"Then I want you to keep his description in mind," continued Tom. "Keep your eyes open, at all times, for any chance glimpse of him. The man who brings me information leading to the capture of that big negro will receive a reward of one hundred dollars in gold." "Keep your eyes open, won't you? You may find him prowling around the wall at any time. He may walk out on the wall, or he may be found hiding near in a boat. Watch for him." All promised eagerly that they would do all in their power to earn the hundred dollars. "That's what I call good business!" cried Mr. Prenter approvingly, as soon as the foreman and the men had gone. "Does the hundred dollars come out of the company treasury, Reade, or from your own pocket?" inquired President Bascomb. "Really I hadn't thought of the matter," answered Tom. "The company can afford to pay its own bills," broke in Mr. Prenter, rather gruffly. "It's about time to turn in, isn't it?" asked Mr. Bascomb, striking a match and glancing at his watch. "I'm going to stay up a little longer, and talk with Reade about the dread mystery of our million dollar breakwater, if he'll let me," hinted Mr. Prenter. Mr. Bascomb rose as though to go into the house. "While we're talking about the matter, sir," suggested Tom, "wouldn't it be a good idea for us to stroll down to the beach and look out along the wall to see how Foreman Corbett and his gang are guarding the breakwater to-night?" "Fine idea," nodded the treasurer of the company. "Then, if you're all going away, and intend to leave the house alone, I think I may as well go with you," grunted Mr. Bascomb. "I don't exactly like the idea of staying here alone in such troublesome times." Harry walked beside Mr. Bascomb, while Tom led the way with the treasurer. Mr. Renshaw brought up the rear. As the party came in sight of the beach and glanced out seaward, they saw many a little, dancing light out on the retaining wall. Each light showed where a workman patrolled under the orders of Foreman Corbett. The latter was aboard the motor boat, "Morton," which ran up and down near the wall, throwing the searchlight over the scene. "Reade," remarked Mr. Prenter, "I don't see that the enemy have any chance to-night to run in and work harm to our property." Hardly had the treasurer spoken when Tom, looking out seaward, saw a sudden, bright flash of light upward. There was a brief pause---then the sullen boom of an explosion reached their ears. "Mystery of all mysteries!" choked Tom Reade. "There goes another section of the wall---blown up under our very eyes!" CHAPTER XI A MESSAGE FROM A COWARD "Now Reade," began President Bascomb, in a shaking voice, "what can you say---" Tom didn't wait to inform him. The young chief engineer was darting out on the wall as fast as he could go.