from the
dummy barrel neutralizing the shot from the service barrel.

"And now to see how it works in practice!" cried Tom one day. "Are you
with me for a long flight, Ned?"

"I sure am!"

The next evening the Mars, with a larger crew than before, and with
Tom, Ned, Mr. Damon and Lieutenant Marbury aboard, set sail.

"But why start at night?" asked Ned.

"You'll see in the morning," Tom answered.

The Mars flew slowly all night, life aboard her, at about the level of
the clouds, going on almost as naturally as though the occupants of the
cabins were on the earth. Excellent meals were served.

"But when are you going to try the guns?" asked Ned, as he got ready to
turn in.

"Tell you in the morning," replied Tom, with a smile.

And, in the morning, when Ned looked down through the plate glass in
the cabin floor, he uttered a cry.

"Why, Tom! We're over the ocean!" he cried.

"I rather thought we'd be," was the calm reply. "I told George to head
straight for the Atlantic. Now we'll have a test with service charges
and projectiles!"

CHAPTER XVIII

IN A STORM

Surprise, for the moment, held Mr. Damon, Ned and Lieutenant Marbury
speechless. They looked from the heaving waters of the ocean below them
to the young pilot of the Mars. He smiled at their astonishment.

"What--what does it mean, Tom?" asked Ned. "You never said you were
going to take a trip as far as this."

"That's right," chimed in Mr. Damon. "Bless my nightcap! If I had known
I was going to be brought so far away from home I'd never have come."

"You're not so very far from Waterford," put in Tom. "We didn't make
any kind of speed coming from Shopton, and we could be back again
inside of four hours if we had to."

"Then you didn't travel fast during the night?" asked the government
man.

"No, we just drifted along," Tom answered. "I gave orders to run the
machinery slowly, as I wanted to get it in good shape for the other
tests that will come soon. But I told George, whom I left in charge
when I turned in, to head for New York. I wanted to get out over the
ocean to try the guns with the new recoil arrangement."

"Well, we're over the ocean all right," spoke Ned, as he looked down at
the heaving waters.

"It isn't the first time," replied Tom cheerfully. "Koku, you may serve
breakfast now," for the giant had been taken along as a sort of cook
and waiter. Koku manifested no surprise or alarm when he found the
airship floati