"Who was the fourth man?" Tom repeated.
"Harrison," answered Kurdy, naming one of the most efficient of the new machinists Tom had hired during the rush.
"Harrison, who has been working on the motor?" cried the young inventor.
"Yes," said Ransom.
"I'm sorry to learn that," Tom went on in a low voice. "He was an expert in his line. But what was your object, anyhow, in attacking Koku?"
"We didn't intend to attack him," explained Ransom, "but he came in when we were at work, and as he went for us we tried to stand him off. Then your colored man heard the racket, and—well, I guess you know the rest."
"But I don't understand why you came into this shed at night," went on Tom. "No one is allowed in here. You had no right, and Koku knew that. What did you want?"
"Look here!" exclaimed Kurdy, "I said we'd make a clean breast of it, and we will. We're only a couple of tools, and we were foolish ever to go in with those fellows; or rather, in with that Frenchman, who promised us big money if we succeeded."
"Succeeded in what?" demanded the young inventor.
"In damaging your new aerial warship, or in getting certain parts of it so he could take them away with him."