Public authority has always been given the power to guarantee metrological public order for the benefit of the common good. This means that the authorities have been the ones to establish the system of weights and measures in force in the transactions. This tutelage has been carried out with normative dispositions which were materialised in patterns kept by the municipality as models to be copied.

In Barcelona, those in charge of making weights and measures were included in the locksmiths’ guild. The municipal authorities reserved the right to supervise the parts produced and, where appropriate, to punish offenders. To carry out these tasks, the municipality appointed specific officers known as tuners and contrasts, who tended to be prominent locksmiths. These, as a witness and guarantee of their verification, stamped the verified weights or scales with a mark stamped next to the coat of arms of the city.

Box with a set of weights. Farriols locksmith workshop, Barcelona, 18th century. Donated by Núria and Eulàlia Tarradell Font.