Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The Quest to Measure Longitude

Dava Sobel
Science Journalist and Author

marine timekeeper H1
Credit: Image provided by Dava Sobel
Throughout the great ages of exploration and sail, from the end of the fifteenth century to the end of the eighteenth, navigators lost track of their longitude almost the moment they lost sight of land. Although they understood, in theory, how to assess their progress east or west, they owned no practical method for determining a ship's position at sea. Warfare and commerce were hamstrung by that lack, and governments offered princely sums to spur invention. Some of the greatest names in the history of science, including Galileo, Huygens, and Newton, worked on the longitude problem without success--until an unknown, self-educated clockmaker from the north of England offered his singularly accurate timekeeper as the unlikely solution.

Dava Sobel is an award winning author. Her best-selling books, "Longitude" and "Galileo's Daughter," will be available for review and purchase before and after the lecture.

Anyone outside NIST wishing to attend must be sponsored by a NIST employee and receive a visitor badge. For more information, call Kum J. Ham at 301-975-4203.

Colloquia are videotaped and available in the NIST Research Library.






Created October 23, 2009, Updated November 15, 2019