“It’s all right, my dears,” said their mother, for Margy and Mun Bun did not like to be laughed at. “Eat as many berries as you wish. They are ripe and fresh and very tempting. We’ll get enough for Rose’s cake, I think.” So while the younger ones ate the lovely fruit, the older ones dropped the berries they picked into the baskets until they had a sufficient quantity—more than two quarts. Once, while they were picking, the six little Bunkers heard a roaring, bellowing sound off behind a second hill. “Oh, maybe that’s the old bull who has gotten loose—Ralph’s bull!” cried Violet, as she ran toward her mother. “I hardly think so,” Mrs. Bunker answered. But the noise sounded again, very much like the bellow of a bull. “Russ, get a club and some stones!” cried Rose. “There isn’t any fence here to jump over. Get a stick and drive away the bull!” Russ caught up a short club—not a very heavy one if it was to be used against a bull. Mrs. Bunker stood up and looked around. Then she laughed. “Don’t be afraid, children,” she said. “It isn’t a bull at all. It’s the whistle of an engine on a distant train. There it goes!” and she pointed to the railroad, about a mile off over the hill. A train was going along, very slowly, it seemed, but probably it was speeding faster than it appeared to be. And as the Bunkers looked they saw a puff of white steam from the locomotive. A little later they heard the whistle. When they had been stooping down the whistle had sounded like the distant bellow of a bull. “I’m glad it wasn’t,” said Rose. “If it had ‘a’ been I’d ‘a’ hit it with a club,” boasted Russ. “An’ I could throw a stone!” declared Mun Bun. “Mother, did you notice how funny the whistle was?” asked Rose. “First we saw the smoke puff up, and then we heard the sound. Why was that?” “Because light, or sight, travels faster than sound,” said Mrs. Bunker. “You can see something much quicker than you can hear it. If you should ever stand far off and see a gun shot off, you would first see the flash and the smoke, and, some seconds later, you would hear the report. Sight and sound travel in what are called waves, almost like the waves of the ocean, except that the sound waves are made of air instead of water. Light waves are different from air or water waves, and travel much faster—almost as fast as electricity.” “And electricity is terribly fast,” said Russ. “Once I took hold of a battery and as soon as I touched the handles I felt a shock.” After this the picking of strawberries went on until enough had been gathered. Then they all ate some and went home, and Rose made the shortcake, Norah helping her. “I’ll set the shortcake in the back pantry to cool for supper,” said Norah, when Rose had finished making it, and very proud the little girl was. The shortcake was put away and the little Bunkers were wondering how next they could have some fun when there came a knock on the kitchen door. “I wonder who that can be?” said Norah. CHAPTER XIII