can't do a thing with Boomerang when he sees fire."

"Now dat's so, Massa Tom. But I could put blinkers on him, an'—"

"No, you let Boomerang stay where he is. Come on, Ned. We'll see what we can do. Mr. Damon—"

"Yes, Tom, I'm right here," answered the peculiar man, for he had come over from his home in Waterford to pay a visit to his friends, Tom and Mr. Swift. "I'll do anything I can to help you, Tom, bless my necktie!" he went on. "Only say the word!"

"We've got to get some of the stuff out of the place!" Tom cried. "We may be able to save it, but I can't take a chance on putting out the fire and letting some of the things in there go up in smoke. Come on!"

Those in the shed where was housed what Tom hoped would prove to be a successful aerial warship rushed to the open. From the other shops and buildings nearby were pouring men and boys, for the Swift plant employed a number of hands now.

Above the shouts and yells, above the crackle of flames, could be heard the clanging of the alarm bell, set ringing by Koku, who had pulled the signal in the airship shed. From there it had gone to every building in the plant, being relayed by the telephone operator, whose duty it was to look after that.

"My, you've got a big enough fire-fighting force, Tom!" cried Ned in his chum's ear.

"Yes, I guess we can master it, if it hasn't gotten the best of us. Say, it's going some, though!"

Tom pointed to where a shed, painted red—a sign of danger—could be seen partly enveloped in smoke, amid the black clouds of which shot out red tongues of flame.

"What have you got it painted red for?" Ned asked pantingly, as they ran on.

"Because—" Tom began, but the rest of the sentence was lost in a yell.

Tom had caught sight of Eradicate and the giant, Koku, unreeling from a central standpipe a long line of hose.

"Don't take that!" Tom cried. "Don't use that hose! Drop it!"

"What's the matter? Is it rotten?" Ned wanted to know.

"No, but if they pull it out the water will be turned on automatically."

"Well, isn't that what you want at a fire—water?" Ned demanded.

"Not at this fire," was Tom's answer. "There's a lot of calcium carbide in that red shed—that's why it's red—to warn the men of danger. You know what happens when water gets on carbide—there's an explosion, and there's enough carbide in that shed to send the whole works sky high.

"Drop that hose!" yelled Tom in louder tones. "Drop it, Rad—Koku! Do you want to kill us all!"

CHAPTER III

A DESPERATE BATTLE

Tom's tones and voice were so insistent that the giant and the colored man had no choice but to obey. They dropped the hose which, half unreeled, lay like some twisted snake in the grass. Had it been pulled out all the way the water would have spurted from the nozzle, for it was of the automatic variety, with which Tom had equipped all his plant.

"But what are you going to do, Tom, if you don't use water?" asked Ned, wonderingly.

"I don't know—yet, but I know water is the worst thing you can put on carbide," returned Tom. For all he spoke Slowly his brain was working fast. Already, even now, he was planning how best to give battle to the flames.

It needed but an instant's thought on the part of Ned to make him understand that Tom was right. It would be well-nigh fatal to use water on carbide. Those of you who have bicycle lanterns, in which that not very pleasant-smelling chemical is used, know that if a few drops of water are allowed to drip slowly on the gray crystals acetylene gas is generated, which makes a brilliant light. But, if the water drips too fast, the gas is generated too quickly, and an explosion results. In lamps, of course, and in lighting plants where carbide is used, there are automatic arrangements to prevent the water flowing too freely to the chemical. But Tom knew if the hose were turned on the fire in the red shed a great explosion would result, for some of the tins of carbide would be melted by the heat.

Yet the fire needed to be coped with. Already the flames were coming through the roof, and the windows and door were spouting red fire and volumes of smoke.

Several other employees of Tom's plant had made ready to unreel more hose, but the warning of the young inventor, shouted to Eradicate and Koku, had had its effect. Every man dropped the line he had begun to unreel.

"Ha! Massa Tom say drop de hose, but how yo' gwine t' squirt watah on a fire wifout a hose; answer me dat?" and Eradicate looked at Koku.

"Me no know," was the slow answer. "I guess Koku go pull shed down and stamp out fire."

"Huh! Maybe yo' could do dat in cannibal land, where yo' all come from," spoke Eradicate, "but yo' can't do dat heah! 'Sides, de red shed will blow up soon. Dere's suffin' else in dere except carbide, an' dat's gwine t' go up soon, dat's suah!"

"Maybe you get your strong man-mule, Boomerang," suggested Koku. "Nothing ever hurt him—explosion or nothing. He can kick shed all to pieces, and put out fire."

"Dat's what I wanted t' do, but Massa Tom say I cain't," explained the colored man. "Golly! Look at dat fire!"

Indeed the blaze was now assuming alarming proportions. The red shed, which was not a small structure, was blazing on all sides. About it stood the men from the various shops.

"Tom, you must do something," said Mr. Swift. "If the flames once reach that helmanite—"

"I know, Father. But that explosive is in double vacuum containers, and it will be safe for some time yet. Besides, it's in the cellar. It's the carbide I'm most worried about. We daren't use water."

"But something will have to be done!" exclaimed Mr. Damon. "Bless my red necktie, if we don't—"

"Better get back a way," suggested Tom. "Something may go off!"

His words of warning had their effect, and the whole circle moved back several paces.

"Is there anything of value in the shed?" asked Ned.

"I should say there was!" Tom answered. "I hoped we could get some of them out, but we can't now—until the fire dies down a bit, at any rate."

"Look, Tom! The pattern shop roof is catching!" shouted Mr. Swift, pointing to where a little spurt of flame showed on the roof of a distant building.

"It's from sparks!" Tom said.

"Any danger of using water there?" Ned wanted to know.

"No, use all you like! That's the only thing to do. Come on, you with the hose!" Tom yelled. "Save the other buildings!"

"But are you going to let the red shed burn?" asked Mr. Swift. "You know what it means, Tom."

"Yes, Father, I know. And I'm going to fight that fire in a new way. But we must save the other buildings, too. Play water on all the other sheds and structures!" ordered the young inventor. "I'll tackle this one myself. Oh, Ned!" he called.

"Yes," answered his chum. "What is it?"

"You take charge of protecting the place where the new aerial warship is stored. Will you? I can't afford to lose that."

"I'll look after it, Tom. No harm in using water there, though; is there?"

"Not if you don't use too much. Some of the woodwork isn't varnished yet, and I wouldn't want it to be wet. But do the best you can. Take Koku and Eradicate with you. They can't do any good here."

"Do you mean to say you're going to give up and let this burn?"

"Not a bit of it, Ned. But I have another plan I want to try. Lively now! The wind's changing, and it's blowing over toward my aerial warship shed. If that catches—"

Tom shook his head protestingly, and Ned set off on the run, calling to the colored man and the giant to get out another line of hose.

"I wonder what Tom is going to do?" mused Ned, as he neared the big shed he and the others had left on the alarm of fire.

Tom, himself, seemed in no doubt as to his procedure. With one look at the blazing red shed, as if to form an