physically," put in Ned. "He acted as if sorry that we had saved his life."

"Too bad," murmured Mary, and then a policeman, who had just come into the yard to get the facts for his report, looked at the figure lying on the grass, and said:

"I know him."

"You do?" cried Tom. "Who is he?"

"Name's Baxter, Josephus Baxter. He's a chemist, and he works in the fireworks factory here. Not as one of the hands, but in the experiment laboratory. I've seen him there late at night lots of times. That's how I got acquainted with him. He was going in around two o'clock one morning, and I stopped him, thinking he was a thief. He proved his identity, and I've passed the time of day with him many a time since."

"Where does he live?" asked Mr. Nestor.

"Down on Clay Street," and the officer mentioned the number. "He lives all alone, so he told me. He's some sort of an inventor, I guess. At least I judged so by his talk. Do you want an ambulance, Doctor?" he asked the physician.

"No, I think he's coming around all right," was the answer. "If we had an auto we could send him home."

"I'll take him in the runabout," eagerly offered Tom. "But if he lives all alone will it be safe to leave him in his house?"

"He ought to be looked after, I suppose," the doctor stated. "He'll be all right in a day or so if no complications set in, but he'll be weak for a while and need attention."

"Then I'll take him home with me!" announced Tom. "We have plenty of room, and Mrs. Baggert will feel right at home with some one to nurse. Bring the runabout here, will you please, Ned?"

As Ned darted off to run up the machine, the man opened his eyes again. For a moment he did not seem to know where he was or what had happened. Then, as he saw the lurid light of the flames which were now dying away and realized his position, he sighed heavily and murmured:

"It's all over!"

"Oh, no, it isn't!" cheerfully exclaimed the doctor. "You will be all right in a few days."

"Myself, yes, maybe," said the man bitterly, and he managed to rise to his feet. "But what of my future? It is all gone! The work of years is lost."

"Burned in the fire?" asked Tom, wondering whether the man was a major stockholder in the company. "Didn't you have any insurance? Though I suppose you couldn't get much on a fireworks plant," he added, for he knew something of insurance matters in connection with his own business.

"Oh, it isn't the fire—that is directly," said the man, in the same bitter tones. "I've lost everything! The scoundrels stole them! And I—Oh, never mind!" he cried. "What's the use of talking? I'm down and out! I might just as well have died in the fire!"

Tom was about to make some remark, but the doctor motioned to him to refrain, and then Ned came up with the runabout. At first Josephus Baxter, which was the name of the man who had been rescued, made some objections to going to Tom's home. But when it was pointed out that he might lapse into a stupor again from the effects of the smoke poisons, in which event he would have no one to minister to him at his lonely home, he consented to go to the residence of the young inventor.

"Though if I do lapse into unconsciousness you might as well let me keep on sleeping until the end," said Mr. Baxter bitterly to Tom and Ned, as they drove away from the scene of the fire with him.

"Oh, you'll feel better in the morning," cheerfully declared Ned.

The man did not answer, and the two chums did not feel much like talking, for they were worn out and weary from their exertions at the fire. The factory had been pretty well consumed, though by strenuous labors the blaze had not extended to adjoining structures. The home of Mary Nestor was saved, and for this Tom Swift was thankful.

Mrs. Baggert, the Swift's housekeeper, was indeed glad to have some one to "fuss over," as Tom put it. She prepared a bed for Mr. Baxter, and in this the weary and ill man sank with a sigh of relief.

"Can I do anything for you?" asked Tom, as he was about to go out and close the door.

"No—thank you," was the halting reply. "I guess nothing can be done. Field and Melling have me where they want me now—down and out."

"Do you mean Amos Field and Jason Melling of the fireworks firm?" asked Tom, for the names were familiar to him in a business way.

"Yes, the—the scoundrels!" exclaimed Mr. Baxter, and from his voice Tom judged that he was growing stronger. "They pretended to be my friends, giving me a shop in which to work and experiment, and when the time came they took my secret formulae. I believe that is what they started the fire for—to conceal their crime!"

"You don't mean that!" cried Tom. "Deliberately to start a fire in a factory where there was powder and other explosives! That would be a terrible crime!"

"Field and Melling are capable of just such crimes as that!" said Josephus Baxter, bitterly. "If they took my formulae they wouldn't stop at arson."

"Were your formulae for the manufacture of fireworks?" asked Tom.

"Not altogether," was the reply. "I had several formulae for valuable chemical combinations. They could be used in fireworks, and that is why I could use the laboratory here. But the main use of my discoveries is in the dye industry. I would have been a millionaire soon, with the rise of the American dye industry following the shutting out of the Germans after the war. But now, with my secret formulae gone, I am no better than a beggar!"

"Perhaps it will not be as bad as you think," said Tom, recognizing the fact that Mr. Baxter was in a nervous and excited state. "Matters may look brighter in the morning."

"I don't see how they can," was the grim answer. "However, I appreciate all that you have done for me. But I fear my case is hopeless."

"I'll see you again in the morning," Tom said, trying to infuse some cheerfulness into his voice.

He found Ned waiting for him when he came downstairs.

"How is he?" asked the young business manager.

"In rather a bad way—mentally, at least," and Tom told of the lost formulae. "Do you know, Ned," he went on, "I have an idea!"

"You generally do have—lots of 'em!" Ned rejoined.

"But this is a new one," went on Tom. "You saw what trouble they had this evening to get a stream of water to the top stories of that factory, didn't you?"

"Yes, the pressure here isn't what it ought to be," Ned agreed. "And some of our engines are old-timers."

"Why is it necessary always to fight a fire with water?" Tom continued. "There are plenty of chemicals that will put out a fire much quicker than water."

"Of course," Ned answered. "There are plenty of chemical fire extinguishers on the market, too, Tom. If your idea is to invent a new hand grenade, stay off it! A lot of money has been lost that way."

"I wasn't thinking of a hand grenade," said Tom, as he drew some sheets of paper across the table to him. "My idea is on a bigger scale. There's no reason, Ned, why a big fire in a tall building, like a sky-scraper, shouldn't be fought from above, as well as from below. Now if I had the right sort of chemicals I could—"

Tom paused in a listening attitude. There was the rush of feet and a voice cried:

"I'll get them! I'll get the scoundrels!"

CHAPTER IV

AN EXPERIMENT

"That can't be Koku and Rad in one of their periodic squabbles, can it?" asked Ned.

"No. It's probably Mr. Baxter," Tom answered. "The doctor said he might get violent once or twice, until the effects of his shock wore off. There is some quieting medicine I can give him. I'll run up."

"Guess I'd better go along," remarked Ned. "Sounds as if you'd need help."

And it did appear so, for again the frenzied shouts sounded:

"I'll get 'em! I'll get the scoundrels who stole my secret formulae that I worked over so many years! Come back now! Don't