The Dartaway had a powerful motor, and once on the right trail the eldest Rover advanced his gasoline and spark, and they went rushing through the air at express-train speed.  The boys were provided with face guards, so they did not mind this.  They did not fly high, and so kept the railroad and other familiar objects fairly well in view.  They passed over several villages, the inhabitants gazing up at them in open-mouthed wonder, and finally came in sight of a big church spire that they knew belonged in Plankville.  Then Dick slowed down the engine, and soon they floated down in an open field close to the main street and not a great distance from the sheriff’s office and the jail.

“Well, it certainly didn’t take long to get here,” cried Tom, as he consulted his watch.

A man who lived close by was approaching and he readily agreed, for a small amount, to guard the biplane.

“Have they caught those men who escaped from the jail?” asked Sam, of the man.

“Got two on ’em,” was the reply.  “Dacker and Penfield.”

“What of Crabtree?” asked Dick.

“Nuthin’ doin’, up to an hour ago.  The sheriff is out with about ten men, lookin’ fer him.”

“Then there is no use of our going to the sherif’s office,” said Dick to his brothers “We’ll go right to the jail.”

“Will they let us in?” asked Sam.

“In the office, yes.  We won’t want to go to the cells,” answered Dick, with a short laugh.

When they reached the office of the jail they found several men present, including the head keeper and one of the State detectives.  The keeper had seen the Rover boys at the time of the capture of Crabtree and the others and he smiled a little as he shook hands.

“Bad business,” he said, in answer to a question Dick put.  “But I can’t exactly blame my men for what happened.”

“Weren’t you here at the time?” asked Tom.

“No, I was out of town—­ calling on my mother, who is very old and quite sick.  There was a fire in the pantry off the kitchen, and for a few minutes it looked as if the old jail would burn to the ground.  Of course the guards got excited, and all they thought of was to put out the blaze—­ and it’s a good thing they did that.  That’s how the prisoners got away.  I suppose you’ve heard that we rounded up two of them.”

“Yes,” answered Dick.  “Have they any idea what became of Crabtree?”

“I haven’t.  If the sheriff knows anything he hasn’t told it.  By the way, boys, I’ll tell you something, now you are here.  That man is a hypnotist!”

“We know it,” said Dick “I thought I told you.”

“He tried to hypnotize one of the men one day,—­ almost got away, doing it!”

“Did he hire any lawyer to defend him?” asked Tom, curiously.

“I don’t know about a lawyer.  He had a man out to see him, several times.  The two were very friendly.”

“They were?” cried Dick.  “I never knew Josiah Crabtree had any friends, outside of the rascals he associated with.  Who was the man?”