Well, that's awfully poetic sounding. So what is the hour of the pearl? It's "the interval between day and night when time stops to examine itself" (14.1).
Uh-huh. We're still a little confused over here, so let's try again: "it is a time of great peace, a deserted time, a little era of rest" (14.1).
This is helping. It's a time when almost nobody's out on the street, and it's not so dark that you can't see anything, but also not so bright that everything looks the way it normally does during the day. Everything's gray, or pearly—and pearls are precious and rare, like this special time that only comes for a little while twice a day.
So, what happens during the hour of the pearl?
(1) the old Chinaman goes by
(2) the two girls and two soldiers leave the bar to sit on the beach
(3) Doc returns from his trip to La Jolla to find his lab destroyed.
Let's figure out what this connection is. The Chinaman is a symbol of loneliness, so it makes sense that he would appear when the streets are nearly empty. The girls and their dates seem to be taking a rest between a big night at the bar and whatever the bright day will bring (probably a hangover, and hopefully no unwanted pregnancies). And Doc's destroyed lab is silent (except for the wet sound of frogs hopping out the front door) until Doc comes back and has to face the mess.
So we can think of the hour of the pearl as a little break between the action of the night and the action of the day; it's the big transition point between Party 1.0 and Party 2.0. Another fun fact: Steinbeck apparently had a thing for pearls. Do you think there's any connection between the hour of the pearl and The Pearl?