Jean-Charles de Borda
Encyclopedia
Jean-Charles, chevalier de Borda (May 4, 1733 – February 19, 1799) was a French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

, physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

, political scientist, and sailor
Sailor
A sailor, mariner, or seaman is a person who navigates water-borne vessels or assists in their operation, maintenance, or service. The term can apply to professional mariners, military personnel, and recreational sailors as well as a plethora of other uses...

.

Life history

Born in the city of Dax
Dax, Landes
Dax is a commune in Aquitaine in south-western France, sub-prefecture of the Landes department.It is particularly famous as a spa, specialising in mud treatment for rheumatism and similar ailments....

, in 1756 Borda wrote Mémoire sur le mouvement des projectiles, a product of his work as a military engineer
Military engineer
In military science, engineering refers to the practice of designing, building, maintaining and dismantling military works, including offensive, defensive and logistical structures, to shape the physical operating environment in war...

. For that, he was elected to the French Academy of Sciences
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 research...

 in 1764.

Borda was a mariner and a scientist, spending time in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

 testing out advances in chronometers. Between 1777 and 1778, he participated in the American Revolutionary War
American Revolutionary War
The American Revolutionary War , the American War of Independence, or simply the Revolutionary War, began as a war between the Kingdom of Great Britain and thirteen British colonies in North America, and ended in a global war between several European great powers.The war was the result of the...

. In 1781, he was put in charge of several vessels in the French Navy
French Navy
The French Navy, officially the Marine nationale and often called La Royale is the maritime arm of the French military. It includes a full range of fighting vessels, from patrol boats to a nuclear powered aircraft carrier and 10 nuclear-powered submarines, four of which are capable of launching...

. In 1782, he was captured by the English
Action of 6 December 1782
The Action of 6 December 1782 was a single-ship action fought between HMS Ruby and the French ship Solitaire off the coast of Martinique. The Ruby easily defeated the Solitaire.-Battle:...

 , and was returned to France shortly after. He returned as an engineer in the French Navy, making improvements to waterwheels and pumps. He was appointed as France's Inspector of Naval Shipbuilding in 1784, and with the assistance of the naval architect Jacques-Noël Sané
Jacques-Noël Sané
Jacques-Noël Sané was a French naval engineer, one of the most successful shipbuilders of the Age of Sail.Sané studied under Duhamel du Monceau...

 in 1786 introduced a massive construction programme to revitalise the French navy based on the standard designs of Sané.

In 1770, Borda formulated a ranked preferential voting system
Voting system
A voting system or electoral system is a method by which voters make a choice between options, often in an election or on a policy referendum....

 that is referred to as the Borda count
Borda count
The Borda count is a single-winner election method in which voters rank candidates in order of preference. The Borda count determines the winner of an election by giving each candidate a certain number of points corresponding to the position in which he or she is ranked by each voter. Once all...

. The French Academy of Sciences
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 research...

 used Borda's method to elect its members for about two decades until it was quashed by Napoleon Bonaparte who insisted that his own method be used after he became president of the Académie in 1801. The Borda count is in use today in some academic institutions, competitions and several political jurisdictions. The Borda count has also served as a basis for other methods such as the Quota Borda system
Quota Borda system
The Quota Borda System or Quota Preference Score is a voting system that was devised by the British philosopher Michael Dummett and first published in 1984 in his book, Voting Procedures, and again in his Principles of Electoral Reform....

 and Nanson's method
Nanson's method
The Borda count can be combined with an Instant Runoff procedure to create hybrid election methods that are called Nanson method and Baldwin method.- Nanson method :The Nanson method is based on the original work of the mathematician Edward J...

.

In 1778, He published his method of reducing Lunar Distances for computing the longitude, still regarded as the best of several similar mathematical procedures for navigation and position-fixing in pre-chronometer days; and used, for example, by Lewis and Clarke
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 to measure their latitude and longitude during their exploration of the North-western United States.

Another of his contributions is his construction of the standard metre, basis of the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...

 to correspond to the measurements of Delambre.

As an instrument maker, he improved the reflecting circle (invented by Tobias Mayer
Tobias Mayer
Tobias Mayer was a German astronomer famous for his studies of the Moon.He was born at Marbach, in Württemberg, and brought up at Esslingen in poor circumstances. A self-taught mathematician, he had already published two original geometrical works when, in 1746, he entered J.B. Homann's...

) and the repeating circle
Repeating circle
The repeating circle is an instrument for geodetic surveying, invented by Etienne Lenoir in 1784, while an assistant of Jean-Charles de Borda, who later improved the instrument. It was notable as being the equal of the great theodolite created by the renowned instrument maker, Jesse Ramsden...

 (invented by his assistant, Etienne Lenoir
Etienne Lenoir (instrument maker)
Etienne Lenoir was a French scientific instrument maker and inventor of the repeating circle.When hired by Jean-Charles de Borda around 1772 to work on the reflecting circle, he was about thirty years old and nearly illiterate. However, his intelligence and mechanical genius allowed him to...

), the latter used to measure the meridian arc
Meridian arc
In geodesy, a meridian arc measurement is a highly accurate determination of the distance between two points with the same longitude. Two or more such determinations at different locations then specify the shape of the reference ellipsoid which best approximates the shape of the geoid. This...

 from Dunkirk to Barcelona
Barcelona
Barcelona is the second largest city in Spain after Madrid, and the capital of Catalonia, with a population of 1,621,537 within its administrative limits on a land area of...

 by Delambre and Méchain
Mechain
Mechain was a medieval cantref in the Kingdom of Powys. It lay almost in the centre of the kingdom, bordering with cantref Caereinion to the south, the two cwmwds of the cantref of Mochnant to the north, and part of the cantref of Deuparth and the cwmwds of Deuddwr and Ystrad Marchell to the...

.

Tables of logarithms

With the advent of the metric system after the French Revolution it was decided that the quarter circle should be divided into 100 degrees instead of 90 degrees, and the degree into 100 seconds instead of 60 seconds. This required the calculation of trigonometric tables and logarithms corresponding to the new size of the degree and instruments for measuring angles in the new system.

Borda constructed instruments for measuring angles in the new units (the instrument could no longer be called a "sextant") which was later used in the measurement of the meridian between Dunkirk and Barcelona by Delambre to determine the length of the metre. The tables of logarithms of sines, secants, and tangents were also required for the purposes of navigation. Borda was an enthusiast for the metric system and constructed tables of these logarithms starting in 1792 but their publication was delayed until after his death and only published in the Year 9 (1801) as Tables of Logarithms of sines, secants, and tangents, co-secants, co-sines, and co-tangents for the Quarter of the Circle divided into 100 degrees, the degree into 100 minutes, and the minute into 100 seconds to ten decimals, and including his tables of logarithms to 7 decimals from 10,000 to 100,000 with tables for obtaining results to 10 decimals.

The division of the degree into hundredths was accompanied by the division of the day into 10 hours of 100 minutes and maps were required to show the new degrees of latitude and longitude. The Republican Calendar
French Republican Calendar
The French Republican Calendar or French Revolutionary Calendar was a calendar created and implemented during the French Revolution, and used by the French government for about 12 years from late 1793 to 1805, and for 18 days by the Paris Commune in 1871...

 was abolished by Napoleon in 1806, but the 400-degree circle lived on as the Gradian.

Honours

  • Five French ships were named Borda
    French ship Borda
    Five ships of the French Navy have born the name Borda in honour of Jean-Charles de Borda:* A 10-gun brig * The Borda , a 110-gun ship of the line* The Borda , a 120-gun ship of the line...

     in his honour.
  • The crater Borda
    Borda (crater)
    Borda is a lunar crater that lies between Santbech to the north-northwest and Reichenbach slightly further away to the south-southeast. It has a low rim that is broken along the southeast by a smaller crater. The rim is intruded into by another small crater along the southwest side, and there is an...

     on the Moon
    Moon
    The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

     is named after him.
  • Asteroide 175726 has been called Borda in his honour.
  • His name is one of the 72 names inscribed on the Eiffel Tower
    The 72 names on the Eiffel Tower
    On the Eiffel Tower, seventy-two names of French scientists, engineers and some other notable people are engraved in recognition of their contributions. This is according to the design by Gustave Eiffel. The engravings are found on the sides of the tower under the first balcony...

    .
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