Time

'til Harrison's chronometer came through
a sailor on the seas could only know
his latitude but not his longitude
or how much farther he might have to go
the moons of Jupiter can work on land
but they're too rarely glimpsed when one's at sea
the function of a watch's second-hand
is better served by Swiss horology
'til then, sea-routes were mostly laid due-West
to strike a landmark then trace down the coast
and even when one knew where winds were best
he dared not plot a course to get the most
a world with GPS can't realize
what Harrison produced to claim his prize