Made by Jesse Ramsden in London in 1775, this "dividing engine" was the first device that could consistently make octants and sextants accurate enough to be used with chronometers for determining longitude at sea. This advance was essential for improvements in sea navigation, and Ramsden was awarded a portion of the British Board of Longitude Prize. Join presenters from the National Air and Space Museum and National Museum of American History to learn about the importance of the Ramsden Dividing Engine and its journey to the Smithsonian.
Meet at the Museum "Great Seal", in the Boeing Milestones of Flight Hall on the first floor.
About the Ask an Expert lecture series: Every Wednesday at noon in the National Mall Building, a Museum staff member talks to the public about the history, collection, or personalities related to a specific artifact or exhibition in the Museum.
Dividing engine, made by Jesse Ramsden, London, 1775. This machine permitted the automatic and highly accurate division of a circle into degrees and fractions of degrees of arc. Invented by Englishman Jesse Ramsden in the 1770s, the machine ultimately led to mass production of precision octants and sextants and gave British manufacturers dominance in the field of marine instruments for decades.
Ramsden's invention was so valuable to the nation's maritime interests that he received a share of the Longitude Prize.