Henry Prevost Babbage, British mathematician, c 1860-1900.
© Science Museum / Science & Society Picture Library
Photograph by Taylor of Cannon Street, London. Henry Babbage was the youngest surviving son of computer pioneer son of Charles Babbage (1791-1871). Henry had shown an interest in his father's work on the Difference Engine and the 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.