Henry Gellibrand (1597–1637) was an

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

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, structure, space, models, and change. History On ...

. He is known for his work on the

Earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic f ...

. He discovered that

magnetic declination Magnetic declination, or magnetic variation, is the angle on the horizontal plane between magnetic north (the direction the north end of a magnetized compass needle points, corresponding to the direction of the Earth's magnetic field lines) and ...

– the angle of dip of a

compass needle A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...

– is not constant but changes over time. He announced this in 1635, relying on previous observations by others, which had not yet been correctly interpreted. He was the son of the physician Henry Gellibrand (1568–1615) and Mary Faversham. His four younger brothers were John, Edward, Thomas and Samuel. Samuel Gellibrand became a prominent seventeenth-century London

bookseller Bookselling is the commercial trading of books which is the retail and distribution end of the publishing process. People who engage in bookselling are called booksellers, bookdealers, bookpeople, bookmen, or bookwomen. The founding of librari ...

.Henry Plomer (1907) A Dictionary of the Booksellers and Printers who Were at Work in England, Scotland and Ireland from 1641 to 1667 He also devised a method for measuring

longitude Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...

, based on

eclipse An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ce ...

s. The mathematical tables of

Henry Briggs Henry Briggs may refer to: *Henry Briggs (mathematician) (1561–1630), English mathematician *Henry Perronet Briggs (1793–1844), English painter *Henry George Briggs (1824–1872), English merchant, traveller, and orientalist *Henry Shaw Briggs ...

, consisting of

logarithm In mathematics, the logarithm is the inverse function to exponentiation. That means the logarithm of a number to the base is the exponent to which must be raised, to produce . For example, since , the ''logarithm base'' 10 o ...

s of

trigonometric function In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all ...

s, were published by Gellibrand in 1633 as ''Trigonometria Britannica''. He was Professor at

Gresham College Gresham College is an institution of higher learning located at Barnard's Inn Hall off Holborn in Central London, England. It does not enroll students or award degrees. It was founded in 1596 under the will of Sir Thomas Gresham, and hosts ove ...

, succeeding

Edmund Gunter Edmund Gunter (158110 December 1626), was an English clergyman, mathematician, geometer and astronomer of Welsh descent. He is best remembered for his mathematical contributions which include the invention of the Gunter's chain, the Gunter's q ...

in 1626. He was buried in

St Peter le Poer St Peter le Poer was a parish church on the west side of Broad Street in the City of London. Of medieval origin, it was rebuilt in 1540, and again in 1792 to a design by Jesse Gibson with a circular nave. It was demolished in 1907. Early histor ...

, a London church that was demolished in 1907.

References

* * {{DEFAULTSORT:Gellibrand, Henry 1597 births 1637 deaths English geophysicists 17th-century English mathematicians

See also

References