Blankly, and with fear in his eyes, Ned gazed at Tom. The young inventor was frantically working at the levers, trying to loosen the jammed rudder--the rudder that enabled the sky racer to be tilted upward.

"Can't you do it?" cried Ned.

Tom shook his head helplessly, but he did not give up. Madly he worked on, and there was need of haste, for every moment the aeroplane was shooting nearer and nearer to the earth.

Ned glanced down. They were headed for the centre of a large grass plot and the bank employee found himself grimly thinking that at least the turf would be softer to fall on than bare ground.

"I--I can't imagine what's happened!" cried Tom.

He was still yanking on the lever, but it would not move, and unless the head of the aeroplane was thrown up quickly, to catch the air, and check its downward right, they would both be killed.

"Shut off the engine and vol-plane!" cried Ned.

"No use," answered Tom. "I can't vol-plane when I can't throw her head up to check her."

But he did shut off the banging, throbbing motor, and then in silence they continued to fall. Ned had half a notion to jump, but he knew that would mean instant death, and there was just a bare chance that if he stayed in the machine it would take off some of the shock.

They could see Mr. Damon now. The old man had run out of his house at the sight of the approaching aeroplane. He knew it well, for he had ridden with Tom many times. He looked up and waved his hand to the boys, but he had no idea of their danger, and he could not have helped them had he been aware of it.

He must have soon guessed that something was wrong though, for a moment later, the lads could hear him shout in terror, and could see him motion to them. Later he said he saw that Tom was coming down at too great an inclination, and he feared that the machine could not be thrown up into the wind quickly enough!

"Here goes something--the lever or the rudder!" cried Tom in desperation, as he gave it a mighty yank. Up to now he had not pulled with all his strength as he feared to break some connecting- rod, wire or lever. But now he must take every chance. "If I can get that rudder up even a little we're safe!" he went on.

Once more he gave a terrific pull on the handle. There was a snapping sound and Tom gave a yell of delight.

"That's the stuff!" he cried. "She's moving! We're all right now!"

And the rudder had moved only just in time, for when the aeroplane was within a hundred feet of the earth the head was suddenly elevated and she glided along on a level "keel."

"Look out!" yelled Ned, for new a new danger presented. They were so near the earth that Tom had over-run his original stepping place, and now the sky racer was headed directly for Mr. Damon's house, and might crash into it.

"All right! I've get her in hand!" said the young inventor reassuringly.

Tom tilted the rudder at a sharp angle to have the air pressure act as a brake. At the same time he swerved the craft to one side so that there was no longer any danger of crashing into the house.

"Bless my--" began Mr. Damon, but in the excitement he really didn't know what to bless, so he stopped short.

A moment later, feeling that the momentum had been checked enough to make it safe to land, Tom directed the craft downward again and came gracefully to earth, a short distance away from his eccentric friend.

"Whew!" gasped the young inventor, as he leaped from his seat. "That was a scary time while it lasted."

"I should say so!" agreed Ned.

"Bless my straw hat!" cried Mr. Damon. "What happened? Did you lose control of her, Tom,"

"No, the deflecting rudder got jammed, and I couldn't move it. I must look and see what's the matter."

"I thought it was all up with you," commented Mr. Damon, as he followed Tom and Ned to the front end of the craft, where the deflecting mechanism was located.

Tom glanced quickly over it. His quick eye caught something, and he uttered an exclamation.

"Look!" the young inventor cried. "No wonder it jammed!" and from a copper sleeve, through which ran the wire that worked the rudder, he pulled a small iron bolt. "That got between the sleeve and the wire, and I couldn't move it," he explained. "But when I pulled hard I loosened it."

"How did it fall in there?" asked Ned.

"It didn't fall there." spoke Tom quietly. "It was put there."

"Put there! Bless my insurance policy! Who did such a dastardly trick?" cried Mr. Damon.

"I don't know," answered Tom still quietly, "but I suspect it was Andy Foger, and he was never any nearer to putting us out of business than a little while ago, Ned."

"Do you mean to say that he deliberately tried to injure you?" asked Mr. Damon.

"Well, he may not have intended to hurt us, but that's what would have happened if I hadn't been able to throw her up into the wind when I did," replied Tom. Then he told of Mr. Swift having seen the red-haired bully near the aeroplane. "Andy may have only intended to put my machine out of working order," went on the young inventor, "but it might have been worse than that," and he could not repress a shudder.

"Are you going to say anything to him?" asked Ned.

"I certainly am!" replied Torn quickly. "He doesn't realize that he might have crippled us both for life. I sure am going to say something to him when I get back."

But Tom did not get the chance, for when he and Ned returned to Shopton,--the sky racer behaving beautifully on the homeward trip,-- it was learned that Mr. Foger had suddenly left town, taking Andy with him.

"Maybe he knew I'd be after him," said Tom grimly, and so that incident was closed for the time being, but it was a long time before Tom and Ned got over their fright.

They had a nice visit with Mr. Damon, and talked of the city of gold to their heart's content, looking at several large maps of Mexico that the eccentric man had procured, and locating, as well as they could from the meager map and description they had, where the underground treasures might be.

"I suppose you are getting ready to go, Mr. Damon?" remarked Ned.

"Hush!" cautioned the odd man, looking quickly around the room. "I haven't said anything to my wife about it yet. You know she doesn't like me to go off on these 'wild goose chases' as she calls them, with you, Tom Swift. But bless my railroad ticket! It's half the fun of my life."

"Then don't you think you can go?" asked the young inventor eagerly, for he had formed a strong like for Mr. Damon, and would very much reprait to go without him.

"Oh, bless my necktie! I think I'll be able to manage it," was the answer. "I'm not going to tell her anything about it until the last minute, and then I'll promise to bring her back one of the golden images. She won't object then."

"Good!" exclaimed Tom. "I hope we can all bring back some of the images."

"Yes, I know who you'll bring one for," said Ned with a laugh, and he took care to get beyond the reach of Tom's fist. "Her first name is Mary," he added.

"You get out!" laughed Tom, blushing at the same time.

"Ah! What a thing it is to be young!" exclaimed Mr. Damon with a mock sigh. The boys laughed, for the old man, though well along in years, was a boy at heart.

They talked at some length, speculating when they might hear from Mr. Illingway, and discussing the sort of an outfit that would be best to take with them.

Then, as the afternoon was drawing to a close, Tom and Ned went back in the aeroplane, hearing the news about the Fogers as I have previously mentioned.

"Well, I'll have to wait until I do see Andy to take it out of his hide," remarked Tom grimly. "I'm glad he's out of the way, though. There won't be any more danger of his overhearing our plans, and I can work in peace on the dirigible balloon."

Though Tom had many air crafts, the one he thought best suited to take with them on their search for the city of gold would have to be constructed from parts of several machines, and it would take some time.

Tom began work on it the next day, his father helping him, as did Mr. Damon and Ned occasionally. Several weeks were spent in this way, meanwhile the mails being anxiously watched for news from Africa.

"Here you are, Tom!" called the postman one morning, as he walked out to the shop where the young inventor was busy over the balloon. "Here's another letter from that Buggy-wuggy place."

"Oh, you mean Gumba Twamba, in Africa!" laughed the lad. "Good! That's what I've been waiting for. Now to see what the missionary says."

"I hope you're not going to go as a missionary to Africa, Tom," said the postman.

"No danger. This is just a letter from a friend there. He sent me some facts so I can go off on another expedition."

"Oh, you're always going off on wild adventures," commented Uncle Sam's messenger with a shake of his head as he hurried away, while Tom tore open the letter from Africa and eagerly read it.