Longitude

In the early years of the eighteenth century, a British fleet foundered on the rocks off of the Scilly Isles due to a navigational error. The problem was an incorrect estimation of longitude, something that had yet to be perfected. As a result, Parliament announced they would award a sum of twenty thousand pounds sterling to anyone who could develop an accurate method of determining longitude. John Harrison (Sir Michael Gambon), a carpenter by trade and amateur clockmaker, decides to try and solve the issue by building an accurate maritime clock. Over many years, Harrison perfected timepieces that would accurately give time at a known location, such as Greenwich, which could then be compared against local time (by measuring the position of the sun in the sky). The time difference could then be converted to degrees of longitude which, combined with the already existing method of calculating latitude, would give the ship's exact location. Harrison's timepieces were a marvel of the age, but it took several experiments and a great many years before his accomplishment was recognized and the cash prize awarded. Interspersed with Harrison's story is that of Rupert Gould (Jeremy Irons), who, just after World War I, located some of Harrison's original timepieces and tried to restore them to working order.