CHAPTER XII.

TUBBY ESCAPES AN ORANGE BOMB.

Whir-r-r-r-r-r!

What a terrific din the aeroplane’s engine created, as the white-winged cloud skimmer stood outside the green shed! It was all the four soldiers, hanging on to her stern braces, could do to hold the struggling machine back. It appeared a thing instinct with life, eager and striving to get free and try its broad pinions against the blue.

The boys stood with round eyes and beating hearts, watching while Lieutenant Duvall tuned up the powerful one-hundred horse-power motor. A smell of burned lubricants filled the air. Clouds of oily, blue smoke rolled from the exhausts, which spat lambent flames viciously as the powerful motor vibrated.

To the soldiers standing about it was an old story, but to the boys everything was new and wonderful. As Lieutenant Duvall stopped the motor to adjust a spark plug connection, they pressed forward to examine the craft. Paul, as may be imagined, was as interested in the smallest wire and coupling as he was in the mighty engine or the broad white planes.

Suddenly the small boy gave an exclamation.

“Look here, sir!” he cried to the lieutenant.

The officer hastened to his side. Paul was examining one of the cross wires. The filament, made of the stoutest drawn steel, formed an important brace to the upper plane. The lad’s sharp eyes had detected that the soldering of its connection was almost worn through.

“Good for you, boy!” exclaimed the officer, as he saw the defect to which Paul had called attention. “That would have given me a bad tumble if you _hadn’t_ noticed it. Here, Mulloy”—addressing one of the soldiers—“get me the soldering outfit. Quick, now!”

With soldierly alertness, the man was off on his errand. Lieutenant Duvall employed the time of his absence explaining the various details of the machine to the boys.

“How about the equalizer?” asked Rob.

“It is not attached to-day,” explained the officer. “The main object of the device is to steady the plane when the operator desires to launch an explosive from his seat. He naturally has to shift, and the equalizer is to take up that shifting motion and distribute it.”

“I see,” nodded Tubby sagaciously, although it is doubtful if the fat boy did.

“Then you are going to practice dropping explosives?” asked Rob.

The officer’s face took on a queer expression.

“I guess we’ll have to call that an army secret, my boy,” he said. “If all goes well, Hampton may become a famous place.”

With this mysterious utterance, the boys had to be content. Mulloy returned at this moment with the solder, and the lieutenant adjusted the weak spot as skilfully as a machinist.

“An aviator has to know how to do everything about his engine,” he explained; “supposing he should drop in a country without a machine shop in reaching distance, or in any enemy’s country, if he couldn’t make his own repairs, he would be in a bad fix.”

“Are all these men trained in that way?” inquired Rob.

Lieutenant Duvall nodded.

“Every one of them,” he said. “They are all from Fort Myer. So was that deserting rascal, Dugan. He was the most expert mechanic I ever saw. In fact, I have heard since his desertion that there was good reason for his skill. Under the name of Beasley, he was one of the best-known safe crackers in the country before he reformed and entered the army with an assumed name. He was a splendid workman, though.”

The officer gave a sigh over the dereliction of Dugan. His professional side was affected by the man’s rascality.

“Nothing has been heard of him since he deserted?” asked Rob.

“Not a thing,” rejoined the officer, buckling on his leggings and adjusting his queer-shaped, padded cap, with goggles attached to its front part.

A few seconds later he was in the driver’s seat, and had his hands on the two levers which, by quadrants and chains, controlled the warping of the wings and rudder. The engine controls also led from these levers, while the motor could be stopped altogether by a motion of the foot on a small metal pedal.

Two soldiers ran to the propeller, a six-foot affair, and began swinging it “against the compression” of the motor. After a few rocks of the two-bladed driving apparatus, an explosion burst from the motor, and presently it was roaring away at full blast. A squad of men held it back, however, awaiting the aviator’s signal to “let go.”

At last it came—a backward sweep of one gauntleted hand.

Whir-r-r-r-r-r-r-r-r-r-r!

Like some scared live thing, the winged man-bird shot forward, scuttling over the smooth surface of the bricked terrace. Absolutely enthralled, the boys stood, with eyes as big as saucers and their mouths half open, in blank astonishment. As the contrivance, after a short scud, began to lift, they broke into an involuntary cheer. The next instant a distance of several feet interposed between the flying machine and the ground. With a graceful turn, the officer brought his flier round, and now came roaring through the air directly above the boys’ heads. As he did so, he gave a shout, and before the astonished onlookers could utter a sound, a round, yellow object came hurtling down at them.

“A bomb! Look out!” yelled one of the soldiers, with well-assumed terror, leaping backward.

In his haste to avoid the explosion of the yellow globe, Tubby fairly fell over and went rolling along the smooth ground like a ball. Rob and the others jumped back with blanched cheeks and frightened eyes, in scarcely less haste. Evidently, by accident, the officer had dropped a deadly explosive—or so it seemed.

The next instant, however, a roar of laughter went up at the boys’ expense.

What had been dropped was an orange. It struck the ground with a terrific splash, scattering juice and pulp in all directions. It was a little joke of the lieutenant’s, who frequently used oranges or eggs at bomb-dropping practice.

The relieved boys could hear his merry laugh as he sailed by, far above them, and rapidly soared higher in the air.

“Huh! Won’t get me that way again,” grunted Tubby, as, amid a roar of laughter, he picked up his rotund form and joined the others.

For half an hour or more the officer swooped and circled above them, appearing to delight in the exercise as much as a wheeling hawk on a summer’s day. Then he descended, and made a landing on the terrace as neatly as if he had just driven up in an automobile. Springs, geared to the pneumatic-tired wheels, broke the force of the landing, and, after one or two light bounces, the machine came to a standstill.

“Your turn,” cried the officer, laughing and turning to Rob as the machine, for the time being, terminated its flight.

He indicated a seat beside him, with an upright back and covered with dark-green padding. Rob did not hesitate, but stepped boldly forward. One of the soldiers offered him a pair of goggles, which he drew on. Then he climbed into the seat and gripped the side handles tightly.

“I’ll break the news to your folks,” howled Tubby, but the rest of his jocose remarks were drowned in the roar of the motor. The next instant they were off. Rob’s breath seemed to be forced backward down his throat by the rapidity of the motion. He gasped and choked, and hung onto his hand rails till the paint flaked off against his palms. The aeroplane, before it arose, seemed to act just like a bucking broncho. Its motions reminded Rob very much of the cayuse he had ridden at Harry Harkness’ ranch on that memorable morning when the cowpunchers gathered to see his battle with the broncho.

Suddenly, however, the see-saw motion changed to a delightful, gliding sensation. It felt like riding along upon the softest feather mattress in the world. They had left the ground and were actually flying. Rob’s heart gave a bound at the idea. He was certainly the first boy in the vicinity of Hampton to have such an experience. His first flash of fear had left him now, and he glanced at the officer seated beside him. Lieutenant Duvall’s face was calm and unperturbed, and Rob felt ashamed of the feeling of fright he had experienced before the machine took the air.

Up and up they rose. Once Rob looked down, but he didn’t do it any more. Somehow it made him feel pale and empty to realize that between his shoe soles and the ground lay a quarter of a mile of empty space.

“Keep your eyes ahead,” the officer advised, and Rob thereafter did so.

But his ride was not destined to become monotonous with such an aviator as the army officer at the levers. Suddenly the machine gave a downward, forward dip, and began rushing to the ground, or rather the ground appeared to be rushing up toward it.

It was all Rob could do to keep from crying out. He firmly believed that an accident had happened and that they would be dashed to bits when the aeroplane struck the ground. His mouth grew dry with terror, and he could have no longer checked a terrified shout, when all at once the motion ceased; or, rather, it altered. The descent was checked when within twenty feet of the ground, and up and round they swung, landing a few minutes after as lightly as a wafted feather upon the broad, smooth terrace of the De Regny mansion. How the old marshal would have gasped if he could have witnessed the antics of this new weapon of warfare cavorting above his ancient domain, from which he had watched so many weary days for his emperor.

“Well?” said the officer, with a twinkle in his eye as Rob, a bit shaky still from his terrible fright, clambered to the ground.

“Well,” rejoined Rob, taking off his goggles, “It was pretty strenuous work, but I enjoyed every minute of it.”

“Now for your friends,” said the officer, but Tubby had strangely vanished, and only Merritt and Paul could avail themselves of the invitation. They both enjoyed rides, and Paul proved so apt a young aviator that on a second trip aloft he was even allowed to handle the levers, at a safe distance above the ground, however.

“You boys certainly have plenty of pluck,” said the officer, after the sport of the afternoon was over. “Some day I may take you for a cross-country ride, or when we start real bomb-dropping work——”

He stopped abruptly and smiled.

“I forgot—that’s a service secret,” he said mystifyingly.

Not until the aeroplane was safely housed did Tubby emerge, and then he had to undergo a fine cross fire of joshing, you may be sure.

“I don’t care,” philosophically remarked the stout youth to himself; “I’m not built for flying, and walking is good enough for me, unless I can own an automobile.”

When Rob reached home that evening his mother told him that there was a visitor to see him.

“He is in the library,” she said.

Rob hastily removed the grime and dirt of his aerial trip, and, wondering who the caller could be, hastened into the room in which the guest was waiting. He gave a cry of surprise, as, in the twilight, he recognized Dale Harding.

“I’ve come to talk things over,” said Freeman Hunt’s particular chum, extending a hand. Rob took it and shook it heartily.

“All right, Dale,” he said, “fire away.”