"See?" asked the Admiral.
"Yes, I see," replied Margaret, who happened to be the one to catch his eye. "I see, but I don't understand. The boat has no sail and it has no oars and it has no engine: what is the—the—?"
"What makes it go?" asked Frances.
"What is the motive power, you were going to say, weren't you?" asked the Admiral. "Ha, ha!" he cried, rubbing his hands. "You'd never guess. Never. Look here!" jumping out of his chair and patting the cushion—a very fat air-cushion blown up extremely tight. "This contains the motive power. All you have to do is to sit on the cushion, give a twist to the chair, and away you go."
"I see," said Margaret again. "Very simple. But what is the motive power? Gasoline?"
His heels went up in the air
"Oh, dear, no!" cried the Admiral, holding up his hands as though horrified at the suggestion. "Nothing so barbarous as gasoline. Unpleasant smells and unnecessary noises are not allowed on the floating Islands. The cushion is filled with snap-dragon's breath."
"Snap-dragon's breath!" cried both little girls, sitting up very straight and opening their eyes very widely.