"I believe I've got it!" he cried. "Listen and see if this doesn't sound reasonable!"
"Go ahead!" said Jack and Dick, eagerly.
"Here it is," said Harry. "'Petrol just arranged. Supply on way. Reach Bray Friday. Von Wedel may come. Red light markers arranged. Ealing Houndsditch Buckingham Admiralty War Office. Closing.'"
They stared at him, mystified.
"I suppose it does make sense," said Dick. "But what on earth does it mean, Harry?"
"Oh, can't you see?" cried Harry. "Von Wedel is a commander of some sort–that's plain, isn't it? And he's to carry out a raid, destroying or attacking the places that are mentioned! How can he do that? He can't be a naval commander. He can't be going to lead troops, because we know they can't land. Then how can he get here? And why should he need petrol?"
They stared at him blankly. Then, suddenly, Dick understood.
"He'll come through the air!" he cried.
"Yes, in one of their big Zeppelins!" said Harry. "I suppose she has been cruising off the coast. She's served as a wireless relay station, too. The plant here at Bray Park could reach her, and she could relay the messages on across the North Sea, to Heligoland or Wilhelmshaven. She's waited until everything was ready."
"That's what they mean by the red light markers, then?"