ain over which _Nissr_ was now sweeping, with the black
mountains left far behind, seemed a fairyland of beauty compared with
the desolation of the Central Arabian Desert.

"This is surely a fitting spot for the exact geometrical center of
Islam," the Master said to Leclair, as they stood looking down. "My
measurements show this secret valley to be that center. Mecca, of
course, has only been a blind, to keep the world from knowing anything
about this, the true heart of the Faith. The Meccans have been
usurping the Black Stone, all these centuries, and these Jannati Shahr
people have submitted because any conflict would have betrayed their
existence to the world. That is my theory. Good, eh?"

"Excellent!" the lieutenant replied. "There must be millions of
Mohammedans, themselves, who have hardly learned of this valley.
Certainly, very few from the outside world ever have been able to
cross the Empty Abodes, and reach it.

"These people here evidently represent a far higher culture than
any other Moslems ever known. Who ever saw a finer city--even not
considering its material--or more wonderful cultivation of land?"

His eyes wandered out over the plain, which lost itself to sight in
the remote south. Roads in various directions, with here and there
a few white dromedaries bearing bright-colored _shugdufs_ (litters),
showed there was travel to some other inhabited spots inside the
forbidding mountain girdle.

Here, there, herds of antelope and flocks of sheep were grazing on
broad meadows, through which trickled sparkling threads of water,
half glimpsed among feathery-tufted date-palms. Plantations of fig and
pomegranate, lime, apricot, and orange trees, with other fruits not
recognized, slid beneath the giant liner as she slowed her pace. And
broad fields of wheat, barley, tobacco, and sugar-cane showed that the
people of the city had no fear of any lack.

Birds were here--pelicans, cranes, and water-fowl along the brooks
and gleaming pools; swift little yellow birds with crownlike crests;
doves, falcons, and hawks of unknown species. Here was life abundant,
after the death of the Empty Abodes. Here was rich color; here arose
a softly perfumed air, balmy, incensed as with strange aromatics. Here
was peace--eternal _kayf_--blessed rest--here indeed lay a scene that
gave full explanation of the ancient name "Arabia Felix."

And at the left, dominating all this beauty, shone and glimmered in
the ardent sun the won