Chapter XIX. On the Trail

"There, Tom Swift, it ought to work now!"

Josephus Baxter held up a large laboratory test tube, in which seethed and bubbled some strange mixture, turning from green to purple, then to red, and next to a white, milky mixture.

"Do you think you've hit on the right combination?" asked the young inventor, whose latest idea, the plan of fighting fires in skyscrapers from an airship as a vantage point, was taking up all his spare moments.

"I'm positive of it," said Mr. Baxter. "I've dabbled in chemicals long enough to be certain of this, even if I can't get on the track of the missing dye formulae."

"That certainly is too bad," declared Tom. "I wish I could help you as much as you have helped me."

"Oh, you have helped me a lot," said the chemist. "You have given me a place to work, much better than the laboratory I had in the old fireworks factory of Field and Melling. And you have paid me, more than liberally, for what little I have done for you."

"You've done a lot for me," declared Tom. "If it had not been for your help this chemical compound would not be nearly as satisfactory as it is, nor as cheap to manufacture, which is a big item."

"Oh, you were on the right track," said Mr. Baxter. "You would have stumbled on it yourself in a short time, I believe. But I will say, Tom Swift, that, between us, we have made a compound that is absolutely fatal to fires. Even a small quantity of it, dropped in the heart of a large blaze, will stop combustion."

"And that's what I want," declared Tom. "I think I shall go ahead now, and proceed with the manufacture of the stuff on a large scale."

"And what do you propose doing with it?" asked Mr. Baxter.

"I'm going to sell the patent and the idea that goes with it to as many large cities as I can," Tom answered. "I'll even manufacture the airships that are needed to carry the stuff over the tops of blazing skyscrapers, dropping it down. I'll supply complete aerial fire-fighting plants."

"And I think you'll do a good business," said the chemist.

It was the conclusion of the final tests of an improved chemical mixture, and the reaction that had taken place in the test tube was the end of the experiment. Success was now again on the side of Tom Swift.

But when that has been said there remains the fact that it was just the other way with the unfortunate Mr. Baxter.

Try as he had, he could not succeed in getting the right chemical combination to perfect the dye process imparted to him by his late French friend. With the disappearance of the secret formulae went the good luck of Josephus Baxter.

He had worked hard, taking advantage of Tom's generosity, to bring back to his memory