He quickly changed the elevation rudder, and so adjusted it as to send the ship downward on a long, slanting course. This gave the desired momentum, and the craft rode on a more even keel—if an airship has a keel.
“Ned, you come here and take charge of things,” called Mr. Glassford, “while Jerry and I look at the motor.”
Ned found little to do, save to keep steady the rudder which controlled the side motion of the ship. Meanwhile, Jerry was looking over the motor.
“I can’t find anything wrong with it,” he said as Mr. Glassford came up. “It seems to be all right.”
“This isn’t exactly like the engine in an automobile,” said the inventor, “though it’s nearer that in construction than anything else. Let me have a look.”
Carefully he went over every part of it. Then he uttered an exclamation.
“I’ve found the trouble!” he cried.
“What is it?”
“One of the spark-plugs has broken, and it backfired. That was the explosion we heard. I’ll soon have it fixed.”