s f : fat
hours lay all along the dunes. These gradually
increased in height day by day as we advanced
until we reached the great mountain of sand, some
three or four hundred feet in height from crest to
hollow, which overhangs the town of El Wad.
As a sandstorm in this country completely obliterates
all traces of former travellers, special means
have to be adopted in order to direct wayfarers on
their road.
Guemeerahs, or artificial landmarks, consisting
of huge pyramids of masonry placed in prominent
positions at intervals of about ten miles, have
accordingly been built all along the line which the
caravans must follow ; and as generally when one
guemeerah has been reached, the next can be seen
on the horizon, there is little difficulty in finding the
way.
Our road wound about among the dunes, so as to
avoid as far as possible all unnecessary gradients.
Alssa, in his capacity of guide, went on ahead
and piloted the caravan. Once where the sand had
drifted so as to cause a ridge across the path, he
hunted about until he found a more level way on
the other side of the dune.
He marked this important geographical discovery
by picking up the thigh-bone of a camel’s skeleton
which lay close at hand and sticking it solemnly
upright by the side of his new path, to act, as he
said, as a guemeerah for future travellers.
These dunes are most tiring to walk over. At
every step, even on the level, the foot sinks in
almost to the ankle. When ascending a steep slope