ried Tom. "How?"

"Heard a noise outside about eleven o'clock--my wife did, she ain't well
an' don't sleep good. I came down with my shotgun, thinkin' chicken
thieves might be around. I heard somebuddy at the flyin' machine and
sneaked up to see who it was. Hang my skin if a young feller wasn't
there with a lighted candle an' some loose hay, and wantin' to start a
fire close to the gasoline tank! I gave a yell, an' he dropped the
candle and legged it for dear life."

"Why didn't you stop him, or shoot him?" queried Sam.

"I was too excited, fer the candle dropped into the hay an' it begun to
blaze up. I stamped the fire out, an' by that time the feller was out o'
sight."

"He must have wanted to blow the biplane up!" exclaimed Captain Colby.

"He sure did, an' he might have burnt up the shed an' the barn, an' the
house, too!" added John Snubble.

The three Rover boys looked at each other. The same thought was in the
mind of each.

"Tad Sobber!" murmured Sam.

"Sure as you're a foot high," added Tom. "Oh, what a mean thing to do!"

"He must have watched what we did, and then planned to wreck the
_Dartaway_," said Dick. "It's just like his meanness."

"Let's go down to the old mill after him," burst out Tom. "I'd like
nothing better than to wipe up the ground with him." And he clenched his
fists tightly.

"Humph! Do you think he'd show himself?" asked Sam. "Not much! He'd hide
where you couldn't find him. Now he and old Crabtree know we are around
they'll take good care not to get caught."

"We might burn down the old mill!" murmured Tom. "It would serve 'em
right, for all their meanness."

"Let it go," was Dick's advice. "Some day we'll catch both of them
red-handed at something, and then we can give 'em what's coming to 'em."

The matter was talked over with John Snubble and the aviator, and the
farmer said he would keep on guard against Sobber and Crabtree and
report to Dick if he found out anything unusual. Then the biplane was
brought forth, and Captain Colby made an examination.

"All these breaks can easily be mended," said the aviator. "We'll go to
work at once. Then I'll give the _Dartaway_ a little try-out, and if she
runs as she should I'll take her back to your home."

"Don't you want a passenger?" asked Sam and Tom in a breath.

"Why, do you want to go?"

"Sure!"

"I'm afraid I'll have to disappoint you. I want to try the machine
several times before I risk taking anybody up."

The S