"The strain on the rudder must be terrific," he thought to himself; "it's a wonder it has held out as long as it has."
Taking a casual glance at the height indicator, Frank gave a start. It indicated twelve thousand feet. It was higher than the boy had ever been before.
For several minutes he was too busy easing the dirigible through a blast that seemed as if it would rip her apart to notice the gauge again. When he had an opportunity to do so, he gave a whistle of surprise.
The dirigible had now climbed on the wings of the storm to an altitude of fourteen thousand feet.
Glancing through the pilot-house window the young helmsman saw tattered shreds of storm clouds driven by at a terrific speed; but fast as they went, the dirigible was hurried along with them at an equal speed. The rapid motion had a tendency first to exhilarate and then to turn dizzy those who participated in it.
All at once a sharp whistle sounded from a tube placed so that it was close to the helmsman's ear.
"A signal from the engine-room," cried Malvoise, "answer it."
"Hullo!" called Frank, turning back the whistler at the mouth of the tube. Then he placed his ear to it.
"Two cylinders are missing fire," came the hail, "to make repairs we shall have to stop the engine."
"Keep on with what power you have," shouted back Frank. "We've got to keep going."