Pierre Vernier (; 19 August 1580 at Ornans, Franche-Comté (at that time ruled by the Spanish Habsburgs, now part of

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

) – 14 September 1637, same location) was a

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

and instrument inventor. He was the inventor and

eponym An eponym is a noun after which or for which someone or something is, or is believed to be, named. Adjectives derived from the word ''eponym'' include ''eponymous'' and ''eponymic''. Eponyms are commonly used for time periods, places, innovati ...

of the

vernier scale A vernier scale ( ), named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, which increases resolution and reduces measurement un ...

used in measuring devices.

Life

He was born in Ornans, France, in 1580. He was taught science by his father. He became captain and castellan of the castle at Ornans, for the King of Spain. He was also later councillor and director general of economy in the County of Burgundy. In

Brussels Brussels, officially the Brussels-Capital Region, (All text and all but one graphic show the English name as Brussels-Capital Region.) is a Communities, regions and language areas of Belgium#Regions, region of Belgium comprising #Municipalit ...

, in the year 1631, Vernier published his treatise ''La construction, l'usage, et les propriétés du quadrant nouveau de mathématique'', and dedicated it to the Infanta. In it, he described the ingenious device which now bears his name, the

. To a quadrant 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 therefore consisting 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 had earlier mentioned this 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,

barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis ...

, or other graduated instrument and was given by

Jérôme Lalande Joseph Jérôme Lefrançois de Lalande (; 11 July 1732 – 4April 1807) was a French astronomer, freemason and writer. He is known for having estimated a precise value of the astronomical unit (the distance from the Earth to the Sun) using measu ...

. Lalande showed that the previous name, ''nonius'' after Pedro Nunes, belonged more properly to a different contrivance. From p. 859: ''"La division qui est aujourd'hui la plus employée est appellée dans plusieurs Auteurs ''division de Nonnius'', quoique Nonnius n'en soit pas l'Auteur; mais il en avoit imaginé une autre qui eut beaucoup de célébrité, & qui pouvoit conduire à celle que nous avons aujourd'hui. Le véritable Auteur de la nôtre fut Pierre Vernier qui la publia dans un petit Ouvrage imprimé à Bruxelles en 1631."'' (The scale which is most used today is called by many authors "Nonnius' scale", although Nonnius is not the inventor of it; but he had imagined another one which was very well known and which could have led to what we have today. The true inventor of our calewas Pierre Vernier who published it in a small work in Brussels in 1631.) The name ''nonius'' continued to be applied to the vernier until the beginning of the 19th century.Daumas, Maurice, ''Scientific Instruments of the Seventeenth and Eighteenth Centuries and Their Makers'', Portman Books, London 1989

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* {{DEFAULTSORT:Vernier, Pierre 1580 births 1637 deaths People from Doubs 17th-century mathematicians from the Holy Roman Empire 17th-century inventors Scientific instrument makers 17th-century artisans People from the County of Burgundy