A thunder of cheers greeted the Golden b.u.t.terfly as she swept by the grandstand on the next lap.

"That girl can drive all right," grudgingly admitted Fanning Harding.

"Yes, and she's pretty as a picture, too," put in Gid Gibbons; "guess you were stuck on her once, weren't you, Fan?"

"Oh, shut up," growled Fanning angrily. "It makes no difference to you, does it?"

The aeroplanes had been racing for an hour now, and neither showed any signs of slacking speed. On the contrary, as they "warmed up," they seemed to go the quicker. All at once an incident occurred which brought the crowd to its feet yelling and cheering as if wild.

The driver of Number Five, as the two machines pa.s.sed the grandstand, had made a deliberate attempt to prevent the Golden b.u.t.terfly overhauling him by jamming his aeroplane over toward a pylon and directly in front of the b.u.t.terfly. For an instant it looked as if a crash must be inevitable, but just as the spectators were beginning to turn pale and the more timid to hide their eyes, the b.u.t.terfly was seen to make a graceful dip and dive clean under the other aeroplane. It was a magnificent bit of aerial driving, and the crowd appreciated it to the full. A roar and a shout went up, to which the driver of Number Six responded with a wave of a gloved hand.

Ten minutes later Number Five, two laps behind, and with a leaking radiator, dropped out of the race, leaving the Golden b.u.t.terfly the winner. Fanning Harding was white as a sheet as he saw an official with a black and white checkered flag step out into the field. This was the signal to the Golden b.u.t.terfly, which was still in the air, that the race was over.

As the Prescott aeroplane dropped to earth in front of the grandstand amid rapturous plaudits, the son of the Sandy Bay banker deliberately arose and made his way toward the judges' stand, to which Hal Homer and the Bancrofts, the core of a shouting, yelling mob of enthusiasts, were already conducting the daring driver of Number Six.

Special policemen made a path for the aviator and his friends, while cries of:

"Take off your helmet!"

"We want to see you!"

"What's the matter with Number Six?" and a hundred other cries arose.

But the driver of Number Six did not respond, and with his helmet still on his head was conducted before the judges to receive their congratulations. The helmet was still in place when Fanning Harding came shoving through the crowd and finally reached the little group.

"As a compet.i.tor I demand that Number Six take off his helmet!" he cried.

The judges turned to him in astonishment.

"This is most unseemly, sir," said one of them; "no doubt in good time Mr. Prescott will take off his helmet."

"Oh, no, he won't," shouted Fanning, at whom all the group was now gazing. "He won't, I tell you, and for a good reason, too. _That's not Roy Prescott at all, but his sister Peggy._"

But the words had not left his lips before Jimsy, with a quick motion, jerked off the aviator's helmet and disclosed the handsome, perspiring features of Roy himself.

In the few minutes he had had, Roy had found time briefly to explain how he and his sister had changed garments.

"Well, I guess that settles that question," cried Jimsy triumphantly, as a mighty shout went up.

"It certainly does," said one of the officials. "Where is that young scamp? Officer, find the young man who made that accusation and bring him here to explain himself."

But the disgruntled Fanning had dived off into the crowd the instant he saw into what a tremendous blunder he had fallen. And although a strict search was made for him he was not to be found.

CHAPTER XXI.

THE PHANTOM AIRSHIP.

In the midst of the hum and excitement and the crossfire of questions which immediately followed, there occurred a startling interruption. From the further side of the grounds there arose a cry, which swelled in volume as it advanced.

"Fire! One of the hangars is on fire!"

The group immediately broke up and orders and commands flew thick and fast. In the midst of the excitement Roy and his chums found an opportunity to slip away.

"There's the fire. Off by our hangar!" shouted Hal Homer, pointing across the field.

By the side of the Prescott's green aero shed a big cloud of smoke was ascending, mingled with yellow flames. It seemed to be a hot blaze.

"It's Fanning Harding's hangar!" cried Roy suddenly; "come on, let's go over and see what the matter is."

"I've got the car right here," said Jimsy. "I'll get you over in a jiffy."

Soon they were speeding across the field toward the blaze. In the meantime an emergency fire corps, composed of men employed on the grounds, had attached a line of hose to a hydrant and were drenching the flames. Such good work did they do that it was not long before they had the fire under control.

As soon as it was out our party, which had managed to get through the lines formed to keep back the curious, gazed into the ruins with some interest.

"Why, say!" cried Jimsy suddenly, "the place was empty."

"So it was!" cried Roy in astonished tones, "except for that big box kite over in the corner there. Whatever kind of a game of bluff has Fanning Harding been playing?"

"I guess I can imagine it," struck in Hal Homer. "From what you have told me his little game was to bluff you into thinking he had a fine airship that could beat yours, and in that way induce you to sell out to him."

"By George, I never thought of that!" exclaimed Roy, "but--hullo, here comes Peggy in the farmer's wagon!"

He ran through the crowd to the side of the wagon, which had been driven in by Farmer Ingalls.

"You dear, dear boy, I've heard all about it already," cried Peggy, throwing her white arms about Roy's neck, while Miss Prescott, whom they had picked up at the hotel, sat by, hardly knowing whether to laugh or to cry, as she expressed it later.

I am not going to describe that reunion by the side of Fanning Harding's burned hangar, but each reader can imagine for herself what a joyous one it was.

"I know a place in town where they sell the bulliest sodas and sundaes,"

cried Jimsy suddenly. "Everybody come up there in the car and we'll celebrate!"

"In one moment, Jimsy," said Roy. "There's one thing still I don't understand about this whole business, and that is this. It is clear enough that Fanning Harding was bluffing about having an aeroplane in that shed, but how was it that he made a night ascent with red and green lanterns?"

"Oh, you mean the time you saw him in the air at night, the time we went to Washington?" asked Jimsy.

"That's it. How do you account for it?"

"Give it up," rejoined the other lad.

"Perhaps this may help to explain it."

Hal Homer came up carrying two much scorched lanterns he had found in the debris of the hangar. One was red, the other was green.

"I don't quite see," said Peggy, but Hal, with an apology interrupted her.