:: Provisional measures to hasten the reform ::
1 August 1793 Act

While the meridian measuring was still in process, the Convention, which wanted to hasten the standardization of measures, decided to adopt a provisional system, subject of the 1 August 1793 Act.

"The National Convention [] states that it is satisfied with the work that has been done by the academy regarding the system of weights and measures; that it adopts these results to implement this system in the whole Republic, under the nomenclature of the table which is annexed to this Act, and to offer it to every nation. Consequently, it decrees that the new system of weights and measures, which is based on the quadrant of the earth measurement and on decimal division, will be used uniformly in the whole Republic. Artists chosen by the Academy of Sciences will create standards of the new weights and measures which will be sent to every departement and district administration."

The "table of the new system of weights and measures and their designation", which is annexed to the Act, went into the following details:

The value of a quarter of a meridian, which is taken as a base, is 5,132,430 toises (a toise being a little more than six feet). This value was found measuring the Paris meridian line, from Dunkirk to Collioures, that Casini de Thury and La Caille did in 1739 and 1740.

The "linear unit",is the ten millionth part of the quarter of a meridian and is called "metre". It is equivalent to 3 feet and 11.44 lignes de Paris (a ligne de Paris being nearly 2.3 mm). A length that is equivalent to 1,000 metres is a "milliaire". Other units are planned, such as the decimetre, centimetre, millimetre.

The unit for land area measurements is the are.

The unit for capacity measurements, the cubic decimetre, is the quart; the cubic metre is called "cade", with its subdivisions decicade and centicade.

The unit of weight- the weight of the cubic decimetre of water - is the "grave" which is equivalent to 2 pounds 5 gros 49 grains, and its subdivisions are: decigrave, centigrave, gravet, decigravet, centigravet; the weight of the cubic metre is called "bar" or "millier".

The value of the grave had been determined thanks to the work of Lavoisier and Hay, who had determined the mass of the cubic decimetre of water - at ice melting point - in January 1793: 18,841 grains of the marc of the pile de Charlemagne.

In October 1793, the first metric patterns were presented to the Convention: the Metre, the Quart and the Grave.


The 22 October 1793 Act prescribed the construction of "weights and measures standards made of platinum, one the size of a meter, one of a quart and one of a grave, which are to be prototype standards for all France".

In July 1795, a provisional standard metre made of brass, that was made by Lenoir, was given to the Committee for public instruction.

By the 19 January 1794 decree, the unit which was called "quart" took the name "cadil". The 7 April 1795 Act replaced the latter name by "litre"; it also replaced "gravet" by "gramme"; and the weight of 1,000 grammes which was previously called "grave" became "kilogramme".

Next page