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The Reforms Of King João VI
Decimal Metric System in Portuguese nomenclature
Sistema Métrico Decimal em nomenclatura portuguesa
Decimal Metric System in Portuguese nomenclature

In Portugal, at the beginning of the 19th century, the question was also raised, because the centuries-old measurement systems used here, established by the Ordinances of the Realm (based on the long-ago reforms of King Manuel I and King Sebastião, with wording that remained unchanged in the Philippine Ordinances), in no way addressed the needs of modern times.

Thus, the Prince Regent, although out of the country (having escaped to Brazil in the aftermath of the French invasions) asked the Comissão para o Exame dos Forais e Melhoramentos da Agricultura (Commission for the Inspection of the Charters and Agricultural Improvements) to find a solution.

Three options were discussed: adapting the current system, giving it required universality and simplicity (which became extremely difficult given the characteristics of the systems being used); creating a totally new system; and adopting an existing system, such as the one created in France, based on the mètre.
The Commission for the Inspection of the Charters and Agricultural Improvements debated the various options and, in 1812, recommended that the weights and measures be reformed in a way commensurate with the “considerable knowledge and enlightenment of the century”.

The adoption of the “Decimal System in Portuguese Nomenclature” was proposed, which was a decimal metric system based on the French mètre, but with names of traditional Portuguese measures, which would therefore be assigned values different than they had before, and with a relation between the various quantities as indicated in the table above.

Further information​

António Neves: aneves@ipq.pt
Museum of Metrology: museu.metrologia@ipq.pt