Pierre Vernier
Encyclopedia
Pierre Vernier was a French 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....

 and instrument inventor. He was inventor and eponym
Eponym
An eponym is the name of a person or thing, whether real or fictitious, after which a particular place, tribe, era, discovery, or other item is named or thought to be named...

 of the vernier scale
Vernier scale
A vernier scale is an additional scale which allows a distance or angle measurement to be read more precisely than directly reading a uniformly-divided straight or circular measurement scale...

 used in measuring devices.

He was born in Ornans
Ornans
Ornans is a commune in the Doubs department in the Franche-Comté region in eastern France.-Personalities:Ornans is the birthplace of the French realist painter, Gustave Courbet . One of Courbet's most famous paintings is Burial at Ornans, which records the burial of his great uncle in September 1848...

, France, in 1580, he was taught science by his father. He later became captain and castellan of the castle at Ornans, for the King of Spain. He was also later councillor and director general of moneys in the County of Burgundy
County of Burgundy
The Free County of Burgundy , was a medieval county , within the traditional province and modern French region Franche-Comté, whose very French name is still reminiscent of the unusual title of its count: Freigraf...

.

At Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

, in 1631, he published , his treatise "La construction, l'usage, et les propriétés du quadrant nouveau de mathematiques", and dedicated it to the Infanta. In it he described the ingenious device which now bears his name, the Vernier scale
Vernier scale
A vernier scale is an additional scale which allows a distance or angle measurement to be read more precisely than directly reading a uniformly-divided straight or circular measurement scale...

.

To a quadrant
Quadrant (instrument)
A quadrant is an instrument that is used to measure angles up to 90°. It was originally proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers.-Types of quadrants:...

 with a primary scale in half degrees Vernier proposed to attach a movable sector, thirty-one half degrees in length but divided into thirty equal parts (each part consisting then of a half degree plus one minute). In measuring an angle, minutes could be easily reckoned by noticing which division line of the sector coincided with a division line of the quadrant.

Christopher Clavius
Christopher Clavius
Christopher Clavius was a German Jesuit mathematician and astronomer who was the main architect of the modern Gregorian calendar...

 had earlier mentioned the idea but had not proposed to attach the scale permanently to the instrument.

The name vernier is now applied to the small movable scale attached to a caliper, sextant
Sextant
A sextant is an instrument used to measure the angle between any two visible objects. Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude. Making this measurement is known as sighting the object, shooting the object, or taking a sight...

, barometer
Barometer
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather...

, or other graduated instrument and was given by Jérôme Lalande
Jérôme Lalande
Joseph Jérôme Lefrançois de Lalande was a French astronomer and writer.-Biography:Lalande was born at Bourg-en-Bresse...

. Lalande showed that the previous name, nonius after Pedro Nunes
Pedro Nunes
Pedro Nunes , was a Portuguese mathematician, cosmographer, and professor, from a New Christian family. Nunes, considered to be one of the greatest mathematicians of his time , is best known for his contributions in the technical field of navigation, which was crucial to the Portuguese period of...

, belonged more properly to a different contrivance. The name nonius continued to be applied to the vernier until the beginning of the 19th century.

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