1714

First - 1714 - The Longitude Prize is offered by the English Parliament

The great age of navigation started in the early 15th century, when Portugal's Prince Henry "the Navigator" began explorations into the Atlantic and south along Africa, using instruments such as the compass and cross-staff. One of its most visible success stories was the (European) discovery of the American continents. In the 200 years following, colonies were set up by any countries that could manage the voyages required, and ships regularly sailed between Europe and the Americas. 

Nonetheless, navigation tools were still rudimentary.  Identifying how far north or south of the equator a ship was could be done by measuring how far above the horizon an astronomical object was. At the North Pole, for example, the North Star should be directly overhead. As one sails south, it would dip further and further down, until at the equator it would be at the horizon. In practice, measuring how the sun changed was used for this straightforward calculation. It had long been possible to make this determination, allowing ships at sea to easily determine their latitude.  However determining longitude - how far east or west had been sailed - was not nearly as simple. There was no effective method to do it accurately and effectively. 

The lack of a method was seen as a definite problem when four British warships were lost in 1707 near the isles of Scilly. The loss of 1400 lives off the southwest coast of Great Britain, because the sailors were uncertain about the location of their ships, led to concern about how to prevent it from happening again. (That the problem may have been in calculating latitude, not longitude, didn't change the perception of the issue.) There had been many proposals for how best to do so, many of which used astronomical observations, as latitude calculations did. Any of them might be useful, with enough additional work spent to refine them. How could the optimal plan be identified?

In 1714, the method chosen was the Longitude Prize, which was created upon the passage of the Longitude Act. The goal of the prize was to find an effective method for measuring longitude. The smallest price, for £10,000 pounds sterling, required accurate measurements within only 60 nautical miles; the largest would need to be twice as accurate, within 30 nautical miles. The prize was eventually awarded to John Harrison, who approached the problem as one of timekeeping rather than observation. He showed that a sufficiently accurate timepiece (chronometer) could be manufactured, yielding a consistent fixed time that could be compared to a ship's time based on local noon (i.e. when the sun was highest in the sky). The difference in time could be converted to distance from the locale represented by the chronometer. 

The prizes - the equivalent of millions of dollars today - were a significant investment not only in keeping ships safe, but also in allowing them to move quickly to their destinations. This made additional exploration possible and also improved the ability of Britain to trade with her colonies.