The International Bureau of Weights and Measures: Foundation and Cooperation

On May 20, 1875, seventeen countries, including France, Germany, the United States, Russia, Italy, and Switzerland, signed the Metre Convention in Paris. They agreed to finance jointly a permanent scientific institution, the Bureau international des poids et mesures, or BIPM. Its central problem was how countries could actually share comparable standards of length and mass, rather than merely endorse the principle of uniform weights and measures.

This need was closely connected to international geodesy. A Berlin conference in 1867 had already called for new meter prototypes suitable for precise comparison and an international institution. German astronomer Wilhelm Foerster and Swiss astronomer Adolphe Hirsch promoted the permanent arrangement. At the diplomatic conference of 1875, French representative Jean-Baptiste Dumas supported sustained scientific work, taking the plan beyond an institution that would merely retain a repository after prototypes were made.

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Article 3 established a three-tier relationship. The General Conference on Weights and Measures, or CGPM, composed of representatives of the contracting states, stood at the top. The International Committee for Weights and Measures, or CIPM, directly guided and supervised the BIPM, which undertook continuing experimental and technical work. The original regulations provided for fourteen committee members from different countries, while voting at the conference was by state, with one vote each.

Spain's Carlos Ibáñez chaired the first committee, with Hirsch as secretary. This arrangement allowed scientists to address instruments, comparison methods, and experimental results continuously while reporting to governments. The bureau had dedicated premises and employees but remained subject to international oversight. Its location in France did not make it a domestic French weights-and-measures administration.

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The original regulations of 1875 specified expenditure as well as tasks. Purchasing or constructing buildings, installing facilities, and acquiring instruments were together capped at 400,000 francs. During the first phase of making and comparing new prototypes, the annual budget was estimated at 75,000 francs, adjustable by the committee as needed but not beyond 100,000. A lower budget was envisaged after distribution of the prototypes. These were institutional planning limits, not expenditures already incurred.

There was also a specific formula for contributions. Article 20 of the regulations used population as a base, applying coefficients of three, two, and one respectively to states where the metric system was compulsory, permitted, or in neither category, then allocating costs by the resulting weights. The director submitted annual reports on finances, equipment, and work, and the committee reported to governments. Funding was thus tied to assigned tasks, disclosed accounts, and international supervision.

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On April 22, 1876, the French government made the Pavillon de Breteuil and surrounding land in the Parc de Saint-Cloud available for use. The building had been damaged during the war of 1870–1871. The committee restored the old pavilion and completed a laboratory building in 1878. The original regulations required a prototype repository, rooms for comparators and balances, laboratories, a library, and archives. Quiet and stability were themselves conditions of measurement.

The institution was initially directed by the Italian G. Govi; the Norwegian O. J. Broch took charge in 1879. The initial budget envisaged salaries for a director, two deputies, four assistants, and maintenance and general-service personnel. This reflects planned responsibilities, not actual staffing in every year. Personnel, premises, and instruments all had to be in place. Signing the treaty did not mean the entire laboratory was operating that day.

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The first core tasks concerned meter and kilogram prototypes. The kilogram project particularly reveals international division of labor. In 1878, three platinum-iridium cylinders were ordered from Johnson Matthey in London and polished and adjusted by A. Collot in Paris. In 1880, four observers compared them at the Paris Observatory with the kilogram standard in the French archives. The BIPM did not yet possess all the equipment needed, so it still depended on other institutions.

The cylinder closest to the old standard was later selected as the international prototype kilogram. Meter prototypes used Tresca's X-shaped cross-section, and the thermal expansion of each bar was determined. Cooperation over standards was not a matter of making metal objects that looked identical. It involved recording the tiny differences between each copy and the common reference, enabling countries to relate their measurements to one another.

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The first CGPM in 1889 approved the international meter and kilogram prototypes. Its proceedings explicitly connected the meter's length with the temperature of melting ice, while national copies came with comparison results and certificates. Consistency of standards depended on known conditions and recorded differences, not assertions that every bar and weight was absolutely identical.

Approval also involved disagreement. Russian representative Wild argued that, since the full measurement details had not yet been published, “probable error” should not be included in the approval text. Hirsch stressed that results should state their degree of uncertainty. The conference amended the wording of approval, but reports and certificates still preserved the relevant error information. Scientific judgment and governmental representatives' deliberations met directly here.

The conference then drew lots to determine which numbered prototypes countries and relevant institutions would receive. The secretary and director kept separate records, and representatives signed acceptance documents. Prototypes awaiting suitable packing could remain at the bureau with receipts issued. From manufacture and comparison to numbering, certification, and delivery, the BIPM turned abstract common units into traceable procedures of cooperation and laid a foundation for repeated later verification.

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