Background
Henry Gellibrand was born on November 17, 1597, in London, United Kingdom. He was the son of a graduate of All Souls College, Oxford.
United Kingdom
Henry Gellibrand
Trinity College, Broad St, Oxford OX1 3BH, United Kingdom
Henry became a commoner of Trinity College, Oxford, in 1615, a few weeks after his father’s death. He received a Bachelor of Arts in 1619 and a Master of Arts in 1623.
United Kingdom
Henry Gellibrand
Trinity College, Broad St, Oxford OX1 3BH, United Kingdom
Henry became a commoner of Trinity College, Oxford, in 1615, a few weeks after his father’s death. He received a Bachelor of Arts in 1619 and a Master of Arts in 1623.
https://www.amazon.com/Discourse-Mathematical-Variation-Magneticall-Needle/dp/B00CIFTC68/?tag=2022091-20
1635
https://www.amazon.com/EPITOME-NAVIGATION-HENRY-GELLIBRAND-author/dp/1385560061
1674
Astronomer educator mathematician scientist
Henry Gellibrand was born on November 17, 1597, in London, United Kingdom. He was the son of a graduate of All Souls College, Oxford.
Henry became a commoner of Trinity College, Oxford, in 1615, a few weeks after his father’s death. He received a Bachelor of Arts in 1619 and a Master of Arts in 1623.
After graduating, Henry took holy orders and he held a curacy at Chiddingstone, Kent. When the professorship of astronomy at Gresham College, London, was vacated following the death of Edmund Gunter, Gellibrand was elected to the chair on 21 January 1627. He completed the second volume of his sponsor Henry Briggs’s Trigonometria Britannica and saw it through the press in 1633.
Gellibrand’s most widely appreciated scientific discovery, which he should share with John Marr, was that of the secular change in the magnetic variation. It was announced, without much comment, in A Discourse Mathematical on the Variation of the Magneticall Needle, Together With Its Admirable Diminution Lately Discovered. His predecessor, Gunter, had noticed that the variation at Limehouse in 1622 differed from the value found by William Borough in 1580, but he ascribed the difference to an error on Borough’s part. In 1633 some rough observations of his own and John Marr’s convinced Gellibrand that the value was now even less, but not until 1634 was he sufficiently confident to make a categorical assertion of its secular change. As his main evidence, he referred to an appendix to Edward Wright’s Certaine Errors in Navigation. This contains a compendium of recorded values of variation at various places made by a number of physicists and navigators the world over.
Gellibrand’s position at Gresham College drew him into matters of mathematical navigation, and an example of his attempts at solving the problem of longitude is a three-page appendix to The Strange and Dangerous Voyage of Captain Thomas James.
The essentially practical quality of Gellibrand’s work, which is of very slight mathematical interest, may also be judged from four works: his Treatise of Building of Ships; a longer Latin work translated by John Newton, An Institution Trigonometrical with the Application to Questions of Astronomy and Navigation; and An Epitome of Navigation. This last and posthumous book contains a number of logarithmic tables, including trigonometrical ones, and has an appendix on the use of the cross-staff, quadrant, and nocturnal in navigation.
Henry Gellibrand was an eminent mathematician and astronomer, who was a reasonably good calculator and a competent writer of textbooks which helped to raise English standards of navigation to new heights. He is known for his work on the Earth's magnetic field. He also devised a method for measuring longitude, based on eclipses.
