But now a new difficulty arose. It seemed that the change in angle made a heavier wind pressure on the big planes, and the speed of the airship was reduced to a bare ten miles an hour. In fact she seemed almost stationary in the air, at times.
"This won't do!" cried Dick. "We've got to turn on more power, even if we do strain the machinery. We've got to have more speed than this!"
"That's right!" cried Mr. Vardon. "I'll turn 'em up, Dick."
And with the increased speed of the big motor that was whirling the propellers came increased danger of a break. Vigilance was redoubled, and they had their reward for their care.
"Here's something wrong!" cried Innis, as he passed a small dynamo that supplied current for the electric lights. "A hot bearing!" and he pointed to where one was smoking.
"Shut down! Quick!" cried Mr. Vardon. "Throw over the storage battery switch. That will run the lights until that shaft cools. It must have run out of oil."
The dynamo was stopped and as the storage battery was not powerful enough to operate all the lights for very long, only part of the incandescents were used, so that the interior of the ship was only dimly lighted.
"Use your portable electric torches to examine the machinery in the dark places," directed the aviator. "We'll use the dynamo again as soon it cools."
This machine, going out of commission, had no effect on the progress of the airship. She was still fighting her way upward, with Dick at the wheel, and Grit crouching uneasily near him. The dog gave voice, occasionally, to pitiful whines.
"What is it, old boy?" asked Dick. "Is something wrong?"