Heeding the flightpaths of birds was just one of numerous haven-finding methods employed by the Polynesians, whose navigational feats arguably have never been surpassed. The Polynesians traveled over thousands of miles of trackless ocean to people remote islands throughout the southern Pacific. Modern navigators still scratch their heads in amazement at their accomplishment. Like Eskimos study the snow, the Polynesians watched the waves, whose direction and type relinquished useful navigational secrets. They followed the faint gleam cast on the horizon by tiny islets still out of sight below the rim of the world.
Seafarers of the Marshall Islands built elaborate maps out of palm twigs and cowrie shells. These ingenious charts, which exist today only in museums, denoted everything from the position of islands to the prevailing direction of the swell. ptolemy. jpg (28650 bytes) Statue of Ptolemy. Charts have aided mariners ever since the Alexandrian astronomer Ptolemy created the first world atlas in the second century A.
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D. The redoubtable Ptolemy even plotted latitude and longitude lines on his atlas’s 27 maps, though the farther one got from the known world centered on the Mediterranean, the dangerously less reliable they became.
Even before Ptolemy, there were sailing directions — the Greeks called them periplus or “circumnavigation” — that were compiled from information collected from sailors far and wide. One of these, The Periplus of the Eritrean Sea, a document written in the first century by a Greek merchant living in Alexandria, described trading routes as far east as India. By the 10th century, Italian-made portolans supplied detailed directions, distances, depths, and coastal descriptions, and by the 13th century, sea maps with scale and bearings began to appear.
The greatest advance in navigation came with the compass. The Chinese apparently knew about the powers of magnetism as early as the third millennium B. C. , when, historians tell us, one army defeated another after the battlefield had become enveloped in dense fog by using a device known as a “point-south carriage. ” This was a standard carriage for carrying royalty with a small, rotating figure mounted on the front, which by magnetism always pointed south. (The Chinese chose to have the arrow point south rather than north.
But no one seems to have manipulated the lodestone for sea navigation until early in the present millennium. The first mention of the compass in the West comes from the Englishman Alexander Neckham, who wrote in 1187 that “sailors use a magnetic needle which swings on a point and shows the direction of the north when the weather is overcast. ” Despite its usefulness, the compass took a long time to come into wide use, as many seamen thought it operated by black magic. (Hence the invention of the binnacle, in which sea capt