Designed by John Harrison between 1735 and 1759.
Harrison's chronometer's resolved the problem of knowing a ships logitudinal position at sea thus making possible accurate sea travel and 'making the device a fundamental key to the modern age'.
Newton observed that “A good watch may serve to keep a reckoning at sea
for some days and to know the time of a celestial observation; and for
this end a good Jewel may suffice till a better sought of watch can be
found out. But when longitude at sea is lost, it cannot be found again
by any watch.”
http://gerald-massey.org.uk/smiles/c_industry_2.htm
http://en.wikipedia.org/wiki/John_Harrison
