"Hard over, Koku!" called Tom to his giant.
As the airship began to respond to the power of her propellers, and the up-tilted rudder, Tom heard, from somewhere below him, a series of shrill blasts on a whistle.
"What's that?" he cried.
"Sounds like a boat below us," answered Mr. Whitford.
"I guess it is," agreed the young inventor. "There she goes again."
Once more came the frantic tooting of a whistle, and mingled with it could be heard voices shouting in fear, but it was only a confused murmur of sound. No words could be made out.
"That's a compressed air whistle!" decided Tom. "It must be some sort of a motor boat in distress. Quick, Mr. Whitford! Tell Ned to switch on the searchlight, and play it right down on the lake. If there's a boat in this storm it can't last long. Even an ocean liner would have trouble. Get the light on quick, and we'll see what we can do!"
It was the work of but an instant to convey the message to Ned. The latter called Mr. Damon to relieve him in the motor room, and, a few seconds later, Ned had switched on the electricity. By means of the lazy-tongs, and the toggle joints, the bank clerk lifted the lantern over until the
