Weighing it is a serious thing and you can hardly operate as Brenno, when he shouted his-VAE victis-against the Romans who were protesting, for the irregular gold weighing to be paid as compensation for war.
Weighing presupposes equality between who sells and who buys, so if something that is bought and sold has to be weighted, there must be an instrument that does not do not tip by choice or by mistake for one part.
The balance is the symbol of justice and equality before the law, but it is better not to mention this topic today in our country, irrespectively of the point of view.
The balance or the measuring instrument shall be accurate and to ensure that, in addition to the technical and constructive aspects there are also regulatory aspects, and when the instruments are for commercial use they must be verified by an external entity , that guarantees equality between the parties (a budget judge).

