then Rollo had come out of the barn, and was sitting upon the door step, thinking of the subject, when his reflections were interrupted in the manner already described.

So, when Rollo saw his father getting out of the carryall, he ran to meet him, and called out to him, talking very loud and rapidly,

“Father, Jonas says that the sun shines farther in, upon the barn floor, in winter than in summer;—does it, do you think?”

But this was not a proper time for Rollo to bring up his philosophical question. His father had a carpet bag and several packages in his hands, and he was also conducting Rollo’s mother in, and thinking about the horse and carryall. So he told Rollo that he must not speak to him then, for he could not attend to him.

Rollo then walked along back into the yard, and began to think of the subject of the sun’s shining in at the south door. He looked up towards the sun, and began to consider what sort of a change in its place, at noon, on different days, would be necessary in order to account for its shining in more at south doors and windows, on some days, than on others. He reflected that if the sun were exactly overhead, at noon, it could not shine in at any doors at all; for the rays would then strike perpendicularly down the sides of the houses. While he was standing thus, lost in thought, looking up to the sun, with his arm across his forehead, to shelter his eyes a little from the dazzling rays, he suddenly felt the pressure of two soft hands upon his ears, as of somebody who had come up behind him. He turned round, and found his cousin Lucy standing there.

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.

The truth was, that Rollo and Lucy were getting decidedly into a dispute. From the sublime heights of practical astronomy, they had fallen, by a sad and very rapid descent, to a childish altercation. Rollo had a very high idea of the superior facilities afforded by Jonas’s barn floor for observing the daily changes in the sun’s meridian altitude, and he did not like the idea of Lucy’s finding that she had equally good opportunities for observation at her home. Lucy was a little fretted at Rollo’s captious spirit; but then her mind soon became unruffled again, and she turned back towards Rollo, and said, as they walked along the yard,

“I don’t think the sunshine on the floor is a shadow, Rollo; but then I don’t see why a shadow would not do, just as well.”

“How?” said Rollo.

“Why, look there at the shadow of that post,—that would do.”

She pointed to a post with a rounded top upon it, which stood by the side of the garden gate. The shadow, clear, distinct, and well defined, was projected upon the walk; and Lucy told Rollo that they might mark the place where the top of that shadow came every day, and that that would do just as well.

“But how could we mark it?” said Rollo.

“Why, we could drive a little stake unto the ground.”

“O, that would not do,” said Rollo. “People would trip over them, and break them down. They would be exactly in the walk.”

Lucy saw that this would be a difficulty, and, for a moment, seemed to be at a loss. At length, she said,

“We might go somewhere else, then, where the people would not come.”

“But what should we do for a post?” said Rollo.

“Could not we get Jonas to drive a tall stake down?” said Lucy.

“Yes,” said Rollo; “I suppose so.”

The children went out into the garden to find a good smooth place, and while they were walking about there, Rollo’s mother came out, and they told her the whole story. She seemed quite interested in the plan, and told them of a better way than any that they had thought of.

“You see,” said she, “that the height of the stake or pole that makes the shadow is not material; for the shadow of a small one will vary just as much, in proportion to its length, as that of a long one will. So, instead of taking a wooden stake, out of doors, you might take a large pin, and drive it down a little way into the window sill, in the house. Then you can mark the shadow with a pen, very exactly.”

“So we can,” said Lucy, clapping her hands.

“And you might put a piece of white paper, or a card down first,” continued Rollo’s mother, “and drive the pin through that, and then mark the places where the end of the shadow comes every day, directly on the card, with a fine pen. Thus you could be a great deal more exact than you can in chalking upon a barn floor.”

Rollo asked his mother if she would not be kind enough to help them fix their apparatus; but she said she would give them particular directions, though she should prefer letting them do the whole themselves, and then, if they met with any difficulties, they might come and report them to her,