f
Asia.

This book by Marco Polo was eagerly read, and the facts that it stated
were so remarkable that many people refused to believe them. It stirred
others with a desire to travel and see those lands for themselves.

Traveling by land, however, was very dangerous, because of the bands
of robbers by which the country was occupied. These outlaws robbed
every one whom they suspected of having any money, and often murdered
travelers in order to gain their possessions. Sea travel, too, was
just as dangerous, but in a different way.

You will remember why sailors dared not venture far out upon the ocean
and search for a water route to the Eastern countries and islands.
The time was soon coming, however, when they would dare to do so, and
two wonderful inventions helped navigators very much.

One came from the finding of the loadstone, or natural magnet. This
is a stone which has the power of attracting iron. A steel needle rubbed
on it becomes magnetized, as we say, and, when suspended by the center
and allowed to move freely, always swings around until it points north
and south. Hung on a pivot and inclosed in a box, this instrument is
called the mariners' compass. It was of great importance to sailors,
because it always told them which way was north. On cloudy days, and
during dark, stormy nights, when the sun and stars could not be seen,
the sailors could now keep on their way, far from land, and still know
in which direction they were going.

[Illustration: Mariners' Compass.]

The other invention was that of the astrolabe. This was an instrument
by means of which sailors measured the height of the sun above the
horizon at noon, and could thus tell the distance of the ship from
the equator. It is in use on all the ships at the present time, but
it has been greatly improved, and is now called the quadrant.

The compass and the astrolabe, together with improved maps and charts,
made it possible for navigators to tell where their ship was when out
of sight of land or in the midst of storm and darkness. This made them
more courageous, and they ventured a little farther from the coast,
but still no one dared to sail far out upon the Sea of Darkness.

COLUMBUS.

One day a man appeared in Portugal, who said he was certain that the
earth was round, and that he could reach India by sailing westward.
Every one laughed at him and asked him how he would like to try. He
answered that he would sail round the earth