Proportional compass by Joseph Jackson, London, 2nd quarter 18th century, brass with steel tips. Proportional compass by Joseph Jackson, London Mathematics 1735-1760

Proportional compasses, 6 3/8-inch; brass engraved "T. Heath Fecit" Proportional compasses, 6 3/8-inch; brass engraved Mathematics 1720-1753

Proportional compass with turn down points, made by W. F. Stanley, Great Turnstile, London Proportional compass Mathematics 1876

Proportional compass made by W. F. Stanley, Great Turnstile, London (old English pattern) Proportional compass Mathematics 1876

Pair of proportional compasses, brass c. 1680 Pair of proportional compasses, brass c. 1680 Mathematics 1678-1682

'whole and Halves' proportional compass by William Ford Stanley, Great Turnstile, London, England, 1876. 'Whole and Halves' proportional compass Mathematics 1876