"Oh, how red your nose is!" cried little Mabel Blake, one day, as her brother Hal came running out of the school yard, where he had been playing with some other boys. Mabel was waiting for him to walk home with her as he had promised.  
"So's your's red, too, Mab!" Harry¹ said. "It's as red—as red as some of the crabs² we boiled at our seashore cottage this summer."
 
"Is my nose red?" asked Mab of some of her girl friends.
 
"It surely is!" replied Jennie Bruce. "All our noses are red!" she went on. "It's the cold that makes 'em so. It's very cold to-day, and soon it will be winter, with lots of snow and ice! Oh! I just love winter!"
 
"Come on, Hal!" called Mab. "Let's hurry home before it gets any colder!"
 
"Let's run!" suggested Hal. "When you run you get warm, and you don't mind the cold."
 
"What makes us get warm when we run?" his sister inquired, as she took hold of his hand and raced along beside him.
 
"I don't know," Hal answered, "but we'll ask Daddy when we get home.
He can tell us everything."
"Huh! Not everything!" cried Sammie Jones, one of the nice boys with whom Hal played, "Your father doesn't know everything."
 
"Yes he does, too!" exclaimed Hal. Doesn't he, Mab?"
 
"Yep!" answered the little girl, shaking her head from side to side so fast that you could hardly tell which were her curls and which was her hair ribbon.
 
"Huh! Does your father know what makes a steam engine go?" asked
Sammie.
"Sure he does!" said Hal. "And he told us about it once, too; didn't he, Mab?"
 
"Yes, he did," the little girl answered. "I know, too. It's hot water in the boiler³ that makes it go. The hot water swells⁴ up, and turns into steam, and the steam pushes on the wheels, and that makes the engine go."
 
"And our Daddy knows what makes an automobile⁵ go, too," went on Hal.
"He knows everything."
"Huh! Well, I guess mine does then, too!" spoke⁶ Sammie. I'm going to ask him what—what—makes it lightning!"
 
"And then will you tell us?" asked Mab, for she and Hal wanted to know about everything they saw.
 
"Yes, I'll tell you," promised Sammie. "And we'll ask Daddy Blake what makes us warm inside when we run," went on Hal, "and then we'll tell you that, Sammie."
 
The children ran home from school, and, thought it was cold, for it was almost winter now, they did not mind it. Their noses got more and more red, it is true, but they knew when they were in the house, near the warm fire, the red would all fade out.
 
Hal and Mab said good-bye to Sammie, as he turned down his street, and then the little Blake boy and girl, hand in hand, ran on to their house.
 
As they reached it they saw their mamma and their Aunt Lolly out in the front yard, bringing in pots of flowers and vines.
 
"Quick, children!" called Mamma Blake, "You are just in time! Here, Hal, you and Mab put down your books" and help us to carry in the flowers. Take only the small pots, and don't drop them, or get any dirt on your clothes."
 
"Oh, I'm sure something will happen if you let the children carry any of the flowers!" cried Aunt Lolly, who was a dear, fussy⁷ little old lady. "They'll drop them on their toes, or spill the dirt on the floor—or something."
 
"Oh, I guess not," laughed Mamma Blake. "Anyhow we need help to get all the plants in before dark. There is going to be a very heavy frost, and everything will freeze hard to-night. It will be very cold!"
 
"Is that why you are bringing in the plants, mamma?" asked Mab.
 
"Yes, so they will not freeze and die," Mrs. Blake answered. "Flowers freeze very easily."
 
The children were glad to help their mother and Aunt Lolly. Roly-Poly, the fat little white poodle dog, tried to help, too, but he upset more plants than he carried in, though he did manage to drag one pot to the steps.
 
Besides, Roly-Poly was always running off to look for a clothespin, or something like that, to bury under the earth, making believe, I suppose, that it was a bone.
 
"The ground will soon be frozen⁸ too hard for you to dig in it with your paws, Roly-Poly," said Mamma Blake, when it was nearly dark, and all the plants had been brought into the warm kitchen. "Come, now children," she called. "Wash your hands, and supper will soon be ready. Then Daddy will be here, and he will shake down the furnace fire, and make it hot, for it is going to be a very cold night."
 
A little later, when supper was almost ready, a step was heard in the front hall.
 
"Oh, here comes Daddy now!" cried Mab, making a rush for the door.
 
"Let's ask him what makes the cold," exclaimed Hal, "and why we get warm inside when we run." Hal was very curious.
 
"Ah, here we are!" cried Mr. Blake, with a jolly laugh, as he came in rubbing his ears. He caught Hal up in one arm, and Mab in the other.
 
"Oh, how cold your cheeks are, Daddy!" cried Mab as she kissed him.
 
"Yes, it is going to be a frosty night, and freeze," he said. "And if it freezes enough I will tell you a secret I have been keeping for some time."
 
"Oh Daddy! Another secret!" cried Mab. "Tell us what it is, please!"
 
"Wait until we see if it freezes hard enough to-night," replied her papa.