Weighing scale
The balance (also balance scale, beam balance and laboratory balance) was the first mass measuring instrument invented. In its traditional form, it consists of a pivoted horizontal lever with arms of equal lengththe beamand a weighing pan suspended from each arm (hence the plural name ""scales" for a weighing instrument). The unknown mass is placed in one pan and standard masses are added to the other pan until the beam is as close to equilibrium as possible. In precision balances, a more accurate determination of the mass is given by the position of a sliding mass moved along a graduated scale. Technically, a balance compares weight rather than mass, but, in a given gravitational field (such as Earth's gravity), the weight of an object is proportional to its mass, so the standard masses used with balances are usually labeled in units of mass (e.g. g or kg).
Södra Bankohuset
From at least the reign of King Magnus Eriksson (1316–1377) the official scales of the city meant an important source of income for the city and the king alike. From no later than the 15th century the scales were located at the city's southern square, and subsequently the building housing the scales and preceding the present building was called "Våghuset" ("Scales House" or Weigh house). As the city introduced more scales, probably in 1637, the southern scales were being used exclusively for the weighing of iron, copper, and other metals, which eventually gave the square next to it its present name "Järntorget" ("The Iron Square"). Given a depiction in an etching from 1660, and the location of the water front and city wall at the time, the Scales House is likely to have been located somewhere in the middle of the present site. It is depicted as having gables facing west and east with rows of six windows facing the alleys; probably occupying an area of 18×18 metres.