"Bless my shoe buttons!" exclaimed a voice, as a man came toward Tom's shop, a little later. "Bless my very necktie! This is odd. I go to the house, and find no one there. I come out here, and not a soul is about. Tom Swift can't have gone off on another one of his wonderful trips, without sending me word. I know he wouldn't do that. And yet, bless my watch and chain, I can't find any one!"

It was Mr. Damon who spoke, as my old readers have already guessed. He peered into one of the shop windows, and saw something like a fog filling the place.

"That's strange," he went on. "I don't see Tom there, and yet it looks as if an experiment was going on. I wonder--"

Mr. Damon heard some one coming up behind him, and turned to see Koku the giant, who was returning . from the errand on which Tom had sent him.

"Oh, Koku, it's you; is it?" the odd man asked. "Bless my cuff buttons! Where is Tom?"

"In shop I guess."

"I don't see him. Still I had better look. There doesn't seem to be any one about."

Mr. Damon opened the shop door, and was met by such an outward rush of choking gas that he staggered back.

"Bless my--" he began but he had to stop, to cough and gasp. "There must have been some sort of an accident," he cried, as he got his lungs full of fresh air. "A bad accident! Tom could never work in that atmosphere. Whew!"

"Accident! What is matter?" cried Koku stepping to the doorway. He, too choked and gasped, but his was such a strong and rugged nature, and his lungs held such a supply of air, that it took more than mere gas to knock him out. He peered in through the wreaths of the acid vapor, and saw the body of his master, lying on the floor--held down by the heavy iron.

In another instant Koku had rushed in, holding his breath, for, now that he was inside the place, the gas made even him feel weak.

"Come back! Come back!" cried Mr. Damon. 'You'll be smothered! Wait until the gas escapes!"

"Then Mr. Tom die!" cried the giant. "I get him--or I no come out."

With one heave of his powerful right arm, Koku lifted the heavy shaft from Tom's legs. Then, gathering the lad up in his left arm, as if he were a baby, Koku staggered out into the fresh air, almost falling with his burden, as he neared Mr. Damon, for the giant was, well-nigh overcome.

"Bless my soul!" cried the odd man. "Is he--is he--"

He did not finish the sentence, but, as Koku laid Tom down on the overcoat of Mr. Damon, which the latter quickly spread on the snow, the eccentric man put his hand over the heart of the young inventor.

"It beats!" he murmured. "He's alive, but very weak. We must get a doctor at once. I'll do what I can. There's no time to spare. Bless my--"

But Mr. Damon concluded that there was no time for blessing anything, and so he stopped short.

"Carry him up to the house, Koku," he said. "I know where there are some medicines, and I'll try to revive him while we're waiting for the doctor Hurry!"

Tom was laid on a lounge, and, just then, Mrs. Baggert came in.

"Telephone for the doctor!" cried Mr. Damon to the housekeeper, who kept her nerve, and did not get excited. "I'll give Tom some ammonia, and other stimulants, and see if I can bring him around. Koku, get me some cold water."

The telephone was soon carrying the message to the doctor, who promised to come at once. Koku, in spite of his size, was quick, and soon brought the water, into which Mr. Damon put some strong medicine, that he found in a closet. Tom's eyelids fluttered as the others forced some liquid between his lips.

"He's coming around!" cried the eccentric man. "I guess he'll be all right, Koku."

"Koku glad," said the giant simply, for he loved Tom with a deep devotion.

"Yes, Koku, if it hadn't been for you, though, I don't believe that he would be alive. That was powerful gas, and a few seconds more in there might have meant the end of Tom. I didn't see him lying on the floor, until after you rushed in. Bless my thermometer! It is very strange."

They gave Tom more medicine, rubbed his arms and legs, and held ammonia under his nose. Slowly he opened his eyes, and in a faint voice asked:

"Where--am--I?"

"In your own house," replied Mr. Damon, cheerfully. "How do you feel?"

"I'm--all--right--now," said Tom slowly. He, felt his strength coming gradually back, and he remembered what had happened, though he did not yet know how he had been saved. The doctor came in at this moment, with a small medical battery, which completed the restorative work begun by the others. Soon Tom could sit up, though he was still weak and rather sick.

"Who brought me out?" he asked, when he had briefly told how the accident occurred.

"Koku did," replied Mr. Damon. "I guess none of the rest of us could have lifted the iron shaft from your legs."

"It's queer how that fell," said Tom, with a puzzled look on his face. "I didn't hit it hard enough to bring it down. Beside, I had it tied to nails, driven into the wall, to prevent just such an accident as this. I must see about it when I get well."

"Not for a couple of days," exclaimed the doctor grimly. "You've got to stay in bed a while yet. You had a narrow escape, Tom Swift."

"Well, I'm glad I went to Giant Land," said the young inventor, with a wan smile. "Otherwise I'd never have Koku," and he looked affectionately at the big man, who laughed happily. In nature Koku was much like a child.

Mr. Swift came home a little later, and Ned Newton called, both being very much surprised to hear of the accident. As for Eradicate, the poor old colored man was much affected, and would have sat beside Tom's bed all night, had they allowed him.

Our hero recovered rapidly, once the fumes of the gas left his system, and, two days later, he was able to go out to the shop again. At his request everything had been left just as it was after he had been brought out. Of course the fumes of the gas were soon dissipated, when the door was opened, and the acids, after mingling and giving off the vapor, had become neutralized, so that they were now harmless.

"Now I'm going to see what made that shaft fall," said Tom to Ned, as the two chums walked over to the bench where the young inventor had been working. "The tap I gave it never ought to have brought it down."

Together they examined the thin, but strong, cords that had been passed around the shaft, having been fastened to two nails, driven into the wall.

"Look!" cried Tom, pointing to one of the cords.

"What is it?" asked Ned.

"The strands were partly cut through, so that only a little jar was enough to break the remaining ones," went on Tom. "They've been cut with a knife, too, and not frayed by vibration against the nail, as might be the case. Ned, someone has been in my shop, meddling, and he wanted this shaft to fall. This is a trick!"

"Great Scott, Tom! You don't suppose any one wanted that shaft to fall on you; do you?"

"No, I don't believe that. Probably some one wanted to damage the shaft, or he might have thought it would topple over against the bench, and break some of my tools, instruments or machinery. I do delicate experiments here, and it wouldn't take much of a blow to spoil them. That's why those cords were cut."

"Who did it? Do you think Andy Foger--"

"No, I think it was the man Koku thought was a chicken thief, and whom we chased the other night. I've got to be on my guard. I wonder if--"

Tom was interrupted by the appearance of Koku, who came out of the shop with a letter the postman had just left.

"I don't know that writing very well, and yet it looks familiar," said Tom, as he tore open the missive. "Hello, here's more trouble!" he exclaimed as he hastily read it.

"What's up now?" asked Ned.

"This is from Mr. Period, the picture man," went on the young inventor. It's a warning."

"A warning?"

"Yes. He says:

"'Dear Tom. Be on your guard. I understand that a rival moving picture concern is after you. They want to make you an offer, and get you away from me. But I trust you. Don't have anything to do with these other fellows. And, at the same time, don't give them a hint as to our plans. Don't tell them anything about your new camera. There is a lot of jealousy and rivalry in this business and they are all after me. They'll probably come to see you, but be on your guard. They know that I have been negotiating with you. Remember the alarm the other night.'"