great elevation, while where the camels began to increase
their ordinary rate of speed, a ridge crossed their path, and as it grew
lighter the travellers' eyes were greeted by the relief of green bushes,
patches of trees, and various traces of this being a place frequented by
man.

As the sun rose, right across the east there were clouds, which seemed
to be very different from those to which they were accustomed, and the
reason was soon made plain by a remark from the Sheikh, who explained
that the river ran from north to south, about a day's journey eastward,
and that if they continued their march a few miles in that direction
they would soon come upon signs of cultivation, and a scattered village
or two.

"And shall we go that way?" asked Frank.

"Only as far as the first village, where we can buy grain--corn, and
dhurra. Then we strike away again into the desert, along whose borders
we must keep. It is safer, and we are less likely to meet with
wandering dervish bands. We only come near the river when it is
necessary to refill the sacks and give the camels better feed than they
can get near the water-holes and fountains."

"I see," said Frank, as he glanced at the professor. "To get to the
neighbourhood of the Mahdi's people quickly we must go slowly."

"Yes, Excellency, it is better so. We stay here two days while three of
the young men and three camels go out to buy corn in the villages
yonder. There is generally food to be purchased there, for the Nile
floods run out widely a little way beyond, and the Khalifa's people have
not reached so far as yet."

"Is there not the ruin of a great temple somewhere in this direction?"

"And of a city too, Excellency--El Gaebor," replied the Sheikh. "Few
people have gone there, for it is half a day's journey from the river
bank. But his Excellency will not stay to visit it now?"

"No, Ibrahim; not now," said the professor. "It is very tempting, but
duty first. We must come and see the ruins after we have fetched my
friend out of the new Mahdi's grasp. Not before."

"Yes, not before," said the doctor quietly; for he spoke little on the
way, passing long hours in a thoughtful silence, as if dreaming over the
duties he had to perform, and acting always as if he felt that he really
was the learned Hakim he assumed to be.

There was a great charm about the wild, rocky place they had reached,
the first rays of the sun as it rose lighting up a most picturesque
s