The rest of that day was spent in overhauling the outfit which they would need to use on their expedition of the morrow. Luckily the boots they wore had been fitted with "hob-nails" so that they were ideal for the tough climb that they had ahead of them. Each member of the three was to carry a pick and of course they all were to be armed, carrying several rounds of ammunition each in their cartridge-belts.
That night after a supper of fried ham, canned corn and pancakes—all cooked by the skilful Ben over a fire of wood collected from the little grove—Frank sent out a wireless to the members of the camp on the river bank and felt much reassured when Lathrop's "All well—good luck," came back through the air. It was delightfully cool on the mountain-side after the oppressive fetid air of the river and its neighborhood, and as Ben had remarked before they turned in:
"Fine weather for sleeping."
But sleep would not come to Frank. He tossed and turned on his transom bed and several times gazed out into the night through the canvas curtains. An unaccountable feeling of unrest possessed him. Could they get the ivory out of the cache before Muley-Hassan and his band arrived by land?
Fast as they had traveled through the air Frank realized that the Arab, who doubtless by this time had been informed by the treacherous Diego of the boys' bold dash, would push on at furious speed in order to head them off. That he would come accompanied by a well-armed band Frank could not doubt. He and Harry and Ben could only put up a feeble resistance against such an attack. There was only one chance to secure the ivory and that was to get at it before the Arab arrived. It all depended then on how quickly they could find the cache. Frank lit the lantern and shielding it so that it would not strike in the eyes of his sleeping brother, drew out the map and scanned it attentively.
Yes, here were the directions written in the queer hand of Muley-Hassan's follower.
"A line from the nose straight down to the cairn of stones."
It seemed simple enough and certainly the nose of the Upturned Face was as clearly to be made out as a ship at sea. But Frank had been too long trained in the hard school of adventure to underestimate the difficulties of any piece of work. They faced a hard job and none realized the fact better than the young leader.
At last he blew the lantern out and once more composed himself to sleep. He was just dozing off when a sufficiently startling interruption occurred. One which drove all further thoughts of rest from his head.
It was an extraordinary sound that brought the boy out of his bed with a bound and caused him to clutch his revolver with a heart that beat loud and thick in spite of himself.