Thomas Earnshaw is a man who lived a long time ago and is famous for making really fancy watches called chronometers. These watches helped sailors know exactly where they were on the ocean by using a special kind of clock that tells time really accurately.
Before Thomas Earnshaw came around, people didn't have very good watches and it was very hard for sailors to know where they were because the stars and the sun would move across the sky and make it hard to tell time. But Thomas Earnshaw figured out a way to make watches that were really good at keeping time even when they were moving around a lot on a boat.
Thomas Earnshaw worked really hard to make his watches as accurate as possible by using special mechanisms that would keep the watch ticking at the same speed even if it was bumped around a lot. This made his watches very popular with sailors and helped them navigate the ocean with more confidence.
Even though Thomas Earnshaw lived a long time ago, his watches are still famous today and are collectors' items that people keep in museums or in their homes. So if you ever hear someone talking about Thomas Earnshaw, you'll know that he was a smart man who made really fancy watches that helped sailors find their way on the ocean.