twenty-four hours ago, though it seemed
a month--the little greenish vapor-wisps floated down, down, sinking
gently on the Sahara air.

This attack, they knew, must be decisive or all would be hopeless. The
last supply of capsules was now being exhausted. Everything had been
staked on one supreme effort. Quickly the attackers discharged their
weapons; then, having done all that could be done, lay prone and
waited.

Once again that hollow moaning sound drifted in across the baked
expanse of the Sahara--a strange, empty sound, unreal and ominous.
Then came a stir of sultry breeze, from the east. It strengthened;
and a fine, crepitant sliding of sand-particles became audible. Rrisa
stirred uneasily.

"Master," he whispered, "we should not delay. If the _jinnee_ of the
waste overtake us, we may be lost."

"The _jinnee_ of the waste?" the Master answered, in a low tone. "What
nonsense is this?"

"The simoom, Master--the storm of sand. We call it the work of evil
spirits!"

The Master made no reply, save to command silence.

For a time nothing happened in the Arabs' camp. Then came a little
stir, off there in the gloom. A sound of voices grew audible. The name
of Allah drifted out of the all-enveloping night, to them, and that of
his Prophet. A cry: "_Ya Abd el Kadir_--" calling on a patron saint,
died before the last word, "_Jilani_," could find utterance. Then
silence, complete and leaden, fell with uncanny suddenness.

The Master laughed, dryly. He touched Leclair's arm.

"Strong medicine for the Beni Harb, Lieutenant," said he. "Their own
_imams_ (priests) have strong medicine, too, but not so strong as that
of the cursed sons of Feringistan. Sleep already lies heavy on the
eyelids of these sons of Allah. And a deeper sleep shall soon overcome
them. Tell me, Lieutenant, can you kill men wholesale?"

"Yes, my Captain."

"Sleeping men, who cannot resist you? Can you kill them
scientifically, in masses, without anger?"

"How do you know now, my Captain, that it will not be in anger?"
And the Frenchman half eased himself up on hands and knees, peering
forward into the night. "After what these Beni Harb--or their close
kin--have done to me and to poor Lebon--listen! What was that?"

"What do you mean?"

"That far, roaring noise?"

"It is nothing! A little wind, maybe; but it is nothing, nothing!
Come, I am ready for the work!"

The Master stood up. Rrisa followed suit. No longer crawling, but
walking er