The fascinating story of John Harrison who, in the 18th century, believed he could make a clock that would work on board a ship—and so solve the problem of finding longitude at sea.

The fascinating story of John Harrison who, in the 18th century, believed he could make a clock that would work on board a ship—and so solve the problem of finding longitude at sea.

Parallel stories: 18th century Harrison builds the marine chronometer for safe navigation at sea; 20th century Gould is obsessed with restoring it.