“That’s all.” He stood up. “Spies strike in the dark—and without warning. I wonder what we have ahead of us!”
CHAPTER XIV
AN IMPORTANT DISCOVERY
That night as he tramped the deck on his silent watch, Johnny found his mind crowded with disturbing thoughts of the significant message the green arrow had flashed over the sea.
“We will strike—” his mind went over the words again and again, “at the earliest possible moment!” Where would they strike? And who was to receive the blow? His shipmates on the Sea Nymph? Old Kennedy and his daughter? Or someone he never had seen?
“I may never know,” he told himself. “Spies strike in the dark.”
Johnny had read that during the World War, spies had swum to the propellers of outgoing ships laden with men and supplies. Hours later, with the ship far out at sea, a bomb had exploded, blowing away the propeller and leaving the ship helpless. He knew, too, that spies had placed incendiary bombs in the holds of ships, and dumped quantities of acid in the very bottom of a vessel, to eat its way through the steel.
“Yes,” he thought, “and even now—in times of supposed peace—they are boring in!”
* * * * * * * *
The Sea Nymph left the river and put out to sea while Johnny slept. When he awoke in mid-afternoon, they were anchored in their old position.
“How would you like to make a solo journey in the steel ball?” Dave asked when he came on deck.