"Father," cried Annie, after a short silence, "I do not understand at
all how the captain finds out the way to America. It is so many miles
from any other land! Tom knows all about it, but he says he can't
exactly explain."

"Come, come, Tom," said his father, "try; nothing can be done without a
trial; tell us now what you know on the subject."

"Well, father," answered Tom, "the man at the wheel has a compass before
him, and he looks at that, and so knows how to point the ship's head. As
America is in the west, he keeps it pointed to the west."

"Quite right, so far," said his father, "but tell us what a compass is."

"Oh! a compass is a round box, and the bottom is marked with four great
points, called North, South, East, and West; then smaller points between
them; and in the middle is a long needle, balanced, so that it turns
round very easily, and as this needle always points to the North, we can
easily find the South, and East, and West."

"But, father," cried Annie, "why does that needle always point to the
North? my needle only points the way I make it when I sew."

"Your needle, dear Annie, has never been touched by the wonderful stone!
You must know that some few hundred years ago, people discovered that a
mineral called the loadstone, found in iron mines, had the quality of
always pointing to the North, and they found, too, that any iron rubbed
with it would possess the same quality. The needle Tom tells us of has
undergone this operation. Before the invention of the compass, it was
only by watching the stars that sailors could direct their course by