The 10 December 1799 Act
Talleyrand,
at the National Institute's request, invited neutral and allied countries to
take part in setting Final standards in June 1798, when the operations were
coming to an end.
The
following countries sent representatives: Denmark, the Batavian Republic
(Van Swiden), the Helvetian Republic (Trallès), Sardinia, Tuscany (Fabbroni),
the Ligurian Republic, the Cisalpine Republic, the Roman Republic, Spain.
The
French representatives were: Borda, Brisson, Coulomb, Darcet, Delambre,
Haüy, Lagrange, Lefèvre-Gineau and Prony.
The
scientists' committee sanctionned the results in Paris in April and May
1799:
•The
Dutch Van Swinden reported in April that the earth's quadrant measurements
finished by Delambre and Méchain in 1798 led to set the Final Metre length
to 3 feet 11.296 lignes of the Toise de l'Académie;
• The
Swiss Trallès reported in May that the measurements made by Lefèvre-Gineau
and Fabbroni led to set the Final Kilogramme weight to 18,827.15 grains of
the average marc of the Pile de Charlemagne.
Later
on, in June 1799, a delegation of the National Institute of Science and Arts
presented to the Legislative Body - Conseil des Cinq-Cents and Conseil des
Anciens - the prototype standards of the Metre and Kilogramme. They were
deposited in the National Archives on the same day.
The
presentation minutes were signed by fifteen scientists, of which nine
Foreign States delegates, and by Lenoir and Fortin.
The
10 December 1799 Act ratified these operations:
"The
metre length, being the ten-millionth part of the earth's quadrant situated
between the North pole and the Equator, is definitely set to 3 feet 11.296
lignes. The platinum metre and kilogramme that were presented to the
legislative body by the National Institute of Science and Arts on the 23
June are the final length and weight measures standards in all France."
The
standards are made of platinum that is produced by Janety, a chemist. The
metre is an end measure, a rectangular section flat ruler that is fitted by
Lenoir. The kilogramme is a diametre-high cylinder that is fitted by Fortin.
[picture]
They
are known as the Mètre des Archives and the Kilogramme des Archives.