"Only Johnnie and I have seen little Amy," said Leonard--"I at the depot before she grew up; and this morning she became a little girl again as a Christmas wonder for my little girl. Johnnie's faith and fairy lore may make the transformation possible to her again, but I fear the rest of us will never catch another glimpse of the child we expected"; for Amy's grown-up air since she had appeared in the breakfast-room had been almost a surprise to him after hearing through the partition her pretty nonsense over her stocking. "I fear you are right," said Amy, with a half-sigh; "and yet it was lovely to feel just like Johnnie once more;" and she stole a shy glance at Webb, who must have heard some of her exclamations. The expression of his face seemed to reassure her, and without further misgiving she joined in a laugh at one of Burt's sallies. CHAPTER VI NATURE'S HALF-KNOWN SECRETS Amy's thoughts naturally reverted before very long to Mrs. Clifford's pets--the flowers--and she asked how they had endured the intense cold of the night. "They have had a narrow escape," the old lady replied. "If Maggie had not suggested the tub of water last night, I fear we should have lost the greater part of them." "Yes," said Mrs. Leonard, "I went to the flower-room with fear and trembling this morning, and when I found the water frozen thick I was in despair." "It was the water freezing that saved the plants," Webb remarked, quietly. "I put water in the root-cellar before I went to bed last night, with like good effect." "Well, for the life of me," said Maggie, "I can't understand why the plants and roots don't freeze when water does." "Come, Burt," added her husband, "you are a college-bred man. You explain how the water draws the frost from the plants." "Oh, bother!" Burt answered, flushing slightly, "I've forgotten. Some principle of latent heat involved, I believe. Ask Webb. If he could live long enough he'd coax from Nature all her secrets. He's the worst Paul Pry into her affairs that I ever knew. So beware, Amy, unless you are more secretive than Nature, which I cannot believe, since you seem so natural." "I'm afraid your knowledge, Burt, resembles latent heat," laughed Leonard. "Come, see what you can do, Webb." "Burt is right," said Webb, good-naturedly; "the principle of latent heat explains it all, and he could refresh his memory in a few moments. The water does not draw the frost from the plants, but before it can freeze it must give out one hundred and forty degrees of latent heat. The flower-room and root-cellar were therefore so much warmer during the night than if the water had not been there. The plants that were nipped probably suffered after the ice became so thick as to check in a great measure the freezing process." "How can ice stop water from freezing?" Alf asked, in much astonishment.