Edmund Gunter (1581 – 10 December 1626),
EnglishEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west and the North Sea to the east, with the English Channel to the south separating it from continental...
mathematicianA mathematician is a person whose primary area of study and/or research is the field of mathematics. Mathematicians are concerned with particular problems related to logic, space, transformations, numbers and more general ideas which encompass these concepts...
, of
WelshWales is a country that is part of the United Kingdom, bordered by England to its east, and the Atlantic Ocean and Irish Sea to its west. It is also an elective region of the European Union...
descent, was born in Hertfordshire in 1581.
He was educated at
Westminster SchoolThe Royal College of St. Peter in Westminster, almost always known as Westminster School, is one of Britain's leading independent schools,, with the highest Oxbridge acceptance rate of any secondary school or college...
, and in 1599 was elected a student of
Christ Church, OxfordThis article is about the Oxford college. For other uses, see Christ Church or Christchurch .Christ Church , is one of the largest constituent colleges of the University of Oxford in England...
. He took orders, became a preacher in 1614, and in 1615 proceeded to the degree of bachelor in divinity. Mathematics, particularly the relationship between mathematics and the real world, was the one over riding interest throughout his life.
In 1620 the wealthy but earnest Sir Henry Savile put up money to fund Oxford University's first two
science faculties, the chairs of astronomy and geometry.
Edmund Gunter (1581 – 10 December 1626),
EnglishEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west and the North Sea to the east, with the English Channel to the south separating it from continental...
mathematicianA mathematician is a person whose primary area of study and/or research is the field of mathematics. Mathematicians are concerned with particular problems related to logic, space, transformations, numbers and more general ideas which encompass these concepts...
, of
WelshWales is a country that is part of the United Kingdom, bordered by England to its east, and the Atlantic Ocean and Irish Sea to its west. It is also an elective region of the European Union...
descent, was born in Hertfordshire in 1581.
He was educated at
Westminster SchoolThe Royal College of St. Peter in Westminster, almost always known as Westminster School, is one of Britain's leading independent schools,, with the highest Oxbridge acceptance rate of any secondary school or college...
, and in 1599 was elected a student of
Christ Church, OxfordThis article is about the Oxford college. For other uses, see Christ Church or Christchurch .Christ Church , is one of the largest constituent colleges of the University of Oxford in England...
. He took orders, became a preacher in 1614, and in 1615 proceeded to the degree of bachelor in divinity. Mathematics, particularly the relationship between mathematics and the real world, was the one over riding interest throughout his life.
In 1620 the wealthy but earnest Sir Henry Savile put up money to fund Oxford University's first two
science faculties, the chairs of astronomy and geometry. Gunter applied to become professor of geometry but Savile was famous for distrusting clever people... and [Gunter's] behavior annoyed him intensely. As was his habit, Gunter arrived with his
sectorThe sector, also known as a proportional compass or military compass, was a major calculating instrument in use from the end of the sixteenth century until the nineteenth century. It is an instrument consisting of two rulers of equal length which are joined by a hinge. A number of scales are...
and
quadrantNot to be confused with quartileQuadrant may refer to:* Quadrant , a measuring instrument capable of measuring angles up to 90°* In science-fiction: Galactic quadrants...
, and began demonstrating how they could be used to calculate the position of stars or the distance of churches,
until Savile could stand it no longer. "Doe you call this reading of Geometric?" he burst out. "This is mere showing of tricks, man!" and, according to a contemporary account, "dismissed him with scorne."
He was shortly thereafter championed by the far wealthier Earl of Bridgewater, who saw to it that on 6 March 1619 Gunter was appointed professor of
astronomyAstronomy is the scientific study of celestial objects and phenomena that originate outside the Earth's atmosphere...
in
Gresham CollegeGresham College is an unusual institution of higher learning off Holborn in central London. It enrolls no students and grants no degrees. The Collège de France offers perhaps a Parisian equivalent....
, London. This post he held till his death.
With Gunter's name are associated several useful inventions, descriptions of which are given in his treatises on the Sector, Cross-staff, Bow,
QuadrantA 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:...
and other instruments. He contrived his sector about the year 1606, and wrote a description of it in Latin, but it was more than sixteen years afterwards before he allowed the book to appear in English. In 1620 he published his
Canon triangulorum.
In 1624 Gunter published a collection of his mathematical works. It was entitled
The description and use of sector, the cross-staffe, and other instruments for such as are studious of mathematical practise. One of the most remarkable things about this book is that it was written, and published, in English not Latin. "I am at the last contented that it should come forth in English," he wrote
resignedly, "Not that I think it worthy either of my labour or the publique view, but to satisfy their importunity who not understand the Latin yet were at the charge to buy the instrument." It was a manual not for cloistered university fellows but for sailors and surveyors in real world.
There is reason to believe that Gunter was the first to discover (in 1622 or 1625) that the magnetic needle does not retain the same
declinationIn astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Dec is comparable to latitude, projected onto the celestial sphere, and is measured in degrees north and south of the celestial equator...
in the same place at all times. By desire of
James IJames VI & I was King of Scots as James VI from 1567 to 1625, and King of England and Ireland as James I from 1603 to 1625....
he published in 1624
The Description and Use of His Majesties Dials in Whitehall Garden, the only one of his works which has not been reprinted. He introduced the words cosine and cotangent, and he suggested to
Henry BriggsHenry Briggs was an English mathematician notable for changing Napier's logarithms into common/Briggesian logarithms.- Personal life :...
, his friend and colleague, the use of the arithmetical complement (see Briggs
Arithmetica Logarithmica, cap. xv.). His practical inventions are briefly noticed below:
Gunter's chain
Gunter's interest in geometry led him to develop a method of sea surveying using triangulation. Linear measurements could be taken between topographical features such as corners of a field, and using triangulation the field or other area could be plotted on a plane, and its area calculated. A chain long, with intermediate measurements indicated, was habitually used for the purpose, and is called
Gunter's chainGunter's chain is a measuring device used for land survey. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter long before the development of the theodolite and other more sophisticated equipment, enabling plots of land to be accurately surveyed and plotted,...
.
The length of the chain normally used led to the linear measurement of being called a
chainA chain is a unit of length; it measures 66 feet or 22 yards or 4 rods or 100 links . There are 10 chains in a furlong, and 80 chains in one statute mile. An acre is the area of 10 square chains...
.
Gunter's quadrant
An instrument made of wood, brass or other substance, containing a kind of stereographic projection of the sphere on the plane of the equinoctial, the eye being supposed to be placed in one of the poles, so that the tropic, ecliptic, and horizon form the arcs of circles, but the hour circles are other curves, drawn by means of several altitudes of the sun for some particular latitude every year. This instrument is used to find the hour of the day, the sun's
azimuthAn Azimuth is the angle from a reference vector in a reference plane to a second vector in the same plane, pointing toward, , something of interest. For example, with the sea as your reference plane, the azimuth of the Sun might be the angle between due North and the point on the horizon the Sun...
, etc., and other common problems of the sphere or globe, and also to take the altitude of an object in degrees.
Gunter's scale
Gunter's scale or Gunter's rule, generally called the "Gunter" by seamen, this is a large plane scale, usually long by about 1 1/2 inches broad (600 mm by 40 mm), and engraved with various scales, or lines. On one side are placed the natural lines (as the line of chords, the line of
sineMaurice Sinet, known as Siné is a French cartoonist.As a young man he studied drawing and graphic arts, while earning a living as a cabaret singer. After his military service he started publishing his drawings and also worked as a photo-retoucher for porn magazines. His first published drawing...
s, tangents, rhumbs, etc), and on the other side the corresponding artificial or logarithmic ones. By means of this instrument questions in
navigationNavigation is the process of reading, and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. The word navigate is derived from the Latin "navigare", meaning "to sail"...
,
trigonometryTrigonometry is a branch of mathematics that deals with triangles, particularly those plane triangles in which one angle has 90 degrees...
, etc., are solved with the aid of a pair of compasses. It is a predecessor of the slide rule, a calculating aid used from the 1600s until the 1970s.
Gunter's line, or
line of numbers refers to the logarithmically divided scale, like the most common scales used on slide rules for multiplication and division.