Kelly Prime

A test test.

Not to the West Indies, but to Lisbon.

In fact, when the HMS Orford was on its way back to Britain, the ship's sailing master had them on course to pass a landmark just south of Dartmouth.

But Harrison, using H-1, sounded the alarm.

He was able to pinpoint the ship's location as 60 miles off course to the west.

So with the blessing of the Royal Society, all eight members of the official Board of Longitude assembled to hear about the successful Portugal trial and to judge Harrison's sea clock.

He didn't want that big trial?

Harrison was so obsessed with getting his invention precisely, exactly, perfectly right that he showed up in a room full of people practically begging to give him a big pile of money, and he pointed out the problems with his own design.

He was apparently the only person in the room to say anything negative about his work.

All this time, John Harrison had been tinkering and tinkering, making prototypes with changes big and small to the same basic formula as H1.

But then, in the mid-1750s, Harrison just happened to get a new pocket watch.

But this watch, which used some of Harrison's improvements, was extremely accurate.

It took him four years to complete his sea watch, H4.

H4 was five inches in diameter and it weighed just three pounds.

So compared to the carry-on luggage of H1, it could fit in a free personal item.

Looking at H4 and the Royal Observatory, I was struck by just how different it looks from any of Harrison's earlier sea clocks.

If the other ones look pretty steampunk, this looks just like so ornate and beautiful and delicate.

Like, how would you describe that?

There's all this like curving filigree, these blue iridescent dots.

There's like rubies and diamonds in there, right?