"At nine o'clock every night, Greenwich time," said Wemmick, "the gun fires. There he is, you see! And when you hear him go, I think you'll say he's a Stinger."

Because navigation was so important to the British, many of their brightest people worked on the problem, because of such tragedies as Sir Cloudsley Shovel's loss of four ships and their crews, because of not being able to know their longitude. So now, if you look at a map, you will see that
time starts at a line through Greenwich, zero longitude.