cant disc, or cylinder, or ball they had deemed it. Perhaps
one of the chief among those adventurous travellers was Marco Polo, a
Venetian, who lived in the latter part of the thirteenth century. He
made known the central and eastern portions of Asia, Japan, the islands
of the Indian Archipelago, part of the continent of Africa, and the
island of Madagascar, and is considered the founder of the modern
geography of Asia.

The adventures of this wonderful man were truly surprising, and although
he undoubtedly exaggerated to some extent in his account of what he had
seen, his narrations are for the most part truthful. He and his
companions were absent on their voyages and travels twenty-one years.

Marco Polo died; but the knowledge of the East opened up by him, his
adventures and his wealth, remained behind to stir up the energies of
European nations. Yet there is no saying how long the world would have
groped on in this twilight of knowledge, and mariners would have
continued to "hug the shore" as in days gone by, had not an event
occurred which at once revolutionised the science of navigation, and
formed a new era in the history of mankind. This was the invention of
the mariner's compass.

CHAPTER FIVE.

THE MARINER'S COMPASS--PORTUGUESE DISCOVERIES.

"What _is_ the compass?" every philosophical youth of inquiring
disposition will naturally ask. We do not say that all youths will make
this inquiry. Many there are who will at once say, "Oh, I know! It's a
needle with a card on the top of it--sometimes a needle with a card
under it--which always points to the north, and shows sailors how to
steer their ships."

Very well explained indeed, my self-sufficient friend; but you have not
answered the question. You have told us what a compass is like, and one
of the uses to which it is applied; but you have not yet told what it
_is_. A man who had never heard of a compass might exclaim, "What! a
needle! Is it a darning needle, or a knitting needle, or a
drawing-through needle? And which end points to the north--the eye or
the point? And if you lay it on the table the wrong end to the north,
will it turn round of its own accord?"

You laugh, perhaps, and explain; but it would have been better to have
explained correctly at first. Thus:--

The mariner's compass is a small, flat bar of magnetised steel, which,
when balanced on a pivot, turns one of its ends persistently towards the
north pole--the other,