“And with all those you have a glider,” agreed Bob. “The engine, and its ‘prop’ are for motive power, and the landing group, either wheels for the earth, or pontoons for the water, or both, combined, in an amphibian, for land-and-water use——”
“We know some things,” agreed Curt. “But we don’t know where Mr. Tredway’s body went—or——”
“What Griff is going to do with his Saturday afternoon,” commented Bob. “I’m going back to the plant, and pretend to finish up work, and see what happens there while it’s supposed to be closed down.”
The others agreed. Something might “break.” Actually, something did!
Although the aircraft manufacturing plant observed a forty-four hour week, closing down on Saturday afternoons, when the three members of the Sky Squad returned, about two o’clock, they were somewhat startled to discover that their “suspects” were there.
Bob, entering the engine section, discovered Griff.
The youth was surprised, “caught in the act!” mused Bob as he saw the youth, with furtive, hasty actions, completing the wrappings of a smallish package which he hurriedly slipped into his coat as he turned aside, trying to conceal his action from Bob and then, noting that he was caught, trying to pass it off as an ordinary action.
“So that’s where some of the smaller parts are going,” Bob concluded, pretending not to be aware that anything was wrong.
“Hello,” he greeted. “I thought I’d come back and take that model engine apart, while no one was here to bother me, so I can get it straight in my head just how the valves operate.”
“Yeah?” Griff was inclined to be gruff, and as he tinkered around trying to pretend to be busy, but, to Bob’s notion, watching the member of the Sky Squad, the latter gave every impression he could of ignorance that he was being supervised, studied, observed.
Had Griff been intruded upon before he finished what he had been doing? Bob wondered as he took off the cylinder head of a small, roughly assembled model of a new design for a Vee-type motor they were working on. It appeared that Mr. Tredway had been “all for” the newer radial engines, while Mr. Parsons exerted all his influence to introduce the model in which the cylinders, in line, came together in a slanting fashion, like a “V” at the crankcase jointure.
Bob took out pistons and pretended to examine the crankpin assembly.
Griff watched covertly and appeared to be exceptionally uneasy.
Curt entered from the wing assembly rooms.
“Hello, Griff.” He nodded, paid little attention to Griff and went over to Bob.
“Interesting?” he hinted. Bob nodded, and began to explain the parts.
“I see.” Curt, bent close, whispered his next words. “Lang is out in the yard, working on the Golden Dart. He has the plates out and he is——”
As he spoke Lang came in.
“Say, Curt,” he called, “run up to the offices, and if Mr. Parsons or Barney is around, get me a new—er—length of cable, will you?”
“Will they give it to me?”
“Sure.”
“Supposing there’s nobody around. The office is closed.”
“Go to the supply room, on the ground floor. The watchman will let you get what you want. All you have to do is to write out a requisition form and put it on the spindle on the desk. You’ll see it.”
“Can you get supplies as easily as that?” Bob asked.
“Surely! Why not?”
Curt and Bob made no comment. The former went to execute Lang’s request.
In the offices, as he neared the open door of the bookkeeper’s little cubby of a room, Curt heard two low voices. He hesitated. He was close enough to be able to recognize in the bent figure leaning over the other, with his back turned, the peculiarly checked brown suit which identified Mr. Parsons.
Evidently neither the partner nor his companion heard Curt, so absorbed were they in some discussion or comparison of figures.
Curt, wondering why they were so engrossed in that work when the office was closed, and so absorbed that they had not heard him—he had not tried to snoop or to creep along the hall!—decided that it must be legitimate business, and that he would not disturb them.
He went on beyond to the rear stairway and down, looking for the watchman.
Al found him there.
“How do you get into the supply room?” asked Al.
“That’s what I’m trying to do. What’s that you’re carrying?”
“It’s an earth inductor compass,” Al explained. “You heard Sandy hail me as we came in.” Curt nodded. “He stayed on to check up my work,” Al informed him. “I’m pretty raw, you know, and Sandy is so good-natured that he didn’t want to see me get into any trouble. I was helping one of the mechs this morning”—he had already picked up some of the slang, shortening “mechanic” as did those in the plant—“and Sandy was going over the instruments I had installed. That Golden Dart is going to be used for an overseas hop, he says—and—” he went close to Curt, “Curt, I think Sandy has helped us to get a line on somebody else to suspect—about the stolen parts, anyhow.”
“How?”
“He called me over and told me, in a joking way, I had a lot to learn. And then he asked me if I knew anything about how this new type compass operated. I knew a little, but not much, and he showed me how little I knew. Curt—” he was very serious—“this is an old, broken thing. Look!”
He indicated the failure of the parts to operate correctly.
“If we’d let that get to the checker, Monday, I’d have been suspected of getting away with the regular, real one. This must have been substituted by the mechanic who was on that job—the one I helped. Or else it was given out by the clerk who has charge of this room. Anyhow, Sandy says I ought to put in a requisition for another one, and then he is going to help me keep an eye out to see what happens on Monday. He wants to help us. I saw he was so afraid I’d get the blame, and he’s so mad about the way things are being taken that I let him in on our secret——”
“About being detectives?”
“Well, only as far as saying we were crazy about aviation and had formed a sort of order we call the Sky Squad, and naturally, being honest, we saw how things were going here and wanted to do what we could to discover who is taking parts.”
“And what did he say about it?”
“He said not to be too hasty to jump to conclusions. He told me that this substituting of the old inductor compass looked like the work of the mech, but it could be the supply clerk, or, maybe, somebody outside the plant entirely who had sent it in, boxed, in a new consignment. He said the safest way would be to put in a new requisition, then we’d see who acted guilty when it was discovered. If the supply clerk is guilty he would never mention it for fear of being caught. If the mech is the culprit, the clerk will raise a howl about the exchange. If they are both innocent, you’ll hear from both of them, and we can trace it to somebody who sent the consignment.”
“Good stuff!” agreed Curt. “But didn’t the mechanic notice it was a broken model of the compass?”
“He gave me the instructions how to assemble it and told me to be careful, and then went over to work on that small speed craft that Griff is testing out. Griff called him, so it looks all right. If the mech noticed this old compass, before he went home, he’ll tell me, first thing Monday. If he knew about it and had taken the other, the good one——”
“He’ll lay low. I see.”
The watchman, making his rounds, observed the pair. Readily enough he admitted them to the supply department. Either he was of too unsuspicious a nature, being rather dull, to wonder or question; or he had been told by Barney that the youths were especially privileged. In either case he made no comment as they found the cable Curt wanted for Lang and the several extra inductor compasses, neatly boxed, among the stacked instruments in the shelves.
Making out two of the slips he saw in a pad, and fixing them on the upstanding spike of a file, Curt handed Al his box and with the cable went to find Lang.
Handing the strand to his chum’s cousin, Curt decided to return to the office building to see what he might see. The excuse that he was studying the blue prints of an airplane would furnish reason for his presence in the office if Mr. Parsons was still there and asked.
Bob, as Lang left, found Griff suddenly and unaccountably pleasant.
“Funny about that cable,” he remarked.
“Sure is,” admitted Bob, watchful, quiet, but willing to follow Griff’s unexpected lead.
“Lang says you had your suspicions of me,” Griff grinned, quite pleasantly. Had he, Bob wondered, been “tipped” by Lang to cultivate friendship? Was there something really underneath the friendship of the partner’s son and Bob’s pilot cousin? Was there something else?
“Why, I suppose when we got excited about that broken rudder pull, we thought of anything and everything,” Bob grinned also.
“Well, you thought wrong, friend. Would you try to do any harm to your buddy, Curtis, if you knew he was to fly a certain crate?”
“No,” Bob admitted, honestly and fervently.
“But some other pilot, jealous, maybe—might! Eh?”
Bob had not in any way considered that possible solution. There was another test pilot, not as popular as his cousin. He gave the most serious attention, but Griff evidently felt that he had said enough, adding only: “But I don’t mean to accuse anybody. Let’s forget it. Come on, let’s forget motors and go up and have a look at them little fleecy clouds.” He caught Bob’s arm, after slipping the cylinder head over the pistons of the model with Bob’s help.
“Ever fly a crate?” he asked.
“Not solo!” Bob admitted, “but Lang has let me take the controls six or seven times when he used to take us up, before we came here to——”
“To what?”
“To learn all there is about building airplanes,” Bob continued without the flicker of an eyelash.
“Hm-m-m! Well, come on, kidlets! I’ll take you up in the prettiest little crate you ever sat in—what’s more, I’ll give you some experience so you can fly them crates after you get wise to how they’re assembled.”
It was evidently a genuinely friendly offer. If it had any hidden motives, Bob, on that sunny Saturday, with a gentle, warm vacation wind blowing, with bonny clouds drifting slowly, gave up watching and went in for air experience.
Al, finally deserted by Sandy, who had errands down town, saw Bob and Griff warm up the little speed sportster he had been rigging. A little envious he watched the check-up, the trial spurts of the fast little engine, the take-off and the soaring of the handsomely designed craft. Then he went on to visit Jimmy-junior, whose father, Sandy, had given him a special invitation to spend the afternoon and to stay to dinner with Jimmy-junior.
Lang, taking the cabin monoplane for a test of his rudder performance, called Curt to go along; so the trio lost interest in detective work and concentrated on enjoyment——
Until evening!
While Griff, who handled an airplane expertly, was executing dives and slips, barrel rolls and figure eights, and a loop or so to demonstrate his skill, Bob, in the rear cockpit seat, wondered whether Griff was trying to frighten him.
That was not his purpose, Bob decided, and he was more convinced when Griff, with a grin, turned, after waggling the stick and holding both hands up beside his head—the signal to “take control.”
Bob nodded.
Under Lang’s tuition, in several airplanes, during tests, Bob had been permitted to handle the stick, rudder and throttle. He knew the elementary movements of straight flying and had some of “the feel of the air” which comes to any person who has the flying sense: that “feel of the air” is akin to knowing what the ship is going to do and, of course, sensing how to meet its various tendencies. When, during a climb, with too steep an angle, the controls begin to get “loggy” for an example, the born pilot, or the trained fellow with his air-sense developed, knows instinctively that the ship is about to stall, and automatically drops the nose and picks up flying speed.
For awhile Bob, flying straight, or banking and turning, remained near the small flying field of the plant. He knew the signals with which a flying instructor guides his pupil, and, handling the dual control section in his own hands, and with his feet, he made simple maneuvers under Griff’s direction, and seemed to please Griff by the quickness with which he caught the corrections signaled to him when he over-banked, or let the ship skid too long without catching the skid.
The trial was over all too soon, and as Griff took over to shoot the field and set down, the most ticklish part of flying tactics, Bob felt a trifle sheepish for having suspected him.
Griff was, really, quite a pleasant fellow.
However, Bob began to think. This sudden affable manner must have some reason behind it. Furthermore, he decided, Griff might be trying to win his confidence through the hidden flattery of telling Bob what a “corking” pilot he would make with a little more training. Bob knew that flying is taught carefully by any self-respecting school, that a thorough ground-school training and many hours of instructed flight will be followed by many solo flights, with intermittent check flights under the instructor’s eyes, before a pilot is considered more than a student. Griff over-flattered.
Bob, as he went home, where Al and Lang had preceded him, his cousin having stopped in for dinner, decided that he would accept Griff’s offered friendship with a grain of salt.
Al was there, of course, but no confidences were exchanged.
Al had already eaten his dinner, with Jimmy-junior, after a fun-filled afternoon during which Jimmy had displayed his airplane models, had supervised many trials while he let his guest wind the sturdy rubber band motors and set the tiny, practicable controls of the toys. Furthermore, he had talked about the Sky Squad idea and had begged to be permitted to join, being air-crazy, as he put it. Al, promising to take the matter up with his brother and with Curt, had said he would do all he could to induce them to agree. He could not broach the matter, however, as Curt, Bob and Lang ate, because Lang was full of the excitement of receiving a telegram from Bob’s and Al’s father, the detective, from a city about fifty miles away, asking Lang to come to the city for a report and a conference.
Glancing at Bob, both Curt and Al saw that the older member of the secret membership was disturbed in his mind. Lang would not tell about Griff, as he visited his uncle over Sunday. That was what Bob was thinking, as Al and Curt saw. But Curt, looking at his watch, reminded Lang that he must stop stuffing down the filet of sole, a form of fish steaks of which he was extremely fond, if he expected to “make” the ’bus that would pass the house on the way to the city, and the railway station.
“I’m going to fly!” Lang declared, reaching for more fish.
“Why not take us, then?” demanded Al.
“No. I’m going to borrow Griff’s sport model. More speedy and I want to check before it is turned over to him finally.”
“There’d be room for one of us,” Bob spoke up.
“No sirree!” and they knew why Lang was so snappish.
Bob pushed back his chair as Al and Curt sprang up. Lang, rising with his superior, amused grin at their anxiety, waved them back and kissing his aunt and thanking her for the fish he loved, he departed.
“I’m going!” said Bob, and explained excitedly to his mother that he had information of importance.
“Lang will tell it,” she said. “Explain to him.”
Bob’s face fell, as did Al’s. They were in a box!
They could not explain to their mother that they suspected Lang, at the very least, of protecting Griff, a friend but not a desirable one. Whatever their own ideas they were none of them blabbers.
Bob ran out on the porch, leaped down the steps, hopped on his bicycle and pedaled down the first side street. He was not entirely sure of his plans, perhaps he half intended to secrete himself in the fuselage of the ’plane, to go on as an unsuspected passenger; possibly he hoped to induce Lang to take him by getting there first.
At any rate, as he neared the plant, he was glad he had come.
Griff, at the gate, was in close communication with a mysteriously furtive stranger!
Twisting his handlebars sharply, Bob sent his bicycle into brush at the end of the aircraft plant grounds where the fence turned; he wanted to get out of sight.
The pair at the gate were having some sort of argument and probably had been too excited and absorbed to notice him, Bob decided.
He dropped his wheel and crept back to the corner of the fenced enclosure to watch.
From that position he could see the man, but only part of Griff’s coat and an arm. The man, as he saw, was vigorously arguing. Griff must have been either pleading or arguing, Bob guessed, from the man’s violent gestures and appearance of “laying down the law.”
Presently a small, flat package came into view.
Bob recalled that he had seen Griff wrapping exactly that sort of parcel earlier.
The man took it, put it rapidly into his coat pocket, inside. With a quick look up and down the deserted highway he swung and crossed to a car parked on the opposite side of the road. Climbing in he speeded up his engine and drove away at constantly increasing speed.
“So they are dividing the ‘spoils’—or Griff was giving him money.” Bob, unable to see Griff, not daring to emerge from his concealment, made the deduction under his breath. “Well, now shall I follow that man? No, because his car is too fast. I can’t catch him on my wheel.”
He decided to wait where he was, to see what would happen. To go in at once might alarm Griff. He might realize that Bob had been near enough to see what had occurred; he might suspect. Bob wanted to keep his presence unknown; Griff had already been warned by Lang; he would jump to the conclusion that Bob was watching.
Almost at once Bob thanked his good sense for holding him concealed.
Griff, as he watched, ran wildly out into the road and began to wave and shout after the receding car.
Its driver did not turn around.
Griff, while Bob stared, dashed back into the gateway. For a moment Bob wondered where the watchman was, then he saw the man, in a small ice-cream and soda water shack, a little distance down the road opposite the fenced property. Griff, Bob guessed, had offered to watch the gate while the man refreshed himself.
Bob hesitated. Where had Griff gone? What was he doing?
The last question was answered by the pop-pop of a motor. Bob knew that Griff rode a motorcycle. He was getting it started. He meant to pursue that car for some reason. Something had caused him to want to talk again with the car driver, Bob mused.
While he watched, keeping all but his head concealed, the motorcycle, with Griff mounted on it, came sputtering into view.
Never glancing around, opening his throttle, he pelted down the road after the car.
Bob, without hesitation, rushed his bicycle into the highway and pedaled after the motorcycle for all he was worth. Griff was too intent on his purpose to notice, he felt sure.
It would be a losing race, Bob feared, unless Griff overtook that rapidly receding car very soon. Muscles could not endure against a machine! Nevertheless Bob rode as fast as his pedals would turn.
As he sent the wheels spinning along it crossed his mind that Lang would be arriving at the plant almost any moment but he kept on all the same.
“It will take Lang awhile to warm up the engine, and, anyway, if I don’t go with him I know another way to communicate with father,” he decided.
The car was almost out of Bob’s sight, the motorcycle was rapidly overtaking it.
At that instant Bob’s heart almost stopped beating!
Far ahead, on a cross road, he saw a huge truck come into view. It was not only between the car and its pursuer; it was also well onto the road and almost directly in front of the motorcycle.
“Griff!” Bob shouted, without thinking that his voice would never be heard. He instinctively cried a warning. If the rider had his head low over his handlebars!——
His coaster brake jammed on, Bob slowed, alighted, his muscles refusing to function for the instant.
But during that instant Griff evidently saw the huge obstacle and swerved. In making the wild curve to go around the rear of the truck Bob saw the youth and cycle go off the road into the ditch.
Evidently unaware that anything had happened the truck driver kept on down the cross road. Bob, remounting, pedaled for all he was worth toward the scene of the accident. As he rode swiftly he saw other figures approaching.
At the point where the motorcycle lay on its side, he was met by Al and Curt, who had been approaching from the opposite way, up the side road. “We decided to come and see Lang hop off,” Al explained as the trio ran toward Griff.
He was sitting up, a little shaken, a little dazed, when they approached. Bob, seeing that he did not appear to be seriously hurt, caught Curt’s arm. “Look here,” he said quickly, “I want to go with Lang. Don’t say I was following—you know—keep it quiet. I must get to see father and tell him——”
“All right. Don’t waste any time. Get out of sight. I’ll tell Al.”
Bob hurried off, as though he was in search of aid, and he felt, as he pedaled back toward the field, that Griff probably had been too much shaken to notice that Bob had come from the direction he had been riding, or deduce that Bob had followed him.
The watchman, and several others from the soda stand came running down the road. They called out as he approached and with a brief explanation that there had been a “spill” but that he thought it was not serious, Bob rode on.
He found Lang riding toward the plant, and swung his bicycle in at the gate and set it against the fence.
“What’s the trouble, up there?”
“Griff took a spill going around the back of a truck that came out of the side road. I think he’s all right.” Bob called out his answer to Lang’s shouted inquiry and saw his cousin ride on to investigate.
Bob, with some idea in his mind that he might crawl into the fuselage of the small speed ’plane, and, thus stowed away, be carried to the city from which his father had telegraphed, changed his mind. The close, smothery fuselage, subjected to the most violent rolling and heaving of the airplane’s progress, would probably make him ill. He preferred to stay outside, to see what happened, and to compel Langley to take him as a passenger.
Watching from the gateway he saw that Griff had been lifted to his feet and had apparently found himself only rather badly shaken. This was Bob’s decision because he saw a passing car driver help the shaken youth into his car, tumble the motorcycle out of the grass and turn it over to the plant watchman to be trundled back, and drive off to take Griff home, it seemed.
Bob met Lang beside the propeller of the little speed craft.
“Get the ignition key from Griff?” he asked.
“I did.”
“Climb in. I’ll give the prop a twist for you.”
Langley got himself set.
“Gas on?” called Bob.
“Gas on.”
“Switch off?”
“Switch off!”
Bob gave the propeller a couple of revolutions.
“Contact!” he cried, leaping aside to avoid the flailing, knife-like edges of the blades. The engine caught on the touch of spark to compressed gas mixture.
While Langley opened the throttle and warmed up his engine, Bob unconcernedly began to clamber into the after cockpit seat.
“You’re not going!”
“Oh, yes, I am.”
“Get out of there!”
“Listen, Lang,” Bob leaned close to Lang’s ear to carry his message above the noise of the radial engine, “which suits you best? To have me with you, to tell dad what I know before your face—or to have me telegraph him while you’re on your way, and let you explain to him what I have to tell?”
Lang, at first furious, presently saw the logic of Bob’s position.
“Oh—all right!” he grunted and “gave her the gun” in somewhat vicious spurts.
Bob, fitting on the “crash helmet” kept in the ’plane by Griff for him that afternoon, and the leather jacket and gloves, smiled.
He was progressing as a Master Sleuth, doing his share creditably for the Sky Squad.
As soon as the engine was sufficiently warm and methodical Lang had checked all his instrument readings, the trim little ship taxied down the smooth field to head into the wind which Bob saw, from the “windsock” blowing out from its mast on the office building, was from the south, a nice, light, Summer evening breeze.
The watchman, coming in, put aside the slightly damaged motorcycle and strolled across to the hangars, into one of which he stepped to throw a switch, lighting the flood light by which they could see to take off. He did not question Lang’s right to use the craft because Lang must have gotten its ignition key from Griff, its owner.
As they took the runway, and increased speed to the throaty roar of the engine, Bob felt that sense of the ship getting “light” which indicates to the pilot that she is ready to take the air. He saw the elevators tip, glancing around swiftly to check the safety of the way ahead, and then saw the lighted earth dropping, contracting into a spot of vivid light against a field otherwise dark; then the watchman shut out the floods to avoid confusing them in the air, and the ship climbed into dark night.
They had climbed several thousand feet and were headed into the north, so that Lang could “pick up” the lights of the airway along which his night flying would be easiest, when Bob saw him double unexpectedly.
For an instant the craft’s nose went almost straight down and Bob was glad he had strapped himself in; then Lang evidently caught control, and the stick, thrust forward as he doubled, with some unexpected convulsion or “stitch,” was pulled back and brought the ship out of the dive gradually.
“What happened?” Bob screamed above the engine noise, the song of wind through wires caused by their dive.
“Cramp!” called Lang, cutting the gun as he held a glide for a moment, turning a white face toward Bob. “Listen. Bob—oh!——”
He bent again. “The fish—too much fish—” Bob guessed, and had he known that Lang’s delay in reaching the field had been due to further refreshments, he would have said, “Fish—and ice-cream!”
At least that was a far more reassuring thought than Bob’s first idea, that some one had tampered with some control of this craft.
“Oh—” Evidently Lang was very ill.
Suddenly, as he saw his companion in the forward seat double, Bob felt the stick waggle against his leg.
In an interval between his spasms of violent pain, Lang held up his two hands alongside his helmet.
It was a signal for Bob to take control.
“All right!” he called, and, with a steady hand, he clutched the stick of the controls in his cockpit, set his feet against the rudder bars, and eased his throttle open to regain speed.
He was not in the least nervous or flurried. He pitied Lang’s cramped stomach and evident suffering, but did not permit it to influence his steady nerve. He had been given enough lessons to know how to hold the craft in level flight. While night flying was not as safe and easy as daytime work, he knew that if he followed the ribbon of lighted highway that ran toward the beacons of the nearest airway, he could always “set down” on the asphalt, if worst came to worst, and if he did smash the trucks, the landing gear, he did not think he would do any more serious damage.
“Had I better set down?” he shouted, gliding for speed as he cut out the engine roar. Lang shook his head and gestured forward. Evidently he was not afraid of any immediate physical collapse and preferred to go on flying to see if he would recover. Bob held on.
He picked up the beacon and, watching Lang’s gestures, swung in a long, banked curve, to head across the wind down the unconfined airway, whose second beacon he could see, far away.
By habit looking around to be sure no other ship was close as he turned, Bob, startled, saw the flying lights of another craft pursuing.
It must be pursuit! It came from the direction they had come. It turned as they turned, only in a more sharpened bank, so as to cut off part of the distance, it seemed to Bob, to close the gap between them.
“Lang!” he shouted, and waggled the stick.
Lang looked around.
Bob’s arm pointed backward and upward.
Lang, leaning out of the cockpit, to see around the wing-tip, stared.
“The cabin ’plane!” he cried. “I know it. Golden Dart.”
“After us?”
“I don’t know!”
But as Bob opened the throttle to regain flying speed without having to dip down too low, there came from the other ship a red flare.
It was, as Bob realized, a signal—not of danger but of command.
“Land!” it commanded.
Bob looked at Lang.
Lang considered. As he hesitated Bob guessed his thoughts. Some one from the small field, some member of the plant staff, probably Mr. Parsons, finding the ’plane belonging to Griff gone, and hearing from the watchman who had taken it, had taken off in the cabin monoplane to stop what he probably considered a prank of Lang and Bob—some night-flying lark.
What would Lang say? Set down? Or—go on?
They could outfly that cabin ship in the speedy, easily maneuvered sport craft—or, they could, with Lang at the controls. But Lang was badly upset in his stomach. What would he decide? Bob mechanically looked around for the best spot to set down.
When he looked up again his heart leaped with exultation.
Lang’s arm pointed straight ahead!
“Go on!” he gestured.
Bob opened the throttle joyously. Here was adventure, pursuit, thrill enough to suit anyone!
Rapidly Bob considered the situation.
The speed craft he and Lang occupied had much the best of it on a straight flight, but, against that, he had to set his inexpert handling. The smaller craft could out-climb, out-maneuver the cabin ship but he had no experience in stunting, especially dangerous at night.
Therefore Lang’s decision was the safest one.
To try to make a landing, Lang evidently concluded, was not wise. He felt that he could take over the controls before that need arose, Bob guessed.
A new complication came, however.
If the cabin ship had the disadvantage of being slower, she had gained an offsetting advantage before they saw her. She was much higher in the air than their craft; she could dive, if her pilot chose, and thus close the distance between them—maybe come down “on their tail,” or ride them to earth, if her pilot proved to be determined to force them to land.
Accordingly Bob opened the throttle wider, and slightly elevated the nose to climb.
Lang, peering upward and to the rear, made a violent, vigorous gesture.
Bob, reading it, understood.
He did not question. Lang called for a sideslip!
Instantly Bob manipulated ailerons and rudder correctly and felt the wind on the cheek toward the lower side of their bank, telling him they were slipping.
Then, applying rudder and other controls to check the slip, dropping the nose again to pick up flying speed quickly, he saw why the maneuver had been executed. The cabin airplane had begun to dive down from above them. Lang, having seen it, anticipated. He had not wanted to wrest away control—too dangerous. He had risked the signal, and Bob had executed his order accurately.
He was glad, all the same, when Lang shook the stick, tapped on his own helmet to sign that he wanted the controls.
Bob relinquished them thankfully enough. At night, in strange surroundings, in an airplane he had only handled a little, he was not foolish enough to wish to risk neck and limb—far less Lang’s than his own!—by trying to outfly a pilot who evidently meant to be vicious, to resort to war tactics if they did not obey his signals.
Lang, somewhat recovered, took over and Bob, delighted, watched his expert manipulation of the splendid little ship. She answered his every command. He barrel-rolled out of the way of any immediate danger, thus leaving the cabin craft well to one side. He started up a loop after a swift dive, but at its top he executed half of a barrel-roll, and since the top of the loop had the nose in the direction opposite their course, the half-roll put the craft on its level, upright course, but going directly away from the former one.
The cabin ship could not be stunted that way, or else its pilot against his will was compelled to recognize superior tactics.
At any rate, as Lang swung around in a wide circle, slowly climbing at the same time, the other craft seemed to be heading uncertainly back.
It came around, however, as soon as Langley straightened out on the former course along the airway; but they rapidly outflew it and when they landed at an airport in the distant city suburbs, the cabin ship was nowhere in sight.
It was nearly eleven o’clock at night when Bob and Langley were ushered up the hotel elevator and along a corridor and into Mr. Wright’s rooms.
The detective, who had been apprised, long distance, by his wife, that his nephew was flying to keep the appointment, was waiting.
Hardly had his surprise at Bob’s presence been expressed and a late supper for the air-hungered pair been ordered than another visitor was announced.
“So this is where you were bound for!”
To Bob’s amazement, Barney spoke.
“Why didn’t you leave word that you were coming here?” he said, rather sharply. “We could all have come together.”
“We didn’t know you were on your way here,” said Langley.
“We thought you were chasing us,” Bob added.
“So I was. The watchman said you hopped but he didn’t say where to. I was coming over to confer with Mr. Wright, but I thought Lang and you, Bob, were joy-riding. So I signaled you to land and when you didn’t I decided to scare you into setting down—but it failed.”
He chuckled.
“I ought to know better than to think I could outfly Lang,” he said. “Well—if you’ve come with information, it’s all right. We can have a conference, all together.”
They did so, over the dinner. Lang listened to Bob’s recital of the latest developments about Griff, with growing anger, until he saw Barney’s face.
“Good boy, Bob,” commented Barney. “I’ve sort of had a notion in my head for some time about——”
“Griff?”
“Yes. I’ve thought he was the one who’s crossed the wires on us and short-circuited the whole plant. So he divided with somebody, did he? Well—he must have gotten it from somebody higher. Have you thought about?——”
“His father?” broke in Bob. “Yes—we have!”
More startling than Bob’s fresh information was the revelation given by Barney, the information which had brought him, flying, to consult the detective he had engaged to solve the puzzling case.
All that Bob had to tell was the suspicious act of the youth, Griff.
Barney, because it was so late, gave only a hint; but what he said caused a great deal of sleeplessness on Bob’s part, at least.
“We got the wrecked airplane up,” Barney told them all, that night. “I’ve had it hauled in and dismantled.”
He paused to give his next words more emphasis.
“There wasn’t one thing wrong with that crate!”
When, during their Sunday morning conference, he amplified his statements, the mystery deepened.
Dismantled, thoroughly examined, by Barney, in person—he did not trust any subordinate in so important a matter—the airplane revealed nothing wrong, either with its engine, with its wings, or with its controls!
“But it fell,” commented the detective. “What, do you imagine, caused the crash?”
“I give it up.” Barney was unable to make a theory. “I hired you to do the doping out of that! I give you the facts. You do the rest.”
“Bob,” his father turned to the youth, “have you jotted down all the suspicious things you mentioned, as I asked you to do?”
Bob nodded and handed over a paper.
After consulting it and comparing it with a sheet on which he had written, Mr. Wright looked up.
“This is what we know,” he began. “For several months, according to Barney’s original explanation, when he gave me the case, airplane parts had been missed. Not very many, but some. We have to decide how they are taken, and then find out who does it and what happens to them, how they are disposed of.”
“How about the man who gives out the instruments and such?” asked Langley quickly. Bob thought he said it to forestall comment about Griff, “or the mechanics whom Al had been told by his rigger boss were possible culprits?”