"It is the very thing that I was dreaming of!" said Luis.
The train stopped. A gang of labourers emerged from it and began working on the road-bed, while the locomotive engineer answered the boys' questions and explained the mechanism of his engine. The boys discussed this later wonder as they wended their way homeward.
"Could it be adapted to the river men might become lords of the water as of the land," said Luis. "It would be only necessary to devise wheels capable of taking hold of the water. Fix them to a great frame like that waggon body and the steam-engine could propel it along the surface of the river!"
"Now you talk folly," exclaimed Pedro. "Does a fish float on the surface? In the water we must travel as the fish does—in it, not over it! Your waggon body, being filled with light air, would upset at your first movement. And your wheels—do you imagine they would take hold of so liquid a thing as water?"
"What would you suggest?"
"I would suggest that your water waggon be jointed in half-a-dozen places, so that it could be made to squirm through the water like a fish. Listen! A fish navigates the water. You desire to navigate the water. Then study the fish! There are fish that use propeller fins and flippers too. So you might devise broad boards to strike the water, as our hands and feet strike it in swimming. But do not talk about waggon wheels in the water!"
They were now beside the broad river. The first steamer to navigate it was seen approaching from the distance. The boys could not yet well distinguish it.
"It is evidently a whale," said Pedro. "What navigates the water? Fish. What is the fish that sometimes is seen swimming with its body half way above the surface? The whale. See, it is spouting water!"
"That is not water, but steam or smoke," said Luis.
"Then it is a dead whale, and the steam is the vapour of putrefaction. That is why it stays so high in the water—a dead whale rises high on its back!"