Longitude

The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time

by Dava Sobel

John Harrison was his name. What he did was to build a clock that would keep accurate time. Before his time(!) the most accurate clocks would vary up to ten seconds a day depending upon the temperature and humidity. You need to to have a very accurate clock to sail the oceans blue (before GPS, of course.)

One of the main solutions was to make the movements out of brass and steel put together so that their varying reactions to heat and humidity would offset each other.

He also invented caged ball bearings.