Koku managed to make Tom understand that the dye inventor was in the main office of the Swift plant talking to Tom's father. The young inventor sent Mary home in his electric runabout in company with Ned Newton, who, fortunately, happened along just then, and hurried to his office.

"Oh, Tom, I'm glad you have arrived," said his father. "You remember Mr. Baxter, of course."

"I should hope so," Tom answered, extending his hand. He noticed that the man whom he had helped save from the fireworks blaze was under the stress of some excitement.

"I hope he hasn't been getting on dad's nerves," thought Tom, as he took a seat. The elder Mr. Swift had been quite ill, and it was thought for a time that he would have to give up helping Tom. But there had been a turn for the better, and the aged inventor had again taken his place in the laboratory, though he was frail.

"What's the trouble now?" asked Tom. "At least I assume there has been some trouble," he went on. "If I am wrong--"

"No, you are right, unfortunately," said Mr. Baxter gloomily. "The trouble is that everything I do is a failure. Up to a little while ago I thought I might succeed, in spite of Field and Melling's theft of the formulae from me. I made a purple dye the other day, and tested it today. It was a miserable failure, and it got on my nerves. I came to see if you could help me."

"In what way?" asked Tom, wondering whether or not he had best tell Mr. Baxter what he had overheard at the Inn.

"Well, I need better laboratory facilities," the man went on. "I know you have been very kind to me, Mr. Swift, and it seems like an imposition to ask for more. But I need a different lot of chemicals, and they cost money. I also need some different apparatus. You have it in your big laboratory. That wouldn't cost you anything. But of course to go out and buy what I need--"

"Oh I guess we can stand that, can't we, Dad?" asked Tom, with a genial smile. "You may have free access to our big laboratory, Mr. Baxter, and I'll see that you get what chemicals you need."

"Oh, thank you!" exclaimed the inventor. "Now I believe I shall succeed in spite of those rascals. Just think, Mr. Swift! They have started a big new dye factory."

"So I have heard," replied Tom.

"And I'm almost sure they're using the secret formulae they stole from me!" exclaimed Mr. Baxter. "But I'll get the best of them yet! I'll invent a better dye than they ever can, even if they use the secrets the old Frenchman gave me. All I need is a better place to work and all the chemicals at my disposal."

"Then we'll try to help you," offered Tom.

"And if I can do anything let me know," put in Mr. Swift. "I shall be glad to get in the harness again, Tom!" he added.

"Well, if you're so anxious to work, Dad, why not give me a hand with my fire extinguisher chemical?" asked Tom. "I haven't been able to hit on the solution, somehow or other."

"Perhaps I may be able to give you a hint or two after I get settled down," suggested Mr. Baxter.

"I shall be glad of any assistance you can give," replied Tom Swift. "And now I'm going to start right in. Dad, you can make the arrangements for Mr. Baxter to use our big laboratory. And let him have credit for any chemicals he needs. Have them put on my bill, for I am buying a lot myself."

"I'll never forget this," said Mr. Baxter, and there were tears in his eyes as he shook hands with Tom, who tried to make light of his generous act.

Tom, after the wrecking of his laboratory, in which accident poor Eradicate was injured, had built himself another--two others, in fact, after having shared Mr. Baxter's temporary one for a time. Tom put up the most completely equipped laboratory that could be devised, and he also erected a smaller one for his own personal use, the main one being at the disposal of his father and the various heads of the different departments of the Shopton plant.

The little conference broke up, and Tom was on his way to his own special private laboratory when there came the sound of some excitement in the corridor outside and Mr. Damon burst in.

"Bless my accident policy, Tom! what's this I hear?" he asked, all in a fluster.

"I'm sure I don't know," answered the young inventor, with a smile. "What about?"

"About you and Mary Nestor being killed!" burst out Mr. Damon. "I heard you fell in the aeroplane and were both dashed to pieces!"

"If you can believe the evidence of your own eyes, I'm far from being in that state," laughed Tom. "And as for Mary, she just left here with Ned Newton."

"Thank goodness!" sighed Mr. Damon, sinking into a chair. "Bless my elevator! I rushed over as soon as I heard the news, and I was almost afraid to come in. I'm so glad it didn't happen!"

"No gladder than I," said Tom. "We had to make a forced landing, that was all," and he made as light of the incident as possible when he saw the look of terror in his father's eyes.

"Some people in Waterford saw you going down," went on Mr. Damon, "and they told me."

"It was a false alarm," replied Tom. "And now, Mr. Damon, if you want to smell some perfumes come with me."

"Are you going into that line, Tom?" asked the eccentric man. "Bless my handkerchief, my wife will be glad of that!"

"I mean I'm going to experiment some more with fire- extinguishing chemicals," laughed the young inventor. "If you want to--"

"Bless my gas mask, I should say not!" cried Mr. Damon. "I don't see how you stand those odors, Tom Swift."

"Guess I'm used to 'em," was the answer. And then, leaving his father to entertain Mr. Damon and to make arrangements for Mr. Baxter's use of the main laboratory, he betook himself to his own private quarters.

The next week or so was a busy time for Tom; so busy, in fact, that he had little chance to see Mr. Baxter. All he knew was that the unfortunate man was also laboring in his own line, and Tom wished him success. He knew that if the man made any discoveries that would help with the fire-extinguishing fluid he would report, as he had promised.

"Well, Tom, how goes it?" asked Ned one day when he came over to call on his chum. "Are you ready to accept contracts for putting out skyscraper blazes in all big cities?"

"Not yet," was the answer. "But I'm going to make another attempt, Ned."

"You mean another experiment?"

"Yes, I have evolved a new combination of chemicals, using something of the carbonate idea as a basis. I found that I couldn't get away from that, much as I wanted to. But my application is entirely new, at least I hope it will prove so."

"When are you going to try it?" asked Ned.

"Right away. All I have to do is to put the chemicals in the metal tank."

"Then I'd better get my leather suit on," remarked Ned, starting to take off his street coat. Tom kept for his chum a full outfit of flying garments, one suit being electrically heated.

"Oh, we aren't going up in any airship," Tom said.

"Why, I thought you were going to test your aerial fire fighting dingus!" exclaimed Ned.

"So I am. But I want to stay on the ground and watch the effect on the blaze as the tank bursts and scatters the chemical fluid."

"Then you want me, and perhaps Mr. Damon to take the stuff up in the machine? Excuse me. I don't believe I care to run an airship myself."

"No," went on Tom, "there isn't any question of an airship this time. No one is going up. Come on out into the yard and I'll show you."

Ned Newton followed his chum out into the big yard near one of the shops. Erected in it, and evidently a new structure, was a large wooden scaffold in square tower shape with a long overhanging arm and a platform on the extremity. Beneath it was a pit dug in the earth, and in this pit, which was directly under the outstanding arm of the tower, was a pile of wood and shavings, oil-soaked.

"Oh, I see the game," remarked Ned. "You're going to drop the stuff from this height instead of doing it from an airship."

"Yes," Tom answered. "There will be time enough to go on with the airship end of it after I get the right combination of chemicals. And by having a metal container with the stuff in dropped from this frame work, I can station myself as near the burning pit as I can get and watch what happens."

"It's a good idea," decided Ned. "I wonder you didn't try that before."

"Mr. Baxter suggested it," replied Tom. "That helpful idea more than pays me for what I have done for him. So now, if you're ready, I'd like to have you watch with me and make some notes, one of us on one side of the pit, and one on the other. There are always two sides to a fire, the leeward and the windward, and I want to see how my chemicals act in both positions."

"I'm with you," said Ned. "Who's going to drop the stuff-- Koku?"

"No, he is a bit too heavy for the framework, which I had put up in a hurry. I'd have Rad do it, but he's out of the game."

"Poor old Rad!" murmured Ned. "Do you think he'll ever get better, Tom?"

"I don't know," sighed the young inventor. "All I can do is to hope. He is very patient, and Koku is devoted to him. All their little bickerings and squabbles seem to have been forgotten."

Tom called some of his workmen, some of them to start the blaze of inflammable material in the pit, while one climbed up to the top of the tower of scantlings and made his way out on the extended arm, where there was a little platform for him to stand until it was time to drop the chemicals.

"Light her up!" cried Tom Swift, and a match was thrown in among the oiled wood. In an instant a fierce blaze shot up, as hot, in proportion, as would come from any burning building.

For the second time Tom was about to make a test on a fairly large scale of his experimental extinguisher mixture.

"All ready up there?" he called to his helper perched high in the air.

"All ready!" came back the answer above the roar and crackle of the flames that made Tom and Ned step back.

Would success or failure attend the young inventor's project?