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, 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 directio