To obtain the ship's latitude with comparatively good results was an
easy matter with the quadrant and its fore-runners, but the great
problem for centuries was how to find the longitude, now universally
and quickly obtained by the chronometer and simple observations in
the morning or at noon. Spring clocks and watches appeared about 1530
but they were unreliable and of no use on long voyages. Sand glasses
like those of the old Colonial churches were used on ships and so
conservative is the British mind that some were in use on British naval
vessels as late as 1828 and one authority states as late as 1839.
Greenwich Observatory was established in 1675 and a Royal Commission
was soon appointed with authority to award prizes for important
inventions in aid of navigation. A prize of L20,000 was finally
offered for a time-keeper that should meet certain requirements which
practically meant absolute accuracy. In 1767, John Harrison produced
the chronometer, based on the principle of an invention of 1735, and
eventually he received the reward. Chronometers were so expensive and
so hard to obtain that few New England ships had them until more than a
half a century later. Other devices were tried to obtain longitude by
lunar observations and by Jupiter's satellites, but these observations
were too difficult to be of practical use. Today, fine watches serve
for short trips and chronometers are carried by nearly all vessels
making long voyages.