There was a sharp crack, and Bomba’s keen eyes noticed a slight quivering of the card.
“Come along,” said Gillis, beckoning to the boy, and Bomba followed him to the tree, where he saw a small hole in the card that had not been there before. But he looked in vain for any sign of scorching.
“Why didn’t the fire burn it?” he asked.
Gillis looked at him perplexedly, and then laughed as he grasped his meaning.
“Bless you,” he said, “it wasn’t the fire you saw coming from the muzzle that struck the card. It was a cartridge just like this,” and he drew one of the pellets from his belt.
Bomba examined it curiously.
“Why didn’t I see this when you fired the iron stick?” he asked.
“It went too fast for you to see,” explained Gillis patiently.
“You could see my arrow if I shot it,” said Bomba.
“That’s different,” said Gillis. “The arrow is bigger, and it doesn’t go as fast. And it doesn’t go as straight, either.”