“Neither,” replied the inventor. “Mine is on an entirely new system. It is the screw principle, as old as the world, but applied in a new direction. I am the greatest inventor in the universe. My name is Hans Voller. Come in and see my machine. It is about to fly.”
He held open the door of the room. Ben could make out a mass of machinery, and a curious contrivance like a big auger.
“We are about to fly!” exclaimed Hans Voller, as he took our hero by the shoulder and shoved him into the dingy apartment, following himself and quickly locking the door. “We must have no spies, for there are many who would steal my ideas,” the man added.
Ben sized him up for a harmless crank, though he did not like the locked door, nor the manner in which the eyes of the German glared at him. Still, the young aviator reflected, the man might be only out of his mind on this one subject of flying machines, and he had been in just as much danger, and more, dozens of times since becoming a “bird-man.”
“Now attend!” exclaimed the inventor, as he put the key of the room in his pocket. “I will explain the principles on which this most wonderful machine works, and then I will demonstrate it to you. You will write it up for your aviation club, and I shall become famous. Do you see that screw?”
Ben nodded to show that he did. It was a curious contrivance of a double spiral, about seven feet high and half that in diameter at the top, tapering down to a point. It was made of woven basket work, covered with cloth, and painted white. Our hero compared it to two spiral stairways twined about a centre pole, similar to one he had seen in a circus once, and down which a man, shut up in a ball, had rolled from the top of the tent to the ground.
“That screw solves the problem,” the inventor went on. “I revolve that thousands of times a minute. It forces the air down, just as a screw of a steamer forces the boat ahead through the water. That lifts my machine up, and then I start my engine and we go ahead. I have not yet made a big machine, but I have tested this one by making it lift heavy weights. I want it to lift a person. I am too heavy for this little model, but you would be about right.”
“I’m afraid I wouldn’t care to try it,” spoke Ben with a laugh.
“There is no danger! You must try it!” the German exclaimed. “See, I rotate the screw by this electric motor I have installed. Sometimes it gets going too fast and something breaks. Then I must look out. I hide behind this wooden screen,” and he pointed to a strong one near the mass of machinery. “Now I have a chance to try my machine on a live person. I have long wanted to. I have made some improvements to-day, and you are just in time. You will fly!”
Before Ben knew what was happening the inventor had grabbed hold of him, pinning his arms to his side, and was advancing toward the big screw, which now began to revolve at a rapid rate.