constellation of the Little Bear, by which the sailors used to
guide their ships before the discovery of the mariner's compass.
Thus we see both a practical and contemplative side to astronomy
through all history. The world owes two debts to that science: one
for its practical uses, and the other for the ideas it has
afforded us of the immensity of creation.

The practical uses of astronomy are of two kinds: One relates to
geography; the other to times, seasons, and chronology. Every
navigator who sails long out of sight of land must be something of
an astronomer. His compass tells him where are east, west, north,
and south, but it gives him no information as to where on the wide
ocean he may be, or whither the currents may be carrying him. Even
with the swiftest modern steamers it is not safe to trust to the
compass in crossing the Atlantic. A number of years ago the
steamer City of Washington set out on her usual voyage from
Liverpool to New York. By rare bad luck the weather was stormy or
cloudy during her whole passage, so that the captain could not get
a sight on the sun, and therefore had to trust to his compass and
his log-line, the former telling him in what direction he had
steamed, and the latter how fast he was going each hour. The
result was that the ship ran ashore on the coast of Nova Scotia,
when the captain thought he was approaching Nantucket.

Not only the navigator but the surveyor in the western wilds must
depend on astronomical observations to learn his exact position on
the earth's surface, or the latitude and longitude of the camp
which he occupies. He is able to do this because the earth is
round, and the direction of the plumb-line not exactly the same at
any two places. Let us suppose that the earth stood still, so as