The Mathematics of the Longitude - Department of Mathematics

place. For that they would have needed a clock or a watch set to the home port
time. But pendulum clocks went haywire on the decks of rolling ships: they
slowed down, or sped up, or stopped running altogether.
Early attempts to find longitude, such as the Lunar eclipses method, the Jupiter's
moon eclipses method and the Lunar distances method were used at sea. But each
of these methods, which will be discussed in later chapters, has it own weakness
and was not practical at sea.
Astronomers tried to give mariners a way to tell time in two places at once by the
moon and stars. Indeed, the great observatories in Paris and London were founded
(in 1666 and 1674, respectively) not to conduct pure research in astronomy, but to
perfect the art of navigation.
None the less, as the 18 th century dawned no better method had come along and
the increasing toll of lost ships and lives was causing growing concern. In a
notorious accident in 1707, Royal Navy ships, believing themselves to be in
deeper water further east, were wrecked on the Scilly Isles with the loss of almost
2000 lives.
Finally in 1714, the British Government offered, by Act of Parliament, 20 000
pounds for a solution which could provide longitude to within half-a-degree (2
minutes of time). The methods would be tested on a ship, sailing over the ocean,
from Great Britain to any such Port in the West Indies as those Commissioners
choose without losing their longitude beyond the limits before mentioned and
should prove to be practicable and useful at sea.