Ben looked in vain for some way of escape. He was tied so tightly he could scarcely move. Close to his head on one side was the motor and on the other the whirring screw, which made such a loud humming that the German’s voice, loud as it was, sounded faint and far off.
The inventor busied himself about his machinery for several seconds, adjusting wires, wheels and levers. Then he put some weights on the beam of the scale. Next he began to figure on some scraps of paper, the while muttering to himself.
“Yes, yes, we shall do it,” Ben heard him say. “It is a success. He shall fly.”
“You’d better let me go before the police come!” exclaimed the young aviator, thinking to frighten the man. The German only laughed.
“The police never come here!” he cried. “It is too lonesome a place. No one lives here but me. The house is deserted. It is falling to pieces, for the owner will not repair it. It is good enough for me. No one shall disturb us.”
“What are you going to do to me?” asked Ben, growing a little calmer.
“I intend you shall fly—that is, theoretically, not actually. This machine is only a model. I put you on the scales. I start my screw. If this little screw can so push against the air, with such force as to cause the beam arm of the scale, with you on the platform, to go up, I know I am successful. That shows that if I make a bigger screw, and revolve it in the opposite direction, so as to lift up, instead of pulling down, as this is doing, I have solved the secret of flying.”
The man seemed rational, and his language showed he knew something of the laws of dynamics and pneumatics, but his eyes had a dangerous glare in them, and Ben, in spite of his outward coolness, was much frightened.
“I now prepare to revolve the screw at its highest speed,” went on the German, and our hero wondered if it could go any faster and not fly apart from centrifugal force. “When it is at top speed, if the beam of the scale goes up, I am the great inventor. If it does not—I am nothing. Now we are ready. You are going to fly, but you are not going to fly. It is all in theory. But I must reverse the motor,” which he quickly did. “I am afraid if I let the screw revolve the other way you would go right out through the roof. We may try that later. I am going to put a string to the electric lever that controls the motor, and pull it from the other room, as there is danger from the great speed if I stay here.”
“Are you going to let me be killed?” cried Ben, now thoroughly frightened, and believing that the man meant to harm him. He certainly was in a desperate plight.