, by his engine, form the product

Late in his life, Babbage sought ways to build a simplified version of the machine, and assembled a small part of it before his death in 1871.
In 1878, a committee of the British Association for the Advancement of Science described

Predicted influence
Babbage understood that the existence of an automatic computer would kindle interest in the field now known as algorithmic efficiency,

• The cyberpunk novelists William Gibson and Bruce Sterling co-authored a steampunk novel of alternative history titled The Difference Engine in which Babbage's difference and Analytical

• Babbage, Charles (1864). "Chapter VIII – Of the Analytical Engine". Passages from the Life of a Philosopher. London: Longman, Green, Longman, Roberts, & Green. pp. 112–141.
• Babbage, Charles (1889). Babbage, Henry P. (ed.). Babbage's Calculating Engines – Being a Collection of Papers Relating to Them; Their History, and Construction