"Say, Tom, are you sure you're all right?"

"Of course I am! What do you mean?"

It was Ned Newton who asked the question, and Tom Swift who answered it. The chums were in the pilot-house of the dipping, swaying Mars, which was nosing her way into the storm, fighting on an upward slant, trying, if possible, to get above the area of atmospheric disturbance.

"Well, I mean are you sure your craft will stand all this straining, pulling and hauling?" went on Ned, as he clung to a brass hand rail, built in the side of the pilot-house wall for the very purpose to which it was now being put.

"If she doesn't stand it she's no good!" cried Tom, as he clung to the steering wheel, which was nearly torn from his hands by the deflections of the rudders.

"Well, it's taking a big chance, it seems to me," went on Ned, as he peered through the rain-spotted bull's-eyes of the pilot- house.

"There's no danger," declared Tom. "I wanted to give the ship the hardest test possible before I formally offered her to the government. If she can't stand a blow like this she isn't what I thought her, and I'll have to build another. But I'm sure she will stand the racket, Ned. She's built strongly, and even if part of the gas bag is carried away, as it was when our propeller shattered, we can still sail. If you think this is anything, wait until we turn about and begin to fight our way against the wind."

"Are you going to do that, Tom?"

"I certainly am. We're going with the gale now, to see what is the highest rate of speed we can attain. Pretty soon I'm going to turn her around, and see if she can make any headway in the other direction. Of course I know she won't make much, if any speed, against the gale; but I must give her that test."

"Well, Tom, you know best, of course," admitted Ned. "But to me it seems like taking a big risk."

And indeed it did seem, not only to Ned, but to some of the experienced men of Tom's crew, that the young inventor was taking more chances than ever before, and Tom, as my old readers well know, had, in his career, taken some big ones.

The storm grew worse as the day progressed, until it was a veritable hurricane of wind and rain. The warnings of the Weather Bureau had not been exaggerated. But through the fierce blow the Mars fought her way. As Tom had said, she was going with the wind. This was comparatively easy. But what would happen when she headed into the storm?

Mr. Damon, in the main cabin, sat and looked at Lieutenant Marbury, the eccentric man now and then blessing something as he happened to think of it.

"Do you--do you think we are in any danger?" he finally asked.

"Not at present," replied the government expert.

"You mean we will be--later?"

"It's hard to say. I guess Tom Swift knows his business, though."

"Bless my accident insurance policy!" murmured Mr. Damon. "I wish I had stayed home. If my wife ever hears of this--" He did not seem able to finish the sentence.

In the engine-room the crew were busy over the various machines. Some of the apparatus was being strained to keep the ship on her course in the powerful wind, and would be under a worse stress when Tom turned his craft about. But, so far, nothing had given way, and everything was working smoothly.

As hour succeeded hour and nothing happened, the timid ones aboard began to take more courage. Tom never for a moment lost heart. He knew what his craft could do, and he had taken her up in a terrific storm with a definite purpose in view. He was the calmest person aboard, with the exception, perhaps, of Koku. The giant did not seem to know what fear was. He depended entirely on Tom, and as long as his young master had charge of matters the giant was content to obey orders.

There was to be no test of the guns this time. They had worked sufficiently well, and, if need be, could have been fired in the gale. But Tom did not want his men to take unnecessary risks, nor was he foolhardy himself.

"We'll have our hands full when we turn around and head into the wind," he said to his chum. "That will be enough."

"Then you're really going to give the Mars that test?"

"I surely am. I don't want any comebacks from Uncle Sam after he accepts my aerial warship. I've guaranteed that she'll stand up and make headway against a gale, and I'm going to prove it"

Lieutenant Marbury was told of the coming trial, and he prepared to take official note of it. While matters were being gotten in readiness Tom turned the wheel over to his assistant pilot and went to the engine-room to see that everything was in good shape to cope with any emergency. The rudders had been carefully examined before the flight was made, to make sure they would not fail, for on them depended the progress of the ship against the powerful wind.

"I rather guess those foreign spies have given up trying to do Tom an injury," remarked Ned to the lieutenant as they sat in the main cabin, listening to the howl of the wind, and the dash of the rain.

"Well, I certainly hope so," was the answer. "But I wouldn't be too sure. The folks in Washington evidently think something is likely to happen, or they wouldn't have sent that warning telegram."

"But we haven't seen anything of the spies," Ned remarked.

"No, but that isn't any sign they are not getting ready to make trouble. This may be the calm before the storm. Tom must still be on the lookout. It isn't as though his inventions alone were in danger, for they would not hesitate to inflict serious personal injury if their plans were thwarted."

"They must be desperate."

"They are. But here comes Tom now. He looks as though something new was about to happen."

"Take care of yourselves now," advised the young aero-inventor, as he entered the cabin, finding it hard work to close the door against the terrific wind pressure.

"Why?" asked Ned.

"Because we are going to turn around and fight our way back against the gale. We may be turned topsy-turvy for a second or two."

"Bless my shoe-horn!" cried Mr. Damon. "Do you mean upside down, Tom?"

"No, not that exactly. But watch out!"

Tom went forward to the pilot-house, followed by Ned and the lieutenant. The latter wanted to take official note of what happened. Tom relieved the man at the wheel, and gradually began to alter the direction of the craft.

At first no change was noticeable. So strong was the force of the wind that it seemed as though the Mars was going in the same direction. But Ned, noticing a direction compass on the wall, saw that the needle was gradually shifting.

"Hold fast!" cried Tom suddenly. Then with a quick shift of the rudder something happened. It seemed as though the Mars was trying to turn over, and slide along on her side, or as if she wanted to turn about and scud before the gale, instead of facing it. But Tom held her to the reverse course.

"Can you get her around?" cried the lieutenant above the roar of the gale.

"I--I'm going to!" muttered Tom through his set teeth.

Inch by inch he fought the big craft through the storm. Inch by inch the indicator showed the turning, until at last the grip of the gale was overcome.

"Now she's headed right into it!" cried Tom in exultation. "She's nosing right into it!"

And the Mars was. There was no doubt of it. She had succeeded, under Tom's direction, in changing squarely about, and was now going against the wind, instead of with it.

"But we can't expect to make much speed," Tom said, as he signaled for more power, for he had lowered it somewhat in making the turn.

But Tom himself scarcely had reckoned on the force of his craft, for as the propellers whirled more rapidly the aerial warship did begin to make headway, and that in the teeth of a terrific wind.

"She's doing it, Tom! She's doing it!" cried Ned exultingly.

"I believe she is," agreed the lieutenant.

"Well, so much the better," Tom said, trying to be calm. "If she can keep this up a little while I'll give her a rest and we'll go up above the storm area, and beat back home."

The Mars, so far, had met every test. Tom had decided on ten minutes more of gale-fighting, when from the tube that communicated with the engine-room came a shrill whistle.

"See what that is, Ned," Tom directed.

"Yes," called Ned into the mouthpiece. "What's the matter?"

"Short circuit in the big motor," was the reply. "We've got to run on storage battery. Send Tom back here! Something queer has happened!"