Cambridge University Library and the National Maritime Museum have digitised the Board of Longitude archive. The archive will available online at https://cudl.lib.cam.ac.uk/collections/longitude from 18th July 2013.

The Board of Longitude sent astronomers on voyages of exploration to test methods of navigation and help make better maps.

This is the second film of the series and looks at some of the techniques they used to make maps and introduces the story of William Gooch, a young astronomer who met an untimely end.