Henry Prevost Babbage with his wife and family, c 1870s.
© Science Museum / Science & Society Picture Library
Henry Prevost was youngest surviving the son of computer pioneer Charles Babbage (1791-1871). Henry had shown a strong interest in his father's work on the Difference Engine and Analytical Engine. After his father's death he built a hand-operated printing calculator based on plans for the mill of the Analytical Engine. This was a four-function calculator designed for addition, subtraction, multiplication and division.