Alexander Dalrymple

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Alexander Dalrymple (July 24, 1737 – June 19, 1808) was a Scottish geographer and the first Hydrographer of the British Admiralty. He was the main proponent of the theory that there existed a vast undiscovered continent in the South Pacific, Terra Australis Incognita. He produced thousands of nautical charts mapping a remarkable number of seas and oceans for the first time and contributing significantly to the safety of shipping. His theories prompted a number of expeditions in search of this mythical land, until James Cook demonstrated its non-existence on his second voyage in 1772–1775.

Dalrymple was born at New Hailes, near Edinburgh, the seventh of sixteen children of Sir James Dalrymple and his wife the daughter of the Earl of Haddington. He went to London in 1752 and was appointed a writer in the British East India Company, being first posted to Madras. While with the EIC he became interested in the possibilities of trade with the East Indies and China and subsequently negotiated a treaty with the sultan of Sulu and visited Canton at the age of only 22. In 1765 he returned to London where was elected a fellow of the Royal Society. There he became acquainted with John Smeaton, who during the course of his studies on windmills had devised a descriptive scale for grading wind speed. This scale was included in the paper for which he was awarded the Copley Medal. In Defining the Wind: The Beaufort Scale and How a 19th-Century Admiral Turned Science into Poetry author Scott Huler relates that Dalrymple's voyages had convinced him that a standard scale for measuring the speed of wind at sea would be of great value to sailors, and that he had included Smeaton's scale in his work Practical Navigation, which was written around 1790 but never published. It is believed that Dalrymple conveyed this information to Francis Beaufort who later refined the wind scale that bears his name and that is still in use today.

Whilst translating some Spanish documents captured in the Philippines in 1752 Dalrymple had found Luis Váez de Torres testimony proving a passage south of New Guinea now known as Torres Strait. This discovery led Dalrymple to publish the Historical Collection of the Several Voyages and Discoveries in the South Pacific Ocean in 1770-1771 which aroused widespread interest in his claim of the existence of an unknown continent. This led Captain Cook to undertake another voyage into the South Pacific. He was bitterly disappointed that it was Captain Cook and not him who was appointed commander of the expedition which eventually led in 1770 to the British discovery and charting of the Eastern coastline of Australia.

In 1782 he was elected a foreign member of the Royal Swedish Academy of Sciences.

See also

  • Royal Society -- Dalrymple was elected to membership in the Society in 1771; and his nomination letter has been posted with other membership records at the Royal Society web site -- here. Those signing that nomination letter were: Benjamin Franklin, Richard Hazard, John Colebrooke, John Pringle, Daniel Wray, Charles Morton, James Burrow, William Hunter, Nevil Maskelyne.


  • Australian Dictionary of Biography. Vol.1 :1788-1850. 1966 Melbourne University Press.
  • Dalrymple, Alexander (ca. 1790). Practical Navigation. Printer's proof. National Library of Scotland, shelfmark Nha.M90 (3)
  • Friendly, Alfred. Beaufort of the Admiralty. New York. Random House, 1977
  • Huler, Scott (2004). Defining the Wind: The Beaufort Scale, and How a 19th-Century Admiral Turned Science into Poetry. Crown. ISBN 978-1400048847

Royal Society