y longer," said Charlie. "It won't pull
brass."
"Then, there's another matter settled," I said. "The magnet does not
pull brass. Is there any thing else it does not pull?"
"Wood," said Charlie. "I tried lots of pieces."
"Any thing else?"
"Stones," said Charlie, eagerly.
"What are these?" I asked, holding up a couple of heavy stones he had
put among the things the magnet pulled.
"I guess I put those there by mistake," said Charlie, testing with, the
magnet a number of stones in the other pile.
"Try them," I said.
"O!" he said, as the magnet lifted them; "I forgot. It does lift some
stones."
"Well, what else have you in that pile of things the magnet did not
pull?"
"Glass, leather, lead, bone, cloth, tin, zinc, corn, and a lot of
things."
"Very well. Now let us see what the magnet does pull."
"Iron keys," said Charlie, "and nails."
"Here's a nail in this other pile."
"That's a brass nail. The magnet pulls only iron nails."
"What else have we in this pile?"
"Needles, hair-pins, screws, wire--iron wire," he added quickly. "Brass
wire doesn't stick, you know."
"How about this?" I asked, taking a small coil of copper wire from my
desk.
"I guess that won't stick," said Charlie. "Because that's copper wire,
and the magnet doesn't seem to pull any thing that isn't iron."
Much to Charlie's satisfaction, the magnet did not pull the copper wire.
Then I took up two stones, one rusty red, the other black, and said:
"What about these?"
"I guess they must have iron in them too," said Charlie. "Have they?"
"They have," I replied. "They are iron ores from which iron is made. Why
did you think there was iron in them?"
"Because they wouldn't have stuck to the magnet if there wasn't."
"Quite true. So you have learned another very important fact. Can you
tell me what it is?"
"The magnet pulls iron," said Charlie.
"Good," said I; "and it is also true that the magnet does not pull--"
"Things that are not iron," said Charlie.
"True again," I said. "So far as our experiments go, the magnet pulls
iron always, and never any thing else."
"But what makes it pull iron?"
"That I can not tell. We see it does pull, but just how the pulling is
done, or what makes it, no one has yet found out.
"For convenience we call the pulling power magnetism. You may keep the
magnet, and at some other time, I will tell you more about it."
* * * * *
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