Gellibrand, Henry

(1597-1637), mathematician

by Gordon Goodwin, rev. H. K. Higton

© Oxford University Press 2004 All rights reserved

Gellibrand, Henry (1597-1637), mathematician, was born in the parish of St Botolph, Aldersgate, London, on 17 November 1597, the eldest son of Henry Gellibrand (d. 1615), fellow of All Souls College, Oxford, and of St Paul's Cray, Kent. He matriculated at Trinity College, Oxford, on 22 March 1616 and took the two degrees in arts, BA (on 25 November 1619) and MA (on 26 May 1623). He took holy orders, and had a curacy at Chiddingstone, Kent, but was led to devote himself entirely to mathematics by one of Sir Henry Savile's lectures. He settled at Oxford and became a friend of Henry Briggs, on whose recommendation he was chosen professor of astronomy at Gresham College in London on 2 January 1627. When Briggs died in 1630 he left his unfinished Trigonometria Britannica to Gellibrand who published the completed work in 1633.

Gellibrand held puritan meetings in his rooms, and encouraged his servant, William Beale, to publish an almanac for 1631, in which the Catholic saints were superseded by those in Foxe's book of martyrs. Laud, then bishop of London, brought them both into the high commission court. They were acquitted on the ground that similar almanacs had been printed before, and this prosecution was used against Laud at his own trial in 1643.

Gellibrand devoted much time to searching for a solution to the longitude problem. In 1631 he arranged an experiment with Captain Thomas James, who was leading an expedition in search of the north-west passage, to observe simultaneously the lunar eclipse due on 29 October. The time difference enabled him to establish the difference in longitude between Gresham College and Charlton Island in James Bay, Canada. An account was published as 'An appendix concerning longitude' in James's book The Strange and Dangerous Voyage of Captaine Thomas James (1633).

Gellibrand was also investigating the phenomenon of the magnetic variation of the compass, which led to his discovery of secular variation. Measurements of the magnetic variation taken at Deptford in 1634 were found to differ from those taken in 1622 by Edmund Gunter by more than two degrees. Later experiments showed the variation to have diminished still further. This discovery contradicted the categorical statement of William Gilbert in De magnete that the magnetic variation in a particular place was constant. Gellibrand published his findings in A discourse mathematical of the variation of the magneticall needle together with its admirable diminution lately discovered (1635).

In 1636 Gellibrand retired to Mayfield, Sussex. He died in London of a fever on 16 February 1637, and was buried in the church of St Peter-le-Poer, Broad Street, London. His main concern had been to improve methods of navigation and much of his work consisted of investigating the ways in which mathematics could help navigators to establish their position. His most popular work was his Epitome of Navigation, which was published posthumously in 1674 and appeared in several further editions. If not a particularly original thinker Gellibrand was nevertheless an able mathematician and textbook writer.

GORDON GOODWIN, rev. H. K. HIGTON

Sources  
E. G. R. Taylor, The mathematical practitioners of Tudor and Stuart England (1954)
DSB
Foster, Alum. Oxon.
J. Ward, The lives of the professors of Gresham College (1740)


© Oxford University Press 2004 All rights reserved

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