"Bless my thermometer!" gasped Mr. Damon. "This is terrible!" The airship was plunging and swaying about in the awful gale. "Can't something be done, Tom?"

"What has happened?" cried Mr. Nestor. "We were on a level keel before. What is it?"

"It's the automatic balancing rudder!" answered Tom. "Something has happened to it. The wind may have broken it! Come on, Ned!" and he led the way to the engine room.

"What are you going to do? Don't you want Koku to shift the deflecting rudder? Here he is," Ned added, as the giant came forward, in response to a signal bell that Tom's chum had rung.

"It's too late to try the deflecting rudder!" tried Tom. "I must see what is the matter with our balancer." As he spoke the ship gave a terrific plunge, and the occupants were thrown sideways. The next moment it was on a level keel again, scudding along with the gale, but there was no telling when the craft would again nearly capsize.

Tom looked at the mechanism controlling the equalizing and equilibrium rudder. It was out of order, and he guessed that the terrific wind was responsible for it.

"What can we do?" cried Ned, as the airship nearly rolled over. "Can't we do anything, Tom?"

"Yes. I'm going to try. Keep calm now. We may come out all right. This is the worst blow we've been in since we were in Russia. Start the gas machine full blast. I want all the vapor I can get."

As I have explained the Flyer was a combined dirigible balloon and aeroplane. It could be used as either, or both, in combination. At present the gas bag was not fully inflated, and Tom had been sending his craft along as an aeroplane.

"What are you going to do?" cried Ned, as he pulled over the lever that set the gas generating machine in operation.

"I'm going up as high as I can go!" cried Tom. "If we can't go down we must go up. I'll get above the hurricane instead of below it. Give me all the gas you can, Ned!"

The vapor hissed as it rushed into the big bag overhead. Tom carried aboard his craft the chemicals needed to generate the powerful lifting gas, of which he alone had the secret. It was more powerful than hydrogen, and simple to make. The balloon of the Flyer was now being distended.

Meanwhile Tom, with Koku, Mr. Damon and Mr. Nestor to help him, worked over the deflecting rudder, and also on the equilibrium mechanism. But they could not get either to operate.

Ned stood by the gas machine, and worked it to the limit. But even with all that energy, so powerful was the wind, that the Flyer rose slowly, the gale actually holding her down as a water-logged craft is held below the waves. Ordinarily, with the gas machine set at its limit the craft would have shot up rapidly.

At times the airship would skim along on the level, and again it would be pitched and tossed about, until it was all the occupants could do to keep their feet. Mr. Damon was continually blessing everything he could remember.

"Now she's going!" suddenly cried Ned, as he looked at the dials registering the pressure of the gas, and showing the height of the airship above the earth.

"Going how?" gasped Tom, as he looked over from where he was working at the equilibrium apparatus. "Going down?"

"Going up!" shouted Ned. "I guess we'll be all right soon!"

It was true. Now that the bag was filled with the powerful lifting gas, under pressure, the Flyer was beginning to get out of the dangerous predicament into which the gale had blown her, Up and up she went, and every foot she climbed the power of the wind became less.

"Maybe it all happened for the best," said Tom, as he noted the height gage. "If we had gone down, the wind might have been worse nearer the earth."

Later they learned that this was so. The most destructive wind storm ever known swept across the southern part of Europe, over which they were flying that night, and, had the airship gone down, she would probably have been destroyed. But, going up, she got above the wind-strata. Up and up she climbed, until, when three miles above the earth, she was in a calm zone. It was rather hard to breathe at this height, and Tom set the oxygen apparatus at work.

This created in the interior of the craft an atmosphere almost like that on the earth, and the travelers were made more at their ease. Getting out of the terrible wind pressure made it possible to work the deflecting rudder, though Tom had no idea of going down, as long as the blow lasted.

"We'll just sail along at this height until morning," he said, "and by then the gale may be over, or we may be beyond the zone of it. Start the propellers, Ned. I think I can manage to repair the equilibrium rudder now."

The propellers, which gave the forward motion to the airship, had been stopped when it was found that the wind was carrying her along, but they were now put in motion again, sending the Flyer forward. In a short time Tom had the equilibrium machine in order, and matters were now normal again.

"But that was a strenuous time while it lasted," remarked the young inventor, as he sat down.

"It sure was," agreed Ned.

"Bless my pen wiper!" cried Mr. Damon. "That was one of the few times when I wish I'd never come with you, Tom Swift," and everyone laughed at that.

The Flyer was now out of danger, going along high in the air through the night, while the gale raged below her. At Tom's suggestion, Koku got a lunch ready, for they were all tired with their labors, and somewhat nervous from the danger and excitement.

"And now for sleep!" exclaimed Tom, as he pushed back his plate. "Ned, set the automatic steering gear, and we'll see where we bring up by morning."

An examination, through a powerful telescope in the bright light of morning, showed the travelers that they were over the outskirts of a large city, which, later, they learned was Rome, Italy.

"We've made a good trip," said Tom. "The gale had us worried, but it sent us along at a lively clip. Now for Switzerland, and the avalanches!"

They made a landing at a village just outside the "Holy City," as Rome is often called, and renewed their supply of gasolene. Naturally they attracted a crowd of curious persons, many of whom had never seen an airship before. Certainly few of them had ever seen one like Tom Swift's.

The next day found them hovering over the Alps, where Tom hoped to be able to get the pictures of snow slides. They went down to earth at a town near one of the big mountain ranges, and there made inquiries as to where would be the best location to look for big avalanches. If they went but a few miles to the north, they were told, they would be in the desired region, and they departed for that vicinity.

"And now we've just got to take our time, and wait for an avalanche to happen," remarked Tom, as they were flying along over the mountain ranges. "As Mr. Damon said, these things aren't made to order. They just happen."

For three days they sailed in and out over the great snow-covered peaks of the Alps. They did not go high up, for they wanted to be near earth when an avalanche would occur, so that near-view pictures could be secured. Occasionally they saw parties of mountain climbers ascending some celebrated peak, and for want of something better to photograph, Tom "snapped" the tourists.

"Well, I guess they're all out of avalanches this season," remarked Ned one afternoon, when they had circled back and forth over a mountain where, so it was said, the big snow slides were frequent.

"It does seem so," agreed Tom. "Still, we're in no hurry. It is easier to be up here, than it is walking around in a jungle, not knowing what minute a tiger may jump out at you."

"Bless my rubbers, yes!" agreed Mr. Damon.

The sky was covered with lowering clouds, and there were occasionally flurries of snow. Tom's airship was well above the snow line on the mountains. The young inventor and Ned sat in the pilot house, taking observations through a spyglass of the mountain chain below them.

Suddenly Ned, who had the glass focused on a mighty peak, cried out:

"There she is, Tom!"

"What?"

"The avalanche! The snow is beginning to slide down the mountain! Say, it's going to be a big one, too. Got your camera ready?"

"Sure! I've had it ready for the last three days. Put me over there, Ned. You look after the airship, and I'll take the pictures!"

Tom sprang to get his apparatus, while his chum hurried to the levers, wheels and handles that controlled the Flyer. As they approached the avalanche they could see the great mass of ice, snow, big stones, and earth sliding down the mountain side, carrying tall trees with it.

"This is just what I wanted!" cried Tom, as he set his camera working. "Put me closer, Ned."

Ned obeyed, and the airship was now hovering directly over the avalanche, and right in its path. The big landslide, as it would have been called in this country, met no village in its path, fortunately, or it would have wiped it out completely. It was in a wild and desolate region that it occurred.

"I want to get a real close view!" cried Tom, as he got some pictures showing a whole grove of giant trees uprooted and carried off. "Get closer Ned, and--"

Tom was interrupted by a cry of alarm from his chum.

"We're falling!" yelled Ned. "Something has gone wrong. We're going down into the avalanche!".