Palms, armspans, and leagues for measuring lengths and distances; ounces and arráteis for weighing jerked beef and sugar; quartilhos for liquids; alqueires for flour and grain. These measurements are as strange to Brazilians today as meters, kilos, and liters were in 1862, when Brazil officially adopted the Decimal Metric System (DMS). The new ways of measuring mass and volume would only become mandatory in 1873, but a decade was not enough to popularize them. Threats of fines and even prison for those who did not use the new measurements sparked an uprising in the Northeast that would become known as the Quebra-Quilos Revolt, literally the kilogram-breaker revolt. According to the newspapers at the time, large groups invaded the weekly markets of countryside towns in the Northeast, breaking the measuring instruments and resisting the reference standards of the new measurement system.
The peasants who lived in the forests of the Borborema mountain range (which extends across the states of Alagoas, Pernambuco, Paraíba, and Rio Grande do Norte) and sold their agricultural products at these markets were called matutos and the men from the imperial government were called doctors. “The matutos took over the city, breaking into the jail, rendering the new weights and measurements useless, and destroying the public archives,” says judge and writer Geraldo Irinêo Joffily (1917–1985) in the book O quebra-quilo: A revolta dos matutos contra os doutores (Quebra-quilo: The revolt of the matutos against the doctors; Thesaurus, 1977).
Joffily describes the first trouble that occurred in the market in Campina Grande, Paraíba, on November 14, 1874: “The matutos persisted with their refusals and complaints, when chief of police João Peixoto appeared with some police soldiers and henchmen of Colonel Alexandrino Cavalcante, owner of the market, trying to disperse the more agitated groups with machete blows; some of the matutos reacted in a surprising way […] The market vendors sought shelter behind the crates of rapadura (solid blocks of unrefined whole cane sugar]; and it was then that a Black man, João Carga d’Agua, well known to everyone, threw the first slab of rapadura at the police, and was imitated by many, since thousands of slabs of rapadura weighing over half a kilo each were piled on mats in the marketplace; a block of rapadura hit the chief of police full on in the head, and he remained out cold for a long time, while the soldiers were surrounded and beaten by the women.” Reporting on the event, the official publications mistook the slabs of rapadura for stones.
Reports from the police and provincial presidents described the revolt as the reaction of a group of ignorant people, distrustful of scientific innovations and manipulated by “undeclared interests,” observes historian María Verónica Secreto, of Fluminense Federal University (UFF) and author of the book (Des)medidos: A revolta dos quebra-quilos (1874-1876) ([Un]measured: The quebra-quilos revolt [1874–1876]; Mauad X, Faperj, 2011). The distrust was directed at the government, not at science: “The State power lacked credibility, seen as an instrument of the ruling class. The population understood that the laws were made for the benefit of a few,” she says. Philosopher Rafael de Oliveira Vaz, of the National Institute of Metrology, Quality, and Technology (INMETRO) reinforces: “The implementation of standards demands trust, which was certainly missing from the Empire’s doctors.”
DIAS, J. L. de M. Medida, normalização e qualidade. 1998. Reproduction Joubert Aragão. Collection of the Brazilian MintA weighing scale manufactured in Brazil in 1856DIAS, J. L. de M. Medida, normalização e qualidade. 1998. Reproduction Joubert Aragão. Collection of the Brazilian Mint
The movement spread to several provinces of the current Northeast (called only the North during the imperial period) between 1874 and 1875, reaching the province of Minas Gerais by 1876. According to Secreto, the size of the revolt reveals the discontent that caused it.
The Northeast was experiencing an intense economic crisis, provoked by droughts and by the drop in sugar and cotton prices on the external market. Instead of measures that would have helped to resolve the problems, the State launched new charges, such as the “floor tax,” applied on goods displayed on the floor at markets, and the “blood tax,” the military recruitment law. The imposition of new measurement standards by the imperial government, which would bring a financial burden with the need to acquire weighing scales and weights, struck the population as another State aggression.
The uprising was suppressed with violence. Captain José Longuinho da Costa Leite (unknown dates of birth/death), tasked with reestablishing the order in Paraíba, became famous as the inventor of the “leather waistcoat,” a form of torture applied to the insurgents. “It consisted of sewing a strip of raw leather, previously soaked for hours, onto the prisoner’s thorax. As the leather dried it compressed the victim’s chest, often causing a torturous death by suffocation,” describes Joffily in his book.
Secreto says that despite the brutality of the repression, the revolts of the period were relatively successful. In addition to complicating military enlistment and postponing civil registry, they managed to delay the standardization of the decimal metric system.
Torsade de Pointes / Wikimedia CommonsA rare photograph of the Quebra-Quilos Revolt, in 1874, in the countryside of Northeast BrazilTorsade de Pointes / Wikimedia Commons
There was also resistance in other South American nations, where the DMS was made official between the 1850s and 1870s, with the exception of the British and Dutch Guianas, which only adhered in 1971, reports historian João Fernando Barreto de Brito in his PhD thesis completed in 2020 at the Federal University of Rio de Janeiro (UFRJ).
In Mexico — which, like Brazil, imposed fines for not using the DMS — there were violent conflicts in 1896, more than 30 years after the promulgation of the law that made the system mandatory (from 1962). In Nova Granada (currently Colombia), the resistance was handled with flexibility: the decree that officially adopted the DMS, from 1853, allowed the population to continue using the traditional measurements. A “hybrid model” was adopted at the time, in which the French system was used for State affairs and the old measurements used in the private domain.
There was resistance in France itself, where the DMS originated, in the eighteenth century. “Standardization was not an easy task, there were lots of different units of measurement,” states Vaz. According to him, the French government established the DMS in 1799, but later, faced with the reaction, backed down. In 1812, two decrees that would only be revoked in 1837 permitted the readoption of the nomenclature of previous units and the use of nonmetric units in commerce.
Jebulon / Wikimedia CommonsSchool poster from 1892Jebulon / Wikimedia Commons
Even today, three countries have still not officially adopted the now-called International System of Units (SI), established in 1960 based on the French metric system. The USA, Liberia, and Myanmar continue to use measurements from the imperial British system, such as feet, yards, and ounces. Despite having officially adopted the decimal metric system in 1965, pressured by the demands of international trade, England continues to live with the traditional measurements and nomenclature from this old system.
The unification of the systems of weights and measurements was the realization of an Enlightenment dream, which sought to lead the nations to progress. In place of the anthropometric measurements (such as palms and armspans), the goal was to arrive at a rational and universal system based on immutable physical phenomena, which would facilitate commercial exchanges in the context of the expansion of capitalism.
The meter was defined after seven years of expeditions, between 1792 and 1799, with the bold task of measuring the size of the earth: one meter is equivalent to one tenth of a millionth of the length of the quadrant of the meridian that links the North Pole to the Equator, passing through Paris.
L. F. Labrousse e J. P. Delion / Wikimedia CommonsA woodcut from 1800 illustrating the new units of measurement in FranceL. F. Labrousse e J. P. Delion / Wikimedia Commons
Conducted by French astronomers Pierre François André Méchain (1744–1804) and Jean Baptiste Joseph Delambre (1749–1822), the expedition was backed by the French Academy of Sciences and King Louis XVI (1754–1793) himself, four months before being deposed in the French Revolution in 1792. Delambre headed north, from Paris to Dunkirk, and Méchain headed south, from Paris to Barcelona. The objective was to measure the fraction of the meridian from Dunkirk to Barcelona, to project, based on trigonometric calculations, the distance between the North Pole and the Equator. For the name of the new unit of measurement, they took an ancient Greek term, which they judged more universal than a French word: meter derived from the word metron, which means “measurement.”
The law that implemented the DMS, from 1793, offered a provisional value to the unit of measurement, based on estimates by physicist and mathematician Pierre-Simon Laplace (1749–1827), mathematician Joseph Louis Lagrange (1736–1813), and physicist Jean Charles de Borda (1733–1799).
The kilogram was the last unit of measurement to be substituted by physical constants
The law also defined the kilogram based on the measurement of the mass of 1 cubic decimeter (dm3) of distilled water at its maximum density and at atmospheric pressure; and the liter, a measure of capacity, as the volume of 1 cubic decimeter. In 1799, the delivery of the platinum prototypes of the definitive meter and kilogram to the Republic Archives in Paris marked the official definition. Today, these pieces are part of the collection of the International Bureau of Weights and Measures (BIPM), created in 1875 by the Meter Convention, signed by 17 countries, including Brazil.
In 1875, more than a decade had already passed since Brazil officially adopted the new system. Imperial Law No. 1,157, signed by Dom Pedro II in 1862, gave a deadline of 10 years for adaptation to the French metric system and determined its inclusion in the programs of primary, public, and private schools. According to an article by mathematician Elenice Zuin, of the Pontifical Catholic University of Minas Gerais (PUC-MG), published in 2017 in Educação Matemática Pesquisa (Education mathematics research), before the law had even been promulgated, Portuguese school books teaching the decimal metric system were already circulating in Brazil. Arithmetic books by Brazilian authors also mentioned the DMS.
Elzauer / Getty ImagesAt the Ver-o-Peso market, in Belém, you can also buy flour by the literElzauer / Getty Images
However, the desire to align Brazil with European countries by adopting the scientific system created in Europe was impeded by the population’s access to formal education and even by the irregular distribution of measurement standards, such as the iron weights used for calibrations, still imported from France. “Brazil did not have the means of disseminating the new system,” comments Vaz.
It was only in the Vargas Era (1930–1945), faced with the demands of industrialization, that the government intensified efforts to implement the DMS. In 1962, the country adhered to the recently created SI, currently made up of seven basic units: meter, for length; kilogram, for mass; second, for time; ampere, for electrical current; Kelvin, for thermodynamic temperature; candela, for luminous intensity; and mole, for amount of substance.
At the 17th General Conference on Weights and Measures, in 1983, it was decided that the meter would be based on the velocity of the speed of light in a vacuum. The meter is now defined as the length light travels in a vacuum in 1/299,792,458 of a second. Other fundamental units of measurement were substituted by physical constants, universal quantities that, in principle, do not change over time.
Japs 88 / Wikimedia CommonsA replica of the prototype kilogram on display at the Cité des Sciences et de l’Industrie museum, in ParisJaps 88 / Wikimedia Commons
In 2019, the kilogram, the last unit of measurement to be redefined, stopped being established based on the metallic cylinder guarded under three glass domes in a safe in the headquarters of the BIPM in Sèvres, on the outskirts of Paris. The basic unit of mass is now defined based on the Planck constant, proposed in 1900 by German physicist Max Planck (1858–1947), which establishes a relationship between the energy of light particles (photons) and the frequency at which they vibrate (see Pesquisa FAPESP issue nº 256).
However, not all technology has the power to eliminate tradition. Today, the decimal metric system coexists, without conflicts, with traditional measurements. Some anthropometric measurements still persist, such as inches, used for measuring TV screens, or feet, for measuring the altitude of an aircraft. In Brazil’s outdoor markets, you can buy bunches of leafy green vegetables and bowls of fruit. According to an article by mathematician Patrícia de Campos Corrêa published in Amazônia: Revista de Educação em Ciências e Matemáticas (Amazonia: Journal of education in sciences and mathematics), other popular units are used in the North of Brazil: cambada de peixes (a bunch of fish), rasa de açaí (a 28 kg basket of açaí berries), paneiro de ananás (a basket of pineapples), and cuia de camarão (a pot of shrimp). In the famous Ver-o-Peso Market (which translates literally as the see-the-weight market) in Belém, the state capital of Pará, new uses for the international system of units can be seen: there you can purchase nuts, manioc flour, and shrimp by the liter. The standard-liter, created as a unit of measurement for liquids, is thus used for solids. The digital scales with the INMETRO seal remain at the side, ready to be shown to the municipal inspectors that appear.
Scientific articles
BRITO, J. F. B. de. Quanto pesa o quilo? A adoção do Sistema Métrico Decimal francês no Brasil e os Quebra-quilos (1862-1875). Doctoral thesis in social history. Universidade Federal do Rio de Janeiro, 2020.
CORRÊA, P. de C. Sistema Métrico Decimal no Pará. Amazônia – Revista de Educação em Ciências e Matemáticas. Vol. 11, no. 22. Jan. 2015.
VAZ, Rafael O. Antecedentes do Sistema Métrico Decimal no Brasil: O artigo “Memória sobre a adopção do Systema Métrico no Brazil e de uma circulação monetária internacional“ (1859), de Cândido Batista de Oliveira. Instituto Nacional de Metrologia, Qualidade e Tecnologia (Inmetro). Nov. 2012.
ZUIN, Elenice. José Joaquim D’Avila: pela defesa de um novo sistema de pesos e medidas no Brasil no século XIX? Educação Matemática Pesquisa. Vol. 19, no. 2, pp. 187–210. Sept. 7, 2017.
Books
CREASE, R. P. A medida do mundo. A busca por um sistema universal de pesos e medidas. Rio de Janeiro: Editora Jorge Zahar, 2013.
DIAS, José Luciano de Mattos. Medida, normalização e qualidade; Aspectos da história da metrologia no Brasil. Rio de Janeiro: Ilustrações, 1998.
JOFFILY, Geraldo Irinêo. O quebra-quilo. A revolta dos matutos contra os doutores (1874). Brasília: Thessaurus, 1977. Disponível em Revista de História, Vol. 54, no. 107 (1976). pp. 69–145, 2023.
LIMA, L. M. de. Derramando susto: os escravos e o Quebra-quilos em Campina Grande. Campina Grande, Editora da Universidade Federal de Campina Grande (EDUFCG), 2006.
MAIOR, A. S. Quebra-quilos – Lutas sociais no outono do Império. São Paulo: Companhia Editora Nacional, 1978.
ROZENBERG, I. M. O Sistema Internacional de Unidades – SI. São Paulo: Instituto Mauá de Tecnologia, 2006.
SECRETO, M. V. (Des) medidos: a revolta dos quebra-quilos (1874–1876). Rio de Janeiro: Mauad X: FAPERJ, 2011.
