CHAPTER VII.
Teddy was thrown down by the concussion, and fell in a heap againstthe commandant. He leaped to his feet and rushed to the window, fromwhich the glass had disappeared. He saw the remnants of the sheet offlame dying away and saw that the low-lying cloud of mist had beenblown from the surface of the ice. A gaping orifice, five hundred feetacross, showed itself where Teddy and the lieutenant had been working.Of the lieutenant and his men no trace could be seen. Two or three ofthe little red flags that had marked the path through the mist stillremained, however, and a small sledge was lying, overturned, beside thesledge route. Four tiny black figures lay in twisted attitudes besidethe sledge. As Teddy looked one of them began to struggle feebly.
Teddy stared, speechless. For a moment he was dazed by the suddennessand the overwhelming nature of the calamity that had befallen theyoung lieutenant and his detachment. Only accident had saved him froma similar fate. Then his professional instinct re-asserted itself, andhe began to piece together what he knew of the bomb. In a moment thesolution came to him.
"Varrhus planned this," he said unsteadily. "He filled up his hollowcold bombs with solid iron. The heat that would come in would firstmelt and then vaporize the interior until the pressure inside was morethan the still-solid crust could stand. And all that vaporized ironwould burst out. What a fiend that man must be!"
An hour later, baffled and discouraged, he was sitting in thelaboratory with his head in his hands, trying desperately to grapplewith this new problem. The new cold bombs apparently could not beassailed without destruction of those who attacked them. It wasimpossible to imagine that volunteers could be found to sacrificetheir lives to destroy each new bomb as it was placed. The horror ofbeing annihilated by a blast of metallic vapor would deter men whowould not hesitate to face death in a less terrible form. And Varrhuswas evidently able to place them again nearly as fast as they wereblown up. Telegrams announcing the explosion of the Jacksonville andCharleston ice floes lay before Teddy, supplemented by a cablegram fromPanama saying that the Miraflores Locks had been destroyed by the blastwhen the Panama cold bomb had burst. Teddy was nearly certain that thenext morning would find the exploded bombs replaced. Varrhus' blackflyer was evidently capable of carrying a great weight at an immensespeed. It also seemed able to reach an almost incredible height, fromthe fact that the second cold bomb had been dropped in the Narrows inbroad daylight without the flyer having been sighted.
Evelyn turned from the instruments with which she had been working. Shehad scraped off a small bit of the lacquerlike surface of the silverbracelet, and had been analyzing it in the hope of finding what elementor combination had been used to produce the mystifying heat-inductiveeffect.
"Teddy," she said depressedly, "I can't find a thing. The lacquereffect seems to be simply the appearance of some way he has treatedthe metal. The surface gives just the same analysis as the filings fromthe inside of the metal. I took a spectro photo and it gives silverlines with a trace of lead. Analysis by arsenic reduction gives thesame result."
"Perhaps those detectives will be able to trace Varrhus by the mailingbox they took," said Teddy, without much hope. "It's not very likely,though. We've _got_ to think of something!"
Silence fell in the laboratory again, broken only by the faintwhistling sound of the flame Evelyn had used in her analytical work.
"The trouble is," said Teddy grimly, "that we've been _trailing_Varrhus, instead of anticipating him. If we could know where he wasgoing to be----"
"He'll have to show up sooner or later," Evelyn commented. "We know,for instance, that he'll have to replace that bomb in the Narrows orlet the harbor stay open. The use of these new explosive bombs meansthat he has to expose himself more than he'd have to with the old ones."
"There ought to be an a?rial patrol above the city----"
Teddy stood up sluggishly, discouragement in every line of his figure.A servant tapped on the door of the laboratory.
"Lieutenant Davis, of the military flying corps, sir."
"Show him in," said Teddy listlessly.
A slim young officer came in. His friendly, boyish face was full of awhimsical humor.
"This is rather an intrusion, I'm afraid," he said half apologetically,"but I thought you might be able to help me out."
"I've done nothing so far," said Teddy in a rather discouraged tone."Miss Hawkins and I were just canvassing the situation. You're talkingabout the iceberg and Varrhus, aren't you?"
"Of course. No one talks about anything else nowadays. My taxi hada tough time getting through the crowds on the streets. They don'tunderstand about the explosion in the Narrows yet."
Teddy introduced him to Evelyn.
"Pleasure, I'm sure," said Davis with a smile. Then his face sobered."That was rotten hard luck about your father, Miss Hawkins. I'm notgood at making speeches, but I hope you realize that every one issympathizing with you and in a measure sharing your sorrow."
Evelyn shook hands.
"I will allow myself to grieve when Varrhus has been disposed of," shesaid quietly. "Until then I dare not let myself think."
Davis released her hand and turned to Teddy.
"Varrhus--or the chap in the black flyer, anyway--killed my bestfriend, Curtiss. He was driving the little Nieuport that attackedVarrhus the day you blew up the first bomb. I was the first man toreach the spot where Curtiss had crashed, and I swore I'd get Varrhusfor that."
"I remember," said Teddy. "Frozen."
Davis nodded, his face grave.
"I have what is probably the fastest little machine in the UnitedStates, at the fort. A two-seater, with twin Liberty Motors that shoother up to a hundred and fifty miles an hour without any trouble atall. I think I can get Varrhus with it. I came to you to learn what youthink about Varrhus' weapons. It's only the part of wisdom to learn allyou can about your opponent, you know."
Teddy found the young man impressing him very favorably.
"I haven't given the matter much thought," he confessed, "but youremember Varrhus' tactics?"
"He dropped like a tumbler pigeon," said Davis, "and Curtiss overshothim. There wasn't a sign of firing except from Curtiss. He simplyoverran the place where Varrhus had been three or four seconds beforeand then dropped. He was frozen stiff when I found him."
"I think," said Teddy carefully, "that Varrhus had shot up a jet ofsome liquified gas, probably hydrogen. It hung suspended in the air fora moment, and in that moment the biplane ran into it. A drop of liquidhydrogen placed in the palm of your hand would freeze your arm solidlyup well past the elbow. It's something over five hundred degrees belowzero. Your friend ran into what amounted to a shower of it."
Davis considered:
"Cheerful thing to fight against, isn't it?" he asked, with a smile."Tactics, mustn't run above the black flyer and mustn't run below it.He can probably shoot it straight down, too."
"And almost certainly from the sides," said Teddy. "The man must havebeen working on this thing for years, and even if he's insane he'd be afool not to make his weapon as efficient as possible."
Davis' expression became rueful.
"And so I'm supposed to keep my distance," he remarked, "and take potshots at him while dancing merrily around in mid-air. Can't we doanything about that stuff to nullify it?"
"Burn it," suggested Evelyn. "Liquid hydrogen burns just as readily asthe same gas at normal temperatures."
The three of them were silent for a moment.
"Would rockets set it afire?" asked Davis presently. "I could keep astream of fire balls shooting out before my machine."
"They ought to." Teddy was losing his discouragement in this newprospect of coming to grips with Varrhus. "I say, will your machineburn readily?"
"Only the gas tank. The wings and struts are fireproof. New process."
Davis stood up suddenly.
"Would it bother you to come over and look at my machine? We couldprobably figure out the thing better then."
Teddy rose almost enth
usiastically.
"We'll go over now if you say so."
The taxicab bearing Teddy and the young aviator down to the fort wasforced to travel slowly amid the throngs of apprehensive people thatoverflowed the sidewalks and made the streets almost impassable. Thelaunch took them swiftly to the fort, and in a few moments they hadarrived at the small aviation field behind the fortifications onStaten Island. Davis led Teddy directly to the shed that contained theswift machine of which he was so proud. It was a splendid product ofthe aircraft maker's art. Twin Liberty Motors developed nearly eighthundred horse power between them, and two great shining propellerspulled the machine through the air with irresistible force.
"You see," said Davis, with some enthusiasm, "the motors aren't in thefusilage, so the gunner sits up here in the bow and can fire freelyin any direction. The one-man planes with synchronized machine gunsfiring through the propeller aren't in it with these for real fighting.They're splendid little machines--I drove one in France--but I honestlybelieve this is better than they are. This one responds to thecontrols every bit as readily, and with a good gunner----"
"Machine gunner in France myself," said Teddy, touching his breast."Would you take a chance on letting me sit up front to-night?"
"To-night?" asked Davis.
"I believe Varrhus will appear to drop another cold bomb to-night. Itwill probably be dropped inside the harbor so the ice cake will touchthe Battery. That will set the people frantic, and make them beg thegovernment to enter into a parley with Varrhus. It's paid no officialattention to him so far, you know."
Davis' expression became keen and rather stern.
"We've four hours before dark. We'll have to set to work."
Teddy went over and stepped up the ladder that leaned against thecockpit.
"I want to see your gasoline supply," he remarked. In a moment hecame down, looking a trifle dubious. "If I'm right about Varrhususing liquid hydrogen for a weapon, and we can set it afire, we'lldive through half a dozen sheets of flame to-night. Something willhave to be done to protect that gas tank from catching fire, and someprotection for the carburetors, too."
"We'll fix that in a hurry," said Davis briskly. "Oh, Simpson! Comehere!"
In twenty minutes there were half a dozen mechanicians at work, andTeddy was carefully inspecting the machine gun at the bow of thefusilage.
Teddy telephoned back to Evelyn what he anticipated would occur thatnight and his own share in it.
"Of course there's some risk in it," he finished, "but I guess we'llcome out."
Evelyn's voice was more anxious than Teddy had expected.
"Do be careful, Teddy," she said in a worried tone. "Please be verycareful. Varrhus has so many fiendish weapons. I'm terribly afraid."
Teddy's voice was grim.
"With the kind assistance of the German government," he remarked, "wehave a few fiendish inventions, too. I'm using explosive bullets onlyto-night. Varrhus is outlawed."
Evelyn spoke almost faintly.
"But take good care of yourself, please, Teddy," she urged. "It werebetter that Varrhus got away this once than that you should be killedfor nothing."
Teddy smiled. "I've no intention of being killed, Evelyn, but I havesome intention that Varrhus shall be."
There was a curious sound from the other end of the wire.
"But--but----" Evelyn's voice died away. "I'm--I'm going to be praying,Teddy. Good-by."
The last was very faint. Teddy turned from the instrument and wentout to where the a?roplane had been rolled from its shed. The sun wassinking and dusk was falling. Time passed and darkness settled downupon the earth. Stars twinkled into being. A long searchlight poked atentative finger of light into the sky.
"We'd better be going," said Davis thoughtfully. "We want to be well upbefore he appears."
Teddy clambered up to his seat and adjusted the straps that wouldhold him in place. He pulled down the helmet and fitted the telephonereceivers securely over his ears. A telephone was necessary forcommunication with Davis, four feet behind him, because of thetremendous roar of the engines. He took the machine-gun butt and foundthe trigger, then made sure the first of a belt of cartridges was inplace. He settled back in his seat as the mechanics began to twirlthe propellers. He was going out to fight the black flyer, but mostincongruously he was not thinking of Varrhus at all. His thoughts dweltwith strange intensity upon Evelyn.