“I don’t believe in destroying anything that is useful,” Reade answered, shaking his head.  “Besides, we are going to capture Sambo yet, and then we shall want that magneto for evidence.”

“What are you going to do to find Nicolas?” Corbett wanted to know.

“I wish I had even an idea,” Tom sighed.  “Corbett, I wish you would hurry over to Blixton and rout out the police.  I’ve an idea that Sambo may have a hiding place in the town.  Nicolas, too, may have been taken that way.  I’ll sit down and write out a good description of the rascal.”

This Reade did, handing the paper to the foreman.

“Who’ll take charge here?  Corbett asked.

“I will, until you get back, but hurry.”

As soon as the foreman had gone Tom stepped into the motor boat, taking the wheel.

“Tune up the engine, Conlon,” Reade directed the engine tender.  “I’m going to take a run around to the west side of the wall.  I’m going to try to find the tubes of high explosive that I’m satisfied were planted in the wall.”

“That’s a fine job for a dark night, sir,” grumbled Conlon.  “Suppose we run into the bombs, and they prove to be contact exploders, too?”

“That’s one of the risks of the business,” Tom retorted grimly.

Before the motor boat had gone far Tom called one of the men aboard to take the wheel.  Then the young chief engineer began to experiment with the searchlight.

“What’s the idea, sir?” asked Conlon, looking on.

“I want to depress the light, so that we can use it to look down into the water.”

“And try to find the bombs?”

“Exactly,” Reade nodded.

“Lucky if we don’t find the bombs with the keel of the boat,” observed Conlon.

Tom succeeded in rigging the light so that he could use it.  By the time that the boat was around at the west side of the retaining wall Tom ordered the boat in close alongside.  Then, with the depressed searchlight he discovered that he could see the sides of the wall to a depth of some eight feet under the surface.

“That may be enough for our needs,” Reade murmured.  “Now, run the boat along, slowly and close.  I want to scan every bit of the wall.”

Less than five minutes later Tom Reade, one hand controlling the searchlight and peering steadily into the water, sang out: 

“Stop!  Back her—–­slowly.  There, come back five feet.  So!  Hold her steady!”

As the engine stopped Conlon stepped forward, kneeling by Reade’s side.

“There are the bombs, man!” cried Tom exultantly.  “See them—–­the two upper ones?”

“I see something that gleams,” admitted Conlon.

“Well, we’ll have them up and aboard in a hurry.  Then you’ll see just what they are.”

“You’re not going to try to raise the things with the boathook, are you?” queried the engine tender, a look of alarm in his eyes.