“Yes, I know,” she replied quietly.
“Oh! You do? Then you tell me.” Even Riggs got a little peeved at times, when these lady sailors tried to tell him.
“All right, here goes. Every two minutes you give the call number of some ship in the convoy on the radio and then—”
“Then you—” he began.
“Who’s telling this?” she demanded.
“Okay, Sally, okay!” Riggs laughed in spite of himself.
“You give a toot on the ship’s whistle,” Sally continued. “At the same time you send out a radio impulse. The radio sound reaches the ship instantly. The sound of the whistle is slower. The signal man on that other boat notes the difference between the time of arrival of radio impulse and whistle. He does a little figuring, then he radios his approximate position in relation to your ship. After that you tell him to move so far this way and that. Then everything is hunky-dory until next time.” Sally caught her breath.
“Say, you know all the answers!” He laughed.
“Not all, but some of them,” she corrected. “You don’t have to be dumb all the time, even if you are a girl.”
“Guess that’s right. Well, now, go to it.” Riggs threw himself down on a long seat that ran the length of the room, and Sally took up her work.