Lucy asked him what he was thinking of, and he told her. He then took Lucy into the barn, and showed her the chalk mark upon the floor. She looked on with a good deal of interest, and said she thought it was an excellent plan; and she wished there was a great barn with a south floor at _their_ house. Lucy knew more about the subject than Rollo did, and she gave him some explanations about it. "You see," said she, "that the sun rises in the east every morning, and comes up higher and higher, every hour, till noon; and then it begins to go down again, and at last it sets in the west. But, at some times in the year, it comes up higher at noon than it does at other times, and so it does not shine so much into the door." "It shines _more_, you mean," said Rollo. "No," said Lucy; "not so much. In the winter the sun moves around by the south, and keeps pretty low all day, and of course shines farther into doors and windows." Then, after a moment's pause, she added, "If we should mark the place on the floor all the year round, we should find what time the sun is farthest to the south." "So we should," said Rollo. "It would be in the winter," said Lucy. "Yes," said Rollo; "in the middle of the winter exactly." "Yes," said Lucy; "and in the middle of the summer it would be nearest overhead." "Jonas and I will try it," said Rollo. "I can try it in the house," said Lucy, "where the sun shines in at my chamber window." "O no," said Rollo; "that won't do." "Why not?" said Lucy. "Because the window does not come down to the floor, and so does not let the sun in enough." "O, that makes no difference," said Lucy; "we have nothing to do with the bottom of the door; you only mark where it shines in the farthest, and that place is made by the top of the door, for it shines in farthest by the top of the door." "Well," said Rollo, "I don't know but that the house will do; but then you can't chalk on the carpet." "Chalk on the carpet?" said Lucy. "Yes, to mark the place." "No," said Lucy, thinking; "but I can mark it some other way." "How?" asked Rollo. "Why, I can put a pin in," said Lucy. "O dear," said Rollo, with a laugh, "put a pin in! That's no way to mark a shadow." "It isn't a shadow," said Lucy. "Yes, it is," said Rollo. "No," said Lucy; "a shadow is dark, and this is bright." "Yes," said Rollo, "this is a bright shadow; some shadows are bright, and some are dark." "O Rollo!" said Lucy; and she turned away from him, a little out of humor.