Three hours after, the air-liner sighted a dim blue line that marked the Red Sea. The Master pointed at this, with a strange smile.

"Once we pass that sea," he commented, "our goal is close. The hour of great things is almost at hand!"

"Provided we get some petrol," put in Bohannan.

"Faith, an open gate, that should have been closed, defeated Napoleon.
A few hundred gallons of gasoline—"

"The gasoline is already in sight, Major," smiled the chief, his glasses on the coastline. "That caravan—see there?—comes very apropos."

The Legion bore down with a rush on the caravan—a small one, not above fifty camels, but well laden. The cameleers left off crying "Ooosh! Ooosh!" and beating their spitting beasts with their mas'hab-sticks, and incontinently took to their heels. Rrisa viewed them with scorn, as he went down in the nacelle with a dozen of the crew.

The work of stripping the caravan immediately commenced. In an hour some five hundred tin cases of petrol had been hoisted aboard. On the last trip down, the Master sent a packet wrapped in white cloth, containing a fair money payment for the merchandise. British goods, he very wisely calculated, could not be commandeered without recompense The packet was lashed to a camel-goad which was driven into the sand, and Nissr once more got slowly under way.

All eyes were now on the barren chalk and sandstone coasts of the Red Sea, beyond which dimly rose the castellated peaks of Jebel Radhwa. At an altitude of 2,150 feet the air-liner slid out over the Sea, the waters of which shone in the mid-afternoon sun with a peculiar luminosity. Only a few sambuks, or native craft, troubled those historic depths; though, down in the direction of Bab el Mandeb—familiar land to the Master—a smudge of smoke told of some steamer beating up toward Suez.

Leaning from the upper port gallery, the Master with Bohannan, Leclair, and "Captain Alden," watched the shadow of the giant air-liner sliding over the tawny sand-bottom. That shadow seemed a scout going on before them, spying out the way to Arabia and to Mecca, the Forbidden City. To the white men that shadow was only a shadow. To Rrisa, who watched it from the lower gallery, it portended ominous evil.

"It goes ahead of us, by Allah!" he murmured. "Into the Empty Abodes, where the sons of Feringistan would penetrate, a shadow goes first! And that is not good." He whispered a prayer, then added: "For the others, I care not. But my Master—his life and mine are bound with the cords of Kismet. And in the shadows I see darkness for all!"