"Oh, yes," said the three children together.
"I saw a star fall, so fast—just like a rocket. Then the light went out, and I wondered where it went," said Susie.
"Falling stars are not stars at all, though they look like them. They are pieces of rock that break off from other worlds and whiz through space."
"Oh!" said Susie.
"Outside of our atmosphere there may be nothing for these masses of rock to strike against, but just as soon as they come into the air, it tries to stop them. The air is not strong enough to stop them, but it grinds them up."
"Grinds them up!" exclaimed Donald. "Isn't that wonderful? But, uncle, what makes them look just like fire?"
"If you put an axe or scythe on a dry grindstone and turn the crank, what do you see?"
"Sparks of fire," said Frank.
"Why do you put grease or oil upon the axles of your buggy?"
"To keep them from becoming hot and dry," said Frank. "One time when father and I were on a train there was a hot box, and we had to stop to cool it."