"Is that why you gave it to him?" asked Charlie.
"The very reason. As soon as he asked for a light it occurred to me that he wanted to use it—or might use it—to give a signal at night to some watching submarine commander waiting for a chance to torpedo us. I thought if I let him do it with this failing light he might do the Huns more damage than he could us."
"How?" asked Joe.
"By not being able to give the proper signals. He'll need to flash a light for some little time to make sure to attract the attention of the submarine, won't he?"
"Probably," agreed Joe.
"Well, then, if, while he's in the midst of signaling, his light goes out, the submarine won't know what to make of it, and will come up closer to find out what's wrong. Then our own guns, or those of the destroyers, can bang away and catch the Germans napping."
"Say, that's great!" cried Charlie, as soon as he understood the plan Blake had so quickly evolved.
"If it works," conceded Joe. "But how are we going to know when that German spy signals the submarine and fails to convey his full meaning, Blake?"
"We'll have to watch him, of course. Catch him in the act, as it were. The defective lamp will help."
"So it will!" exclaimed Joe. "Blake, I take back all I thought of you. I imagined you were making a mistake to let that lamp go out of your possession; but now I see your game. It's a good one! But we've got to be on the watch for this spy!"