"Something's given way," answered Tom quickly."I'm afraid the magneto isn't sparking as it ought to.""Well, can't we volplane hack to earth?" asked the odd man, for he had become familiar with this feat when anything happened to the motor.

"We could," answered Tom, "but I'm not going to." "Why not?""Because we're too far from Shopton--and dad! I'm going to keep on.I've got to--if I want to be there in time!""But if the motor doesn't work?" "I'll make her work!"Tom was desperately manipulating the various levers and handles connected with the electrical ignition system.He tried in vain to get the magneto to resume the giving out of sparks, and, failing in that, he switched on the batteries.But, to his horror, the dry cells had given out.There was no way of getting a spark unless the little electrical machine would work.

The propellers were still whirring around by their own momentum, and if Tom could switch in the magneto in time all might yet be well.

They had started to fall, but, by quickly bringing up the head plane tips, Tom sent his craft soaring upward again on a bank of air.

"Here!" he cried to Mr.Damon."Take the steering-wheel and kept her on this level as long as you can.""What are you going to do?" "I've got to fix that magneto!" "But if she dips down?""Throw up the head planes as I did.It's our only chance! I can't go down now, so far from Shopton!"Mr.Damon reached over and took the wheel from Tom's hands.Then the young inventor, leaning forward, for the magneto was within easy reach, looked to see what the trouble was.He found it quickly.A wire had vibrated loose from a binding-post.In a second Tom had it in place again; and, ere the propellers had ceased revolving, he had turned the switch.The magneto took up the work in a flash.Once more the spark exploded the gasoline mixture, and the propellers sent the Humming-Bird swiftly ahead.

"We'll make it now!" declared Tom grimly.

"We're almost there," added Mr.Damon, as he relinquished the wheel to the young pilot.The craft had gone down some, but Tom sent her up again.

Nearer and nearer home they came, until at last the spires of the Shopton churches loomed into view.Then he was over the village.Now he was within sight of his own house.

Tom coasted down a bank of air, and brought the Humming- Bird up with a jerk of the ground brakes.Before the wheels had ceased turning he had leaped out.

"It's Massa Tom!" cried Eradicate, as he saw Tom alight.

The young inventor hurried into the house.He was met by the nurse, who held up a warning finger.Tom's heart almost stopped beating.He was aware that Dr.Gladby came from the room where Mr.Swift lay.

"Is he--is he--am I too late?" gulped Tom."Hush!" cautioned the nurse.

Tom reeled, and would have fallen had not the doctor caught him, for the lad was weak and wornout.

"He is going to get well!" were the joyful words he heard, as if in a dream, and then his strength suddenly came back to him."The crisis is just passed, Tom," went on Dr.Gladby, "and your father will recover, and be stronger than ever.Your good news of winning was like a tonic to him.Now let me congratulate you on the race." Tom had flashed by wireless a brief message of his success.

"Dad's news is better than all the congratulations in the world," he saidsoftly, as he grasped the doctor's hand.

******

It was a week later.Mr.Swift improved rapidly once the course of the disease was permanently checked, and he was soon able to sit up.Tom was with him in the room, talking of the great race, and how he had won.He fingered the certified check for ten thousand dollars that had just come to him by mail.

"You certainly did wonderfully well," said the aged inventor, softly."Wonderfully well, Tom.I'm proud of you.""You may well be," added Mr.Damon."Bless my shoelaces, but I thought Andy Foger had us there one spell; didn't you, Tom?""Indeed I did.But you helped me win, Mr.Damon." "Nonsense!" exclaimed the odd man.

"Yes, you did.You helped me a lot."

"Well, are you going to keep after more air-prizes, Tom, or are you going to try for something else?" asked his father.