ESHS/HSS Annual Meeting

Metrication and Mesures Usuelles: A Survey of the Metre’s Tacit History

• In Event: The Politics of Standardization

English Abstract

The introduction of the metric system in revolutionary France is usually seen as the culmination of the Enlightened “quantifying spirit”, replacing local, customary units with a universal system of measurement. To revise this seemingly straightforward march of reason, the presentation examines the work invested in reforming measurement practices by centering on a hitherto overlooked phase in metrication: the mesures usuelles. Enacted between 1812 and 1840, this reform allowed the use in retail commerce of a parallel set of base units, which followed a non-decimal system of division. These units bore the same name as Parisian pre-metric standards, but their value was calibrated to metric units. Despite representing the longest phase of metrication, historians have dismissed the mesures as a setback and “assault on the integrity of the metric system”. Yet the mesures were crucial for instituting the metric system. Metrication began with surveyors inventorying local measures across France, disqualifying some as obsolete, while promoting others into representative regional units. The mesures , bearing the names of old units, but with their values rounded to the new metric regime, were intended to make this selective documentation and rectification of “old” measures inconspicuous. Concomitantly, as a synthesis between metric values and non-decimal systems of division, the mesures were to facilitate the adoption of metric units—highly counter-intuitive and consequently unpopular among non-experts—in everyday transactions. Through repeated use, the mesures would engender a new practical knowledge, allowing metric units to become established as the new usual, habitual measures.

Author

• Svit Komel, University of Ljubljana