An aviator, swinging northward in a June twilight, found himself constantly annoyed by the driver of a machine whose only motive in life seemed to be to get in the way. Turn as he might to right or left, sail high or low, the obstinate and impertinent pursuer was always at hand to threaten him.

To the west, lay Bedloe’s island, showing the Statue of Liberty, ruddy in the sunlight. To the east, Governor’s island presented the battlements of Fort Columbus and Castle William. To the north, or to the northeast, to be more exact, lay Battery park, a smear of green at the lower end of Manhattan island.

For a time people on ferryboats traversing New York bay looked upward in momentary expectation of a battle in the air. Then the two flying machines passed north along the line of Broadway, crossed over Bronx park, and came to the vicinity of Pelham bay, in Westchester county.

Here the aviator who had shown such pugnacity in his dashes and swirls at the other, and who had been repulsed only by the finest skill and tact, wheeled straight to the west and was soon lost to sight in the gathering darkness.

For a moment it seemed that the aviator who had thus far acted only on the defensive was about to become the aggressor and follow in the wake of his persecutor. In fact, he was about to swing away in pursuit when the ringing of a bell at a hangar below attracted his attention. Then, with a frown showing on a boyish face, he swung to the north a short distance and volplaned to a level space in front of the hangar.

Descending from his seat, the aviator was greeted, rather anxiously it seemed, by two boys not far from his own age. Very little was said until the flying machine had been run into the great shed, and then the three turned away to a rather elaborate office building which stood in a grove of trees at the entrance to the grounds.

A chill wind was blowing off Long Island sound, and the boys found a grate fire burning brightly in a private room at the rear of the structure. They seated themselves before the leaping flames and looked expectantly into each other’s faces for a moment before speaking.

Those who have read the opening volume of this series will need little introduction to James Stuart, Ben Whitcomb and Carl Nichols. Street boys of sixteen, they had, some months before, met Louis Havens, the famous millionaire aviator, and accompanied him on a trip to Mexico which had brought both fame and fortune to every member of the party.

On their return to New York from the “Burning Mountain” the boys had planned a course in college, but, at the request of Mr. Havens, they had promised to undertake a daring commission from the New York chief of police. A short time before their return to the city the night-watchman of the Buyers’ Bank had been murdered, the monster safe dynamited, and thousands of dollars in currency and securities taken.

It was believed by the chief of police that the burglars—two of the craftiest and most desperate criminals on the continent—were in hiding in the wild and mountainous region south of Monterey bay, on the Pacific coast.

On the theory that the Flying Machine Boys would be able to visit every nook and corner of the region where the criminals were supposed to be, with comparative ease, in their new and up-to-date machines, and, also, that the appearance of the lads in that section would not be apt to arouse the suspicions of the hunted men, the chief of police had proposed the journey to Havens, and he had induced the boys to accept the almost princely offer made by the official.

On account of the hazardous nature of the proposed trip, and because of the long distances to be traveled, special attention had been given to the Louise and the Bertha, the two aeroplanes ordered made by the boys immediately upon their arrival at New York. These machines had been completed the previous day, and the trip over New York bay made by Jimmie Stuart that afternoon had been the first tryout for the Louise, a very strong aeroplane, capable of carrying, when necessity required, two passengers and at least a hundred pounds of camp equipage and provisions.

“Who’s your friend?” asked Carl Nichols, short, fat, blue of eyes and pink of skin, as the three boys sat before the open grate fire in the private room in the office building at Havens’ hangar.

“He’s no friend of mine!” Jimmie Stuart, red-headed and freckled-faced, declared. “He picked me up down on the Jersey coast and did his best to get me into a mix-up. I dodged him all the way to Bronx park because, you see, I was not quite sure of my machine.”

“Did you get a good look at the fellow?” asked Ben Whitcomb, grave-faced, athletic, and inclined to worry over troubles which had not yet materialized. “It looked to me as if you might have slapped his face, he was so near to you when you passed over Battery park.”

“Oh, yes!” Jimmie answered. “I got a view of his face from almost every angle! He’s a low-browed brute, with ears like wings, and a hunch in his shoulders which makes you think of one of the muckers at Croton dam.”

“He certainly can run a machine, though!” Carl Nichols declared, “and he has an aeroplane that can go some, too!”

“But what’s the idea?” asked Ben. “Why should he be chasing you around in that impudent way?”

“I’ve got a notion,” Jimmie replied, “that he wanted to try out the Louise. He resorted to every trick known to airmen to induce me to make some kind of an error in handling the machine. He’s an expert himself, and he evidently wanted to know whether I am capable of operating a peach of a flying-machine like the Louise.”

“I don’t believe it was just idle curiosity that made the fellow stick to you in that way,” Carl interrupted. “I’ve been thinking that the purpose of our trip to the Pacific coast may have become known to friends of Phillips and Mendosa, the men who are believed to have dynamited the safe of the Buyers’ Bank and murdered the night-watchman. The crooks may have men on guard here!”

“That seems hardly probable,” Ben suggested. “The police have a pretty good case against Phillips and Mendosa, and, so far as my knowledge goes, a crook who stands in the shadow of the electric chair has few friends willing to interest themselves in his behalf.”

“Yes, but look here,” Jimmie argued, “Phillips and Mendosa lifted thousands of dollars in currency. So far as the officers know they still have the entire proceeds of the robbery in their possession. Even murderers with so many dollars in their possession are not likely to lack capable friends.”

“I guess that’s right,” Carl put in, “and the two murderers will of course scatter money like water in order to keep out of the clutches of the law!”

“Yes,” Ben suggested, “the clues point so directly to Phillips and Mendosa that they would naturally spend every dollar they stole in order to keep away from the New York officers.”

While the boys talked, the door to the private office opened softly. Mr. Havens stood for a moment on the threshold and then stepped up to the fire. The young man was tall, slender and supple, with a dusky complexion and black hair and eyes. He was twenty-four years of age, but looked much younger. The millions he possessed had been inherited from his father, and instead of spending them along the Great White Way, he was devoting his entire attention to aviation.

“What’s the argument, boys?” he asked, standing before the grate with a smile on his face. “Machines working all right?”

“Finely!” replied Jimmie. “I had a fine ride over the bay this afternoon. The Louise motor runs like a watch!”

“I saw you from Battery park,” Havens answered.

“Then you must have seen the gink chasing me up?” Jimmie asked, tentatively.

“I noticed that,” Havens replied. “What was the occasion of it?”

“That’s just what we were discussing,” Jimmie said.

“And we had about concluded,” Ben interrupted, “that our plans regarding the visit to the Pacific coast must have leaked out.”

“That doesn’t seem possible!” exclaimed Havens. “Why,” he went on, “even the intimates of the chief of police at headquarters know nothing whatever of the matter. There must be some other explanation of what took place this afternoon.”

“I have known crooks to have friends among the men higher up!” laughed Jimmie. “It may be so in this case.”

“There is one sure thing about it,” Havens went on, “and that is that if any hint regarding your proposed trip in quest of the murderers has by any chance become known to the friends of the crooks, the exact tactics shown this afternoon would be likely to be resorted to.”

“Yes,” Ben agreed, “it does seem that the first thing the crooks would do would be to prevent our departure for the Pacific Coast. A group of flying machine boys certainly represents a new element in secret service work! We must watch our machines after this!”

“If the fresh aviator really belongs to the crowd of crooks connected with the murderers,” Carl broke in, “we’ll hear from him again. He’ll follow us to the coast! He wouldn’t cease his efforts after chasing the Louise up New York bay.”

“He will have to chase us up if he continues his surveillance, for he won’t have long to spy on us here,” Jimmie declared. “We’re to leave for the Pacific coast day after to-morrow, as I understand it!”

“How about to-night?” asked Havens.

The boys sprang to their feet excitedly.

“To-night!” shouted Carl. “That will be fine!”

“That appears to me to be a good way of dodging trouble,” Ben acknowledged.

“I’d like to go to-night, all right,” Jimmie broke in, “but I’d like to form the acquaintance of that impudent aviator before I go!”

“I have an idea that you’ll meet him before you reach Monterey bay!” Havens replied. “You would know him again?” he asked.

“Of course!” replied the boy. “He’s a low-browed brute with wing ears and a hunch in his shoulders. I’d know him anywhere.”

“Do you really think he’ll chase us up?” asked Carl hopefully.

“I certainly do!” answered Havens.

“That will be great!” exclaimed Jimmie. “A flying machine race across the continent surely appeals to me. Are you going along with us, Mr. Havens?” he asked, then.

“I hope so,” was the reply, “although I’m not quite sure of getting through with several business deals now under way. However,” he went on, “you boys can go on with the Louise and the Bertha to-night, and I can catch you somewhere on the way over with the Mary Ann.”

“Not me!” Jimmie laughed. “You can’t catch me with the Mary Ann as long as I’m on board the Louise!”

“We’ll decide that point on the way across!” Havens replied.

“Well,” Ben suggested, “if we’re going to start to-night, we ought to be getting our camp equipment ready.”

“Aw, never mind the camp equipment!” exclaimed Jimmie. “We don’t want to carry a load of stuff across the continent. We can carry one light silk tent, like we had in Mexico, and a few provisions, and buy all the mountain outfit after we get in Monterey.”

“That listens good to me!” Carl put in. “If Mr. Havens is going to race us for three thousand miles in the Mary Ann, we don’t want to carry much excess baggage.”

“How soon can you get ready, boys?” asked Havens. “My idea is,” he went on, “that you ought to get out of the hangar as soon as possible. We may be over-anxious regarding the matter, but it is my belief that you’ll be followed unless you get away secretly. Now, you boys all go to bed in the bunks in the hangar and I’ll attend to the details. When the tent and provisions are on board, with plenty of gasoline, I’ll let you know. Then you can get away at once.”

The boys objected to going to bed, declaring that they were too excited to sleep, but at last, in deference to the wishes of Mr. Havens, they sought their bunks. An hour later Jimmie awoke to a sense of suffocation. Ben and Carl were sleeping soundly not far away and the great shed was very still.

As the boy sat up and sniffed the air a burst of flame showed at the front, sweeping fast toward the Louise and the Bertha.

CHAPTER II

A SHOT IN THE NIGHT

There was a fairly efficient fire department at the Havens’ hangar, and by the time Jimmie was out of his bunk, rolling his chums out on the floor, two streams of water were playing upon the flames.

Contrary to the expectation of the incendiaries, there had been several workmen busy about the office building packing provisions into the smallest space possible and tying oiled silk tents and clothing for transportation on the flying machines. Consequently when the fire burst out at the hangar there was little delay in getting out the firemen.

There were thousands of dollars’ worth of property in and about the office building and hangar, and Mr. Havens not only maintained an efficient corps of fire fighters but also kept his possessions there well insured. The fire was extinguished before any damage had been done except to one wall of the hangar.

After the danger was entirely over Mr. Havens and the three boys gathered in the private room of the office building for the purpose of discussing the situation. It was easy to see that the boys were all greatly excited, and that Mr. Havens was decidedly angry.

“You see how it is, boys,” the latter said, “you’ll have to fight the Phillips and Mendosa gang from now until the two murderers are placed in the electric chair. I fully believe that it was the intention of their accomplices to not only destroy the aeroplanes but to cause your death. It is a desperate gang to battle with.”

While the boys talked, laying plans for their guidance while journeying across the continent, Hilton, one of the night-watchmen, knocked softly on the door and then looked in with a frightened face.

“What is it?” asked Havens.

“I presume, sir,” the night-watchman answered, “that you heard the shot? It might have been heard a mile, I think, sir.”

“We heard nothing of the kind,” replied Mr. Havens, rather anxiously. “Tell us something about it.”

“It was just after the fire was extinguished,” Hilton replied. “We were standing by the door of the little fire-apparatus house when we saw a man sneaking through the shrubbery to the west of the hangar. He turned and ran the minute he saw that he was discovered, but we caught him—a measly little dried up kind of a man, with a face like a monkey.”

“Where is he now?” asked Havens.

“Why, that’s what I came in to tell you about,” Hilton continued, fumbling with his hat, which he held in front of him with both hands. “When we caught him, we took him back to the engine-house and began asking him questions, believing, of course, that it was he who had made all the trouble.”

“And what did he say?” demanded Havens, excitedly.

For a moment it seemed that the solution of the fire mystery was at hand. It was probable that the man caught sneaking about the hangar had either been responsible for the blaze or had witnessed the act of incendiarism. They all waited anxiously for Hilton’s reply.

“Well, sir,” continued the night-watchman, “we stood him up agin’ the wall by the engine-house door and tried to frighten him into answering our questions. He was scared all right!”

“But what did he say?” repeated Havens, impatiently.

“He didn’t say anything,” was the reply, “and I’ll tell you why he didn’t say anything. He was under the strong light of the electric in the ceiling of the engine-house. We were all gathered about him, but none of us stood in front. Before he could say a word in answer to our questions, a shot came from out of the darkness and he just crumpled down on the floor. We thought he was dead.”

“Did one of my men shoot him?” asked Havens, angrily.

“No, sir,” replied Hilton. “Your men were all gathered in the engine-house. The shot came from a point south of the hangar.”

“Is the man dead?”

“That’s what we can’t exactly make out, sir,” the night-watchman answered. “He lies perfectly still, but sometimes we think we can detect a flutter of breath at his lips. No, sir, you may be sure that none of your men shot the fellow.”

“Who did shoot him, then?” demanded Jimmie, excitedly.

“Wait a moment,” said Havens addressing the night-watchman. “Don’t offer any theories. Tell us the facts in the case, and then go and see that the man is not permitted to escape.”

“I have told you all I know, sir,” answered Hilton. “It’s just as I tell you. He was in the strong light near the engine-room door, and a shot came out of the darkness and he dropped. Your men were all in the engine-room at the time it happened.”

“That’s all!” Havens said, abruptly. “See that the fellow is given every attention, and also that he does not escape. Perhaps you would better summon a surgeon. Use the ’phone in the engine-house.”

Hilton bowed and turned away, grumbling that workmen were always blamed for everything that took place, whether they were guilty or not. Mr. Havens and the boys sat watching each other with astonishment showing in their eyes for at least a minute after the departure of the night-watchman. Havens was the first to speak.

“What do you make of that, boys?” he asked.

“It seems to me to be a problem easy of solution,” Ben answered. “The men who planned the destruction of the building and the death of those sleeping in it employed this man to do their dirty work. He set fire to the building, but didn’t get away in time. The captured man is undoubtedly a fellow not to be trusted, so the chief incendiary shot him in order to close his lips.”

“It strikes me,” Mr. Havens said, with a laugh, “that you ought to make a pretty good detective. In my opinion, you have grasped the situation exactly.”

“Oh, Ben is the only original Sherlock Holmes,” laughed Jimmie. “Give him a piece of rock and a blade of grass and he’ll tell you how the world was made! He’s got the deduction stunt down to cases!”

“You bet he has!” laughed Carl. “Don’t you remember how he figured out the Devil’s Pool down in Mexico?”

“I guess you all had a hand in that Devil’s Pool proposition,” laughed Ben. “But, honest, now,” he continued, “don’t you think the man was shot in order to prevent his snitching on his friends?”

“He certainly was!” answered Mr. Havens. “And now,” he continued, rising from his chair and moving toward the door, “it remains for us to determine whether he is dead. If he is dead, that settles the matter so far as we’re concerned. If he isn’t, he may be induced by the use of the third degree to betray his accomplices.”

“Huh!” laughed Jimmie. “I wouldn’t put a sheep-stealing dog through the third degree! They tried it on me once,” he continued, “when they found me sleeping in a dry goods box in an alley near where a burglary had been committed. They kept me without sleep or food for two days and two nights, though they had all I knew about the case the first minute.”

“You’re right about the cops,” Carl laughed. “When I write a book descriptive of the criminal classes in the United States, I’m going to give the police the place of honor in the book. If anybody should ask you, you just say that the leading criminal class in the United States revolves around police headquarters.”

Havens smiled at the natural enmity of street boys for the police and opened the door. As he did so Hilton again made his appearance in the outer office.

“The surgeon will be here directly,” he reported.

“How’s the patient?” asked Havens.

“Still unconscious,” was the reply, “though he seems to be breathing a little easier. He’s bleeding pretty badly, though.”

“You remain here and watch the office until we come back,” directed Havens, and in company with the three boys he turned toward the building where the fire-fighting apparatus was stored.

When they reached the place they found the figure of an undersized, wrinkled-faced man of fifty or more lying on the brick floor of the room. There was a pool of blood in view, and a wound in the head showed its source.

Half a dozen men were gathered about the still figure, all looking excited and anxious. Havens bent down and lifted the head from the floor.

“That wound,” he decided, “is by no means a fatal one. In fact, I can’t understand why he should lie for such a long time in this condition. The bullet merely cut the scalp, it seems to me. Any of you people ever see him before?” he asked in a moment.

The men shook their heads.

“Have you examined his clothing for marks of identification?” asked Havens, then. “He may have letters or something about him which will disclose his name and address.”

“No, sir,” one of the men answered. “We never thought of that. At least,” he went on with a shamefaced grin, “I thought of it just as you came in but, to tell you the truth, I didn’t care to touch him.”

Jimmie bent down and ran his fingers hastily through the pockets in the clothing of the unconscious man.

“Not a thing!” he said presently. “Not even a lead pencil or a pocket knife! The fellow probably left his card case at home,” he added with a chuckle. “We’ll have to get his number in some other way.”

While they stood talking at the door of the engine-house, a surgeon residing at a village not far away came hastily into the circle of light. After speaking most respectfully to the millionaire and nodding carelessly to the boys, he proceeded to make an examination of the injured man. Havens and the lads stood by waiting anxiously for his decision.

If the man was really likely to die from his wound, that would end all hope of learning from him the names of those associated with him in the crime. If the fellow would soon recover, then a clue to the whole chain forged by the friends of the murderers for the destruction of the boys might be discovered.

“Well?” asked Havens as the surgeon lifted his face in a moment.

Instead of answering directly, the surgeon sniffed the air.

“You’ve had a fire here?” he questioned.

“Never mind the fire now,” said Havens, impatiently. “Give me your opinion of this man’s condition. Is his wound fatal?”

“It is my duty,” said the surgeon, with assumed dignity, “to report this case to the police instantly. But,” he continued, with a subservient bow in the direction of the millionaire, “I’ll give you all the information I can before sending word to the county authorities.”

“Holy smoke!” shouted Jimmie. “Why don’t you give it, then?”

“Yes, why don’t you give it?” added Carl. “What are you waiting for?”

The surgeon regarded the two boys with a glance cold enough to crack the lenses in his eye glasses and turned back to the millionaire.

“The man is not fatally injured,” he announced, with a great deal of added dignity. “In fact, I can’t understand why he lies so long in this condition. It can be accounted for, however, on the theory that the bullet in passing along the surface of the skull drove a splinter of bone into the brain. In that case, no recovery can reasonably be expected until after a delicate operation has been performed.”

“Well,” Havens decided in a moment, “do you know where there is a hospital to which the man may be taken immediately?”

“There are plenty in New York city, of course,” suggested the surgeon.

“But,” returned Havens, “I don’t want him taken to New York city, or even placed in the custody of the officers of Westchester county. My desire is that you have him placed in a private hospital and make him your special charge until you receive different instructions. I have reasons of my own, of course, for taking this course, all of which you shall know in due time. Will you do it?”

The surgeon replied that he should be most happy to oblige the millionaire, and in a short time the wounded man was reposing on a cot in a private room in a private hospital not far from Long Island sound.

“And now, boys,” Mr. Havens said after a short time, “the machines are packed, it only remains for you to take your seats and beat the friends of Phillips and Mendosa to the Pacific coast.”