passengers or, as was more common, sold them into slavery.
Indeed, until the middle of the fi rst century b.c.e., pirates
were one of the chief sources of slaves for the Roman world.
Important captives, particularly high-ranking Roman citi-
zens, were held for ransom. Even Julius Caesar was a captive
of pirates. Th e pirate menace was ended in 67 b.c.e., when
the Roman general Pompey swept the Mediterranean free of
them. Pirates would not again be a threat until the empire
began to lose control of the seaways in the third century c.e.
Navigating a Roman ship was more art than science,
since the Romans had no navigational instruments. As a con-
sequence, whenever possible, a ship of the period kept the
shore in sight, its crew watching for landmarks to tell them
their position. An important aid to navigation was the light-
house. Most major Mediterranean ports had such structures,
the Pharos at Alexandria being the most famous. Lighthouses
ranged in height from four to 12 stories and used a mirror of
polished bronze to refl ect light from a fi re. Th e beacon would
warn night-traveling ships of hidden rocks and shallow water
or act as a guide into port.
In addition to landmarks and lighthouses, Roman crews
oft en depended on changing water depths to tell them where
they were, since specifi c locations along a coast had known
depths. To measure the depth of water, mariners used a lead
line. Th is line was a rope that had a series of knots at spaced
intervals and that had a lead or stone weight tied to it. Th e
weighted end of the line was tossed overboard, and when it
hit bottom, the number of knots were counted to determine
the depth.
Another piece of knowledge useful in Roman navigation
was the composition of the sea bottom across which a ship
was sailing. Th at composition could oft en provide a clue as
to a ship’s location because certain types of material—gravel,
sand, or mud, for instance—were known to be present off
certain coastlines. Roman mariners sampled the sea bottom
with the lead line, whose weight had a depression fi lled with
tallow, or animal fat, to which sea fl oor material stuck then to
be drawn up to the surface.
Th e Romans probably had charts and certainly had perip-
loi, books containing the distances between various seaports,
along with the locations of rivers and freshwater sources. A
ship’s navigator could calculate his ship’s position along its
route using the distances given by a periplus if he knew how
far his vessel had traveled during a day. He made this calcula-
tion using dead reckoning. He fi rst had to determine how fast
his ship was traveling. Th e navigator estimated this speed by
observing seaweed or drift wood passing by the ship. Th is ob-
servation gave him an approximation of how much distance
the ship covered in an hour. Th en, at the end of a day’s sail,
based on his observed speed, the navigator calculated how far
the vessel had traveled. He now had a rough idea of where
along its route the ship was. Th e method was imprecise, and
oft en the calculation was far off the mark.
Determining position by dead reckoning also required
that the navigator know in which direction his vessel washeaded; otherwise, the craft might be sailing away from its
destination. During the day the navigators determined di-
rection by observing the sun. Sailing into it was going west;
sailing away from it was going east. Additionally, the naviga-
tor knew the ship was going north or south depending on
the sun’s height above the horizon at noon. Th e sun would be
higher or lower in the sky depending on whether a ship was
headed north or south. Th e height of the sun also depends on
the time of year, the sun rising higher in the summer than in
the winter, but an experienced navigator took this fact into ac-
count. To measure the sun’s height, the navigator would hold
out a hand and determine how many fi ngers were needed to
span the gap between the sun and the horizon.
At night the navigator established direction using the
stars. One star—the polestar, or Polaris—was particularly
useful since it marks the position of the North Pole and re-
mains fi xed throughout the night. (Other stars appear to re-
volve around the sky due to the rotation of the earth.) A ship
traveling east would have the polestar on its right, and a ship
traveling west would have the polestar on its left. A navigator
could also obtain a rough idea of a ship’s north-south position
using the polestar by counting how many fi ngers were needed
to span the gap between Polaris and the northern horizon.
Th e fewer the fi ngers, the farther south the ship was since in
moving south, Polaris drops toward the northern horizon.THE AMERICAS
BY LAWRENCE WALDRON
Native American hunters have long been credited with pos-
sessing the most acute tracking skills. Th eir ability to observe
signs on the earth, in the air, and in the movements of animals
and birds has astounded many observers. Th ere is no reason
to assume that Native American seafarers were any diff erent.
Just as earthbound hunters would observe the movement of
celestial bodies to predict changes in weather, animal behav-
ior, and crop growth, so too would Native Americans living
on coasts, along rivers, and on arctic ice navigate by observ-
ing and predicting their environment.
Native Americans in ancient times were intimately fa-
miliar with the courses of key celestial bodies; the diff erent
kinds of cloud cover; the varieties of terrestrial, riverine, and
marine species; and the fl ight patterns of birds. Th ey also
would have possessed some knowledge of geology, though
they would have employed taxonomic classifi cations and no-
menclature very much unlike our own. All these skills would
have constituted the Native American navigation kit, neces-
sary knowledge not only for achieving intended destinations
and predictable travels but also for preserving self, family,
and culture along the course of those travels.
Both on foot and by boat, Native Americans displayed
great maneuverability and speed, due largely to their suc-
cess as navigators, trackers, and aquatic farers. Th e Ameri-
can continents from Alaska to Argentina appear to have
been settled within a thousand years of the fi rst arrival of960 seafaring and navigation: The Americas0895-1194_Soc&Culturev4(s-z).i960 960 10/10/07 2:30:34 PM