after Dick had made an inspection. "The engine is cold, that's all."

"Humph, well I'm not! But come on, let us give her another twist."

The brothers took hold again, and, at a word from Dick, each gave the wooden paddles of the propellers a vigorous turn. There came a sudden hiss, followed by a crack and a bang, and then off the engine started with the loudness of a gattling gun.

"Hurrah! she's started!" yelled Tom, triumphantly. "Say, but she makes some noise, doesn't she?" he added.

"I should say yes. That's because airship engines don't have mufflers, like autos," yelled back Dick, to make himself heard above the explosions.

"And see those propellers go around!" went on Tom, in deep admiration. "All you can see is a whirr! We sure have a dandy engine in this craft, Dick!"

"Looks so, doesn't it?" returned Dick, also in admiration. "I reckon the Dartaway will give a good account of herself, when she is properly handled. Now, I had better stop the propellers, I guess," he added, moving toward the front of the biplane to do so.

"Yes! yes! stop em!" yelled Tom, suddenly. "Hurry up, Dick! See how she is straining to break the ropes! Say, she wants to go up!"

Dick was startled and with good reason. Even while his brother was speaking there came a sudden snap, and one of the ropes flew apart. Then up out of the ground came the stake holding another rope. The big biplane, thus released on one side, slewed around, and Tom was knocked flat. Then came another snap and two more ropes flew apart.

"She's going! stop her!" screamed Tom, from where he lay, and the next moment he saw Dick struck full in the face by the machine. Down went the youth backwards, and as he fell, with a rush and a roar, the biplane sped over the level ground for a distance of two hundred feet and then went sailing into the air, headed almost point blank for the Rover homestead, less than fifty rods away!

CHAPTER II

SOMETHING ABOUT THE ROVER BOYS

"Oh, Dick, are you hurt?"

The cry came from Tom, as he turned over on the ground and struggled to his feet. He had seen his brother hurled backwards, and he saw that Dick made no move to arise. He had been struck in the head, and blood was flowing from a wound over his left ear.

"Oh, maybe he's killed!" gasped poor Tom, and then, for the moment he forgot all about the flying machine, that was rushing so madly through the air towards the Rover homestead. He hurried to his brother's side, at the same time calling for others to come to his assistance.

To my old readers the lads already mentioned will need no introduction. For the benefit of others let me state that the Rover boys were three in number, Dick being the oldest, fun-loving Tom coming next, and sturdy Sam being the youngest. They were the sons of Anderson Rover, a widower, and when at home, as at present, lived with their father and their Uncle Randolph and Aunt Martha at a pleasant place known as Valley Brook farm, in New York state.

While their father was in Africa on a mission of importance, the three boys had been sent by their uncle to boarding school, as related in the first volume of this series, entitled, "The Rover Boys at School." The place was Putnam Hall Military Academy, and there the lads had made many friends and also a few enemies.

From school the boys had made a short trip on the ocean, and then another trip into the jungle after their father. Then had followed a trip out West, and another on the Great Lakes. Later the youths had camped out in the mountains during the winter, shooting quite some game. Then they had returned to school, to go into camp during the summer with the other cadets.

The boys by this time thought their adventures at an end, but more were soon to follow. There came a long trip on land and sea, and then a voyage down the Ohio River, and soon after this the Rovers found themselves on the plains, where they had some adventures far out of the ordinary. From the plains they went further south, and in southern waters—the same being the Gulf of Mexico—they solved the mystery of the deserted steam yacht.

"Now back to the farm for me!" Sam had said at this time, and all were glad to go back, and also to return to Putnam Hall, from which seat of learning they presently graduated with honors. Then Mr. Anderson Rover got word of a valuable treasure, and he and the boys, with a number of their friends, went to Treasure Isle in search of it. They were followed by some of their enemies and the latter did all in their power to cause trouble.

Although the boys had finished at Putnam Hall, their days of learning were not yet over, and soon they set off for Brill College, a high-grade seat of learning located in one of our middle-western states. They had with them an old school chum named John Powell, usually called "Songbird," because of his habit of making up and reciting so-called poetry, and were presently joined by another old school companion named William Philander Tubbs, a dudish chap who thought more of his dress and the society of ladies than he did of his studies. Tom loved to play jokes on Tubbs, who was generally too dense to see where the fun came in.

From the college the boys had taken another trip, as related in the fifteenth volume of this series, called "The Rover Boys Down East." There was a mystery about that trip, of which the outside world knew little, but as that trip has something to do with the events which are to follow in this story, I will here give such details as seem necessary.

When the Rover Boys went to Putnam Hall they met three girls, Dora Stanhope and her two cousins, Nellie and Grace Laning. Dora's mother was a widow, living not far from the school, and it was not long before a warm friendship sprang up between Dick and Dora,—a friendship that grew more and more intimate as the days went by. Dick thought the world of Dora, and the two were now practically engaged to be married. As for Tom and Sam, they had taken to the two Laning girls from the start, and though Tom was too full of fun to pay much attention to girls, yet whenever Nellie was mentioned, he would grow red in the face; and it was noticed that whenever Grace was present Sam was usually on hand to keep her company.

The treasure unearthed on Treasure Isle had belonged to the Stanhope estate, the bulk of it going to Mrs. Stanhope and Dora and the remainder to the Lanings, because Mrs. Laning was Mrs. Stanhope's sister. But the treasure had been claimed by a certain rascal named Sid Merrick and his nephew, Tad Sobber, and when Merrick lost his life during a hurricane at sea, Sobber continued to do all he could to get the money and jewels into his possession.

"It's mine!" he told Dick Rover one day. "It's mine, all mine, and some day I'm going to get it!"

"You keep on, Tad Sobber, and some day you'll land in prison," had been Dick's answer. "We found that treasure, and the courts have decided that it belongs to the Stanhope estate, and you had better keep your hands off."

But Tad Sobber was not satisfied, and soon he made a move that caused the worst kind of trouble. There was a learned but unscrupulous man named Josiah Crabtree who had once been a teacher at Putnam Hall, but who had been discharged and who had,