3 4 c m
40cm
actual image size: 32cm x 26cm
Description
A circular slide rule made by Apps. A circular slide rule affords a long and therefore accurate logarithmic line in a small amount of space. The potential of circular rules was not really utilized until the Victorian period, when several spiral and helical designs appeared on the market.
Image Details
Image Ref.
10328304
© Science Museum / Science & Society Picture Library