Henry Gellibrand
Henry Gellibrand (born November 17, 1597 in Aldersgate, London , † February 16, 1637 there ) was an English astronomer .
After studying at Oxford , Gellibrand was a pastor in Chiddingstone, Kent. He later studied mathematics at Oxford, among others with Henry Savile , and in 1627 became professor of astronomy at Gresham College in London. After the death of Henry Briggs (1630), he published the 2nd volume of the Trigonometrica Britannica (later called Briggi's logarithm tables ).
From the simultaneous observation of a lunar eclipse on October 29, 1631 in Charlton Island , James Bay, Canada and in London agreed with Thomas James and the time difference between the occurrence of the event, Gellibrand was later able to determine the distance of the places where the observation was made was made. Gellibrand became famous for his discovery that the earth's magnetic field is not - as William Gilbert still believed - constant. One clue is that the declination of a compass needle changes over the course of decades. Gellibrand carried out carefully controlled measurements in London in 1634. He compared his measurement results with those of William Borough from 1580 and those of Edmund Gunter from 1622 and found that - at least in London - the declination had steadily decreased over the past decades (by about 7 degrees of arc ). From this, Gellibrand drew the - correct - conclusion that the declination (and thus the magnetism) is changeable all over the world (technical term: secular variation ; see also: pole shift ).
He reported on his results in 1635 under the title: “A discourse mathematical on the variation of the magnetic needle, together with its admirable diminution lately discovered” .
Gellibrand died at the age of 39 after a fever. Like his predecessor at Gresham College, Edmund Gunter, Gellibrand was buried in the London church of St. Peter le Poor, which was demolished at the end of the 19th century .
literature
- Gordon Goodwin: Gellibrand, Henry . In: Leslie Stephen (Ed.): Dictionary of National Biography . Volume 21: Garnett - Gloucester. , MacMillan & Co, Smith, Elder & Co., New York City / London 1890, pp. 117 - 118 (English, (year of death 1636)).
- Gordon Goodwin, rev. HK Higton: Gellibrand, Henry (1597-1637). In: Henry Colin Gray Matthew, Brian Harrison (Eds.): Oxford Dictionary of National Biography , from the earliest times to the year 2000 (ODNB). Oxford University Press, Oxford 2004, ISBN 0-19-861411-X , ( oxforddnb.com license required ), as of 2004 (year of death 1637).
Web links
- John J. O'Connor, Edmund F. Robertson : Henry Gellibrand. In: MacTutor History of Mathematics archive .
- Gellibrand, Henry , In: The Galileo Project , Rice-University, Houston, Texas (English)
- Dirk Lorenzen : The man with the wandering compass , broadcast on November 17, 2012 in the series Sternzeit des Deutschlandfunk
Individual evidence
- ↑ Edmund Gunter , In: David Singmaster: BSHM Gazetteer - LONDON People DG , The British Society for the History of Mathematics (English)
| personal data | |
|---|---|
| SURNAME | Gellibrand, Henry |
| BRIEF DESCRIPTION | English astronomer |
| DATE OF BIRTH | November 17, 1597 |
| PLACE OF BIRTH | Aldersgate, London |
| DATE OF DEATH | February 16, 1637 |
| Place of death | London |