“We must get him out at once!” declared Mr. Jenks.

“I knew something would happen on this voyage,” came from Mr. Parker.  “I predicted it from the first!”

Tom thought considerable, but he did not answer the scientist just then.  Another communication was coming to him by wireless.  He listened intently.

“Father says,” the lad told his companions “that Eradicate only had a glimpse of the man at the last moment.  He was looking from the rear storeroom window—­he’s the same man who called on me that time—­Rad remembers him very well.”

“Bless my shoes!  What’s to be done?” inquired Mr. Damon, looking around helplessly.

“We must get him out, that’s all,” decided Mr. Jenks; with vigor.  “Get him out and drop him overboard!”

“Drop him overboard!” cried Mr. Parker, in horror.

“Not exactly, but get rid of him,” proceeded the diamond seeker.  “That man is one of my enemies.  He has been sent by the band of diamond makers hidden among the mountains, to spy on me, and, if possible, prevent me from seeking to discover their secret.  He tried to work on Tom’s Swift’s fears, and frighten him from using his airship on this quest.  Then, when he failed, the man must have sneaked into the shed, and hidden himself in the ship.  We must get rid of him, or he may wreck the Red Cloud!”

“That’s so!” cried Tom.  “We must try to capture him.  I think we had better—­” the lad paused, and again listened to the wireless message.  “Father says Eradicate saw the man have a gun, so we must be careful,” the young inventor translated the dots and dashes.

“Bless my powder horn!” exploded Mr. Damon.

“We shall have to proceed cautiously then,” spoke Mr. Jenks.  “If he is like any others in the gang he is a desperate man.”

“Better sneak up on him then, if we can,” proposed Mr. Parker.  “There are enough of us to cope with one man, even if he is armed.  You have weapons aboard, haven’t you?” he inquired of Tom.

“Yes,” was the hesitating answer, “but I don’t want to use them if I can help it.  Not only because of the danger, and a dislike of shedding blood, but because a stray bullet might pierce the gas bag and damage the ship.”

“That’s so,” agreed Mr. Jenks.  “Well, I guess if we go at it the right way we can capture him without any shooting.  But we must talk more quietly—­we ought to have whispered—­he may have heard us.”

“I don’t think so,” replied Tom.  “The storeroom is far enough off so that he couldn’t hear us.  Besides, the motor makes such a racket that he couldn’t distinguish what we were talking about, even if he heard our voices.  So, unless he heard the wireless working, and suspects something from that, he probably doesn’t know that we are aware of his presence aboard.”

“But why do you think he has remained quiet all this while, Tom?” asked Mr. Damon.

“Probably he wants to wait until the ship is farther out west,” suggested Mr. Jenks.  “Then he will be nearer his friends, and can get help, if he needs it.”