9 JOHN HARRISON’S MARINE CHRONOMETER

Invented in 1761, this device very literally changed the world. Developed over three decades by clockmaker John Harrison, the marine chronometer allowed seafarers—for the first time—to accurately gauge the hour at a reference point during long periods navigating the oceans, facilitating the accurate celestial calculation of longitude (which previously had been a matter of perilous guesswork, as earlier clocks were drastically affected by the conditions at sea). Harrison’s creation made the exploration of the farthest corners of the earth possible; without it, the British Empire may never have risen to such heights, and the country of Australia (as we know it) might not exist.