THE REASONING OF CHILDREN
Two young Brazilian boys strolled in the shade, conversing. They were simple youths of the interior, knowing only the plenty of the primitive plantation where, undisturbed by laboursaving devices, Nature yielded man her fruits at the price of the sweat of his brow.
They were ignorant of machines to the extent that they had never seen a waggon or a wheel-barrow. Horses and oxen bore the burdens of plantation life on their backs, and placid Indian labourers wielded the spade and the hoe.
Yet they were thoughtful boys. At this moment they discussed things beyond all that they had seen or heard.
"Why not devise a better means of transport than the backs of horses and of oxen?" Luis argued. "Last summer I hitched horses to a barn door, loaded it with sacks of maize, and hauled in one load what ten horses could not have brought on their backs. True, it required seven horses to drag it, while five men had to sit around its edges and hold the load from falling off."
"What would you have?" answered Pedro. "Nature demands compensations. You cannot get something from nothing or more from less !"
"If we could put rollers under the drag, less pulling power would be needed."
"Bah ! the force saved would be used up in the labour of shifting the rollers."
"The rollers might be attached to the drag at fixed points by means of holes running through their centres," mused Luis. " Or why should not circular blocks of wood be fixed at the four corners of the drag ? . . . Look, Pedro, yonder along the road. What is coming ? The very thing I imagined, only better ! One horse is pulling it at a good trot!"
The first waggon to appear in that region of the interior stopped, and its driver spoke with the boys.
"These round things ?" he answered to their questions; "they are called wheels."
Pedro accepted his explanation of the principle slowly.
"There must be some hidden defect in the device," he insisted. "Look around us. Nowhere does Nature employ the device you call the wheel. Observe the mechanism of the human body; observe the horse's frame; observe . . ."
"Observe that horse and man and waggon with its wheels are speeding from us," replied Luis, laughing. " Cannot you yield to accomplished facts? You tire me with your appeals to Nature. Has man ever accomplished anything worth having except by combating Nature? We do violence to her when we chop down a tree! I would go further than this invention of the waggon. Conceive a more powerful motive force than that horse . . ."
"Attach two horses to the waggon."
"I mean a machine," said Luis.
" A mechanical horse with powerful iron legs!" suggested Pedro.
"No; I would have a motor waggon. If I could find an artificial force I would cause it to act on a point in the circumference of each wheel. Then the waggon could carry its own puller!"
"You might as well attempt to lift yourself from the ground by pulling at your boot straps!" laughed Pedro. "Listen, Luis. Man is subject to certain natural laws. The horse, it is true, carries more than his own weight, but by a device of Nature's own—his legs. Had you the artificial force you dream of you would have to apply it naturally. I have it! It would have to be applied to poles to push your waggon from behind!"
"I hold to applying the force to the wheels," insisted Luis.
"By the nature of things you would lose power," said Pedro. "A wheel is harder to force on from a point inside its circumference than when the motive power is applied to that circumference directly, as by pushing or pulling the waggon."
"To relieve friction I would run my power waggon on smooth iron rails, then the loss in power would be gained in speed."
"Smooth iron rails!" laughed Pedro. "Why, the wheels would slip on them. You would have to put notches all round their circumference and corresponding notches in the rails. And what would there be to prevent the power waggon slipping off the rails even then?"
The boys had been walking briskly. Now a shrieking noise startled them. Before them stretched in long lines a railway in course of construction, and from among the hills came toward them, at what seemed immense speed, a construction train.
"It is an avalanche!" cried Pedro.
"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!"
"No," said Luis; "it is really a steam water waggon."
"With smoke coming from fire in it, as from the locomotive?"
"Yes."
" But the fire would burn it up. . . ."
"The body is doubtless iron, like the locomotive."
"Iron would sink. Throw your hatchet in the river and see."
The steam-boat came to shore, close to the boys. Running to it, to their joy, they perceived on its deck an old friend of their family, a neighbouring planter.
"Come, boys!" he said, "and I will show you round this steam-boat."
After a long inspection of the machinery the two boys sat with their old friend on the foredeck in the shade of an awning.
"Pedro," said Luis, "will not men some day invent a ship to sail in the sky?"
The common-sense old planter glanced with apprehension at the youth's face, flushed with ardour.
"Have you been much in the sun, Luis?" he asked.
"Oh, he is always talking in that flighty way," Pedro reassured him. "He takes pleasure in it."
"No, my boy," said the planter; "man will never navigate a ship in the sky."
"But on St John's Eve, when we all make bonfires, we also send up little tissue-paper spheres with hot air in them," insisted Luis. "If we could construct a very great one, big enough to lift a man, a light car, and a motor, might not the whole system be propelled through the air, as a steam-boat is propelled through the water?"
"Boys, never talk foolishness!" exclaimed the old friend of the family hurriedly as the captain of the boat approached. It was too late. The captain had heard the boy's observation; instead of calling it folly he excused him.
"The great balloon which you imagine has existed since 1783," he said; "but, though capable of carrying a man or several men, it cannot be controlled—it is at the mercy of the slightest breeze. As long ago as 1852 a French engineer named Giffard made a brilliant failure with what he called a 'dirigible balloon,' furnished with the motor and propeller Luis has dreamed of. All he did was to demonstrate the impossibility of directing a balloon through the air."
"The only way would be to build a flying machine on the model of the bird," spoke up Pedro with authority.
"Pedro is a very sensible boy," observed the old planter. "It is a pity Luis is not more like him and less visionary, Tell me, Pedro, how did you come to decide in favour of the bird as against the balloon?"
"Easily," replied Pedro glibly. "It is the most ordinary-common sense. Does man fly? No. Does the bird fly? Yes. Then if man would fly let him imitate the bird. Nature has made the bird, and Nature never goes wrong. Had the bird been furnished with a great air bag I might have suggested a balloon."
"Exactly!" exclaimed both captain and planter.
But Luis, sitting in his corner, muttered, unconvinced as Galileo: "It will move!"