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, and she would tell them how to surmount them. So she recommended to them to go and find a blank card, or piece of white pasteboard, or of stiff white paper, as big as a common card. "Then," said she, "choose some window where the sun shines in at noon, and put the card down upon the sill, and drive the pin down through it. But you must not drive the pin through the middle of the card, for the shadow will always be off to the north of the pin, and therefore the pin may be pretty near the south end of the card. Then the shadow will be more likely to come wholly upon the card, even when it is longest. You had better place the card in such a position, too, that its sides shall lie in the direction of north and south. Then the shadow at noon will lie along exactly in the middle of it. You must get a large and stout pin, too; and drive it in firmly, a little way, with a small hammer. It will be well, too, to drive another smaller pin into the other end of the card, so as to keep it fixed in its north and south position." "How can we know when it is north and south, exactly?" said Lucy. "You cannot do it exactly," said Rollo's mother; "but you can get it pretty near. One way is to borrow father's little compass, and adjust it by that. Another way is to see when it is exactly twelve o'clock by the clock, and then the shadow of the pin will of itself be about north. "Then you might move the north end of the card until the shadow is brought exactly into the middle of the card, and then put the other pin in, and fix it in that place. Then if you make a mark along where the shadow comes, that mark will be a north and south line, and you can mark the place where the shadow of the pin's head crosses that line, when it crosses it every day at noon." The children said that they believed they understood the directions, and they determined to try the plan. They thought they would fix two cards, one at Rollo's house, and one at Lucy's; and they immediately went off in pursuit of blank cards and big pins. PRUNING. One afternoon, Rollo saw his father coming out into the garden, with a little saw and a knife, and a small pot of paint in his hands. "Father," said he, "are you going to prune your trees now?" "Yes," said his father. "Then, shall I go and get my wheelbarrow?" "Yes," replied his father, again. So Rollo ran off after his wheelbarrow. It had been arranged, between him and his father that morning, that they should work in the garden an hour or two in the afternoon, and that Rollo should pick up all the cuttings from the trees, and wheel them away, and then, when they were dry, make a bonfire with them.