Rulers and slide rules, 1723.
© Science Museum / Science & Society Picture Library
Carpenter's rule, four-foot gauging rod, Everard's sliding rule, and 'Cogeshals' rule. These last two refer to an Excise officer, Thomas Everard, who proposed his sliding rule in 1684, and Henry Coggeshall (1623-1690). Illustration from 'The construction and principal uses of mathematical instruments' by N Bion (1652-1733), published in London in 1723.