Every night the young people
in our caravan get a lesson on navigation. Every young Nabataean
man knew how to navigate by the stars. That's one of the things
that made us a great nation of merchants. We could travel over
trackless deserts and oceans using only the stars to guide us.
To obtain our latitude, we measure the altitude above the horizon
to a known star, and then deduct this from this the altitude of
the North Pole Star, (since the North Pole Star is the one star
that does not move in the sky). Small children learn to measure
the altitude of the Pole Star directly using the width of a finger.
When held at arm's length, the width of four fingers is considered
to measure 4 isba'. In a 360 degree circle there are 224 isba'.
This is the simplest method, and is known as the science of qiyas.
It is considered that a day's sailing due north would raise the
Pole Star 1 isba' from the horizon. For those of us traveling
on land, the isba' is further divided into 8 zam. Thus land distances
are often measured in zams.
In our lesson tonight, the
older men teach us to navigate using a kamal. This is a rectangular
shaped board (about 1 x 2 inches) on the end of a string. The
string had knots in it at nine places to help us measure. The
kamal is more accurate than using fingers. To use the kamal we
hold the end of the string in our teeth. The lower edge of the
kamal is placed on the horizon while the edge is moved along the
string until the upper corner touched the required star. The knot
at which the stop tells us the exact number of isba' of altitude
of the star. The altitude of the Pole Star can then be deduced
from the rahmani. An alternative way of using a kamal is to move
the knots through the teeth until the kamal covers the required