Daddy Blake laughed when Mab said that.  
"Yes, the bottle is broken," he said, "but it was the ice that broke it."
 
"How could it?" Hal wanted to know.
 
"I told you last night," said Daddy Blake, when the children were at breakfast table a little later, "that heat made things get larger, and that cold made them get smaller. That was true, but sometimes, as you see now, freezing cold makes water get larger. That is when it is cold enough to make ice.
 
"As long as there was only water in the bottle it was all right, the glass was not broken. But in the night it got colder and colder. All the warmth was drawn¹ off into the cold air. Then the water froze, and swelled² up. The ice tried to push the cork⁴ out of the bottle, just as you would try to push up the lid of a box if you were shut up inside one."
 
"I guess the wires over the cork wouldn't let the ice push it out," spoke⁵ Hal.
 
"That's it," Daddy Blake answered. "And so, as the ice could not lift out the cork, it swelled to the sides, instead of to the top, and pushing out as hard as it could, it broke the bottle. The glass fell away, and left a little statue of ice, just the shape of the bottle, standing⁶ in its place.
 
"How wonderful!" cried Mab, her blue eyes open wide.
 
"Yes, the freezing of ice is very wonderful," Daddy Blake said, as he passed Hal his third slice of bread and jam. "If the cracks in a great rock became filled with water, and the water froze, the swelling⁷ of the ice would split the great, strong stone.
 
"There is scarcely anything that can stand against the swelling of freezing ice. If you filled a big, hollow cannon⁸ ball with water, and let it freeze, the ice would burst the iron."
 
"It burst our milk bottle once, I know," said Aunt Lolly.
 
"Yes," spoke Daddy Blake. "That is why, on cold mornings, the milkman raises the tin top on the bottle. That gives the frozen milk a chance to swell³ up out of the top, and saves the bottle from cracking."
 
"One morning last winter," said Mamma Blake, "when we had milk bottles with the pasteboard tops, the milk froze and there was a round bit of frozen milk sticking up out of the bottle, with the round pasteboard cover on top, like a hat."
 
"And that's what saved the bottle from breaking," said Daddy Blake, "If I had not wired down the cork of our bottle the water would have pushed itself up, after it was frozen, and would have stuck out of the bottle neck, like a round icicle."
 
"But what about our secret?" asked Hal. "Is it cold enough for you to tell us about it?"
 
"I think so," answered Daddy Blake, with a queer little twinkle in his eyes. "As long as the water in the bottle was frozen, the pond will soon be covered with ice," he said. "And we need ice to make use of the secret."
 
"Oh, I just wonder what it is?" cried Mab, clapping her hands.
 
"I think I can guess," spoke Hal.
 
Daddy Blake went out in the hall, and came back with two paper bundles. He placed one at Mab's place, and gave the other to Hal.
 
"I want something, so I can cut the string!" Hal cried, and he laid his package down on the floor, while he searched through his pockets for his knife.
 
Just then Roly-Poly came into the breakfast room, barking. He saw Hal's package on the floor, and, thinking, I suppose, that it must be meant for him to play with, the little poodle dog at once began to drag it away. Though, as the ground was frozen, I don't know how he was going to bury it, if that was what he intended to do.
 
"Hi there, Roly!" cried Hal. "Come back with that, if you please, sir!"
 
"Bow-wow!" barked the little poodle dog, and I suppose he was saying:
 
"Oh, can't I have it a little while?"
 
By this time Mab had her package open.
 
"Oh!" she cried. "It's skates! Ice skates! Oh, I've always wanted a pair!"
 
"Ha! That's what I thought they were, when Daddy talked so much about ice and freezing," said Hal.
 
He had managed, in the meanwhile, to get his bundle away from
Roly-Poly.
Opening it, Hal found in the package a pair of shining ice skates, just like those Mab was trying on her shoes.
 
"Oh, thank you, Daddy!" Hal cried.
 
"And I thank you, too!" added Mab. I'd get up and kiss you, only my mouth is all jam. I'll kiss you twice as soon as I've washed."
 
"That will do," laughed her father. "Do you like your skates, children?"
 
"Oh, do we?" they cried, and by the way they said it you could easily tell that they did.
 
"And Daddy's going to take us skating; aren't you?" asked Hal as he measured his skates on his shoes to see if they would fit. They did. Oh! Daddy Blake knew just how to buy things to have them right, I tell you.
 
"Yes, I'll take you skating, and show you how to stand up on the ice—that is as soon as it is thick enough on the pond to make it safe, and hold us up," promised the children's father.
 
Just then Mamma Blake came running up from down the cellar. She was much excited.
 
"Oh, come quickly!" she called to her husband. "Something has happened to the stationary⁹ wash-tubs. The water is spurting¹⁰ all over the cellar. Oh, do hurry!"