“In damaging your new aerial warship, or in getting certain parts of it so he could take them away with him.”

Tom gave a surprised whistle.

“A frenchman!” he exclaimed.  “Is he one of the—?”

“Yes, he’s one of the foreign spies,” interrupted Ransom.  “You’d find it out, anyhow, if we didn’t tell you.  They are after you, Tom Swift, and after your machines.  They had vowed to get them by fair means or foul, for some of the European governments are desperate.”

“But we were only tools in their hands.  So were Feldman and Harrison, but they knew more about the details.  We were only helping them.”

“Then we must try to capture them,” decided Tom.  “Ned, see if the chase had any results.  I’ll look after these chaps—­Koku and I.”

“Oh, we give in,” admitted Kurdy.  “We know when we’ve had enough,” and he rubbed his head gently where the giant had banged it against that of his fellow-conspirator.

“Do you mean that you four came into this shop, at midnight, to damage the Mars?” asked Tom.

“That’s about it, Mr. Swift,” replied Kurdy rather shamefacedly.  “We were to damage it beyond repair, set fire to the whole place, if need be, and, at the same time, take away certain vital parts.

“Harrison, Feldman, Ransom and I came in, thinking the coast was clear.  But Koku must have seen us enter, or he suspected we were here, for he came in after us, and the fight began.  We couldn’t stop him, and he did for us.  I’m rather glad of it, too, for I never liked the work.  It was only that they tempted me with a promise of big money.”

“Who tempted you?” demanded Tom.

“That Frenchman—­La Foy, he calls himself, and some other foreigners in your shops.”

“Are there foreigners here?” cried Tom.

“Bless my chest protector!” cried Mn Damon, who had come in and had been a silent listener to this.  “Can it be possible?”

“That’s the case,” went on Kurdy.  “A lot of the new men you took on are foreign spies from different European nations.  They are trying to learn all they can about your plans, Mr. Swift!”

“Are they friendly among themselves?” asked Tom.

“No; each one is trying to get ahead of the other.  So far the Frenchman seems to have had the best of it.  But to-night his plan failed.”

“Tell me more about it,” urged Tom.

“That’s about all we know,” spoke Ransom.  “We were only hired to do the rough work.  Those higher up didn’t appear.  Feldman was only a step above us.”

“Then my suspicions of him were justified,” thought Tom.  “He evidently met La Foy in the woods to make plans.  But Koku and Eradicate spoiled them.”

The two captives seemed willing enough to make a confession, but they did not know much.  As they said, they were merely tools, acting for others.  And events had happened just as they had said.

The four conspirators had managed, by means of a false key, and by disconnecting the burglar alarm, to enter the airship shed.  They were about to proceed with their work of destruction when Koku came on the scene.