s. He is not
to shave, anoint his head, pare his nails, or bathe until the end of the
pilgrimage. Among the various rites to be performed after reaching Mecca
is walking seven times around the Kaaba, first slowly, then quickly.
Before leaving the city the pilgrim drinks water from the holy well,
Zemzem.

Many pious pilgrims visit Medina, now the terminus of a railway, before
going on to Mecca. This is another of the sacred cities of Islam, since
it is the scene of Muhammad's labors after his hegira from Mecca; it
also contains his tomb. Formerly no unbeliever was permitted to traverse
the streets of Medina or look upon the tomb of the great prophet, but
tourists are now allowed within the gates. The city is enclosed by a
wall forty feet high which is flanked with thirty towers. Two of its
four gates are massive structures with double towers. Like Mecca, Medina
is supported chiefly by pilgrims.

CHAPTER X

THE SAHARA

An expanse of land as large as the main body of the United States
stretches across the northern part of Africa. From the Atlantic Ocean to
the Red Sea, and from the foot of the Atlas Mountains to the Sudan, it
is a weird panorama of rock waste--level, rugged, shingly, and
mountainous, according to locality. In places only it is penetrated by
large and permanently flowing streams. On the eastern borderland the
Nile pours a mighty flood, winding a sinuous passage along its
self-made flood-plain, the Egypt of history. In the west the Niger has
forced its way into the confines of the desert and then, as if rebuffed,
turns its course southward.

This great domain of the simoom has every diversity of surface. The
higher summits of the Tarso Mountains are eight thousand feet above sea
level; the Shott, a chain of salt lakes south of the Atlas Mountains,
are about one hundred feet below sea level. The depression in which
these lakes is situated probably was once the head of the Gulf of Sidra;
but the never-ceasing winds have partly filled the depression, cutting
off the head of the gulf in the same manner that wind-blown sands
severed what is now Imperial Valley from the Gulf of California. Around
the briny lakes are marshes of quicksands, and woe betide the luckless
traveller who strays to the one side or the other of the beaten trails.
Unless help is at hand, life will have neither joys nor troubles for him
after a few brief minutes of struggle.

The Sahara proper begins at the south slope of the