ng over the sea. Whatever Tom did was right to him. He
had great confidence in his master.

"No, it isn't the first time we've taken a water flight," spoke Ned. "I
was only surprised at the suddenness of it, that's all."

"It's my first experience so far out above the water," observed
Lieutenant Marbury, "though of course I've sailed on many seas. Why,
we're out of sight of land."

"About ten miles out, yes," admitted Tom. "Far enough to make it safe
to test the guns with real projectiles. That is what I want to do."

"And we've been running all night?" asked Mr. Damon.

"Yes, but at slow speed. The engines are in better shape now than ever
before," Tom said. "Well, if you're ready we'll have breakfast."

The meal was served by Koku with as much unconcern as though they were
in the Swift homestead back in Shopton, instead of floating near the
clouds. And while it was being eaten in the main cabin, and while the
crew was having breakfast in their quarters, the aerial warship was
moving along over the ocean in charge of George Watson, one of Tom's
engineers, who was stationed in the forward pilot-house.

"So you're going to give the guns a real test this time, is that it,
Tom?" asked Ned, as he pushed back his plate, a signal that he had
eaten enough.

"That's about it."

"But don't you think it's a bit risky out over the water this way.
Supposing something should--should happen?" Ned hesitated.

"You mean we might fall?" asked Tom, with a smile.

"Yes; or turn upside down."

"Nothing like that could happen. I'm so sure that I have solved the
problem of the recoil of the guns that I'm willing to take chances. But
if any of you want to get off the Mars while the test is being made, I
have a small boat I can lower, and let you row about in that until--"

"No, thank you!" interrupted Mr. Damon, as he looked below. There was
quite a heavy swell on, and the ocean did not appear very attractive.
They would be much more comfortable in the big Mars.

"I think you won't have any trouble," asserted Lieutenant Marbury. "I
believe Tom Swift has the right idea about the guns, and there will be
so small a shock from the recoil that it will not be noticeable."

"We'll soon know," spoke Tom. "I'm going to get ready for the test now."

They were now well out from shore, over the Atlantic, but to make
certain no ships would be endangered by the projectiles, Tom and the
others searched the waters to the horizon with powe