“Oh, Eddy,” cried Lily with impatience, “you must not interrupt us every minute!”
“Poor little fellow! it is very natural that he should like to understand,” observed George “I’ll try to explain it to you, Eddy. There is a strange substance, called loadstone, dug out of the ground, for which iron has a wonderful fancy. If a lump of it were placed in Lily’s work-box, all her needles and scissors, and her keys, if she had any, would jump to it, and cling to it in a minute, just as you would jump into mother’s arms.”
“Oh, I wish that I had a lump as big as my head! I should like to see the poker and the tongs and the shovel all jumping!” exclaimed Eddy, full of merriment at the thought.
“And the odd thing is,” continued George, “that when iron is well rubbed with this loadstone, it seems as though it grew just like it, for it gets the very same curious property of attracting other bits of iron. One of the boys at my school had a large steel magnet—that is, steel that had been rubbed with the loadstone—and it was the funniest thing in the world to see a dozen needles sticking to it at once, like so many quills upon a porcupine.”
“But what has this to do with the compass?” inquired Lily.
“It has a great deal to do with the compass. It has been discovered that magnets, when put in such a position that they can freely move in any direction, are sure always to turn towards the north: so little instruments are formed, holding a small piece of steel made into a magnet, not fixed, but left to tremble and tremble, till, like a tiny finger, it points towards the North Pole.”
“What is the use of that?” said Eddy.
“It is of wonderful use,” answered George. “Why, only think of poor sailors at sea; when there is nothing but water, wide water, around them, and when the clouds hide the sun or the stars, how can they tell which way to steer?”
“I don’t know,” said Eddy, quite puzzled.
“They look at their clever little compass—they see in what direction it points—they know from it where the north and south lie; and the tiny magnet serves as a guide.”