Automatic pan balance, 1964.

Roman balance, AD 350.

Roman balance and weights, AD 350.

Ancient Roman balance.

Equal arm postal balance, 1850-1880.

100 ounce 'Auctioneers' Plate Valuing' balance and weights, 1901-1902.

Balance with scale pans, c 1370-1350 BC.

Chinese scales, 19th century.

Giant Steelyard interactive, Science Museum, London, 1993.

Lodestone in silver case with keeper, 1762.

Lodestone in silver case with keeper, 1762.

Persian equal-arm balance, c 1800-1810.