The younger man looked surprised. "Magic?"
"Yes," said the other man.
"Nonsense," said the woman. She went back to the cave and the young man put the end of his spear into the fire and tried to scrape the side of the pot with the flint head, but the flint was cold and it cracked. He pulled it back and was looking angrily at it when she came out again and sat on the ground. She had an armful of roots which she began to scrape with a sharp stone. "The spearhead is made of the wrong sort of stone," she said, without looking up. "That is why it broke in the fire."
"It's made of the right kind!" the young man shouted. "All spearheads are made of that kind! They always have been and they always will be! How did you know it broke in the fire? You weren't looking."
"I heard it make the sound it makes when the fire breaks it."
The young man glowered and pushed his under lip out. "This kind of stone was put in the cave for us to make knives and spears. And it makes a very sharp edge when you know how to form it."
"No sharper than this knife," she said, holding up the stone in her hand. "This doesn't break so easily."
The young man took it and examined it carefully. "How do you strike it to make it this shape?" he said, and then, grudgingly, "It is very smooth—a very good shape."
"You don't strike it," she said, taking it back and going on scraping the roots. "You rub it on another stone—first on the kind that has the bright sparkles in it, and then under water on the flat gray kind. It's much better than your knives and the fire doesn't break it so easily."