With startled glances at each other, Tom and his father rushed from the library to the side of the house, whence came the cries of Eradicate.

"What is it, Rad! what is it?" questioned Tom.

"Is someone hurt?" Mr. Swift wanted to know.

"He mighty soon will be!" exclaimed the colored man. "Look where he am holdin' on! Lucky fo' him he grabbed dat chimbley!"

Tom and his father looked to where Eradicate pointed, and saw a strange sight. A small biplane-airship had become entangled in some of the aerials of Tom's wireless apparatus, and the craft had turned turtle, being held from falling by some of the wire braces.

The birdman had fallen out, but had managed to cling to the chimney, so that he had not reached the ground, and there he clung, while the motor of his airship was banging away, and revolving the propeller blades dangerously close to his head.

"Are you hurt?" cried Tom, to the unknown birdman.

"No, but I'm likely to be unless I get out of here!" was the gasped-out answer.

"Hold fast!" cried Tom. "We'll have you down in a jiffy. Here, Rad, you get the long ladder. Where's Koku? That giant is never around when he's wanted. Find Koku, Rad, and send him here."

"Yas, sah, Massa Tom; directly, sah!" and the colored man hastened off as fast as his aged legs would take him.

And while preparations are thus under way to rescue the birdman from the roof, I will take just a few minutes to tell you a little something more about Tom Swift and his numerous inventions, as set forth in the previous books of this series.

"Tom Swift and His Motor Cycle" was the first book, and in that I related how Tom made the acquaintance of a Mr. Wakefield Damon, of the neighboring town of Waterford, and how Tom bought that gentleman's motor cycle, after it had tried to climb a tree with its rider in the saddle. Mr. Wakefield Damon was an odd man, whose favorite expression was "Bless my shoelaces!" or something equally absurd. Waterford was not far from Shopton, where Tom and his father made their home.

Mr. Swift was also an inventor of note, and Tom soon followed in his father's footsteps. They lived in a large house, with many shops about it, for their work at times required much machinery.

Mrs. Baggert was the housekeeper who looked after Tom and his father, and got their meals, when they consented to take enough time from their inventive work to eat. Another member of the household was Eradicate Sampson, a genial old colored man, who said he was named Eradicate because he used to eradicate the dirt about the place.

Koku, just referred to by Tom, was an immense man, a veritable giant, whom Tom had brought back with him from one of his trips, after escaping from captivity. The young inventor really brought two giants, brothers they were, but one had gone to a museum, and the other took service with our hero, making himself very useful when it came to lifting heavy machinery.

Tom had a close friend in Ned Newton, who was employed in the Shopton bank. Another friend was Miss Mary Nestor, a young lady whose life Tom had once saved. He had many other friends, and some enemies, whom you will meet from time to time in this story.

After Tom had had many adventures on his motor cycle he acquired a motor boat, and in that he and Ned went through some strenuous times on Lake Carlopa, near Tom's home. Then followed an airship, for Tom got that craze, and in the book concerning that machine I related some of the things that happened to him. He had even more wonderful adventures in his submarine, and with his electric runabout our hero was instrumental in saving a bank from ruin by making a trip in the speediest car on the road.

After Tom Swift had sent his wireless message, and saved the castaways of Earthquake Island, he thought he would give up his inventive work for a time, and settle down to a life of ease and quiet.

But the call of the spirit of adventure was still too strong for him to resist. That was why he sought out the diamond makers, and learned the secret of Phantom Mountain. And when he went to the Caves of Ice, and there saw his airship wrecked, Tom was well-nigh discouraged, But he managed to get back to civilization, and later undertook a journey to elephant land, with his powerful electric rifle.

Marvelous adventures underground did Tom Swift have when he went to the City of Gold, and I have set down some of them in the book bearing the latter title. Later on he sought the platinum treasure in his air glider. And when Tom was taken captive, in giant land, only his speedy airship saved him from a hard fate.

By this time moving pictures were beginning to occupy a large place in the scientific, as well as the amusement world, and Tom invented a Wizard Camera which did excellent work. Then came the need of a powerful light, to enable Uncle Sam's custom officers on the border to detect the smugglers, and Tom was successful in making his apparatus.

He thought he would take a rest after that, but with the opening of the Panama Canal came the need of powerful guns to protect that important waterway, and Tom made a Giant Cannon, which enabled the longest shots on record to be fired.

Now, some months had passed, after the successful trial of the big weapon, and Tom longed for new activities. He found them in the idea of a photo telephone, and he and his father were just talking of this when interrupted by the accident to the birdman on the roof of the Swift home.

"Have you got that ladder, Rad?" cried the young inventor, anxiously, as he saw the dangerous position of the man from the airship.

"Yas, sah, Massa Tom! I'se a-camin' wif it!"

"And where's Koku? We'll need him!"

"He's a-camin', too!"

"Here Koku!" exclaimed a deep voice, and a big man came running around the corner of the house. "What is it, Master?"

"We must get him down, Koku!" said Tom, simply. "I will go up on the roof. You had better come, too. Rad, go in the house and get a mattress from the bed. Put it down on the ground where he's likely to fall. Lively now!"

"Yas, sah, Massa Tom!"

"Me git my own ladder--dat one not strong 'nuff!" grunted Koku, who did not speak very good English. He had a very strong ladder, of his own make, built to hold his enormous bulk, and this he soon brought and placed against the side of the house.

Meanwhile Tom and his father had raised the one Eradicate had brought, though Tom did most of the lifting, for his father was elderly, and had once suffered from heart trouble.

"We're coming for you!" cried the young inventor as he began to ascend the ladder, at the same time observing that the giant was coming with his. "Can you hold on a little longer?"

"Yes, I guess so. But I dare not move for fear the propellers will strike me."

"I see. I'll soon shut off the motor," said Tom. "What happened, anyhow?"

"Well, I was flying over your house. I was on my way to pay you a visit, but I didn't intend to do it in just this way," and the birdman smiled grimly. "I didn't see your wireless aerials until I was plumb into them, and then it was too late. I hope I haven't damaged them any."

"Oh, they are easily fixed," said Tom. "I hope you and your biplane are not damaged. This way, Koku!" he called to the giant.

"Say, is--is he real, or am I seeing things?" asked the aviator, as he looked at the big man.

"Oh, he's real, all right," laughed Tom. "Now, then, I'm going to shut off your motor, and then you can quit hugging that chimney, and come down."

"I'll be real glad to," said the birdman.

Making his way cautiously along the gutters of the roof, Tom managed to reach the motor controls. He pulled out the electrical switch, and with a sort of cough and groan the motor stopped. The big propellers ceased revolving, and the aviator could leave his perch in safety.

This he did, edging along until he could climb down and meet Tom, who stood near the ladder.

"Much obliged," said the birdman, as he shook hands with Tom. "My name is Grant Halling. I'm a newcomer in Mansburg," he added, naming a town not far from Shopton. "I know you by reputation, so you don't need to introduce yourself."

"Glad to meet you," said the young inventor, cordially. "Rather a queer place to meet a friend," he went on with a laugh and a glance down to the ground. "Can you climb?"

"Oh, yes, I'm used to that. The next thing will be to get my machine down."

"Oh, we can manage that with Koku's help," spoke Tom. "Koku, get some ropes, and see what you and Rad can do toward getting the aeroplane down," he added to the giant. "Let me know if you need any help."

"Me can do!" exclaimed the big man. "Me fix him!"

Tom and Mr. Halling made their way down the ladder, while the giant proceeded to study out a plan for getting the airship off the roof.

"You say you were coming over to see me, when you ran into my wireless aerials?" asked Tom, curiously, when he had introduced his father to the birdman.

"Yes," went on Mr. Halling. "I have been having some trouble with my motor, and I thought perhaps you could tell me what was wrong. My friend, Mr. Wakefield Damon, sent me to you."

"What! Do you know Mr. Damon?" cried Tom.

"I've known' him for some years. I met him in the West, but I hadn't seen him lately, until I came East. He sent me to see you, and said you would help me."

"Well, any friend of Mr. Damon's is a friend of mine!" exclaimed Tom, genially. "I'll have a look at your machine as soon as Koku gets it down. How is Mr. Damon, anyhow? I haven't seen him in over two weeks."

"I'm sorry to say he isn't very well, Mr. Swift."

"Is he ill? What is the trouble?"

"He isn't exactly ill," went on Mr. Halling, "but he is fretting himself into a sickness, worrying over his lost fortune."

"His lost fortune!" cried Tom, in surprise at the bad news concerning his friend. "I didn't know he had lost his money!"

"He hasn't yet, but he's in a fair way to, he says. It's something about bad investments, and he did speak of the trickery of one man, I didn't get the particulars. But he certainly feels very badly over it."

"I should think he would," put in Mr. Swift. "Tom, we must look into this. If we can help Mr. Damon--"

"We certainly will," interrupted Tom. "Now come in the house, Mr. Halling. I'm sure you must be quite shaken up by your upset."

"I am, to tell you the truth, though it isn't the first accident I've had in my airship."

They were proceeding toward the house, when there came a cry from Koku, who had fastened a rope about the airship to lower it.

"Master! Master!" cried the giant. "The rope am slippin'. Grab the end of it!"