Picture Number:10328276 Credit:Science Museum/Science & Society Picture Library
A circular slide rule, made by John Brown, with two brass radial arms and an stronomical quadrant engraved on the back. 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.
Object Number: 1954-433
Date Made: 1660-1680
Place of Production: World > Europe > United Kingdom > England