Henry Sutton's slide rule, 1663.
© Science Museum / Science & Society Picture Library
Henry Sutton was one of the best known mathematical engravers of his day. Renowned for his accuracy he was in great demand for drawing diagrams for mathematical books. Sutton's slide rule consists of fixed scales and moveable index arms. A spiral slide rule affords a long and therefore accurate logarithmic line in a small amount of space. The potential of spiral rules was not really utilized until the Victorian period, when several spiral and helical designs appeared on the market.