Person: Hadley, John
John Hadley was an English instrument maker who improved the Gregorian reflecting telescope and invented the quadrant for navigation.
Mathematical Profile (Excerpt):
- George Hadley became high sheriff of Hertfordshire when John was nine years old.
- John was five years older than Henry and three years older than George.
- Hadley was elected a fellow of the Royal Society on 21 March 1717 and he attained high office in the Society when he was elected Vice President on 12 February 1728.
- We have indicated above that Hadley had a financial position which enabled him to devote both time and money to science.
- This motivated Hadley to tackle the problem and in 1730 he invented the reflecting octant which measured the altitude of the sun or of a star.
- In 1731 Hadley showed his new quadrant to theRoyal Society and published a description in his paper Description of a new instrument for taking angles which appeared in the Philosophical Transactions of the Royal Society.
- Hadley published A description of a new instrument for taking the latitude or other altitude at sea (1734).
Born 16 April 1682, Bloomsbury, London, England. Died 14 February 1744, East Barnet, Hertfordshire, England.
View full biography at MacTutor
Tags relevant for this person:
Astronomy, Geography, Origin England
Thank you to the contributors under CC BY-SA 4.0! 
- Github:
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- non-Github:
- @J-J-O'Connor
- @E-F-Robertson
References
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive
