Gabriel Mouton (1618 – 28 September 1694) was a French

abbot Abbot is an ecclesiastical title given to the head of an independent monastery for men in various Western Christian traditions. The name is derived from ''abba'', the Aramaic form of the Hebrew ''ab'', and means "father". The female equivale ...

and

scientist A scientist is a person who Scientific method, researches to advance knowledge in an Branches of science, area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engag ...

. He was a doctor of theology from

Lyon Lyon (Franco-Provençal: ''Liyon'') is a city in France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of the French Alps, southeast of Paris, north of Marseille, southwest of Geneva, Switzerland, north ...

, but was also interested in

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

and

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

. His 1670 book, the ''Observationes diametrorum solis et lunae apparentium'', proposed a natural standard of length based on the circumference of the Earth, divided decimally. It was influential in the adoption of the

metric system The metric system is a system of measurement that standardization, standardizes a set of base units and a nomenclature for describing relatively large and small quantities via decimal-based multiplicative unit prefixes. Though the rules gover ...

in 1799.

The milliare

Based on the measurements of the size of the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

conducted by Riccioli of Bologna (at 321,815 Bologna feet to the degree), Mouton proposed a

decimal The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers (''decimal fractions'') of th ...

system of measurement based on the circumference of the Earth, explaining the advantages of a system based on nature. His suggestion was a unit, the ''milliare'', that was defined as a

minute of arc A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

along a

meridian arc In geodesy and navigation, a meridian arc is the curve (geometry), curve between two points near the Earth's surface having the same longitude. The term may refer either to a arc (geometry), segment of the meridian (geography), meridian, or to its ...

, and a system of sub-units, dividing successively by factors of ten into the ''centuria'', ''decuria'', ''virga'', ''virgula'', ''decima'', ''centesima'', and ''millesima''. The ''virga'', 1/1000 of a minute of arc, corresponding to 64.4 Bologna inches, or ~2.04 m, was reasonably close to the then current unit of length, the Parisian ''toise'' (~1.95 m) – a feature which was meant to make acceptance of the new unit easier. As a practical implementation, Mouton suggested that the actual standard be based on

pendulum A pendulum is a device made of a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate i ...

movement, so that a pendulum located in Lyon of length one ''virgula'' (1/10 ''virga'') would change direction 3959.2 times in half an hour. The resulting pendulum would have a length of ~20.54 cm. His ideas attracted interest at the time, and were supported by Jean Picard as well as Huygens in 1673, and also studied at

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

. In 1673,

Leibniz Gottfried Wilhelm Leibniz (or Leibnitz; – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat who is credited, alongside Sir Isaac Newton, with the creation of calculus in addition to many ...

independently made proposals similar to those of Mouton. It would be over a century later, however, that the

French Academy of Sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...

weights and measures committee suggested the decimal

that defined the ''Metre'' as, at least initially, a division of the circumference of the Earth. The first official adoption of this system occurred in France in 1791. By today's measures, his ''milliare'' corresponds directly to a nautical mile, and his ''virga'' would by definition have been 1.852 m.

Notes

References

* G. Bigourdan
''Le systeme metrique des poids et mesures''
1901, chapter ''Les precurseurs de la reforme des poids et mesures'' * Ferdinand Hoefer: ''Historie de l'astronomie'', Paris 1873

External links

Metrication - Genesis
*

{{DEFAULTSORT:Mouton, Gabriel 1618 births 1694 deaths 17th-century French mathematicians 17th-century French Roman Catholic priests Catholic clergy scientists

The milliare

See also

Notes

References

External links