vered the rope
with a single blow. With a crash that could be heard up in the air
where the Red Cloud hovered, the rear wheels of the auto dropped to the
ground. Then came two loud reports.

"Both tires busted!" commented Mr. Sharp dryly, and Tom, looking down,
saw the trio of lads ruefully contemplating the collapsed rubber of the
rear wheels. The tables had been effectually turned on Andy Foger. His
auto was disabled, and the airship, with a graceful sweep, mounted
higher and higher, continuing on its way to the coast.

Chapter Seven

Mr. Damon Will Go

"Well, I guess they've had their lesson," remarked Tom, as he took an
observation through the telescope and saw Andy and his cronies hard at
work trying to repair the ruptured tires. "That certainly was a corking
good trick."

"Yes," admitted Mr. Sharp modestly. "I once did something similar, only
it was a horse and wagon instead of an auto. But let's try for another
speed record. The conditions are just right."

They arrived at the coast much sooner than they had dared to hope, the
Red Cloud proving herself a veritable wonder.

The remainder of that day, and part of the next, was spent in working
on the submarine.

"We'll launch her day after to-morrow," declared Mr. Swift
enthusiastically. "Then to see whether my calculations are right or
wrong."

"It won't be your fault if it doesn't work," said his son. "You
certainly have done your best."

"And so have you and Mr. Sharp and the others, for that matter. Well, I
have no doubt but that everything will be all right, Tom."

"There!" exclaimed Mr. Sharp the next morning, as he was adjusting a
certain gage. "I knew I'd forget something. That special brand of
lubricating oil. I meant to bring it from Shopton, and I didn't."

"Maybe I can get it in Atlantis," suggested Tom, naming the coast city
nearest to them. "I'll take a walk over. It isn't far."

"Will you? I'll be glad to have you," resumed the balloonist. "A gallon
will be all we'll need."

Tom was soon on his way. He had to walk, as the roads were too poor to
permit him to use the motor-cycle, and the airship attracted too much
attention to use on a short trip. He was strolling along, when from
the other side of a row of sand dunes, that lined the uncertain road to
Atlantis, he heard some one speaking. At first the tones were not
distinct, but as the lad drew nearer to the voice he heard an
exclamation.

"Bless my gold-headed cane! I