While talking, Bob had screwed on to each end of the cylinder a metal cap which had attached to its middle an insulated wire. He now laid the cylinder on a table and fastened each of the wires to a terminal of a small, but powerful electric motor.
"All right now, switch her on and let's see her hum."
Instantly Jack threw over the lever, but, alas for the hopes of the boys, nothing resulted. As they looked at each other keen disappointment was evident on both faces. Almost instantly, however, Jack grabbed his brother by the arm and almost shouted.
"Well, if I'm not the original clumsy Claude."
"What is it? Tell me quick."
"Why, don't you see? I gave you two positive caps instead of a positive and negative."
Bob quickly picked up the cylinder, and a glance told him that his brother was right. Quickly unscrewing one cap he replaced it with a similar appearing one, but which was marked — instead of +.
"Now we're off again, switch her on," and this time, to their intense delight, no sooner was the switch thrown than the little motor sprang to life, and the armature began to revolve with a whirl which seemed to shout success to the two boys. Catching hold of each other's hands they danced about the room fairly shouting their joy.
"For mercy sakes, what is this, a new kind of a war dance?" asked a mild voice, and stopping just at the beginning of a wild yell, the boys saw that their father had entered the room.
"Oh, dad," cried both boys, running to him and catching him by the arms. "It works, it works. Just see it go."