"These," he said, pointing to a pile of things on one side of the box. "And these things it doesn't pull."
"Let us see what you have in this pile," I said, looking at the first little heap; "keys?"
"Trunk keys," said Charlie. "It doesn't pull door keys. I tried ever so many."
"Try this key," said I, taking one from my pocket. "This is a trunk key. See if the magnet pulls it."
"No-o," said Charlie, thoughtfully, "it doesn't; but it pulled all the rest of the trunk keys I could find."
"Try this key to my office door."
Charlie tried it, and to his great amazement the key stuck fast to the magnet.
"Surely," said I, "it pulls some door keys, and fails to pull some trunk keys."
Charlie was more puzzled than ever. He looked at the keys, thought a moment, then picked up my trunk key, and said: "This key is brass; the rest are iron."
"That's so," I said.