John Harrison was a self-educated English carpenter and clockmaker who invented the marine chronometer, a long-sought after device for solving the "longitude problem" - a practical method of calculating longitude while at sea. His solution revolutionized navigation and greatly increased the safety of long-distance sea travel. Wikipedia*
On the C-SPAN Networks:
John Harrison has two videos in the C-SPAN Video Library; the first appearance was a 1992 Senate Committee. The year with the highest average number of views per program was 2012 with an average of 318 views per program.