Tim yelled until it seemed his lungs would burst but the roar of the Lark’s own powerful motor drowned out his cries. Finally Ralph, who had been working desperately in the cockpit of his own plane, looked up at his chum. Death was staring him in the face, but there was no hint of fear in the eyes that gazed at Tim.

The flying reporter signalled Ralph to reach for the lever which opened the emergency gas tank. If there was fuel in the reserve tank, the motor might catch again and they would have another chance.

The lever which controlled the valve of the emergency tank was on the other side of the cockpit and Tim, hanging on his precarious perch, watched his chum strain to reach it. Ralph lunged toward the lever and his outstretched hands knocked it open. The fuel flooded down into the carburetor and hissed into the red hot cylinders. With a quiver the engine of the training plane came to life.

Tim couldn’t restrain a shout as he saw Ralph gain control of the plane again.

Hunter lost no time in bringing the ships together and the Lark crept down and over the upper wing of Ralph’s plane.

Tim steeled himself for the attempt. He had never tried to change from one plane to another but he had watched the stunt a dozen times. The feat looked easy then, but actually to attempt it with a friend’s life in the balance was an entirely different thing.

Just ahead Tim could see the flashing arc of the propeller of Ralph’s plane. If Hunter misjudged the distance, if they struck a bump, if—if any one of half a dozen things happened he might be thrown into the deadly whirl. But Hunter was a master pilot and——

Before Tim’s madly racing mind could conjure up other thoughts they were over Ralph’s plane. Six feet, five feet, four feet separated the under carriage of the Lark from the upper wing of the training ship. Tim released his hold on the axle.

The next moment the air was forced from his lungs as he sprawled against the surface of the wing. His desperately reaching fingers hooked themselves over the wires along the upper edge of the wing and he was safe.

Tim was stiff from the cold and bruised by his fall but he swiftly made his way in from the tip of the wing and crawled down into the forward cockpit. His action was not a moment too soon for the supply of fuel in the reserve tank was exhausted. He grabbed the dual controls in the forward cockpit and within thirty seconds had set the plane down on the field. Hunter, who had beaten him down, ran toward him and together they clambered into the rear cockpit.

Ralph’s face was drawn with lines of pain.

“I guess I’ve made a supreme mess of things,” he gritted, before they could ask him what had happened.

A doctor who had been summoned by one of the mechanics when Tim and Hunter went aloft, shoved Hunter aside and slipped into the cockpit beside Ralph, whose legs, useless, were doubled under him.

“Here you chaps,” called the doctor, “help me lift this boy out of here.” Together they hoisted Ralph out of the cockpit and carried him into the office where they laid him on a cot in Hunter’s room.

The doctor’s examination required only a few minutes and he was smiling when he turned to the others in the room.

“Nothing serious,” he reassured them. “When he had that crackup this morning he bruised his legs pretty badly and also strained his back. The reaction took place this afternoon and resulted in a temporary paralysis of the legs. Keep him good and warm for an hour or two and he’ll be O. K. His legs may be a little sore and stiff for a day or two but that’s all.”

The doctor picked up his things and departed. When he had gone, Ralph looked up at Tim, his eyes clouded with grief.

“I’m sorry I’m such a flop, Tim,” he said. “I tried hard to make good because you told Carson I could do it.”

“Make good?” exclaimed Tim. “Why Ralph, you’re a flyer if ever there was one. It takes nerves and brains to do what you did this afternoon to keep a ship aloft with your legs paralyzed and your gas supply dwindling down to nothing. Believe me, that was flying.”

The cold winds of winter had been replaced by the warmer breezes of early spring and clouds that had been heavy with snow unleashed their burden of rain. It was poor weather for flying and Tim, after checking over his plane, was preparing to leave the airport.

The deep humming of a powerful motor attracted his attention and he turned toward the sound. Out of the low gray clouds in the west a black monoplane flashed into view. It was coming fast and low. The craft shot over the field and as it flashed by, Tim noted that it was a dull black. The fact that there were no numbers indicating its department of commerce rating troubled him. Then the pilot of the unknown plane banked sharply, and with motor on full, sped back over the field.

An arm flashed over the edge of the fuselage and a white object floated down. Tim splashed across the muddy field and retrieved the letter from the puddle in which it had fallen. By that time the black plane had disappeared with only a faint drumming of its motor to tell of its passing.

The flying reporter held the letter gingerly. When he turned it over he was astounded to find that it was addressed to him. On the envelope, in a rough scrawl, were the words, “For Tim Murphy.”

Tim tore open the envelope and extracted the single sheet of plain paper. The words were few but they burned their way into his mind.

“Murphy,” he read, “you’ve spoiled my game once. Don’t do it again.” It was signed, “The Sky Hawk.”

A queer feeling, certainly not that of fear, yet hardly that of elation, held Tim for a moment. So he had crossed the path of the Sky Hawk, the famous bandit who had been terrorizing the airways of the east. Tim smiled a little grimly. So far he had always been able to take care of himself and he had won his first tilt with the sky robber.

Stories about the Sky Hawk had been front page news some months before when he had staged a number of daring aerial holdups on eastern airways, but recently he had disappeared, which accounted for the failure to first connect him with the robbery of the Transcontinental Air Mail. There were many tales about the Sky Hawk. Some were that he was a super-flyer, a famous World war ace who had gone wrong; others had him leading a desperate band of aerial gunmen. One thing Tim knew; if the Sky Hawk had been piloting the plane which had attacked the mail, he had a number of accomplices.

The flying reporter walked over to the manager’s office and laid the letter on Hunter’s desk.

“I was afraid of something like that,” said the airport chief when he finished reading the note. “The possibility of the Sky Hawk had occurred to me before but I thought I’d get laughed off the field if I mentioned it. You’ll take good care of yourself, won’t you, Tim?”

“Sure, Carl, and while I’m here I want to find out what you know about this flying circus that blew in a couple of weeks ago. Why didn’t they stop at your field?”

“They landed here first but when they found we charged a percentage on all passengers carried, they pulled out and rented a pasture on the other side of town.”

“Guess I’ll drift over that way,” said Tim. “There may be a story.”

The flying reporter took the office car he had used to come down to the field and fifteen minutes later had skirted the edge of the city and reached a level tract of land where several canvas hangars had been erected. A sign over the gate announced that the “Ace Company” was ready for business. Tim turned his car from the main road and into the field. There was no one on duty at the gate and he started for one of the hangars where he could hear men at work.

He was about to push aside the canvas flap when a burly mechanic fairly jumped out of the tent.

“What you doing here?” he bawled.

“Just looking around,” replied Tim. “I’m Murphy of the News?”

“Oh, so you’re Murphy of the News?” mimicked the mechanic. “Well, we don’t want any flying snoopers sticking their noses in here. Now get out and stay out!”

Tim appraised the mechanic. He was six feet or better and weighed a good two hundred pounds. To try to argue with him would be foolhardy and Tim turned and started for his car.

Halfway to the car he paused for a moment, a peculiar mark on the soft turf of the field attracting his attention. It was the mark of a tailskid and from its clean-cut appearance, must have been made within the last hour!