“But you don’t know where he is, Tom.”

“I’ll find out.  He isn’t such an easy man to miss—­he’s too conspicuous.  Besides, if he’s just left in his auto we may catch him before he gets to Shopton.”

“Do you think he’s going there?”

“I think so.  And I think, Ned, that he’s become suspicious and will light out.  Something must have happened, while he was telephoning, and he got frightened, as big a bluff as he is.  But we’ll get him.  Come on!  Will you turn over the propellers, please?  I’ll show you how to do it,” Tom went on to a big, strong man standing close to the blades.

“Sure I’ll do it,” was the answer.  “I was a helper once at an airship meet, and I know how.”

“Get back out of the way in time,” the young inventor warned him.  “They start very suddenly, sometimes.”

“All right, friend, I’ll watch out,” was the reply, and with Tom and Ned in their seats, the former at the steering wheel, the craft of the air was soon throbbing and trembling under the first turn, for the cylinders were still warm from the run from Mrs. Damon’s house.

The telephone was in an outlying section of Waterford—­a section devoted in the main to shops and factories, and the homes of those employed in various lines of manufacture.  Peters had chosen his place well, for there were many roads leading to and from this section, and he could easily make his escape.

“But we’ll get after him,” thought Tom, grimly, as he let the airship run down the straight road a short distance on the bicycle wheels, to give it momentum enough so that it would rise.

Then, with the tilting of the elevation rudder, the craft rose gracefully, amid admiring cheers from the crowd.  Tom did not go up very far, as he wanted to hover near the ground, to pick out the speeding auto containing Peters.

But this time luck was not with Tom.  He and Ned did sight a number of cars speeding along the highway toward Shopton, but when they got near enough to observe the occupants they were disappointed not to behold the man they sought.  Tom circled about for some time, but it was of no use, and then he headed his craft back toward Waterford.

“Where are you going?” asked Ned, yelling the words into the ear of his chum.

“Back to Mrs. Damon’s,” answered Tom, in equally loud tones.

It was impossible to talk above the roaring and throbbing of the motor, so the two lads kept silent until the airship had landed near Mrs. Damon’s home.

“I want to see if Mrs. Damon is all right,” Tom explained, as he jumped from the still moving machine.  “Then we’ll go to Shopton, and cause Peters’s arrest.  I can make a charge against him now, and the evidence of the photo telephone will convict him, I’m sure.  And I also want to see if Mrs. Damon has had any other word.”

She had not, however, though she was more nervous and worried than ever.

“Oh, Tom, what shall I do?” she exclaimed.  “I am so frightened!  What do you suppose they will do to Mr. Damon?”