Prior to John Harrison's invention of the longitudinal clock, it was very hard to navigate the seas and many were lost. The seafarer would hold a quadrant up to his eye and navigate via the stars. This method was full of gaps and lapses due to the inherent movement of the navigator's own body with the roll and pitch of the ship. It took John Harrison most of his life to perfect his clock and keep time precisely. He invented the grasshopper escapement which gives the clock its tick-tock. Can you imagine all the tyranny that has resulted from this tick-tock.