As Tom neared the outskirts of Shopton, he saw several young boys in a field trying to fly a kite. But the boys were having trouble getting it aloft.
“Hey, there’s Tom Swift! He’ll help us!” cried Billy Barstow, the son of an Enterprises employee. The group of boys hailed the young inventor.
Tom chuckled and strolled out across the field to meet them. “What’s the matter? Won’t she go up?”
“Sure won’t!” Billy complained. “And we spent
THE INVISIBLE STRING 17
all afternoon building this kite. You’re an expert, Tom. What’s wrong?”
“From the way it’s sagging, I’d say the tail’s too long.” Tom reeled in the kite and tore off part of the rag tail. In a few minutes he had the red kite soaring high in the blue, then turned it back to Billy.
“Oh, boy! How about that?” yelped Kenny Smith gleefully. “Just like magic!”
Tom grinned. “No magic about it,” he explained. “Your kite was just tail-heavy. What makes a kite stay up, anyhow-ever stop to think?”
“The wind,” Billy volunteered.
“What else?”
Tom’s question brought puzzled looks. The boys could only shrug blankly.
“Well, for instance, what will happen if you let go of the string?” Tom persisted.
“The kite’ll fly away,” said Kenny.
“And probably keep going forever!” Billy added. “At least till the wind dies down.”
“Drop the string and see what happens,” Tom suggested.
Billy hesitated, then let go. At once the kite started falling toward the ground.
Billy quickly grabbed the string again and reeled in. As soon as the cord was taut, the kite seemed to regain its “lift” from the wind.